1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Driver for Atmel AT91 Serial ports 4 * Copyright (C) 2003 Rick Bronson 5 * 6 * Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd. 7 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. 8 * 9 * DMA support added by Chip Coldwell. 10 */ 11 #include <linux/circ_buf.h> 12 #include <linux/tty.h> 13 #include <linux/ioport.h> 14 #include <linux/slab.h> 15 #include <linux/init.h> 16 #include <linux/serial.h> 17 #include <linux/clk.h> 18 #include <linux/clk-provider.h> 19 #include <linux/console.h> 20 #include <linux/sysrq.h> 21 #include <linux/tty_flip.h> 22 #include <linux/platform_device.h> 23 #include <linux/of.h> 24 #include <linux/dma-mapping.h> 25 #include <linux/dmaengine.h> 26 #include <linux/atmel_pdc.h> 27 #include <linux/uaccess.h> 28 #include <linux/platform_data/atmel.h> 29 #include <linux/timer.h> 30 #include <linux/err.h> 31 #include <linux/irq.h> 32 #include <linux/suspend.h> 33 #include <linux/mm.h> 34 #include <linux/io.h> 35 36 #include <asm/div64.h> 37 #include <asm/ioctls.h> 38 39 #define PDC_BUFFER_SIZE 512 40 /* Revisit: We should calculate this based on the actual port settings */ 41 #define PDC_RX_TIMEOUT (3 * 10) /* 3 bytes */ 42 43 /* The minium number of data FIFOs should be able to contain */ 44 #define ATMEL_MIN_FIFO_SIZE 8 45 /* 46 * These two offsets are substracted from the RX FIFO size to define the RTS 47 * high and low thresholds 48 */ 49 #define ATMEL_RTS_HIGH_OFFSET 16 50 #define ATMEL_RTS_LOW_OFFSET 20 51 52 #include <linux/serial_core.h> 53 54 #include "serial_mctrl_gpio.h" 55 #include "atmel_serial.h" 56 57 static void atmel_start_rx(struct uart_port *port); 58 static void atmel_stop_rx(struct uart_port *port); 59 60 #ifdef CONFIG_SERIAL_ATMEL_TTYAT 61 62 /* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we 63 * should coexist with the 8250 driver, such as if we have an external 16C550 64 * UART. */ 65 #define SERIAL_ATMEL_MAJOR 204 66 #define MINOR_START 154 67 #define ATMEL_DEVICENAME "ttyAT" 68 69 #else 70 71 /* Use device name ttyS, major 4, minor 64-68. This is the usual serial port 72 * name, but it is legally reserved for the 8250 driver. */ 73 #define SERIAL_ATMEL_MAJOR TTY_MAJOR 74 #define MINOR_START 64 75 #define ATMEL_DEVICENAME "ttyS" 76 77 #endif 78 79 #define ATMEL_ISR_PASS_LIMIT 256 80 81 struct atmel_dma_buffer { 82 unsigned char *buf; 83 dma_addr_t dma_addr; 84 unsigned int dma_size; 85 unsigned int ofs; 86 }; 87 88 struct atmel_uart_char { 89 u16 status; 90 u16 ch; 91 }; 92 93 /* 94 * Be careful, the real size of the ring buffer is 95 * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer 96 * can contain up to 1024 characters in PIO mode and up to 4096 characters in 97 * DMA mode. 98 */ 99 #define ATMEL_SERIAL_RINGSIZE 1024 100 #define ATMEL_SERIAL_RX_SIZE array_size(sizeof(struct atmel_uart_char), \ 101 ATMEL_SERIAL_RINGSIZE) 102 103 /* 104 * at91: 6 USARTs and one DBGU port (SAM9260) 105 * samx7: 3 USARTs and 5 UARTs 106 */ 107 #define ATMEL_MAX_UART 8 108 109 /* 110 * We wrap our port structure around the generic uart_port. 111 */ 112 struct atmel_uart_port { 113 struct uart_port uart; /* uart */ 114 struct clk *clk; /* uart clock */ 115 struct clk *gclk; /* uart generic clock */ 116 int may_wakeup; /* cached value of device_may_wakeup for times we need to disable it */ 117 u32 backup_imr; /* IMR saved during suspend */ 118 int break_active; /* break being received */ 119 120 bool use_dma_rx; /* enable DMA receiver */ 121 bool use_pdc_rx; /* enable PDC receiver */ 122 short pdc_rx_idx; /* current PDC RX buffer */ 123 struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */ 124 125 bool use_dma_tx; /* enable DMA transmitter */ 126 bool use_pdc_tx; /* enable PDC transmitter */ 127 struct atmel_dma_buffer pdc_tx; /* PDC transmitter */ 128 129 spinlock_t lock_tx; /* port lock */ 130 spinlock_t lock_rx; /* port lock */ 131 struct dma_chan *chan_tx; 132 struct dma_chan *chan_rx; 133 struct dma_async_tx_descriptor *desc_tx; 134 struct dma_async_tx_descriptor *desc_rx; 135 dma_cookie_t cookie_tx; 136 dma_cookie_t cookie_rx; 137 dma_addr_t tx_phys; 138 dma_addr_t rx_phys; 139 struct tasklet_struct tasklet_rx; 140 struct tasklet_struct tasklet_tx; 141 atomic_t tasklet_shutdown; 142 unsigned int irq_status_prev; 143 unsigned int tx_len; 144 145 struct circ_buf rx_ring; 146 147 struct mctrl_gpios *gpios; 148 u32 backup_mode; /* MR saved during iso7816 operations */ 149 u32 backup_brgr; /* BRGR saved during iso7816 operations */ 150 unsigned int tx_done_mask; 151 u32 fifo_size; 152 u32 rts_high; 153 u32 rts_low; 154 bool ms_irq_enabled; 155 u32 rtor; /* address of receiver timeout register if it exists */ 156 bool is_usart; 157 bool has_frac_baudrate; 158 bool has_hw_timer; 159 struct timer_list uart_timer; 160 161 bool tx_stopped; 162 bool suspended; 163 unsigned int pending; 164 unsigned int pending_status; 165 spinlock_t lock_suspended; 166 167 bool hd_start_rx; /* can start RX during half-duplex operation */ 168 169 /* ISO7816 */ 170 unsigned int fidi_min; 171 unsigned int fidi_max; 172 173 struct { 174 u32 cr; 175 u32 mr; 176 u32 imr; 177 u32 brgr; 178 u32 rtor; 179 u32 ttgr; 180 u32 fmr; 181 u32 fimr; 182 } cache; 183 184 int (*prepare_rx)(struct uart_port *port); 185 int (*prepare_tx)(struct uart_port *port); 186 void (*schedule_rx)(struct uart_port *port); 187 void (*schedule_tx)(struct uart_port *port); 188 void (*release_rx)(struct uart_port *port); 189 void (*release_tx)(struct uart_port *port); 190 }; 191 192 static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART]; 193 static DECLARE_BITMAP(atmel_ports_in_use, ATMEL_MAX_UART); 194 195 #if defined(CONFIG_OF) 196 static const struct of_device_id atmel_serial_dt_ids[] = { 197 { .compatible = "atmel,at91rm9200-usart-serial" }, 198 { /* sentinel */ } 199 }; 200 #endif 201 202 static inline struct atmel_uart_port * 203 to_atmel_uart_port(struct uart_port *uart) 204 { 205 return container_of(uart, struct atmel_uart_port, uart); 206 } 207 208 static inline u32 atmel_uart_readl(struct uart_port *port, u32 reg) 209 { 210 return __raw_readl(port->membase + reg); 211 } 212 213 static inline void atmel_uart_writel(struct uart_port *port, u32 reg, u32 value) 214 { 215 __raw_writel(value, port->membase + reg); 216 } 217 218 static inline u8 atmel_uart_read_char(struct uart_port *port) 219 { 220 return __raw_readb(port->membase + ATMEL_US_RHR); 221 } 222 223 static inline void atmel_uart_write_char(struct uart_port *port, u8 value) 224 { 225 __raw_writeb(value, port->membase + ATMEL_US_THR); 226 } 227 228 static inline int atmel_uart_is_half_duplex(struct uart_port *port) 229 { 230 return ((port->rs485.flags & SER_RS485_ENABLED) && 231 !(port->rs485.flags & SER_RS485_RX_DURING_TX)) || 232 (port->iso7816.flags & SER_ISO7816_ENABLED); 233 } 234 235 static inline int atmel_error_rate(int desired_value, int actual_value) 236 { 237 return 100 - (desired_value * 100) / actual_value; 238 } 239 240 #ifdef CONFIG_SERIAL_ATMEL_PDC 241 static bool atmel_use_pdc_rx(struct uart_port *port) 242 { 243 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 244 245 return atmel_port->use_pdc_rx; 246 } 247 248 static bool atmel_use_pdc_tx(struct uart_port *port) 249 { 250 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 251 252 return atmel_port->use_pdc_tx; 253 } 254 #else 255 static bool atmel_use_pdc_rx(struct uart_port *port) 256 { 257 return false; 258 } 259 260 static bool atmel_use_pdc_tx(struct uart_port *port) 261 { 262 return false; 263 } 264 #endif 265 266 static bool atmel_use_dma_tx(struct uart_port *port) 267 { 268 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 269 270 return atmel_port->use_dma_tx; 271 } 272 273 static bool atmel_use_dma_rx(struct uart_port *port) 274 { 275 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 276 277 return atmel_port->use_dma_rx; 278 } 279 280 static bool atmel_use_fifo(struct uart_port *port) 281 { 282 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 283 284 return atmel_port->fifo_size; 285 } 286 287 static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port, 288 struct tasklet_struct *t) 289 { 290 if (!atomic_read(&atmel_port->tasklet_shutdown)) 291 tasklet_schedule(t); 292 } 293 294 /* Enable or disable the rs485 support */ 295 static int atmel_config_rs485(struct uart_port *port, struct ktermios *termios, 296 struct serial_rs485 *rs485conf) 297 { 298 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 299 unsigned int mode; 300 301 /* Disable interrupts */ 302 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); 303 304 mode = atmel_uart_readl(port, ATMEL_US_MR); 305 306 if (rs485conf->flags & SER_RS485_ENABLED) { 307 dev_dbg(port->dev, "Setting UART to RS485\n"); 308 if (rs485conf->flags & SER_RS485_RX_DURING_TX) 309 atmel_port->tx_done_mask = ATMEL_US_TXRDY; 310 else 311 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; 312 313 atmel_uart_writel(port, ATMEL_US_TTGR, 314 rs485conf->delay_rts_after_send); 315 mode &= ~ATMEL_US_USMODE; 316 mode |= ATMEL_US_USMODE_RS485; 317 } else { 318 dev_dbg(port->dev, "Setting UART to RS232\n"); 319 if (atmel_use_pdc_tx(port)) 320 atmel_port->tx_done_mask = ATMEL_US_ENDTX | 321 ATMEL_US_TXBUFE; 322 else 323 atmel_port->tx_done_mask = ATMEL_US_TXRDY; 324 } 325 atmel_uart_writel(port, ATMEL_US_MR, mode); 326 327 /* Enable interrupts */ 328 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); 329 330 return 0; 331 } 332 333 static unsigned int atmel_calc_cd(struct uart_port *port, 334 struct serial_iso7816 *iso7816conf) 335 { 336 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 337 unsigned int cd; 338 u64 mck_rate; 339 340 mck_rate = (u64)clk_get_rate(atmel_port->clk); 341 do_div(mck_rate, iso7816conf->clk); 342 cd = mck_rate; 343 return cd; 344 } 345 346 static unsigned int atmel_calc_fidi(struct uart_port *port, 347 struct serial_iso7816 *iso7816conf) 348 { 349 u64 fidi = 0; 350 351 if (iso7816conf->sc_fi && iso7816conf->sc_di) { 352 fidi = (u64)iso7816conf->sc_fi; 353 do_div(fidi, iso7816conf->sc_di); 354 } 355 return (u32)fidi; 356 } 357 358 /* Enable or disable the iso7816 support */ 359 /* Called with interrupts disabled */ 360 static int atmel_config_iso7816(struct uart_port *port, 361 struct serial_iso7816 *iso7816conf) 362 { 363 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 364 unsigned int mode; 365 unsigned int cd, fidi; 366 int ret = 0; 367 368 /* Disable interrupts */ 369 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); 370 371 mode = atmel_uart_readl(port, ATMEL_US_MR); 372 373 if (iso7816conf->flags & SER_ISO7816_ENABLED) { 374 mode &= ~ATMEL_US_USMODE; 375 376 if (iso7816conf->tg > 255) { 377 dev_err(port->dev, "ISO7816: Timeguard exceeding 255\n"); 378 memset(iso7816conf, 0, sizeof(struct serial_iso7816)); 379 ret = -EINVAL; 380 goto err_out; 381 } 382 383 if ((iso7816conf->flags & SER_ISO7816_T_PARAM) 384 == SER_ISO7816_T(0)) { 385 mode |= ATMEL_US_USMODE_ISO7816_T0 | ATMEL_US_DSNACK; 386 } else if ((iso7816conf->flags & SER_ISO7816_T_PARAM) 387 == SER_ISO7816_T(1)) { 388 mode |= ATMEL_US_USMODE_ISO7816_T1 | ATMEL_US_INACK; 389 } else { 390 dev_err(port->dev, "ISO7816: Type not supported\n"); 391 memset(iso7816conf, 0, sizeof(struct serial_iso7816)); 392 ret = -EINVAL; 393 goto err_out; 394 } 395 396 mode &= ~(ATMEL_US_USCLKS | ATMEL_US_NBSTOP | ATMEL_US_PAR); 397 398 /* select mck clock, and output */ 399 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO; 400 /* set parity for normal/inverse mode + max iterations */ 401 mode |= ATMEL_US_PAR_EVEN | ATMEL_US_NBSTOP_1 | ATMEL_US_MAX_ITER(3); 402 403 cd = atmel_calc_cd(port, iso7816conf); 404 fidi = atmel_calc_fidi(port, iso7816conf); 405 if (fidi == 0) { 406 dev_warn(port->dev, "ISO7816 fidi = 0, Generator generates no signal\n"); 407 } else if (fidi < atmel_port->fidi_min 408 || fidi > atmel_port->fidi_max) { 409 dev_err(port->dev, "ISO7816 fidi = %u, value not supported\n", fidi); 410 memset(iso7816conf, 0, sizeof(struct serial_iso7816)); 411 ret = -EINVAL; 412 goto err_out; 413 } 414 415 if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) { 416 /* port not yet in iso7816 mode: store configuration */ 417 atmel_port->backup_mode = atmel_uart_readl(port, ATMEL_US_MR); 418 atmel_port->backup_brgr = atmel_uart_readl(port, ATMEL_US_BRGR); 419 } 420 421 atmel_uart_writel(port, ATMEL_US_TTGR, iso7816conf->tg); 422 atmel_uart_writel(port, ATMEL_US_BRGR, cd); 423 atmel_uart_writel(port, ATMEL_US_FIDI, fidi); 424 425 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXEN); 426 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY | ATMEL_US_NACK | ATMEL_US_ITERATION; 427 } else { 428 dev_dbg(port->dev, "Setting UART back to RS232\n"); 429 /* back to last RS232 settings */ 430 mode = atmel_port->backup_mode; 431 memset(iso7816conf, 0, sizeof(struct serial_iso7816)); 432 atmel_uart_writel(port, ATMEL_US_TTGR, 0); 433 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->backup_brgr); 434 atmel_uart_writel(port, ATMEL_US_FIDI, 0x174); 435 436 if (atmel_use_pdc_tx(port)) 437 atmel_port->tx_done_mask = ATMEL_US_ENDTX | 438 ATMEL_US_TXBUFE; 439 else 440 atmel_port->tx_done_mask = ATMEL_US_TXRDY; 441 } 442 443 port->iso7816 = *iso7816conf; 444 445 atmel_uart_writel(port, ATMEL_US_MR, mode); 446 447 err_out: 448 /* Enable interrupts */ 449 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); 450 451 return ret; 452 } 453 454 /* 455 * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty. 456 */ 457 static u_int atmel_tx_empty(struct uart_port *port) 458 { 459 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 460 461 if (atmel_port->tx_stopped) 462 return TIOCSER_TEMT; 463 return (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXEMPTY) ? 464 TIOCSER_TEMT : 465 0; 466 } 467 468 /* 469 * Set state of the modem control output lines 470 */ 471 static void atmel_set_mctrl(struct uart_port *port, u_int mctrl) 472 { 473 unsigned int control = 0; 474 unsigned int mode = atmel_uart_readl(port, ATMEL_US_MR); 475 unsigned int rts_paused, rts_ready; 476 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 477 478 /* override mode to RS485 if needed, otherwise keep the current mode */ 479 if (port->rs485.flags & SER_RS485_ENABLED) { 480 atmel_uart_writel(port, ATMEL_US_TTGR, 481 port->rs485.delay_rts_after_send); 482 mode &= ~ATMEL_US_USMODE; 483 mode |= ATMEL_US_USMODE_RS485; 484 } 485 486 /* set the RTS line state according to the mode */ 487 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) { 488 /* force RTS line to high level */ 489 rts_paused = ATMEL_US_RTSEN; 490 491 /* give the control of the RTS line back to the hardware */ 492 rts_ready = ATMEL_US_RTSDIS; 493 } else { 494 /* force RTS line to high level */ 495 rts_paused = ATMEL_US_RTSDIS; 496 497 /* force RTS line to low level */ 498 rts_ready = ATMEL_US_RTSEN; 499 } 500 501 if (mctrl & TIOCM_RTS) 502 control |= rts_ready; 503 else 504 control |= rts_paused; 505 506 if (mctrl & TIOCM_DTR) 507 control |= ATMEL_US_DTREN; 508 else 509 control |= ATMEL_US_DTRDIS; 510 511 atmel_uart_writel(port, ATMEL_US_CR, control); 512 513 mctrl_gpio_set(atmel_port->gpios, mctrl); 514 515 /* Local loopback mode? */ 516 mode &= ~ATMEL_US_CHMODE; 517 if (mctrl & TIOCM_LOOP) 518 mode |= ATMEL_US_CHMODE_LOC_LOOP; 519 else 520 mode |= ATMEL_US_CHMODE_NORMAL; 521 522 atmel_uart_writel(port, ATMEL_US_MR, mode); 523 } 524 525 /* 526 * Get state of the modem control input lines 527 */ 528 static u_int atmel_get_mctrl(struct uart_port *port) 529 { 530 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 531 unsigned int ret = 0, status; 532 533 status = atmel_uart_readl(port, ATMEL_US_CSR); 534 535 /* 536 * The control signals are active low. 537 */ 538 if (!(status & ATMEL_US_DCD)) 539 ret |= TIOCM_CD; 540 if (!(status & ATMEL_US_CTS)) 541 ret |= TIOCM_CTS; 542 if (!(status & ATMEL_US_DSR)) 543 ret |= TIOCM_DSR; 544 if (!(status & ATMEL_US_RI)) 545 ret |= TIOCM_RI; 546 547 return mctrl_gpio_get(atmel_port->gpios, &ret); 548 } 549 550 /* 551 * Stop transmitting. 552 */ 553 static void atmel_stop_tx(struct uart_port *port) 554 { 555 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 556 bool is_pdc = atmel_use_pdc_tx(port); 557 bool is_dma = is_pdc || atmel_use_dma_tx(port); 558 559 if (is_pdc) { 560 /* disable PDC transmit */ 561 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS); 562 } 563 564 if (is_dma) { 565 /* 566 * Disable the transmitter. 567 * This is mandatory when DMA is used, otherwise the DMA buffer 568 * is fully transmitted. 569 */ 570 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS); 571 atmel_port->tx_stopped = true; 572 } 573 574 /* Disable interrupts */ 575 atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); 576 577 if (atmel_uart_is_half_duplex(port)) 578 if (!atomic_read(&atmel_port->tasklet_shutdown)) 579 atmel_start_rx(port); 580 } 581 582 /* 583 * Start transmitting. 584 */ 585 static void atmel_start_tx(struct uart_port *port) 586 { 587 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 588 bool is_pdc = atmel_use_pdc_tx(port); 589 bool is_dma = is_pdc || atmel_use_dma_tx(port); 590 591 if (is_pdc && (atmel_uart_readl(port, ATMEL_PDC_PTSR) 592 & ATMEL_PDC_TXTEN)) 593 /* The transmitter is already running. Yes, we 594 really need this.*/ 595 return; 596 597 if (is_dma && atmel_uart_is_half_duplex(port)) 598 atmel_stop_rx(port); 599 600 if (is_pdc) { 601 /* re-enable PDC transmit */ 602 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN); 603 } 604 605 /* Enable interrupts */ 606 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); 607 608 if (is_dma) { 609 /* re-enable the transmitter */ 610 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN); 611 atmel_port->tx_stopped = false; 612 } 613 } 614 615 /* 616 * start receiving - port is in process of being opened. 617 */ 618 static void atmel_start_rx(struct uart_port *port) 619 { 620 /* reset status and receiver */ 621 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA); 622 623 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXEN); 624 625 if (atmel_use_pdc_rx(port)) { 626 /* enable PDC controller */ 627 atmel_uart_writel(port, ATMEL_US_IER, 628 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | 629 port->read_status_mask); 630 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN); 631 } else { 632 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY); 633 } 634 } 635 636 /* 637 * Stop receiving - port is in process of being closed. 638 */ 639 static void atmel_stop_rx(struct uart_port *port) 640 { 641 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXDIS); 642 643 if (atmel_use_pdc_rx(port)) { 644 /* disable PDC receive */ 645 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS); 646 atmel_uart_writel(port, ATMEL_US_IDR, 647 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | 648 port->read_status_mask); 649 } else { 650 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXRDY); 651 } 652 } 653 654 /* 655 * Enable modem status interrupts 656 */ 657 static void atmel_enable_ms(struct uart_port *port) 658 { 659 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 660 uint32_t ier = 0; 661 662 /* 663 * Interrupt should not be enabled twice 664 */ 665 if (atmel_port->ms_irq_enabled) 666 return; 667 668 atmel_port->ms_irq_enabled = true; 669 670 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) 671 ier |= ATMEL_US_CTSIC; 672 673 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR)) 674 ier |= ATMEL_US_DSRIC; 675 676 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI)) 677 ier |= ATMEL_US_RIIC; 678 679 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD)) 680 ier |= ATMEL_US_DCDIC; 681 682 atmel_uart_writel(port, ATMEL_US_IER, ier); 683 684 mctrl_gpio_enable_ms(atmel_port->gpios); 685 } 686 687 /* 688 * Disable modem status interrupts 689 */ 690 static void atmel_disable_ms(struct uart_port *port) 691 { 692 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 693 uint32_t idr = 0; 694 695 /* 696 * Interrupt should not be disabled twice 697 */ 698 if (!atmel_port->ms_irq_enabled) 699 return; 700 701 atmel_port->ms_irq_enabled = false; 702 703 mctrl_gpio_disable_ms(atmel_port->gpios); 704 705 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) 706 idr |= ATMEL_US_CTSIC; 707 708 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR)) 709 idr |= ATMEL_US_DSRIC; 710 711 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI)) 712 idr |= ATMEL_US_RIIC; 713 714 if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD)) 715 idr |= ATMEL_US_DCDIC; 716 717 atmel_uart_writel(port, ATMEL_US_IDR, idr); 718 } 719 720 /* 721 * Control the transmission of a break signal 722 */ 723 static void atmel_break_ctl(struct uart_port *port, int break_state) 724 { 725 if (break_state != 0) 726 /* start break */ 727 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTBRK); 728 else 729 /* stop break */ 730 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STPBRK); 731 } 732 733 /* 734 * Stores the incoming character in the ring buffer 735 */ 736 static void 737 atmel_buffer_rx_char(struct uart_port *port, unsigned int status, 738 unsigned int ch) 739 { 740 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 741 struct circ_buf *ring = &atmel_port->rx_ring; 742 struct atmel_uart_char *c; 743 744 if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE)) 745 /* Buffer overflow, ignore char */ 746 return; 747 748 c = &((struct atmel_uart_char *)ring->buf)[ring->head]; 749 c->status = status; 750 c->ch = ch; 751 752 /* Make sure the character is stored before we update head. */ 753 smp_wmb(); 754 755 ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1); 756 } 757 758 /* 759 * Deal with parity, framing and overrun errors. 760 */ 761 static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status) 762 { 763 /* clear error */ 764 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA); 765 766 if (status & ATMEL_US_RXBRK) { 767 /* ignore side-effect */ 768 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); 769 port->icount.brk++; 770 } 771 if (status & ATMEL_US_PARE) 772 port->icount.parity++; 773 if (status & ATMEL_US_FRAME) 774 port->icount.frame++; 775 if (status & ATMEL_US_OVRE) 776 port->icount.overrun++; 777 } 778 779 /* 780 * Characters received (called from interrupt handler) 781 */ 782 static void atmel_rx_chars(struct uart_port *port) 783 { 784 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 785 unsigned int status, ch; 786 787 status = atmel_uart_readl(port, ATMEL_US_CSR); 788 while (status & ATMEL_US_RXRDY) { 789 ch = atmel_uart_read_char(port); 790 791 /* 792 * note that the error handling code is 793 * out of the main execution path 794 */ 795 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME 796 | ATMEL_US_OVRE | ATMEL_US_RXBRK) 797 || atmel_port->break_active)) { 798 799 /* clear error */ 800 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA); 801 802 if (status & ATMEL_US_RXBRK 803 && !atmel_port->break_active) { 804 atmel_port->break_active = 1; 805 atmel_uart_writel(port, ATMEL_US_IER, 806 ATMEL_US_RXBRK); 807 } else { 808 /* 809 * This is either the end-of-break 810 * condition or we've received at 811 * least one character without RXBRK 812 * being set. In both cases, the next 813 * RXBRK will indicate start-of-break. 