1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * serial_tegra.c 4 * 5 * High-speed serial driver for NVIDIA Tegra SoCs 6 * 7 * Copyright (c) 2012-2019, NVIDIA CORPORATION. All rights reserved. 8 * 9 * Author: Laxman Dewangan <ldewangan@nvidia.com> 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/debugfs.h> 14 #include <linux/delay.h> 15 #include <linux/dmaengine.h> 16 #include <linux/dma-mapping.h> 17 #include <linux/dmapool.h> 18 #include <linux/err.h> 19 #include <linux/io.h> 20 #include <linux/irq.h> 21 #include <linux/module.h> 22 #include <linux/of.h> 23 #include <linux/of_device.h> 24 #include <linux/pagemap.h> 25 #include <linux/platform_device.h> 26 #include <linux/reset.h> 27 #include <linux/serial.h> 28 #include <linux/serial_8250.h> 29 #include <linux/serial_core.h> 30 #include <linux/serial_reg.h> 31 #include <linux/slab.h> 32 #include <linux/string.h> 33 #include <linux/termios.h> 34 #include <linux/tty.h> 35 #include <linux/tty_flip.h> 36 37 #define TEGRA_UART_TYPE "TEGRA_UART" 38 #define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE) 39 #define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3) 40 41 #define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096 42 #define TEGRA_UART_LSR_TXFIFO_FULL 0x100 43 #define TEGRA_UART_IER_EORD 0x20 44 #define TEGRA_UART_MCR_RTS_EN 0x40 45 #define TEGRA_UART_MCR_CTS_EN 0x20 46 #define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \ 47 UART_LSR_PE | UART_LSR_FE) 48 #define TEGRA_UART_IRDA_CSR 0x08 49 #define TEGRA_UART_SIR_ENABLED 0x80 50 51 #define TEGRA_UART_TX_PIO 1 52 #define TEGRA_UART_TX_DMA 2 53 #define TEGRA_UART_MIN_DMA 16 54 #define TEGRA_UART_FIFO_SIZE 32 55 56 /* 57 * Tx fifo trigger level setting in tegra uart is in 58 * reverse way then conventional uart. 59 */ 60 #define TEGRA_UART_TX_TRIG_16B 0x00 61 #define TEGRA_UART_TX_TRIG_8B 0x10 62 #define TEGRA_UART_TX_TRIG_4B 0x20 63 #define TEGRA_UART_TX_TRIG_1B 0x30 64 65 #define TEGRA_UART_MAXIMUM 8 66 67 /* Default UART setting when started: 115200 no parity, stop, 8 data bits */ 68 #define TEGRA_UART_DEFAULT_BAUD 115200 69 #define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8 70 71 /* Tx transfer mode */ 72 #define TEGRA_TX_PIO 1 73 #define TEGRA_TX_DMA 2 74 75 #define TEGRA_UART_FCR_IIR_FIFO_EN 0x40 76 77 /** 78 * struct tegra_uart_chip_data: SOC specific data. 79 * 80 * @tx_fifo_full_status: Status flag available for checking tx fifo full. 81 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not. 82 * Tegra30 does not allow this. 83 * @support_clk_src_div: Clock source support the clock divider. 84 * @fifo_mode_enable_status: Is FIFO mode enabled? 85 * @uart_max_port: Maximum number of UART ports 86 * @max_dma_burst_bytes: Maximum size of DMA bursts 87 * @error_tolerance_low_range: Lowest number in the error tolerance range 88 * @error_tolerance_high_range: Highest number in the error tolerance range 89 */ 90 struct tegra_uart_chip_data { 91 bool tx_fifo_full_status; 92 bool allow_txfifo_reset_fifo_mode; 93 bool support_clk_src_div; 94 bool fifo_mode_enable_status; 95 int uart_max_port; 96 int max_dma_burst_bytes; 97 int error_tolerance_low_range; 98 int error_tolerance_high_range; 99 }; 100 101 struct tegra_baud_tolerance { 102 u32 lower_range_baud; 103 u32 upper_range_baud; 104 s32 tolerance; 105 }; 106 107 struct tegra_uart_port { 108 struct uart_port uport; 109 const struct tegra_uart_chip_data *cdata; 110 111 struct clk *uart_clk; 112 struct reset_control *rst; 113 unsigned int current_baud; 114 115 /* Register shadow */ 116 unsigned long fcr_shadow; 117 unsigned long mcr_shadow; 118 unsigned long lcr_shadow; 