814 */ 815 atmel_uart_writel(port, ATMEL_US_IDR, 816 ATMEL_US_RXBRK); 817 status &= ~ATMEL_US_RXBRK; 818 atmel_port->break_active = 0; 819 } 820 } 821 822 atmel_buffer_rx_char(port, status, ch); 823 status = atmel_uart_readl(port, ATMEL_US_CSR); 824 } 825 826 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx); 827 } 828 829 /* 830 * Transmit characters (called from tasklet with TXRDY interrupt 831 * disabled) 832 */ 833 static void atmel_tx_chars(struct uart_port *port) 834 { 835 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 836 bool pending; 837 u8 ch; 838 839 pending = uart_port_tx(port, ch, 840 atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY, 841 atmel_uart_write_char(port, ch)); 842 if (pending) { 843 /* we still have characters to transmit, so we should continue 844 * transmitting them when TX is ready, regardless of 845 * mode or duplexity 846 */ 847 atmel_port->tx_done_mask |= ATMEL_US_TXRDY; 848 849 /* Enable interrupts */ 850 atmel_uart_writel(port, ATMEL_US_IER, 851 atmel_port->tx_done_mask); 852 } else { 853 if (atmel_uart_is_half_duplex(port)) 854 atmel_port->tx_done_mask &= ~ATMEL_US_TXRDY; 855 } 856 } 857 858 static void atmel_complete_tx_dma(void *arg) 859 { 860 struct atmel_uart_port *atmel_port = arg; 861 struct uart_port *port = &atmel_port->uart; 862 struct tty_port *tport = &port->state->port; 863 struct dma_chan *chan = atmel_port->chan_tx; 864 unsigned long flags; 865 866 uart_port_lock_irqsave(port, &flags); 867 868 if (chan) 869 dmaengine_terminate_all(chan); 870 uart_xmit_advance(port, atmel_port->tx_len); 871 872 spin_lock(&atmel_port->lock_tx); 873 async_tx_ack(atmel_port->desc_tx); 874 atmel_port->cookie_tx = -EINVAL; 875 atmel_port->desc_tx = NULL; 876 spin_unlock(&atmel_port->lock_tx); 877 878 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) 879 uart_write_wakeup(port); 880 881 /* 882 * xmit is a circular buffer so, if we have just send data from the 883 * tail to the end, now we have to transmit the remaining data from the 884 * beginning to the head. 885 */ 886 if (!kfifo_is_empty(&tport->xmit_fifo)) 887 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx); 888 else if (atmel_uart_is_half_duplex(port)) { 889 /* 890 * DMA done, re-enable TXEMPTY and signal that we can stop 891 * TX and start RX for RS485 892 */ 893 atmel_port->hd_start_rx = true; 894 atmel_uart_writel(port, ATMEL_US_IER, 895 atmel_port->tx_done_mask); 896 } 897 898 uart_port_unlock_irqrestore(port, flags); 899 } 900 901 static void atmel_release_tx_dma(struct uart_port *port) 902 { 903 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 904 struct dma_chan *chan = atmel_port->chan_tx; 905 906 if (chan) { 907 dmaengine_terminate_all(chan); 908 dma_release_channel(chan); 909 dma_unmap_single(port->dev, atmel_port->tx_phys, 910 UART_XMIT_SIZE, DMA_TO_DEVICE); 911 } 912 913 atmel_port->desc_tx = NULL; 914 atmel_port->chan_tx = NULL; 915 atmel_port->cookie_tx = -EINVAL; 916 } 917 918 /* 919 * Called from tasklet with TXRDY interrupt is disabled. 920 */ 921 static void atmel_tx_dma(struct uart_port *port) 922 { 923 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 924 struct tty_port *tport = &port->state->port; 925 struct dma_chan *chan = atmel_port->chan_tx; 926 struct dma_async_tx_descriptor *desc; 927 struct scatterlist sgl[2], *sg; 928 unsigned int tx_len, tail, part1_len, part2_len, sg_len; 929 dma_addr_t phys_addr; 930 931 /* Make sure we have an idle channel */ 932 if (atmel_port->desc_tx != NULL) 933 return; 934 935 if (!kfifo_is_empty(&tport->xmit_fifo) && !uart_tx_stopped(port)) { 936 /* 937 * DMA is idle now. 938 * Port xmit buffer is already mapped, 939 * and it is one page... Just adjust 940 * offsets and lengths. Since it is a circular buffer, 941 * we have to transmit till the end, and then the rest. 942 * Take the port lock to get a 943 * consistent xmit buffer state. 944 */ 945 tx_len = kfifo_out_linear(&tport->xmit_fifo, &tail, 946 UART_XMIT_SIZE); 947 948 if (atmel_port->fifo_size) { 949 /* multi data mode */ 950 part1_len = (tx_len & ~0x3); /* DWORD access */ 951 part2_len = (tx_len & 0x3); /* BYTE access */ 952 } else { 953 /* single data (legacy) mode */ 954 part1_len = 0; 955 part2_len = tx_len; /* BYTE access only */ 956 } 957 958 sg_init_table(sgl, 2); 959 sg_len = 0; 960 phys_addr = atmel_port->tx_phys + tail; 961 if (part1_len) { 962 sg = &sgl[sg_len++]; 963 sg_dma_address(sg) = phys_addr; 964 sg_dma_len(sg) = part1_len; 965 966 phys_addr += part1_len; 967 } 968 969 if (part2_len) { 970 sg = &sgl[sg_len++]; 971 sg_dma_address(sg) = phys_addr; 972 sg_dma_len(sg) = part2_len; 973 } 974 975 /* 976 * save tx_len so atmel_complete_tx_dma() will increase 977 * tail correctly 978 */ 979 atmel_port->tx_len = tx_len; 980 981 desc = dmaengine_prep_slave_sg(chan, 982 sgl, 983 sg_len, 984 DMA_MEM_TO_DEV, 985 DMA_PREP_INTERRUPT | 986 DMA_CTRL_ACK); 987 if (!desc) { 988 dev_err(port->dev, "Failed to send via dma!\n"); 989 return; 990 } 991 992 dma_sync_single_for_device(port->dev, atmel_port->tx_phys, 993 UART_XMIT_SIZE, DMA_TO_DEVICE); 994 995 atmel_port->desc_tx = desc; 996 desc->callback = atmel_complete_tx_dma; 997 desc->callback_param = atmel_port; 998 atmel_port->cookie_tx = dmaengine_submit(desc); 999 if (dma_submit_error(atmel_port->cookie_tx)) { 1000 dev_err(port->dev, "dma_submit_error %d\n", 1001 atmel_port->cookie_tx); 1002 return; 1003 } 1004 1005 dma_async_issue_pending(chan); 1006 } 1007 1008 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) 1009 uart_write_wakeup(port); 1010 } 1011 1012 static int atmel_prepare_tx_dma(struct uart_port *port) 1013 { 1014 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1015 struct tty_port *tport = &port->state->port; 1016 struct device *mfd_dev = port->dev->parent; 1017 dma_cap_mask_t mask; 1018 struct dma_slave_config config; 1019 struct dma_chan *chan; 1020 int ret; 1021 1022 dma_cap_zero(mask); 1023 dma_cap_set(DMA_SLAVE, mask); 1024 1025 chan = dma_request_chan(mfd_dev, "tx"); 1026 if (IS_ERR(chan)) { 1027 atmel_port->chan_tx = NULL; 1028 goto chan_err; 1029 } 1030 atmel_port->chan_tx = chan; 1031 dev_info(port->dev, "using %s for tx DMA transfers\n", 1032 dma_chan_name(atmel_port->chan_tx)); 1033 1034 spin_lock_init(&atmel_port->lock_tx); 1035 /* UART circular tx buffer is an aligned page. */ 1036 BUG_ON(!PAGE_ALIGNED(tport->xmit_buf)); 1037 atmel_port->tx_phys = dma_map_single(port->dev, tport->xmit_buf, 1038 UART_XMIT_SIZE, DMA_TO_DEVICE); 1039 1040 if (dma_mapping_error(port->dev, atmel_port->tx_phys)) { 1041 dev_dbg(port->dev, "need to release resource of dma\n"); 1042 goto chan_err; 1043 } else { 1044 dev_dbg(port->dev, "%s: mapped %lu@%p to %pad\n", __func__, 1045 UART_XMIT_SIZE, tport->xmit_buf, 1046 &atmel_port->tx_phys); 1047 } 1048 1049 /* Configure the slave DMA */ 1050 memset(&config, 0, sizeof(config)); 1051 config.direction = DMA_MEM_TO_DEV; 1052 config.dst_addr_width = (atmel_port->fifo_size) ? 1053 DMA_SLAVE_BUSWIDTH_4_BYTES : 1054 DMA_SLAVE_BUSWIDTH_1_BYTE; 1055 config.dst_addr = port->mapbase + ATMEL_US_THR; 1056 config.dst_maxburst = 1; 1057 1058 ret = dmaengine_slave_config(atmel_port->chan_tx, 1059 &config); 1060 if (ret) { 1061 dev_err(port->dev, "DMA tx slave configuration failed\n"); 1062 goto chan_err; 1063 } 1064 1065 return 0; 1066 1067 chan_err: 1068 dev_err(port->dev, "TX channel not available, switch to pio\n"); 1069 atmel_port->use_dma_tx = false; 1070 if (atmel_port->chan_tx) 1071 atmel_release_tx_dma(port); 1072 return -EINVAL; 1073 } 1074 1075 static void atmel_complete_rx_dma(void *arg) 1076 { 1077 struct uart_port *port = arg; 1078 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1079 1080 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx); 1081 } 1082 1083 static void atmel_release_rx_dma(struct uart_port *port) 1084 { 1085 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1086 struct dma_chan *chan = atmel_port->chan_rx; 1087 1088 if (chan) { 1089 dmaengine_terminate_all(chan); 1090 dma_release_channel(chan); 1091 dma_unmap_single(port->dev, atmel_port->rx_phys, 1092 ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); 1093 } 1094 1095 atmel_port->desc_rx = NULL; 1096 atmel_port->chan_rx = NULL; 1097 atmel_port->cookie_rx = -EINVAL; 1098 } 1099 1100 static void atmel_rx_from_dma(struct uart_port *port) 1101 { 1102 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1103 struct tty_port *tport = &port->state->port; 1104 struct circ_buf *ring = &atmel_port->rx_ring; 1105 struct dma_chan *chan = atmel_port->chan_rx; 1106 struct dma_tx_state state; 1107 enum dma_status dmastat; 1108 size_t count; 1109 1110 1111 /* Reset the UART timeout early so that we don't miss one */ 1112 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO); 1113 dmastat = dmaengine_tx_status(chan, 1114 atmel_port->cookie_rx, 1115 &state); 1116 /* Restart a new tasklet if DMA status is error */ 1117 if (dmastat == DMA_ERROR) { 1118 dev_dbg(port->dev, "Get residue error, restart tasklet\n"); 1119 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT); 1120 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx); 1121 return; 1122 } 1123 1124 /* CPU claims ownership of RX DMA buffer */ 1125 dma_sync_single_for_cpu(port->dev, atmel_port->rx_phys, 1126 ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); 1127 1128 /* 1129 * ring->head points to the end of data already written by the DMA. 1130 * ring->tail points to the beginning of data to be read by the 1131 * framework. 1132 * The current transfer size should not be larger than the dma buffer 1133 * length. 1134 */ 1135 ring->head = ATMEL_SERIAL_RX_SIZE - state.residue; 1136 BUG_ON(ring->head > ATMEL_SERIAL_RX_SIZE); 1137 /* 1138 * At this point ring->head may point to the first byte right after the 1139 * last byte of the dma buffer: 1140 * 0 <= ring->head <= sg_dma_len(&atmel_port->sg_rx) 1141 * 1142 * However ring->tail must always points inside the dma buffer: 1143 * 0 <= ring->tail <= sg_dma_len(&atmel_port->sg_rx) - 1 1144 * 1145 * Since we use a ring buffer, we have to handle the case 1146 * where head is lower than tail. In such a case, we first read from 1147 * tail to the end of the buffer then reset tail. 1148 */ 1149 if (ring->head < ring->tail) { 1150 count = ATMEL_SERIAL_RX_SIZE - ring->tail; 1151 1152 tty_insert_flip_string(tport, ring->buf + ring->tail, count); 1153 ring->tail = 0; 1154 port->icount.rx += count; 1155 } 1156 1157 /* Finally we read data from tail to head */ 1158 if (ring->tail < ring->head) { 1159 count = ring->head - ring->tail; 1160 1161 tty_insert_flip_string(tport, ring->buf + ring->tail, count); 1162 /* Wrap ring->head if needed */ 1163 if (ring->head >= ATMEL_SERIAL_RX_SIZE) 1164 ring->head = 0; 1165 ring->tail = ring->head; 1166 port->icount.rx += count; 1167 } 1168 1169 /* USART retreives ownership of RX DMA buffer */ 1170 dma_sync_single_for_device(port->dev, atmel_port->rx_phys, 1171 ATMEL_SERIAL_RX_SIZE, DMA_FROM_DEVICE); 1172 1173 tty_flip_buffer_push(tport); 1174 1175 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT); 1176 } 1177 1178 static int atmel_prepare_rx_dma(struct uart_port *port) 1179 { 1180 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1181 struct device *mfd_dev = port->dev->parent; 1182 struct dma_async_tx_descriptor *desc; 1183 dma_cap_mask_t mask; 1184 struct dma_slave_config config; 1185 struct circ_buf *ring; 1186 struct dma_chan *chan; 1187 int ret; 1188 1189 ring = &atmel_port->rx_ring; 1190 1191 dma_cap_zero(mask); 1192 dma_cap_set(DMA_CYCLIC, mask); 1193 1194 chan = dma_request_chan(mfd_dev, "rx"); 1195 if (IS_ERR(chan)) { 1196 atmel_port->chan_rx = NULL; 1197 goto chan_err; 1198 } 1199 atmel_port->chan_rx = chan; 1200 dev_info(port->dev, "using %s for rx DMA transfers\n", 1201 dma_chan_name(atmel_port->chan_rx)); 1202 1203 spin_lock_init(&atmel_port->lock_rx); 1204 /* UART circular rx buffer is an aligned page. */ 1205 BUG_ON(!PAGE_ALIGNED(ring->buf)); 1206 atmel_port->rx_phys = dma_map_single(port->dev, ring->buf, 1207 ATMEL_SERIAL_RX_SIZE, 1208 DMA_FROM_DEVICE); 1209 1210 if (dma_mapping_error(port->dev, atmel_port->rx_phys)) { 1211 dev_dbg(port->dev, "need to release resource of dma\n"); 1212 goto chan_err; 1213 } else { 1214 dev_dbg(port->dev, "%s: mapped %zu@%p to %pad\n", __func__, 1215 ATMEL_SERIAL_RX_SIZE, ring->buf, &atmel_port->rx_phys); 1216 } 1217 1218 /* Configure the slave DMA */ 1219 memset(&config, 0, sizeof(config)); 1220 config.direction = DMA_DEV_TO_MEM; 1221 config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 1222 config.src_addr = port->mapbase + ATMEL_US_RHR; 1223 config.src_maxburst = 1; 1224 1225 ret = dmaengine_slave_config(atmel_port->chan_rx, 1226 &config); 1227 if (ret) { 1228 dev_err(port->dev, "DMA rx slave configuration failed\n"); 1229 goto chan_err; 1230 } 1231 /* 1232 * Prepare a cyclic dma transfer, assign 2 descriptors, 1233 * each one is half ring buffer size 1234 */ 1235 desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx, 1236 atmel_port->rx_phys, 1237 ATMEL_SERIAL_RX_SIZE, 1238 ATMEL_SERIAL_RX_SIZE / 2, 1239 DMA_DEV_TO_MEM, 1240 DMA_PREP_INTERRUPT); 1241 if (!desc) { 1242 dev_err(port->dev, "Preparing DMA cyclic failed\n"); 1243 goto chan_err; 1244 } 1245 desc->callback = atmel_complete_rx_dma; 1246 desc->callback_param = port; 1247 atmel_port->desc_rx = desc; 1248 atmel_port->cookie_rx = dmaengine_submit(desc); 1249 if (dma_submit_error(atmel_port->cookie_rx)) { 1250 dev_err(port->dev, "dma_submit_error %d\n", 1251 atmel_port->cookie_rx); 1252 goto chan_err; 1253 } 1254 1255 dma_async_issue_pending(atmel_port->chan_rx); 1256 1257 return 0; 1258 1259 chan_err: 1260 dev_err(port->dev, "RX channel not available, switch to pio\n"); 1261 atmel_port->use_dma_rx = false; 1262 if (atmel_port->chan_rx) 1263 atmel_release_rx_dma(port); 1264 return -EINVAL; 1265 } 1266 1267 static void atmel_uart_timer_callback(struct timer_list *t) 1268 { 1269 struct atmel_uart_port *atmel_port = from_timer(atmel_port, t, 1270 uart_timer); 1271 struct uart_port *port = &atmel_port->uart; 1272 1273 if (!atomic_read(&atmel_port->tasklet_shutdown)) { 1274 tasklet_schedule(&atmel_port->tasklet_rx); 1275 mod_timer(&atmel_port->uart_timer, 1276 jiffies + uart_poll_timeout(port)); 1277 } 1278 } 1279 1280 /* 1281 * receive interrupt handler. 1282 */ 1283 static void 1284 atmel_handle_receive(struct uart_port *port, unsigned int pending) 1285 { 1286 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1287 1288 if (atmel_use_pdc_rx(port)) { 1289 /* 1290 * PDC receive. Just schedule the tasklet and let it 1291 * figure out the details. 1292 * 1293 * TODO: We're not handling error flags correctly at 1294 * the moment. 1295 */ 1296 if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) { 1297 atmel_uart_writel(port, ATMEL_US_IDR, 1298 (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)); 1299 atmel_tasklet_schedule(atmel_port, 1300 &atmel_port->tasklet_rx); 1301 } 1302 1303 if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE | 1304 ATMEL_US_FRAME | ATMEL_US_PARE)) 1305 atmel_pdc_rxerr(port, pending); 1306 } 1307 1308 if (atmel_use_dma_rx(port)) { 1309 if (pending & ATMEL_US_TIMEOUT) { 1310 atmel_uart_writel(port, ATMEL_US_IDR, 1311 ATMEL_US_TIMEOUT); 1312 atmel_tasklet_schedule(atmel_port, 1313 &atmel_port->tasklet_rx); 1314 } 1315 } 1316 1317 /* Interrupt receive */ 1318 if (pending & ATMEL_US_RXRDY) 1319 atmel_rx_chars(port); 1320 else if (pending & ATMEL_US_RXBRK) { 1321 /* 1322 * End of break detected. If it came along with a 1323 * character, atmel_rx_chars will handle it. 1324 */ 1325 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA); 1326 atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXBRK); 1327 atmel_port->break_active = 0; 1328 } 1329 } 1330 1331 /* 1332 * transmit interrupt handler. (Transmit is IRQF_NODELAY safe) 1333 */ 1334 static void 1335 atmel_handle_transmit(struct uart_port *port, unsigned int pending) 1336 { 1337 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1338 1339 if (pending & atmel_port->tx_done_mask) { 1340 atmel_uart_writel(port, ATMEL_US_IDR, 1341 atmel_port->tx_done_mask); 1342 1343 /* Start RX if flag was set and FIFO is empty */ 1344 if (atmel_port->hd_start_rx) { 1345 if (!(atmel_uart_readl(port, ATMEL_US_CSR) 1346 & ATMEL_US_TXEMPTY)) 1347 dev_warn(port->dev, "Should start RX, but TX fifo is not empty\n"); 1348 1349 atmel_port->hd_start_rx = false; 1350 atmel_start_rx(port); 1351 } 1352 1353 atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx); 1354 } 1355 } 1356 1357 /* 1358 * status flags interrupt handler. 1359 */ 1360 static void 1361 atmel_handle_status(struct uart_port *port, unsigned int pending, 1362 unsigned int status) 1363 { 1364 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1365 unsigned int status_change; 1366 1367 if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC 1368 | ATMEL_US_CTSIC)) { 1369 status_change = status ^ atmel_port->irq_status_prev; 1370 atmel_port->irq_status_prev = status; 1371 1372 if (status_change & (ATMEL_US_RI | ATMEL_US_DSR 1373 | ATMEL_US_DCD | ATMEL_US_CTS)) { 1374 /* TODO: All reads to CSR will clear these interrupts! */ 1375 if (status_change & ATMEL_US_RI) 1376 port->icount.rng++; 1377 if (status_change & ATMEL_US_DSR) 1378 port->icount.dsr++; 1379 if (status_change & ATMEL_US_DCD) 1380 uart_handle_dcd_change(port, !(status & ATMEL_US_DCD)); 1381 if (status_change & ATMEL_US_CTS) 1382 uart_handle_cts_change(port, !(status & ATMEL_US_CTS)); 1383 1384 wake_up_interruptible(&port->state->port.delta_msr_wait); 1385 } 1386 } 1387 1388 if (pending & (ATMEL_US_NACK | ATMEL_US_ITERATION)) 1389 dev_dbg(port->dev, "ISO7816 ERROR (0x%08x)\n", pending); 1390 } 1391 1392 /* 1393 * Interrupt handler 1394 */ 1395 static irqreturn_t atmel_interrupt(int irq, void *dev_id) 1396 { 1397 struct uart_port *port = dev_id; 1398 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1399 unsigned int status, pending, mask, pass_counter = 0; 1400 1401 spin_lock(&atmel_port->lock_suspended); 1402 1403 do { 1404 status = atmel_uart_readl(port, ATMEL_US_CSR); 1405 mask = atmel_uart_readl(port, ATMEL_US_IMR); 1406 pending = status & mask; 1407 if (!pending) 1408 break; 1409 1410 if (atmel_port->suspended) { 1411 atmel_port->pending |= pending; 1412 atmel_port->pending_status = status; 1413 atmel_uart_writel(port, ATMEL_US_IDR, mask); 1414 pm_system_wakeup(); 1415 break; 1416 } 1417 1418 atmel_handle_receive(port, pending); 1419 atmel_handle_status(port, pending, status); 1420 atmel_handle_transmit(port, pending); 1421 } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT); 1422 1423 spin_unlock(&atmel_port->lock_suspended); 1424 1425 return pass_counter ? IRQ_HANDLED : IRQ_NONE; 1426 } 1427 1428 static void atmel_release_tx_pdc(struct uart_port *port) 1429 { 1430 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1431 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; 1432 1433 dma_unmap_single(port->dev, 1434 pdc->dma_addr, 1435 pdc->dma_size, 1436 DMA_TO_DEVICE); 1437 } 1438 1439 /* 1440 * Called from tasklet with ENDTX and TXBUFE interrupts disabled. 1441 */ 1442 static void atmel_tx_pdc(struct uart_port *port) 1443 { 1444 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1445 struct tty_port *tport = &port->state->port; 1446 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; 1447 1448 /* nothing left to transmit? */ 1449 if (atmel_uart_readl(port, ATMEL_PDC_TCR)) 1450 return; 1451 uart_xmit_advance(port, pdc->ofs); 1452 pdc->ofs = 0; 1453 1454 /* more to transmit - setup next transfer */ 1455 1456 /* disable PDC transmit */ 1457 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS); 1458 1459 if (!kfifo_is_empty(&tport->xmit_fifo) && !uart_tx_stopped(port)) { 1460 unsigned int count, tail; 1461 1462 dma_sync_single_for_device(port->dev, 1463 pdc->dma_addr, 1464 pdc->dma_size, 1465 DMA_TO_DEVICE); 1466 1467 count = kfifo_out_linear(&tport->xmit_fifo, &tail, 1468 UART_XMIT_SIZE); 1469 pdc->ofs = count; 1470 1471 atmel_uart_writel(port, ATMEL_PDC_TPR, pdc->dma_addr + tail); 1472 atmel_uart_writel(port, ATMEL_PDC_TCR, count); 1473 /* re-enable PDC transmit */ 1474 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN); 1475 /* Enable interrupts */ 1476 atmel_uart_writel(port, ATMEL_US_IER, 1477 atmel_port->tx_done_mask); 1478 } else { 1479 if (atmel_uart_is_half_duplex(port)) { 1480 /* DMA done, stop TX, start RX for RS485 */ 1481 atmel_start_rx(port); 1482 } 1483 } 1484 1485 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) 1486 uart_write_wakeup(port); 1487 } 1488 1489 static int atmel_prepare_tx_pdc(struct uart_port *port) 1490 { 1491 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1492 struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; 1493 struct tty_port *tport = &port->state->port; 1494 1495 pdc->buf = tport->xmit_buf; 1496 pdc->dma_addr = dma_map_single(port->dev, 1497 pdc->buf, 1498 UART_XMIT_SIZE, 1499 DMA_TO_DEVICE); 1500 pdc->dma_size = UART_XMIT_SIZE; 1501 pdc->ofs = 0; 1502 1503 return 0; 1504 } 1505 1506 static void atmel_rx_from_ring(struct uart_port *port) 1507 { 1508 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1509 struct circ_buf *ring = &atmel_port->rx_ring; 1510 unsigned int status; 1511 u8 flg; 1512 1513 while (ring->head != ring->tail) { 1514 struct atmel_uart_char c; 1515 1516 /* Make sure c is loaded after head. */ 1517 smp_rmb(); 1518 1519 c = ((struct atmel_uart_char *)ring->buf)[ring->tail]; 1520 1521 ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1); 1522 1523 port->icount.rx++; 1524 status = c.status; 1525 flg = TTY_NORMAL; 1526 1527 /* 1528 * note that the error handling code is 1529 * out of the main execution path 1530 */ 1531 if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME 1532 | ATMEL_US_OVRE | ATMEL_US_RXBRK))) { 1533 if (status & ATMEL_US_RXBRK) { 1534 /* ignore side-effect */ 1535 status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); 1536 1537 port->icount.brk++; 1538 if (uart_handle_break(port)) 1539 continue; 1540 } 1541 if (status & ATMEL_US_PARE) 1542 port->icount.parity++; 1543 if (status & ATMEL_US_FRAME) 1544 port->icount.frame++; 1545 if (status & ATMEL_US_OVRE) 1546 port->icount.overrun++; 1547 1548 status &= port->read_status_mask; 