119 unsigned long ier_shadow; 120 bool rts_active; 121 122 int tx_in_progress; 123 unsigned int tx_bytes; 124 125 bool enable_modem_interrupt; 126 127 bool rx_timeout; 128 int rx_in_progress; 129 int symb_bit; 130 131 struct dma_chan *rx_dma_chan; 132 struct dma_chan *tx_dma_chan; 133 dma_addr_t rx_dma_buf_phys; 134 dma_addr_t tx_dma_buf_phys; 135 unsigned char *rx_dma_buf_virt; 136 unsigned char *tx_dma_buf_virt; 137 struct dma_async_tx_descriptor *tx_dma_desc; 138 struct dma_async_tx_descriptor *rx_dma_desc; 139 dma_cookie_t tx_cookie; 140 dma_cookie_t rx_cookie; 141 unsigned int tx_bytes_requested; 142 unsigned int rx_bytes_requested; 143 struct tegra_baud_tolerance *baud_tolerance; 144 int n_adjustable_baud_rates; 145 int required_rate; 146 int configured_rate; 147 bool use_rx_pio; 148 bool use_tx_pio; 149 bool rx_dma_active; 150 }; 151 152 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup); 153 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup); 154 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup, 155 bool dma_to_memory); 156 157 static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup, 158 unsigned long reg) 159 { 160 return readl(tup->uport.membase + (reg << tup->uport.regshift)); 161 } 162 163 static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val, 164 unsigned long reg) 165 { 166 writel(val, tup->uport.membase + (reg << tup->uport.regshift)); 167 } 168 169 static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u) 170 { 171 return container_of(u, struct tegra_uart_port, uport); 172 } 173 174 static unsigned int tegra_uart_get_mctrl(struct uart_port *u) 175 { 176 struct tegra_uart_port *tup = to_tegra_uport(u); 177 178 /* 179 * RI - Ring detector is active 180 * CD/DCD/CAR - Carrier detect is always active. For some reason 181 * linux has different names for carrier detect. 182 * DSR - Data Set ready is active as the hardware doesn't support it. 183 * Don't know if the linux support this yet? 184 * CTS - Clear to send. Always set to active, as the hardware handles 185 * CTS automatically. 186 */ 187 if (tup->enable_modem_interrupt) 188 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS; 189 return TIOCM_CTS; 190 } 191 192 static void set_rts(struct tegra_uart_port *tup, bool active) 193 { 194 unsigned long mcr; 195 196 mcr = tup->mcr_shadow; 197 if (active) 198 mcr |= TEGRA_UART_MCR_RTS_EN; 199 else 200 mcr &= ~TEGRA_UART_MCR_RTS_EN; 201 if (mcr != tup->mcr_shadow) { 202 tegra_uart_write(tup, mcr, UART_MCR); 203 tup->mcr_shadow = mcr; 204 } 205 } 206 207 static void set_dtr(struct tegra_uart_port *tup, bool active) 208 { 209 unsigned long mcr; 210 211 mcr = tup->mcr_shadow; 212 if (active) 213 mcr |= UART_MCR_DTR; 214 else 215 mcr &= ~UART_MCR_DTR; 216 if (mcr != tup->mcr_shadow) { 217 tegra_uart_write(tup, mcr, UART_MCR); 218 tup->mcr_shadow = mcr; 219 } 220 } 221 222 static void set_loopbk(struct tegra_uart_port *tup, bool active) 223 { 224 unsigned long mcr = tup->mcr_shadow; 225 226 if (active) 227 mcr |= UART_MCR_LOOP; 228 else 229 mcr &= ~UART_MCR_LOOP; 230 231 if (mcr != tup->mcr_shadow) { 232 tegra_uart_write(tup, mcr, UART_MCR); 233 tup->mcr_shadow = mcr; 234 } 235 } 236 237 static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl) 238 { 239 struct tegra_uart_port *tup = to_tegra_uport(u); 240 int enable; 241 242 tup->rts_active = !!(mctrl & TIOCM_RTS); 243 set_rts(tup, tup->rts_active); 244 245 enable = !!(mctrl & TIOCM_DTR); 246 set_dtr(tup, enable); 247 248 enable = !!(mctrl & TIOCM_LOOP); 249 set_loopbk(tup, enable); 250 } 251 252 static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl) 253 { 254 struct tegra_uart_port *tup = to_tegra_uport(u); 255 unsigned long lcr; 256 257 lcr = tup->lcr_shadow; 258 if (break_ctl) 259 lcr |= UART_LCR_SBC; 260 else 261 lcr &= ~UART_LCR_SBC; 262 tegra_uart_write(tup, lcr, UART_LCR); 263 tup->lcr_shadow = lcr; 264 } 265 266 /** 267 * tegra_uart_wait_cycle_time: Wait for N UART clock periods 268 * 269 * @tup: Tegra serial port data structure. 270 * @cycles: Number of clock periods to wait. 271 * 272 * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART 273 * clock speed is 16X the current baud rate. 274 */ 275 static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup, 276 unsigned int cycles) 277 { 278 if (tup->current_baud) 279 udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16)); 280 } 281 282 /* Wait for a symbol-time. */ 283 static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup, 284 unsigned int syms) 285 { 286 if (tup->current_baud) 287 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000, 288 tup->current_baud)); 289 } 290 291 static int tegra_uart_wait_fifo_mode_enabled(struct tegra_uart_port *tup) 292 { 293 unsigned long iir; 294 unsigned int tmout = 100; 295 296 do { 297 iir = tegra_uart_read(tup, UART_IIR); 298 if (iir & TEGRA_UART_FCR_IIR_FIFO_EN) 299 return 0; 300 udelay(1); 301 } while (--tmout); 302 303 return -ETIMEDOUT; 304 } 305 306 static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits) 307 { 308 unsigned long fcr = tup->fcr_shadow; 309 unsigned int lsr, tmout = 10000; 310 311 if (tup->rts_active) 312 set_rts(tup, false); 313 314 if (tup->cdata->allow_txfifo_reset_fifo_mode) { 315 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 316 tegra_uart_write(tup, fcr, UART_FCR); 317 } else { 318 fcr &= ~UART_FCR_ENABLE_FIFO; 319 tegra_uart_write(tup, fcr, UART_FCR); 320 udelay(60); 321 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 322 tegra_uart_write(tup, fcr, UART_FCR); 323 fcr |= UART_FCR_ENABLE_FIFO; 324 tegra_uart_write(tup, fcr, UART_FCR); 325 if (tup->cdata->fifo_mode_enable_status) 326 tegra_uart_wait_fifo_mode_enabled(tup); 327 } 328 329 /* Dummy read to ensure the write is posted */ 330 tegra_uart_read(tup, UART_SCR); 331 332 /* 333 * For all tegra devices (up to t210), there is a hardware issue that 334 * requires software to wait for 32 UART clock periods for the flush 335 * to propagate, otherwise data could be lost. 336 */ 337 tegra_uart_wait_cycle_time(tup, 32); 338 339 do { 340 lsr = tegra_uart_read(tup, UART_LSR); 341 if ((lsr & UART_LSR_TEMT) && !(lsr & UART_LSR_DR)) 342 break; 343 udelay(1); 344 } while (--tmout); 345 346 if (tup->rts_active) 347 set_rts(tup, true); 348 } 349 350 static long tegra_get_tolerance_rate(struct tegra_uart_port *tup, 351 unsigned int baud, long rate) 352 { 353 int i; 354 355 for (i = 0; i < tup->n_adjustable_baud_rates; ++i) { 356 if (baud >= tup->baud_tolerance[i].lower_range_baud && 357 baud <= tup->baud_tolerance[i].upper_range_baud) 358 return (rate + (rate * 359 tup->baud_tolerance[i].tolerance) / 10000); 360 } 361 362 return rate; 363 } 364 365 static int tegra_check_rate_in_range(struct tegra_uart_port *tup) 366 { 367 long diff; 368 369 diff = ((long)(tup->configured_rate - tup->required_rate) * 10000) 370 / tup->required_rate; 371 if (diff < (tup->cdata->error_tolerance_low_range * 100) || 372 diff > (tup->cdata->error_tolerance_high_range * 100)) { 373 dev_err(tup->uport.dev, 374 "configured baud rate is out of range by %ld", diff); 375 return -EIO; 376 } 377 378 return 0; 379 } 380 381 static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) 382 { 383 unsigned long rate; 384 unsigned int divisor; 385 unsigned long lcr; 386 