1549 1550 if (status & ATMEL_US_RXBRK) 1551 flg = TTY_BREAK; 1552 else if (status & ATMEL_US_PARE) 1553 flg = TTY_PARITY; 1554 else if (status & ATMEL_US_FRAME) 1555 flg = TTY_FRAME; 1556 } 1557 1558 1559 if (uart_handle_sysrq_char(port, c.ch)) 1560 continue; 1561 1562 uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg); 1563 } 1564 1565 tty_flip_buffer_push(&port->state->port); 1566 } 1567 1568 static void atmel_release_rx_pdc(struct uart_port *port) 1569 { 1570 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1571 int i; 1572 1573 for (i = 0; i < 2; i++) { 1574 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i]; 1575 1576 dma_unmap_single(port->dev, 1577 pdc->dma_addr, 1578 pdc->dma_size, 1579 DMA_FROM_DEVICE); 1580 kfree(pdc->buf); 1581 } 1582 } 1583 1584 static void atmel_rx_from_pdc(struct uart_port *port) 1585 { 1586 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1587 struct tty_port *tport = &port->state->port; 1588 struct atmel_dma_buffer *pdc; 1589 int rx_idx = atmel_port->pdc_rx_idx; 1590 unsigned int head; 1591 unsigned int tail; 1592 unsigned int count; 1593 1594 do { 1595 /* Reset the UART timeout early so that we don't miss one */ 1596 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO); 1597 1598 pdc = &atmel_port->pdc_rx[rx_idx]; 1599 head = atmel_uart_readl(port, ATMEL_PDC_RPR) - pdc->dma_addr; 1600 tail = pdc->ofs; 1601 1602 /* If the PDC has switched buffers, RPR won't contain 1603 * any address within the current buffer. Since head 1604 * is unsigned, we just need a one-way comparison to 1605 * find out. 1606 * 1607 * In this case, we just need to consume the entire 1608 * buffer and resubmit it for DMA. This will clear the 1609 * ENDRX bit as well, so that we can safely re-enable 1610 * all interrupts below. 1611 */ 1612 head = min(head, pdc->dma_size); 1613 1614 if (likely(head != tail)) { 1615 dma_sync_single_for_cpu(port->dev, pdc->dma_addr, 1616 pdc->dma_size, DMA_FROM_DEVICE); 1617 1618 /* 1619 * head will only wrap around when we recycle 1620 * the DMA buffer, and when that happens, we 1621 * explicitly set tail to 0. So head will 1622 * always be greater than tail. 1623 */ 1624 count = head - tail; 1625 1626 tty_insert_flip_string(tport, pdc->buf + pdc->ofs, 1627 count); 1628 1629 dma_sync_single_for_device(port->dev, pdc->dma_addr, 1630 pdc->dma_size, DMA_FROM_DEVICE); 1631 1632 port->icount.rx += count; 1633 pdc->ofs = head; 1634 } 1635 1636 /* 1637 * If the current buffer is full, we need to check if 1638 * the next one contains any additional data. 1639 */ 1640 if (head >= pdc->dma_size) { 1641 pdc->ofs = 0; 1642 atmel_uart_writel(port, ATMEL_PDC_RNPR, pdc->dma_addr); 1643 atmel_uart_writel(port, ATMEL_PDC_RNCR, pdc->dma_size); 1644 1645 rx_idx = !rx_idx; 1646 atmel_port->pdc_rx_idx = rx_idx; 1647 } 1648 } while (head >= pdc->dma_size); 1649 1650 tty_flip_buffer_push(tport); 1651 1652 atmel_uart_writel(port, ATMEL_US_IER, 1653 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); 1654 } 1655 1656 static int atmel_prepare_rx_pdc(struct uart_port *port) 1657 { 1658 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1659 int i; 1660 1661 for (i = 0; i < 2; i++) { 1662 struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i]; 1663 1664 pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL); 1665 if (pdc->buf == NULL) { 1666 if (i != 0) { 1667 dma_unmap_single(port->dev, 1668 atmel_port->pdc_rx[0].dma_addr, 1669 PDC_BUFFER_SIZE, 1670 DMA_FROM_DEVICE); 1671 kfree(atmel_port->pdc_rx[0].buf); 1672 } 1673 atmel_port->use_pdc_rx = false; 1674 return -ENOMEM; 1675 } 1676 pdc->dma_addr = dma_map_single(port->dev, 1677 pdc->buf, 1678 PDC_BUFFER_SIZE, 1679 DMA_FROM_DEVICE); 1680 pdc->dma_size = PDC_BUFFER_SIZE; 1681 pdc->ofs = 0; 1682 } 1683 1684 atmel_port->pdc_rx_idx = 0; 1685 1686 atmel_uart_writel(port, ATMEL_PDC_RPR, atmel_port->pdc_rx[0].dma_addr); 1687 atmel_uart_writel(port, ATMEL_PDC_RCR, PDC_BUFFER_SIZE); 1688 1689 atmel_uart_writel(port, ATMEL_PDC_RNPR, 1690 atmel_port->pdc_rx[1].dma_addr); 1691 atmel_uart_writel(port, ATMEL_PDC_RNCR, PDC_BUFFER_SIZE); 1692 1693 return 0; 1694 } 1695 1696 /* 1697 * tasklet handling tty stuff outside the interrupt handler. 1698 */ 1699 static void atmel_tasklet_rx_func(struct tasklet_struct *t) 1700 { 1701 struct atmel_uart_port *atmel_port = from_tasklet(atmel_port, t, 1702 tasklet_rx); 1703 struct uart_port *port = &atmel_port->uart; 1704 1705 /* The interrupt handler does not take the lock */ 1706 uart_port_lock(port); 1707 atmel_port->schedule_rx(port); 1708 uart_port_unlock(port); 1709 } 1710 1711 static void atmel_tasklet_tx_func(struct tasklet_struct *t) 1712 { 1713 struct atmel_uart_port *atmel_port = from_tasklet(atmel_port, t, 1714 tasklet_tx); 1715 struct uart_port *port = &atmel_port->uart; 1716 1717 /* The interrupt handler does not take the lock */ 1718 uart_port_lock(port); 1719 atmel_port->schedule_tx(port); 1720 uart_port_unlock(port); 1721 } 1722 1723 static void atmel_init_property(struct atmel_uart_port *atmel_port, 1724 struct platform_device *pdev) 1725 { 1726 struct device_node *np = pdev->dev.of_node; 1727 1728 /* DMA/PDC usage specification */ 1729 if (of_property_read_bool(np, "atmel,use-dma-rx")) { 1730 if (of_property_read_bool(np, "dmas")) { 1731 atmel_port->use_dma_rx = true; 1732 atmel_port->use_pdc_rx = false; 1733 } else { 1734 atmel_port->use_dma_rx = false; 1735 atmel_port->use_pdc_rx = true; 1736 } 1737 } else { 1738 atmel_port->use_dma_rx = false; 1739 atmel_port->use_pdc_rx = false; 1740 } 1741 1742 if (of_property_read_bool(np, "atmel,use-dma-tx")) { 1743 if (of_property_read_bool(np, "dmas")) { 1744 atmel_port->use_dma_tx = true; 1745 atmel_port->use_pdc_tx = false; 1746 } else { 1747 atmel_port->use_dma_tx = false; 1748 atmel_port->use_pdc_tx = true; 1749 } 1750 } else { 1751 atmel_port->use_dma_tx = false; 1752 atmel_port->use_pdc_tx = false; 1753 } 1754 } 1755 1756 static void atmel_set_ops(struct uart_port *port) 1757 { 1758 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1759 1760 if (atmel_use_dma_rx(port)) { 1761 atmel_port->prepare_rx = &atmel_prepare_rx_dma; 1762 atmel_port->schedule_rx = &atmel_rx_from_dma; 1763 atmel_port->release_rx = &atmel_release_rx_dma; 1764 } else if (atmel_use_pdc_rx(port)) { 1765 atmel_port->prepare_rx = &atmel_prepare_rx_pdc; 1766 atmel_port->schedule_rx = &atmel_rx_from_pdc; 1767 atmel_port->release_rx = &atmel_release_rx_pdc; 1768 } else { 1769 atmel_port->prepare_rx = NULL; 1770 atmel_port->schedule_rx = &atmel_rx_from_ring; 1771 atmel_port->release_rx = NULL; 1772 } 1773 1774 if (atmel_use_dma_tx(port)) { 1775 atmel_port->prepare_tx = &atmel_prepare_tx_dma; 1776 atmel_port->schedule_tx = &atmel_tx_dma; 1777 atmel_port->release_tx = &atmel_release_tx_dma; 1778 } else if (atmel_use_pdc_tx(port)) { 1779 atmel_port->prepare_tx = &atmel_prepare_tx_pdc; 1780 atmel_port->schedule_tx = &atmel_tx_pdc; 1781 atmel_port->release_tx = &atmel_release_tx_pdc; 1782 } else { 1783 atmel_port->prepare_tx = NULL; 1784 atmel_port->schedule_tx = &atmel_tx_chars; 1785 atmel_port->release_tx = NULL; 1786 } 1787 } 1788 1789 /* 1790 * Get ip name usart or uart 1791 */ 1792 static void atmel_get_ip_name(struct uart_port *port) 1793 { 1794 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1795 int name = atmel_uart_readl(port, ATMEL_US_NAME); 1796 u32 version; 1797 u32 usart, dbgu_uart, new_uart; 1798 /* ASCII decoding for IP version */ 1799 usart = 0x55534152; /* USAR(T) */ 1800 dbgu_uart = 0x44424755; /* DBGU */ 1801 new_uart = 0x55415254; /* UART */ 1802 1803 /* 1804 * Only USART devices from at91sam9260 SOC implement fractional 1805 * baudrate. It is available for all asynchronous modes, with the 1806 * following restriction: the sampling clock's duty cycle is not 1807 * constant. 1808 */ 1809 atmel_port->has_frac_baudrate = false; 1810 atmel_port->has_hw_timer = false; 1811 atmel_port->is_usart = false; 1812 1813 if (name == new_uart) { 1814 dev_dbg(port->dev, "Uart with hw timer"); 1815 atmel_port->has_hw_timer = true; 1816 atmel_port->rtor = ATMEL_UA_RTOR; 1817 } else if (name == usart) { 1818 dev_dbg(port->dev, "Usart\n"); 1819 atmel_port->has_frac_baudrate = true; 1820 atmel_port->has_hw_timer = true; 1821 atmel_port->is_usart = true; 1822 atmel_port->rtor = ATMEL_US_RTOR; 1823 version = atmel_uart_readl(port, ATMEL_US_VERSION); 1824 switch (version) { 1825 case 0x814: /* sama5d2 */ 1826 fallthrough; 1827 case 0x701: /* sama5d4 */ 1828 atmel_port->fidi_min = 3; 1829 atmel_port->fidi_max = 65535; 1830 break; 1831 case 0x502: /* sam9x5, sama5d3 */ 1832 atmel_port->fidi_min = 3; 1833 atmel_port->fidi_max = 2047; 1834 break; 1835 default: 1836 atmel_port->fidi_min = 1; 1837 atmel_port->fidi_max = 2047; 1838 } 1839 } else if (name == dbgu_uart) { 1840 dev_dbg(port->dev, "Dbgu or uart without hw timer\n"); 1841 } else { 1842 /* fallback for older SoCs: use version field */ 1843 version = atmel_uart_readl(port, ATMEL_US_VERSION); 1844 switch (version) { 1845 case 0x302: 1846 case 0x10213: 1847 case 0x10302: 1848 dev_dbg(port->dev, "This version is usart\n"); 1849 atmel_port->has_frac_baudrate = true; 1850 atmel_port->has_hw_timer = true; 1851 atmel_port->is_usart = true; 1852 atmel_port->rtor = ATMEL_US_RTOR; 1853 break; 1854 case 0x203: 1855 case 0x10202: 1856 dev_dbg(port->dev, "This version is uart\n"); 1857 break; 1858 default: 1859 dev_err(port->dev, "Not supported ip name nor version, set to uart\n"); 1860 } 1861 } 1862 } 1863 1864 /* 1865 * Perform initialization and enable port for reception 1866 */ 1867 static int atmel_startup(struct uart_port *port) 1868 { 1869 struct platform_device *pdev = to_platform_device(port->dev); 1870 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1871 int retval; 1872 1873 /* 1874 * Ensure that no interrupts are enabled otherwise when 1875 * request_irq() is called we could get stuck trying to 1876 * handle an unexpected interrupt 1877 */ 1878 atmel_uart_writel(port, ATMEL_US_IDR, -1); 1879 atmel_port->ms_irq_enabled = false; 1880 1881 /* 1882 * Allocate the IRQ 1883 */ 1884 retval = request_irq(port->irq, atmel_interrupt, 1885 IRQF_SHARED | IRQF_COND_SUSPEND, 1886 dev_name(&pdev->dev), port); 1887 if (retval) { 1888 dev_err(port->dev, "atmel_startup - Can't get irq\n"); 1889 return retval; 1890 } 1891 1892 atomic_set(&atmel_port->tasklet_shutdown, 0); 1893 tasklet_setup(&atmel_port->tasklet_rx, atmel_tasklet_rx_func); 1894 tasklet_setup(&atmel_port->tasklet_tx, atmel_tasklet_tx_func); 1895 1896 /* 1897 * Initialize DMA (if necessary) 1898 */ 1899 atmel_init_property(atmel_port, pdev); 1900 atmel_set_ops(port); 1901 1902 if (atmel_port->prepare_rx) { 1903 retval = atmel_port->prepare_rx(port); 1904 if (retval < 0) 1905 atmel_set_ops(port); 1906 } 1907 1908 if (atmel_port->prepare_tx) { 1909 retval = atmel_port->prepare_tx(port); 1910 if (retval < 0) 1911 atmel_set_ops(port); 1912 } 1913 1914 /* 1915 * Enable FIFO when available 1916 */ 1917 if (atmel_port->fifo_size) { 1918 unsigned int txrdym = ATMEL_US_ONE_DATA; 1919 unsigned int rxrdym = ATMEL_US_ONE_DATA; 1920 unsigned int fmr; 1921 1922 atmel_uart_writel(port, ATMEL_US_CR, 1923 ATMEL_US_FIFOEN | 1924 ATMEL_US_RXFCLR | 1925 ATMEL_US_TXFLCLR); 1926 1927 if (atmel_use_dma_tx(port)) 1928 txrdym = ATMEL_US_FOUR_DATA; 1929 1930 fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym); 1931 if (atmel_port->rts_high && 1932 