unsigned long flags; 387 int ret; 388 389 if (tup->current_baud == baud) 390 return 0; 391 392 if (tup->cdata->support_clk_src_div) { 393 rate = baud * 16; 394 tup->required_rate = rate; 395 396 if (tup->n_adjustable_baud_rates) 397 rate = tegra_get_tolerance_rate(tup, baud, rate); 398 399 ret = clk_set_rate(tup->uart_clk, rate); 400 if (ret < 0) { 401 dev_err(tup->uport.dev, 402 "clk_set_rate() failed for rate %lu\n", rate); 403 return ret; 404 } 405 tup->configured_rate = clk_get_rate(tup->uart_clk); 406 divisor = 1; 407 ret = tegra_check_rate_in_range(tup); 408 if (ret < 0) 409 return ret; 410 } else { 411 rate = clk_get_rate(tup->uart_clk); 412 divisor = DIV_ROUND_CLOSEST(rate, baud * 16); 413 } 414 415 spin_lock_irqsave(&tup->uport.lock, flags); 416 lcr = tup->lcr_shadow; 417 lcr |= UART_LCR_DLAB; 418 tegra_uart_write(tup, lcr, UART_LCR); 419 420 tegra_uart_write(tup, divisor & 0xFF, UART_TX); 421 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER); 422 423 lcr &= ~UART_LCR_DLAB; 424 tegra_uart_write(tup, lcr, UART_LCR); 425 426 /* Dummy read to ensure the write is posted */ 427 tegra_uart_read(tup, UART_SCR); 428 spin_unlock_irqrestore(&tup->uport.lock, flags); 429 430 tup->current_baud = baud; 431 432 /* wait two character intervals at new rate */ 433 tegra_uart_wait_sym_time(tup, 2); 434 return 0; 435 } 436 437 static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup, 438 unsigned long lsr) 439 { 440 char flag = TTY_NORMAL; 441 442 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) { 443 if (lsr & UART_LSR_OE) { 444 /* Overrrun error */ 445 flag = TTY_OVERRUN; 446 tup->uport.icount.overrun++; 447 dev_dbg(tup->uport.dev, "Got overrun errors\n"); 448 } else if (lsr & UART_LSR_PE) { 449 /* Parity error */ 450 flag = TTY_PARITY; 451 tup->uport.icount.parity++; 452 dev_dbg(tup->uport.dev, "Got Parity errors\n"); 453 } else if (lsr & UART_LSR_FE) { 454 flag = TTY_FRAME; 455 tup->uport.icount.frame++; 456 dev_dbg(tup->uport.dev, "Got frame errors\n"); 457 } else if (lsr & UART_LSR_BI) { 458 /* 459 * Break error 460 * If FIFO read error without any data, reset Rx FIFO 461 */ 462 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE)) 463 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR); 464 if (tup->uport.ignore_status_mask & UART_LSR_BI) 465 return TTY_BREAK; 466 flag = TTY_BREAK; 467 tup->uport.icount.brk++; 468 dev_dbg(tup->uport.dev, "Got Break\n"); 469 } 470 uart_insert_char(&tup->uport, lsr, UART_LSR_OE, 0, flag); 471 } 472 473 return flag; 474 } 475 476 static int tegra_uart_request_port(struct uart_port *u) 477 { 478 return 0; 479 } 480 481 static void tegra_uart_release_port(struct uart_port *u) 482 { 483 /* Nothing to do here */ 484 } 485 486 static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes) 487 { 488 struct circ_buf *xmit = &tup->uport.state->xmit; 489 int i; 490 491 for (i = 0; i < max_bytes; i++) { 492 BUG_ON(uart_circ_empty(xmit)); 493 if (tup->cdata->tx_fifo_full_status) { 494 unsigned long lsr = tegra_uart_read(tup, UART_LSR); 495 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL)) 496 break; 497 } 498 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX); 499 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 500 tup->uport.icount.tx++; 501 } 502 } 503 504 static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup, 505 unsigned int bytes) 506 { 507 if (bytes > TEGRA_UART_MIN_DMA) 508 bytes = TEGRA_UART_MIN_DMA; 509 510 tup->tx_in_progress = TEGRA_UART_TX_PIO; 511 tup->tx_bytes = bytes; 512 tup->ier_shadow |= UART_IER_THRI; 513 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 514 } 515 516 static void tegra_uart_tx_dma_complete(void *args) 517 { 518 struct tegra_uart_port *tup = args; 519 struct circ_buf *xmit = &tup->uport.state->xmit; 520 struct dma_tx_state state; 521 unsigned long flags; 522 unsigned int count; 523 524 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); 525 count = tup->tx_bytes_requested - state.residue; 526 async_tx_ack(tup->tx_dma_desc); 527 spin_lock_irqsave(&tup->uport.lock, flags); 528 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); 529 tup->tx_in_progress = 0; 530 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 531 uart_write_wakeup(&tup->uport); 532 tegra_uart_start_next_tx(tup); 533 spin_unlock_irqrestore(&tup->uport.lock, flags); 534 } 535 536 static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup, 537 unsigned long count) 538 { 539 struct circ_buf *xmit = &tup->uport.state->xmit; 540 dma_addr_t tx_phys_addr; 541 542 tup->tx_bytes = count & ~(0xF); 543 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail; 544 545 dma_sync_single_for_device(tup->uport.dev, tx_phys_addr, 546 tup->tx_bytes, DMA_TO_DEVICE); 547 548 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan, 549 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV, 550 DMA_PREP_INTERRUPT); 551 if (!tup->tx_dma_desc) { 552 dev_err(tup->uport.dev, "Not able to get desc for Tx\n"); 553 return -EIO; 554 } 555 556 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete; 557 tup->tx_dma_desc->callback_param = tup; 558 tup->tx_in_progress = TEGRA_UART_TX_DMA; 559 tup->tx_bytes_requested = tup->tx_bytes; 560 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc); 561 dma_async_issue_pending(tup->tx_dma_chan); 562 return 0; 563 } 564 565 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup) 566 { 567 unsigned long tail; 568 unsigned long count; 569 struct circ_buf *xmit = &tup->uport.state->xmit; 570 571 if (!tup->current_baud) 572 return; 573 574 tail = (unsigned long)&xmit->buf[xmit->tail]; 575 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 576 if (!count) 577 return; 578 579 if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA) 580 tegra_uart_start_pio_tx(tup, count); 581 else if (BYTES_TO_ALIGN(tail) > 0) 582 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail)); 583 else 584 tegra_uart_start_tx_dma(tup, count); 585 } 586 587 /* Called by serial core driver with u->lock taken. */ 588 static void tegra_uart_start_tx(struct uart_port *u) 589 { 590 struct tegra_uart_port *tup = to_tegra_uport(u); 591 struct circ_buf *xmit = &u->state->xmit; 592 593 if (!uart_circ_empty(xmit) && !tup->tx_in_progress) 594 tegra_uart_start_next_tx(tup); 595 } 596 597 static unsigned int tegra_uart_tx_empty(struct uart_port *u) 598 { 599 struct tegra_uart_port *tup = to_tegra_uport(u); 600 unsigned int ret = 0; 601 unsigned long flags; 602 603 spin_lock_irqsave(&u->lock, flags); 604 if (!tup->tx_in_progress) { 605 unsigned long lsr = tegra_uart_read(tup, UART_LSR); 606 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS) 607 ret = TIOCSER_TEMT; 608 } 609 spin_unlock_irqrestore(&u->lock, flags); 610 return ret; 611 } 612 613 static void tegra_uart_stop_tx(struct uart_port *u) 614 { 615 struct tegra_uart_port *tup = to_tegra_uport(u); 616 struct circ_buf *xmit = &tup->uport.state->xmit; 617 struct dma_tx_state state; 618 unsigned int count; 619 620 if (tup->tx_in_progress != TEGRA_UART_TX_DMA) 621 return; 622 623 dmaengine_terminate_all(tup->tx_dma_chan); 624 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); 625 count = tup->tx_bytes_requested - state.residue; 626 async_tx_ack(tup->tx_dma_desc); 627 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); 