atmel_port->rts_low) 1933 fmr |= ATMEL_US_FRTSC | 1934 ATMEL_US_RXFTHRES(atmel_port->rts_high) | 1935 ATMEL_US_RXFTHRES2(atmel_port->rts_low); 1936 1937 atmel_uart_writel(port, ATMEL_US_FMR, fmr); 1938 } 1939 1940 /* Save current CSR for comparison in atmel_tasklet_func() */ 1941 atmel_port->irq_status_prev = atmel_uart_readl(port, ATMEL_US_CSR); 1942 1943 /* 1944 * Finally, enable the serial port 1945 */ 1946 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); 1947 /* enable xmit & rcvr */ 1948 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); 1949 atmel_port->tx_stopped = false; 1950 1951 timer_setup(&atmel_port->uart_timer, atmel_uart_timer_callback, 0); 1952 1953 if (atmel_use_pdc_rx(port)) { 1954 /* set UART timeout */ 1955 if (!atmel_port->has_hw_timer) { 1956 mod_timer(&atmel_port->uart_timer, 1957 jiffies + uart_poll_timeout(port)); 1958 /* set USART timeout */ 1959 } else { 1960 atmel_uart_writel(port, atmel_port->rtor, 1961 PDC_RX_TIMEOUT); 1962 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO); 1963 1964 atmel_uart_writel(port, ATMEL_US_IER, 1965 ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); 1966 } 1967 /* enable PDC controller */ 1968 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN); 1969 } else if (atmel_use_dma_rx(port)) { 1970 /* set UART timeout */ 1971 if (!atmel_port->has_hw_timer) { 1972 mod_timer(&atmel_port->uart_timer, 1973 jiffies + uart_poll_timeout(port)); 1974 /* set USART timeout */ 1975 } else { 1976 atmel_uart_writel(port, atmel_port->rtor, 1977 PDC_RX_TIMEOUT); 1978 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO); 1979 1980 atmel_uart_writel(port, ATMEL_US_IER, 1981 ATMEL_US_TIMEOUT); 1982 } 1983 } else { 1984 /* enable receive only */ 1985 atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY); 1986 } 1987 1988 return 0; 1989 } 1990 1991 /* 1992 * Flush any TX data submitted for DMA. Called when the TX circular 1993 * buffer is reset. 1994 */ 1995 static void atmel_flush_buffer(struct uart_port *port) 1996 { 1997 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 1998 1999 if (atmel_use_pdc_tx(port)) { 2000 atmel_uart_writel(port, ATMEL_PDC_TCR, 0); 2001 atmel_port->pdc_tx.ofs = 0; 2002 } 2003 /* 2004 * in uart_flush_buffer(), the xmit circular buffer has just 2005 * been cleared, so we have to reset tx_len accordingly. 2006 */ 2007 atmel_port->tx_len = 0; 2008 } 2009 2010 /* 2011 * Disable the port 2012 */ 2013 static void atmel_shutdown(struct uart_port *port) 2014 { 2015 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2016 2017 /* Disable modem control lines interrupts */ 2018 atmel_disable_ms(port); 2019 2020 /* Disable interrupts at device level */ 2021 atmel_uart_writel(port, ATMEL_US_IDR, -1); 2022 2023 /* Prevent spurious interrupts from scheduling the tasklet */ 2024 atomic_inc(&atmel_port->tasklet_shutdown); 2025 2026 /* 2027 * Prevent any tasklets being scheduled during 2028 * cleanup 2029 */ 2030 del_timer_sync(&atmel_port->uart_timer); 2031 2032 /* Make sure that no interrupt is on the fly */ 2033 synchronize_irq(port->irq); 2034 2035 /* 2036 * Clear out any scheduled tasklets before 2037 * we destroy the buffers 2038 */ 2039 tasklet_kill(&atmel_port->tasklet_rx); 2040 tasklet_kill(&atmel_port->tasklet_tx); 2041 2042 /* 2043 * Ensure everything is stopped and 2044 * disable port and break condition. 2045 */ 2046 atmel_stop_rx(port); 2047 atmel_stop_tx(port); 2048 2049 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA); 2050 2051 /* 2052 * Shut-down the DMA. 2053 */ 2054 if (atmel_port->release_rx) 2055 atmel_port->release_rx(port); 2056 if (atmel_port->release_tx) 2057 atmel_port->release_tx(port); 2058 2059 /* 2060 * Reset ring buffer pointers 2061 */ 2062 atmel_port->rx_ring.head = 0; 2063 atmel_port->rx_ring.tail = 0; 2064 2065 /* 2066 * Free the interrupts 2067 */ 2068 free_irq(port->irq, port); 2069 2070 atmel_flush_buffer(port); 2071 } 2072 2073 /* 2074 * Power / Clock management. 2075 */ 2076 static void atmel_serial_pm(struct uart_port *port, unsigned int state, 2077 unsigned int oldstate) 2078 { 2079 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2080 2081 switch (state) { 2082 case UART_PM_STATE_ON: 2083 /* 2084 * Enable the peripheral clock for this serial port. 2085 * This is called on uart_open() or a resume event. 2086 */ 2087 clk_prepare_enable(atmel_port->clk); 2088 2089 /* re-enable interrupts if we disabled some on suspend */ 2090 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->backup_imr); 2091 break; 2092 case UART_PM_STATE_OFF: 2093 /* Back up the interrupt mask and disable all interrupts */ 2094 atmel_port->backup_imr = atmel_uart_readl(port, ATMEL_US_IMR); 2095 atmel_uart_writel(port, ATMEL_US_IDR, -1); 2096 2097 /* 2098 * Disable the peripheral clock for this serial port. 2099 * This is called on uart_close() or a suspend event. 2100 */ 2101 clk_disable_unprepare(atmel_port->clk); 2102 if (__clk_is_enabled(atmel_port->gclk)) 2103 clk_disable_unprepare(atmel_port->gclk); 2104 break; 2105 default: 2106 dev_err(port->dev, "atmel_serial: unknown pm %d\n", state); 2107 } 2108 } 2109 2110 /* 2111 * Change the port parameters 2112 */ 2113 static void atmel_set_termios(struct uart_port *port, 2114 struct ktermios *termios, 2115 const struct ktermios *old) 2116 { 2117 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2118 unsigned long flags; 2119 unsigned int old_mode, mode, imr, quot, div, cd, fp = 0; 2120 unsigned int baud, actual_baud, gclk_rate; 2121 int ret; 2122 2123 /* save the current mode register */ 2124 mode = old_mode = atmel_uart_readl(port, ATMEL_US_MR); 2125 2126 /* reset the mode, clock divisor, parity, stop bits and data size */ 2127 if (atmel_port->is_usart) 2128 mode &= ~(ATMEL_US_NBSTOP | ATMEL_US_PAR | ATMEL_US_CHRL | 2129 ATMEL_US_USCLKS | ATMEL_US_USMODE); 2130 else 2131 mode &= ~(ATMEL_UA_BRSRCCK | ATMEL_US_PAR | ATMEL_UA_FILTER); 2132 2133 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); 2134 2135 /* byte size */ 2136 switch (termios->c_cflag & CSIZE) { 2137 case CS5: 2138 mode |= ATMEL_US_CHRL_5; 2139 break; 2140 case CS6: 2141 mode |= ATMEL_US_CHRL_6; 2142 break; 2143 case CS7: 2144 mode |= ATMEL_US_CHRL_7; 2145 break; 2146 default: 2147 mode |= ATMEL_US_CHRL_8; 2148 break; 2149 } 2150 2151 /* stop bits */ 2152 if (termios->c_cflag & CSTOPB) 2153 mode |= ATMEL_US_NBSTOP_2; 2154 2155 /* parity */ 2156 if (termios->c_cflag & PARENB) { 2157 /* Mark or Space parity */ 2158 if (termios->c_cflag & CMSPAR) { 2159 if (termios->c_cflag & PARODD) 2160 mode |= ATMEL_US_PAR_MARK; 2161 else 2162 mode |= ATMEL_US_PAR_SPACE; 2163 } else if (termios->c_cflag & PARODD) 2164 mode |= ATMEL_US_PAR_ODD; 2165 else 2166 mode |= ATMEL_US_PAR_EVEN; 2167 } else 2168 mode |= ATMEL_US_PAR_NONE; 2169 2170 uart_port_lock_irqsave(port, &flags); 2171 2172 port->read_status_mask = ATMEL_US_OVRE; 2173 if (termios->c_iflag & INPCK) 2174 port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE); 2175 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) 2176 port->read_status_mask |= ATMEL_US_RXBRK; 2177 2178 if (atmel_use_pdc_rx(port)) 2179 /* need to enable error interrupts */ 2180 atmel_uart_writel(port, ATMEL_US_IER, port->read_status_mask); 2181 2182 /* 2183 * Characters to ignore 2184 */ 2185 port->ignore_status_mask = 0; 2186 if (termios->c_iflag & IGNPAR) 2187 port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE); 2188 if (termios->c_iflag & IGNBRK) { 2189 port->ignore_status_mask |= ATMEL_US_RXBRK; 2190 /* 2191 * If we're ignoring parity and break indicators, 2192 * ignore overruns too (for real raw support). 2193 */ 2194 if (termios->c_iflag & IGNPAR) 2195 port->ignore_status_mask |= ATMEL_US_OVRE; 2196 } 2197 /* TODO: Ignore all characters if CREAD is set.*/ 2198 2199 /* update the per-port timeout */ 2200 uart_update_timeout(port, termios->c_cflag, baud); 2201 2202 /* 2203 * save/disable interrupts. The tty layer will ensure that the 2204 * transmitter is empty if requested by the caller, so there's 2205 * no need to wait for it here. 2206 */ 2207 imr = atmel_uart_readl(port, ATMEL_US_IMR); 2208 atmel_uart_writel(port, ATMEL_US_IDR, -1); 2209 2210 /* disable receiver and transmitter */ 2211 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXDIS); 2212 atmel_port->tx_stopped = true; 2213 2214 /* mode */ 2215 if (port->rs485.flags & SER_RS485_ENABLED) { 2216 atmel_uart_writel(port, ATMEL_US_TTGR, 2217 port->rs485.delay_rts_after_send); 2218 mode |= ATMEL_US_USMODE_RS485; 2219 } else if (port->iso7816.flags & SER_ISO7816_ENABLED) { 2220 atmel_uart_writel(port, ATMEL_US_TTGR, port->iso7816.tg); 2221 /* select mck clock, and output */ 2222 mode |= ATMEL_US_USCLKS_MCK | ATMEL_US_CLKO; 2223 /* set max iterations */ 2224 mode |= ATMEL_US_MAX_ITER(3); 2225 if ((port->iso7816.flags & SER_ISO7816_T_PARAM) 2226 == SER_ISO7816_T(0)) 2227 mode |= ATMEL_US_USMODE_ISO7816_T0; 2228 else 2229 mode |= ATMEL_US_USMODE_ISO7816_T1; 2230 } else if (termios->c_cflag & CRTSCTS) { 2231 /* RS232 with hardware handshake (RTS/CTS) */ 2232 if (atmel_use_fifo(port) && 2233 !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) { 2234 /* 2235 * with ATMEL_US_USMODE_HWHS set, the controller will 2236 * be able to drive the RTS pin high/low when the RX 2237 * FIFO is above RXFTHRES/below RXFTHRES2. 2238 * It will also disable the transmitter when the CTS 2239 * pin is high. 2240 * This mode is not activated if CTS pin is a GPIO 2241 * because in this case, the transmitter is always 2242 * disabled (there must be an internal pull-up 2243 * responsible for this behaviour). 2244 * If the RTS pin is a GPIO, the controller won't be 2245 * able to drive it according to the FIFO thresholds, 2246 * but it will be handled by the driver. 2247 */ 2248 mode |= ATMEL_US_USMODE_HWHS; 2249 } else { 2250 /* 2251 * For platforms without FIFO, the flow control is 2252 * handled by the driver. 2253 */ 2254 mode |= ATMEL_US_USMODE_NORMAL; 2255 } 2256 } else { 2257 /* RS232 without hadware handshake */ 2258 mode |= ATMEL_US_USMODE_NORMAL; 2259 } 2260 2261 /* 2262 * Set the baud rate: 2263 * Fractional baudrate allows to setup output frequency more 2264 * accurately. This feature is enabled only when using normal mode. 2265 * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8)) 2266 * Currently, OVER is always set to 0 so we get 2267 * baudrate = selected clock / (16 * (CD + FP / 8)) 2268 * then 2269 * 8 CD + FP = selected clock / (2 * baudrate) 2270 */ 2271 if (atmel_port->has_frac_baudrate) { 2272 div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2); 2273 cd = div >> 3; 2274 fp = div & ATMEL_US_FP_MASK; 2275 } else { 2276 cd = uart_get_divisor(port, baud); 2277 } 2278 2279 /* 2280 * If the current value of the Clock Divisor surpasses the 16 bit 2281 * ATMEL_US_CD mask and the IP is USART, switch to the Peripheral 2282 * Clock implicitly divided by 8. 2283 * If the IP is UART however, keep the highest possible value for 2284 * the CD and avoid needless division of CD, since UART IP's do not 2285 * support implicit division of the Peripheral Clock. 2286 */ 2287 if (atmel_port->is_usart && cd > ATMEL_US_CD) { 2288 cd /= 8; 2289 mode |= ATMEL_US_USCLKS_MCK_DIV8; 2290 } else { 2291 cd = min_t(unsigned int, cd, ATMEL_US_CD); 2292 } 2293 2294 /* 2295 * If there is no Fractional Part, there is a high chance that 2296 * we may be able to generate a baudrate closer to the desired one 2297 * if we use the GCLK as the clock source driving the baudrate 2298 * generator. 2299 */ 2300 if (!atmel_port->has_frac_baudrate) { 2301 if (__clk_is_enabled(atmel_port->gclk)) 2302 clk_disable_unprepare(atmel_port->gclk); 2303 gclk_rate = clk_round_rate(atmel_port->gclk, 16 * baud); 2304 actual_baud = clk_get_rate(atmel_port->clk) / (16 * cd); 2305 if (gclk_rate && abs(atmel_error_rate(baud, actual_baud)) > 2306 abs(atmel_error_rate(baud, gclk_rate / 16))) { 2307 clk_set_rate(atmel_port->gclk, 16 * baud); 2308 ret = clk_prepare_enable(atmel_port->gclk); 2309 if (ret) 2310 goto gclk_fail; 2311 2312 if (atmel_port->is_usart) { 2313 mode &= ~ATMEL_US_USCLKS; 2314 mode |= ATMEL_US_USCLKS_GCLK; 2315 } else { 2316 mode |= ATMEL_UA_BRSRCCK; 2317 } 2318 2319 /* 2320 * Set the Clock Divisor for GCLK to 1. 2321 * Since we were able to generate the smallest 2322 * multiple of the desired baudrate times 16, 2323 * then we surely can generate a bigger multiple 2324 * with the exact error rate for an equally increased 2325 * CD. Thus no need to take into account 2326 * a higher value for CD. 2327 */ 2328 cd = 1; 2329 } 2330 } 2331 2332 gclk_fail: 2333 quot = cd | fp << ATMEL_US_FP_OFFSET; 2334 2335 if (!(port->iso7816.flags & SER_ISO7816_ENABLED)) 2336 atmel_uart_writel(port, ATMEL_US_BRGR, quot); 2337 2338 /* set the mode, clock divisor, parity, stop bits and data size */ 2339 atmel_uart_writel(port, ATMEL_US_MR, mode); 2340 2341 /* 2342 * when switching the mode, set the RTS line state according to the 2343 * new mode, otherwise keep the former state 2344 */ 2345 if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) { 2346 unsigned int rts_state; 2347 2348 if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) { 2349 /* let the hardware control the RTS line */ 2350 rts_state = ATMEL_US_RTSDIS; 2351 } else { 2352 /* force RTS line to low level */ 2353 rts_state = ATMEL_US_RTSEN; 2354 } 2355 2356 atmel_uart_writel(port, ATMEL_US_CR, rts_state); 2357 } 2358 2359 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); 2360 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); 2361 atmel_port->tx_stopped = false; 2362 2363 /* restore interrupts */ 2364 atmel_uart_writel(port, ATMEL_US_IER, imr); 2365 2366 /* CTS flow-control and modem-status interrupts */ 2367 if (UART_ENABLE_MS(port, termios->c_cflag)) 2368 atmel_enable_ms(port); 2369 else 2370 atmel_disable_ms(port); 2371 2372 uart_port_unlock_irqrestore(port, flags); 2373 } 2374 2375 static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios) 2376 { 2377 if (termios->c_line == N_PPS) { 2378 port->flags |= UPF_HARDPPS_CD; 2379 uart_port_lock_irq(port); 2380 atmel_enable_ms(port); 2381 uart_port_unlock_irq(port); 2382 } else { 2383 port->flags &= ~UPF_HARDPPS_CD; 2384 if (!UART_ENABLE_MS(port, termios->c_cflag)) { 2385 uart_port_lock_irq(port); 2386 atmel_disable_ms(port); 2387 uart_port_unlock_irq(port); 2388 } 2389 } 2390 } 2391 2392 /* 2393 * Return string describing the specified port 2394 */ 2395 static const char *atmel_type(struct uart_port *port) 2396 { 2397 return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL; 2398 } 2399 2400 /* 2401 * Release the memory region(s) being used by 'port'. 2402 */ 2403 static void atmel_release_port(struct uart_port *port) 2404 { 2405 struct platform_device *mpdev = to_platform_device(port->dev->parent); 2406 int size = resource_size(mpdev->resource); 2407 2408 release_mem_region(port->mapbase, size); 2409 2410 if (port->flags & UPF_IOREMAP) { 2411 iounmap(port->membase); 2412 port->membase = NULL; 2413 } 2414 } 2415 2416 /* 2417 * Request the memory region(s) being used by 'port'. 2418 */ 2419 static int atmel_request_port(struct uart_port *port) 2420 { 2421 struct platform_device *mpdev = to_platform_device(port->dev->parent); 2422 int size = resource_size(mpdev->resource); 2423 2424 if (!request_mem_region(port->mapbase, size, "atmel_serial")) 2425 return -EBUSY; 2426 2427 if (port->flags & UPF_IOREMAP) { 2428 port->membase = ioremap(port->mapbase, size); 2429 if (port->membase == NULL) { 2430 release_mem_region(port->mapbase, size); 2431 return -ENOMEM; 2432 } 2433 } 2434 2435 return 0; 2436 } 2437 2438 /* 2439 * Configure/autoconfigure the port. 2440 */ 2441 static void atmel_config_port(struct uart_port *port, int flags) 2442 { 2443 if (flags & UART_CONFIG_TYPE) { 2444 port->type = PORT_ATMEL; 2445 atmel_request_port(port); 2446 } 2447 } 2448 2449 /* 2450 * Verify the new serial_struct (for TIOCSSERIAL). 2451 */ 2452 static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser) 2453 { 2454 int ret = 0; 2455 if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL) 2456 ret = -EINVAL; 2457 if (port->irq != ser->irq) 2458 ret = -EINVAL; 2459 if (ser->io_type != SERIAL_IO_MEM) 2460 ret = -EINVAL; 2461 if (port->uartclk / 16 != ser->baud_base) 2462 ret = -EINVAL; 2463 if (port->mapbase != (unsigned long)ser->iomem_base) 2464 ret = -EINVAL; 2465 if (port->iobase != ser->port) 2466 ret = -EINVAL; 2467 if (ser->hub6 != 0) 2468 ret = -EINVAL; 2469 return ret; 2470 } 2471 2472 #ifdef CONFIG_CONSOLE_POLL 2473 static int atmel_poll_get_char(struct uart_port *port) 2474 { 2475 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_RXRDY)) 2476 cpu_relax(); 2477 2478 return atmel_uart_read_char(port); 2479 } 2480 2481 static void atmel_poll_put_char(struct uart_port *port, unsigned char ch) 2482 { 2483 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY)) 2484 cpu_relax(); 2485 2486 atmel_uart_write_char(port, ch); 2487 } 2488 #endif 2489 2490 static const struct uart_ops atmel_pops = { 2491 .tx_empty = atmel_tx_empty, 2492 .set_mctrl = atmel_set_mctrl, 2493 .get_mctrl = atmel_get_mctrl, 2494 .stop_tx = atmel_stop_tx, 2495 .start_tx = atmel_start_tx, 2496 .stop_rx = atmel_stop_rx, 2497 .enable_ms = atmel_enable_ms, 2498 .break_ctl = atmel_break_ctl, 2499 .startup = atmel_startup, 2500 .shutdown = atmel_shutdown, 2501 .flush_buffer = atmel_flush_buffer, 2502 .set_termios = atmel_set_termios, 2503 .set_ldisc = atmel_set_ldisc, 2504 .type = atmel_type, 2505 .release_port = atmel_release_port, 2506 .request_port = atmel_request_port, 2507 .config_port = atmel_config_port, 2508 .verify_port = atmel_verify_port, 2509 .pm = atmel_serial_pm, 2510 #ifdef CONFIG_CONSOLE_POLL 2511 .poll_get_char = atmel_poll_get_char, 2512 .poll_put_char = atmel_poll_put_char, 2513 #endif 2514 }; 2515 2516 static const struct serial_rs485 atmel_rs485_supported = { 2517 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX, 2518 .delay_rts_before_send = 1, 2519 .delay_rts_after_send = 1, 2520 }; 2521 2522 /* 2523 * Configure the port from the platform device resource info. 2524 */ 2525 static int atmel_init_port(struct atmel_uart_port *atmel_port, 2526 struct platform_device *pdev) 2527 { 2528 int ret; 2529 struct uart_port *port = &atmel_port->uart; 2530 struct platform_device *mpdev = to_platform_device(pdev->dev.parent); 2531 2532 atmel_init_property(atmel_port, pdev); 2533 atmel_set_ops(port); 2534 2535 port->iotype = UPIO_MEM; 2536 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP; 2537 port->ops = &atmel_pops; 2538 port->fifosize = 1; 2539 port->dev = &pdev->dev; 2540 port->mapbase = mpdev->resource[0].start; 2541 port->irq = platform_get_irq(mpdev, 0); 2542 port->rs485_config = atmel_config_rs485; 2543 port->rs485_supported = atmel_rs485_supported; 2544 port->iso7816_config = atmel_config_iso7816; 2545 port->membase = NULL; 2546 2547 memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring)); 2548 2549 ret = uart_get_rs485_mode(port); 2550 if (ret) 2551 return ret; 2552 2553 port->uartclk = clk_get_rate(atmel_port->clk); 2554 2555 /* 2556 * Use TXEMPTY for interrupt when rs485 or ISO7816 else TXRDY or 2557 * ENDTX|TXBUFE 2558 */ 2559 if (atmel_uart_is_half_duplex(port)) 2560 atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; 2561 else if (atmel_use_pdc_tx(port)) { 2562 port->fifosize = PDC_BUFFER_SIZE; 2563 atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; 2564 } else { 2565 atmel_port->tx_done_mask = ATMEL_US_TXRDY; 2566 } 2567 2568 return 0; 2569 } 2570 2571 #ifdef CONFIG_SERIAL_ATMEL_CONSOLE 2572 static void atmel_console_putchar(struct uart_port *port, unsigned char ch) 2573 { 2574 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY)) 2575 cpu_relax(); 2576 atmel_uart_write_char(port, ch); 2577 } 2578 2579 /* 2580 * Interrupts are disabled on entering 2581 */ 2582 static void atmel_console_write(struct console *co, const char *s, u_int count) 2583 { 2584 struct uart_port *port = &atmel_ports[co->index].uart; 2585 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2586 unsigned int status, imr; 2587 unsigned int pdc_tx; 2588 2589 /* 2590 * First, save IMR and then disable interrupts 2591 */ 2592 imr = atmel_uart_readl(port, ATMEL_US_IMR); 2593 atmel_uart_writel(port, ATMEL_US_IDR, 2594 ATMEL_US_RXRDY | atmel_port->tx_done_mask); 2595 2596 /* Store PDC transmit status and disable it */ 2597 pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN; 2598 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS); 2599 2600 /* Make sure that tx path is actually able to send characters */ 2601 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN); 2602 atmel_port->tx_stopped = false; 2603 2604 uart_console_write(port, s, count, atmel_console_putchar); 2605 2606 /* 2607 * Finally, wait for transmitter to become empty 2608 * and restore IMR 2609 */ 2610 do { 2611 status = atmel_uart_readl(port, ATMEL_US_CSR); 2612 } while (!(status & ATMEL_US_TXRDY)); 2613 2614 /* Restore PDC transmit status */ 2615 if (pdc_tx) 2616 atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN); 2617 2618 /* set interrupts back the way they were */ 2619 atmel_uart_writel(port, ATMEL_US_IER, imr); 2620 } 2621 2622 /* 2623 * If the port was already initialised (eg, by a boot loader), 2624 * try to determine the current setup. 2625 */ 2626 static void __init atmel_console_get_options(struct uart_port *port, int *baud, 2627 int *parity, int *bits) 2628 { 2629 unsigned int mr, quot; 2630 2631 /* 2632 * If the baud rate generator isn't running, the port wasn't 2633 * initialized by the boot loader. 