628 tup->tx_in_progress = 0; 629 } 630 631 static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup) 632 { 633 struct circ_buf *xmit = &tup->uport.state->xmit; 634 635 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes); 636 tup->tx_in_progress = 0; 637 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 638 uart_write_wakeup(&tup->uport); 639 tegra_uart_start_next_tx(tup); 640 } 641 642 static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup, 643 struct tty_port *port) 644 { 645 do { 646 char flag = TTY_NORMAL; 647 unsigned long lsr = 0; 648 unsigned char ch; 649 650 lsr = tegra_uart_read(tup, UART_LSR); 651 if (!(lsr & UART_LSR_DR)) 652 break; 653 654 flag = tegra_uart_decode_rx_error(tup, lsr); 655 if (flag != TTY_NORMAL) 656 continue; 657 658 ch = (unsigned char) tegra_uart_read(tup, UART_RX); 659 tup->uport.icount.rx++; 660 661 if (uart_handle_sysrq_char(&tup->uport, ch)) 662 continue; 663 664 if (tup->uport.ignore_status_mask & UART_LSR_DR) 665 continue; 666 667 tty_insert_flip_char(port, ch, flag); 668 } while (1); 669 } 670 671 static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, 672 struct tty_port *port, 673 unsigned int count) 674 { 675 int copied; 676 677 /* If count is zero, then there is no data to be copied */ 678 if (!count) 679 return; 680 681 tup->uport.icount.rx += count; 682 683 if (tup->uport.ignore_status_mask & UART_LSR_DR) 684 return; 685 686 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys, 687 count, DMA_FROM_DEVICE); 688 copied = tty_insert_flip_string(port, 689 ((unsigned char *)(tup->rx_dma_buf_virt)), count); 690 if (copied != count) { 691 WARN_ON(1); 692 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n"); 693 } 694 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys, 695 count, DMA_TO_DEVICE); 696 } 697 698 static void do_handle_rx_pio(struct tegra_uart_port *tup) 699 { 700 struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); 701 struct tty_port *port = &tup->uport.state->port; 702 703 tegra_uart_handle_rx_pio(tup, port); 704 if (tty) { 705 tty_flip_buffer_push(port); 706 tty_kref_put(tty); 707 } 708 } 709 710 static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup, 711 unsigned int residue) 712 { 713 struct tty_port *port = &tup->uport.state->port; 714 unsigned int count; 715 716 async_tx_ack(tup->rx_dma_desc); 717 count = tup->rx_bytes_requested - residue; 718 719 /* If we are here, DMA is stopped */ 720 tegra_uart_copy_rx_to_tty(tup, port, count); 721 722 do_handle_rx_pio(tup); 723 } 724 725 static void tegra_uart_rx_dma_complete(void *args) 726 { 727 struct tegra_uart_port *tup = args; 728 struct uart_port *u = &tup->uport; 729 unsigned long flags; 730 struct dma_tx_state state; 731 enum dma_status status; 732 733 spin_lock_irqsave(&u->lock, flags); 734 735 status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); 736 737 if (status == DMA_IN_PROGRESS) { 738 dev_dbg(tup->uport.dev, "RX DMA is in progress\n"); 739 goto done; 740 } 741 742 /* Deactivate flow control to stop sender */ 743 if (tup->rts_active) 744 set_rts(tup, false); 745 746 tup->rx_dma_active = false; 747 tegra_uart_rx_buffer_push(tup, 0); 748 tegra_uart_start_rx_dma(tup); 749 750 /* Activate flow control to start transfer */ 751 if (tup->rts_active) 752 set_rts(tup, true); 753 754 done: 755 spin_unlock_irqrestore(&u->lock, flags); 756 } 757 758 static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup) 759 { 760 struct dma_tx_state state; 761 762 if (!tup->rx_dma_active) { 763 do_handle_rx_pio(tup); 764 return; 765 } 766 767 dmaengine_terminate_all(tup->rx_dma_chan); 768 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); 