2634 */ 2635 quot = atmel_uart_readl(port, ATMEL_US_BRGR) & ATMEL_US_CD; 2636 if (!quot) 2637 return; 2638 2639 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_CHRL; 2640 if (mr == ATMEL_US_CHRL_8) 2641 *bits = 8; 2642 else 2643 *bits = 7; 2644 2645 mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_PAR; 2646 if (mr == ATMEL_US_PAR_EVEN) 2647 *parity = 'e'; 2648 else if (mr == ATMEL_US_PAR_ODD) 2649 *parity = 'o'; 2650 2651 *baud = port->uartclk / (16 * quot); 2652 } 2653 2654 static int __init atmel_console_setup(struct console *co, char *options) 2655 { 2656 struct uart_port *port = &atmel_ports[co->index].uart; 2657 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2658 int baud = 115200; 2659 int bits = 8; 2660 int parity = 'n'; 2661 int flow = 'n'; 2662 2663 if (port->membase == NULL) { 2664 /* Port not initialized yet - delay setup */ 2665 return -ENODEV; 2666 } 2667 2668 atmel_uart_writel(port, ATMEL_US_IDR, -1); 2669 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); 2670 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); 2671 atmel_port->tx_stopped = false; 2672 2673 if (options) 2674 uart_parse_options(options, &baud, &parity, &bits, &flow); 2675 else 2676 atmel_console_get_options(port, &baud, &parity, &bits); 2677 2678 return uart_set_options(port, co, baud, parity, bits, flow); 2679 } 2680 2681 static struct uart_driver atmel_uart; 2682 2683 static struct console atmel_console = { 2684 .name = ATMEL_DEVICENAME, 2685 .write = atmel_console_write, 2686 .device = uart_console_device, 2687 .setup = atmel_console_setup, 2688 .flags = CON_PRINTBUFFER, 2689 .index = -1, 2690 .data = &atmel_uart, 2691 }; 2692 2693 static void atmel_serial_early_write(struct console *con, const char *s, 2694 unsigned int n) 2695 { 2696 struct earlycon_device *dev = con->data; 2697 2698 uart_console_write(&dev->port, s, n, atmel_console_putchar); 2699 } 2700 2701 static int __init atmel_early_console_setup(struct earlycon_device *device, 2702 const char *options) 2703 { 2704 if (!device->port.membase) 2705 return -ENODEV; 2706 2707 device->con->write = atmel_serial_early_write; 2708 2709 return 0; 2710 } 2711 2712 OF_EARLYCON_DECLARE(atmel_serial, "atmel,at91rm9200-usart", 2713 atmel_early_console_setup); 2714 OF_EARLYCON_DECLARE(atmel_serial, "atmel,at91sam9260-usart", 2715 atmel_early_console_setup); 2716 2717 #define ATMEL_CONSOLE_DEVICE (&atmel_console) 2718 2719 #else 2720 #define ATMEL_CONSOLE_DEVICE NULL 2721 #endif 2722 2723 static struct uart_driver atmel_uart = { 2724 .owner = THIS_MODULE, 2725 .driver_name = "atmel_serial", 2726 .dev_name = ATMEL_DEVICENAME, 2727 .major = SERIAL_ATMEL_MAJOR, 2728 .minor = MINOR_START, 2729 .nr = ATMEL_MAX_UART, 2730 .cons = ATMEL_CONSOLE_DEVICE, 2731 }; 2732 2733 static bool atmel_serial_clk_will_stop(void) 2734 { 2735 #ifdef CONFIG_ARCH_AT91 2736 return at91_suspend_entering_slow_clock(); 2737 #else 2738 return false; 2739 #endif 2740 } 2741 2742 static int __maybe_unused atmel_serial_suspend(struct device *dev) 2743 { 2744 struct uart_port *port = dev_get_drvdata(dev); 2745 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2746 2747 if (uart_console(port) && console_suspend_enabled) { 2748 /* Drain the TX shifter */ 2749 while (!(atmel_uart_readl(port, ATMEL_US_CSR) & 2750 ATMEL_US_TXEMPTY)) 2751 cpu_relax(); 2752 } 2753 2754 if (uart_console(port) && !console_suspend_enabled) { 2755 /* Cache register values as we won't get a full shutdown/startup 2756 * cycle 2757 */ 2758 atmel_port->cache.mr = atmel_uart_readl(port, ATMEL_US_MR); 2759 atmel_port->cache.imr = atmel_uart_readl(port, ATMEL_US_IMR); 2760 atmel_port->cache.brgr = atmel_uart_readl(port, ATMEL_US_BRGR); 2761 atmel_port->cache.rtor = atmel_uart_readl(port, 2762 atmel_port->rtor); 2763 atmel_port->cache.ttgr = atmel_uart_readl(port, ATMEL_US_TTGR); 2764 atmel_port->cache.fmr = atmel_uart_readl(port, ATMEL_US_FMR); 2765 atmel_port->cache.fimr = atmel_uart_readl(port, ATMEL_US_FIMR); 2766 } 2767 2768 /* we can not wake up if we're running on slow clock */ 2769 atmel_port->may_wakeup = device_may_wakeup(dev); 2770 if (atmel_serial_clk_will_stop()) { 2771 unsigned long flags; 2772 2773 spin_lock_irqsave(&atmel_port->lock_suspended, flags); 2774 atmel_port->suspended = true; 2775 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); 2776 device_set_wakeup_enable(dev, 0); 2777 } 2778 2779 uart_suspend_port(&atmel_uart, port); 2780 2781 return 0; 2782 } 2783 2784 static int __maybe_unused atmel_serial_resume(struct device *dev) 2785 { 2786 struct uart_port *port = dev_get_drvdata(dev); 2787 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2788 unsigned long flags; 2789 2790 if (uart_console(port) && !console_suspend_enabled) { 2791 atmel_uart_writel(port, ATMEL_US_MR, atmel_port->cache.mr); 2792 atmel_uart_writel(port, ATMEL_US_IER, atmel_port->cache.imr); 2793 atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->cache.brgr); 2794 atmel_uart_writel(port, atmel_port->rtor, 2795 atmel_port->cache.rtor); 2796 atmel_uart_writel(port, ATMEL_US_TTGR, atmel_port->cache.ttgr); 2797 2798 if (atmel_port->fifo_size) { 2799 atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_FIFOEN | 2800 ATMEL_US_RXFCLR | ATMEL_US_TXFLCLR); 2801 atmel_uart_writel(port, ATMEL_US_FMR, 2802 atmel_port->cache.fmr); 2803 atmel_uart_writel(port, ATMEL_US_FIER, 2804 atmel_port->cache.fimr); 2805 } 2806 atmel_start_rx(port); 2807 } 2808 2809 spin_lock_irqsave(&atmel_port->lock_suspended, flags); 2810 if (atmel_port->pending) { 2811 atmel_handle_receive(port, atmel_port->pending); 2812 atmel_handle_status(port, atmel_port->pending, 2813 atmel_port->pending_status); 2814 atmel_handle_transmit(port, atmel_port->pending); 2815 atmel_port->pending = 0; 2816 } 2817 atmel_port->suspended = false; 2818 spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); 2819 2820 uart_resume_port(&atmel_uart, port); 2821 device_set_wakeup_enable(dev, atmel_port->may_wakeup); 2822 2823 return 0; 2824 } 2825 2826 static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port, 2827 struct platform_device *pdev) 2828 { 2829 atmel_port->fifo_size = 0; 2830 atmel_port->rts_low = 0; 2831 atmel_port->rts_high = 0; 2832 2833 if (of_property_read_u32(pdev->dev.of_node, 2834 "atmel,fifo-size", 2835 &atmel_port->fifo_size)) 2836 return; 2837 2838 if (!atmel_port->fifo_size) 2839 return; 2840 2841 if (atmel_port->fifo_size < ATMEL_MIN_FIFO_SIZE) { 2842 atmel_port->fifo_size = 0; 2843 dev_err(&pdev->dev, "Invalid FIFO size\n"); 2844 return; 2845 } 2846 2847 /* 2848 * 0 <= rts_low <= rts_high <= fifo_size 2849 * Once their CTS line asserted by the remote peer, some x86 UARTs tend 2850 * to flush their internal TX FIFO, commonly up to 16 data, before 2851 * actually stopping to send new data. So we try to set the RTS High 2852 * Threshold to a reasonably high value respecting this 16 data 2853 * empirical rule when possible. 2854 */ 2855 atmel_port->rts_high = max_t(int, atmel_port->fifo_size >> 1, 2856 atmel_port->fifo_size - ATMEL_RTS_HIGH_OFFSET); 2857 atmel_port->rts_low = max_t(int, atmel_port->fifo_size >> 2, 2858 atmel_port->fifo_size - ATMEL_RTS_LOW_OFFSET); 2859 2860 dev_info(&pdev->dev, "Using FIFO (%u data)\n", 2861 atmel_port->fifo_size); 2862 dev_dbg(&pdev->dev, "RTS High Threshold : %2u data\n", 2863 atmel_port->rts_high); 2864 dev_dbg(&pdev->dev, "RTS Low Threshold : %2u data\n", 2865 atmel_port->rts_low); 2866 } 2867 2868 static int atmel_serial_probe(struct platform_device *pdev) 2869 { 2870 struct atmel_uart_port *atmel_port; 2871 struct device_node *np = pdev->dev.parent->of_node; 2872 void *data; 2873 int ret; 2874 bool rs485_enabled; 2875 2876 BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1)); 2877 2878 /* 2879 * In device tree there is no node with "atmel,at91rm9200-usart-serial" 2880 * as compatible string. This driver is probed by at91-usart mfd driver 2881 * which is just a wrapper over the atmel_serial driver and 2882 * spi-at91-usart driver. All attributes needed by this driver are 2883 * found in of_node of parent. 2884 */ 2885 pdev->dev.of_node = np; 2886 2887 ret = of_alias_get_id(np, "serial"); 2888 if (ret < 0) 2889 /* port id not found in platform data nor device-tree aliases: 2890 * auto-enumerate it */ 2891 ret = find_first_zero_bit(atmel_ports_in_use, ATMEL_MAX_UART); 2892 2893 if (ret >= ATMEL_MAX_UART) { 2894 ret = -ENODEV; 2895 goto err; 2896 } 2897 2898 if (test_and_set_bit(ret, atmel_ports_in_use)) { 2899 /* port already in use */ 2900 ret = -EBUSY; 2901 goto err; 2902 } 2903 2904 atmel_port = &atmel_ports[ret]; 2905 atmel_port->backup_imr = 0; 2906 atmel_port->uart.line = ret; 2907 atmel_port->uart.has_sysrq = IS_ENABLED(CONFIG_SERIAL_ATMEL_CONSOLE); 2908 atmel_serial_probe_fifos(atmel_port, pdev); 2909 2910 atomic_set(&atmel_port->tasklet_shutdown, 0); 2911 spin_lock_init(&atmel_port->lock_suspended); 2912 2913 atmel_port->clk = devm_clk_get(&pdev->dev, "usart"); 2914 if (IS_ERR(atmel_port->clk)) { 2915 ret = PTR_ERR(atmel_port->clk); 2916 goto err; 2917 } 2918 ret = clk_prepare_enable(atmel_port->clk); 2919 if (ret) 2920 goto err; 2921 2922 atmel_port->gclk = devm_clk_get_optional(&pdev->dev, "gclk"); 2923 if (IS_ERR(atmel_port->gclk)) { 2924 ret = PTR_ERR(atmel_port->gclk); 2925 goto err_clk_disable_unprepare; 2926 } 2927 2928 ret = atmel_init_port(atmel_port, pdev); 2929 if (ret) 2930 goto err_clk_disable_unprepare; 2931 2932 atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0); 2933 if (IS_ERR(atmel_port->gpios)) { 2934 ret = PTR_ERR(atmel_port->gpios); 2935 goto err_clk_disable_unprepare; 2936 } 2937 2938 if (!atmel_use_pdc_rx(&atmel_port->uart)) { 2939 ret = -ENOMEM; 2940 data = kmalloc(ATMEL_SERIAL_RX_SIZE, GFP_KERNEL); 2941 if (!data) 2942 goto err_clk_disable_unprepare; 2943 atmel_port->rx_ring.buf = data; 2944 } 2945 2946 rs485_enabled = atmel_port->uart.rs485.flags & SER_RS485_ENABLED; 2947 2948 ret = uart_add_one_port(&atmel_uart, &atmel_port->uart); 2949 if (ret) 2950 goto err_add_port; 2951 2952 device_init_wakeup(&pdev->dev, 1); 2953 platform_set_drvdata(pdev, atmel_port); 2954 2955 if (rs485_enabled) { 2956 atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR, 2957 ATMEL_US_USMODE_NORMAL); 2958 atmel_uart_writel(&atmel_port->uart, ATMEL_US_CR, 2959 ATMEL_US_RTSEN); 2960 } 2961 2962 /* 2963 * Get port name of usart or uart 2964 */ 2965 atmel_get_ip_name(&atmel_port->uart); 2966 2967 /* 2968 * The peripheral clock can now safely be disabled till the port 2969 * is used 2970 */ 2971 clk_disable_unprepare(atmel_port->clk); 2972 2973 return 0; 2974 2975 err_add_port: 2976 kfree(atmel_port->rx_ring.buf); 2977 atmel_port->rx_ring.buf = NULL; 2978 err_clk_disable_unprepare: 2979 clk_disable_unprepare(atmel_port->clk); 2980 clear_bit(atmel_port->uart.line, atmel_ports_in_use); 2981 err: 2982 return ret; 2983 } 2984 2985 /* 2986 * Even if the driver is not modular, it makes sense to be able to 2987 * unbind a device: there can be many bound devices, and there are 2988 * situations where dynamic binding and unbinding can be useful. 2989 * 2990 * For example, a connected device can require a specific firmware update 2991 * protocol that needs bitbanging on IO lines, but use the regular serial 2992 * port in the normal case. 2993 */ 2994 static void atmel_serial_remove(struct platform_device *pdev) 2995 { 2996 struct uart_port *port = platform_get_drvdata(pdev); 2997 struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); 2998 2999 tasklet_kill(&atmel_port->tasklet_rx); 3000 tasklet_kill(&atmel_port->tasklet_tx); 3001 3002 device_init_wakeup(&pdev->dev, 0); 3003 3004 uart_remove_one_port(&atmel_uart, port); 3005 3006 kfree(atmel_port->rx_ring.buf); 3007 3008 /* "port" is allocated statically, so we shouldn't free it */ 3009 3010 clear_bit(port->line, atmel_ports_in_use); 3011 3012 pdev->dev.of_node = NULL; 3013 } 3014 3015 static SIMPLE_DEV_PM_OPS(atmel_serial_pm_ops, atmel_serial_suspend, 3016 atmel_serial_resume); 3017 3018 static struct platform_driver atmel_serial_driver = { 3019 .probe = atmel_serial_probe, 3020 .remove_new = atmel_serial_remove, 3021 .driver = { 3022 .name = "atmel_usart_serial", 3023 .of_match_table = of_match_ptr(atmel_serial_dt_ids), 3024 .pm = pm_ptr(&atmel_serial_pm_ops), 3025 }, 3026 }; 3027 3028 static int __init atmel_serial_init(void) 3029 { 3030 int ret; 3031 3032 ret = uart_register_driver(&atmel_uart); 3033 if (ret) 3034 return ret; 3035 3036 ret = platform_driver_register(&atmel_serial_driver); 3037 if (ret) 3038 uart_unregister_driver(&atmel_uart); 3039 3040 return ret; 3041 } 3042 device_initcall(atmel_serial_init); 3043