769 770 tegra_uart_rx_buffer_push(tup, state.residue); 771 tup->rx_dma_active = false; 772 } 773 774 static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup) 775 { 776 /* Deactivate flow control to stop sender */ 777 if (tup->rts_active) 778 set_rts(tup, false); 779 780 tegra_uart_terminate_rx_dma(tup); 781 782 if (tup->rts_active) 783 set_rts(tup, true); 784 } 785 786 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup) 787 { 788 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE; 789 790 if (tup->rx_dma_active) 791 return 0; 792 793 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan, 794 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM, 795 DMA_PREP_INTERRUPT); 796 if (!tup->rx_dma_desc) { 797 dev_err(tup->uport.dev, "Not able to get desc for Rx\n"); 798 return -EIO; 799 } 800 801 tup->rx_dma_active = true; 802 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete; 803 tup->rx_dma_desc->callback_param = tup; 804 tup->rx_bytes_requested = count; 805 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc); 806 dma_async_issue_pending(tup->rx_dma_chan); 807 return 0; 808 } 809 810 static void tegra_uart_handle_modem_signal_change(struct uart_port *u) 811 { 812 struct tegra_uart_port *tup = to_tegra_uport(u); 813 unsigned long msr; 814 815 msr = tegra_uart_read(tup, UART_MSR); 816 if (!(msr & UART_MSR_ANY_DELTA)) 817 return; 818 819 if (msr & UART_MSR_TERI) 820 tup->uport.icount.rng++; 821 if (msr & UART_MSR_DDSR) 822 tup->uport.icount.dsr++; 823 /* We may only get DDCD when HW init and reset */ 824 if (msr & UART_MSR_DDCD) 825 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD); 826 /* Will start/stop_tx accordingly */ 827 if (msr & UART_MSR_DCTS) 828 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS); 829 } 830 831 static irqreturn_t tegra_uart_isr(int irq, void *data) 832 { 833 struct tegra_uart_port *tup = data; 834 struct uart_port *u = &tup->uport; 835 unsigned long iir; 836 unsigned long ier; 837 bool is_rx_start = false; 838 bool is_rx_int = false; 839 unsigned long flags; 840 841 spin_lock_irqsave(&u->lock, flags); 842 while (1) { 843 iir = tegra_uart_read(tup, UART_IIR); 844 if (iir & UART_IIR_NO_INT) { 845 if (!tup->use_rx_pio && is_rx_int) { 846 tegra_uart_handle_rx_dma(tup); 847 if (tup->rx_in_progress) { 848 ier = tup->ier_shadow; 849 ier |= (UART_IER_RLSI | UART_IER_RTOIE | 850 TEGRA_UART_IER_EORD | UART_IER_RDI); 851 tup->ier_shadow = ier; 852 tegra_uart_write(tup, ier, UART_IER); 853 } 854 } else if (is_rx_start) { 855 tegra_uart_start_rx_dma(tup); 856 } 857 spin_unlock_irqrestore(&u->lock, flags); 858 return IRQ_HANDLED; 859 } 860 861 switch ((iir >> 1) & 0x7) { 862 case 0: /* Modem signal change interrupt */ 863 tegra_uart_handle_modem_signal_change(u); 864 break; 865 866 case 1: /* Transmit interrupt only triggered when using PIO */ 867 tup->ier_shadow &= ~UART_IER_THRI; 868 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 869 tegra_uart_handle_tx_pio(tup); 870 break; 871 872 case 4: /* End of data */ 873 case 6: /* Rx timeout */ 874 if (!tup->use_rx_pio) { 875 is_rx_int = tup->rx_in_progress; 876 /* Disable Rx interrupts */ 877 ier = tup->ier_shadow; 878 ier &= ~(UART_IER_RDI | UART_IER_RLSI | 879 UART_IER_RTOIE | TEGRA_UART_IER_EORD); 880 tup->ier_shadow = ier; 881 tegra_uart_write(tup, ier, UART_IER); 882 break; 883 } 884 fallthrough; 885 case 2: /* Receive */ 886 if (!tup->use_rx_pio) { 887 is_rx_start = tup->rx_in_progress; 888 tup->ier_shadow &= ~UART_IER_RDI; 889 tegra_uart_write(tup, tup->ier_shadow, 890 UART_IER); 891 } else { 892 do_handle_rx_pio(tup); 893 } 894 break; 895 896 case 3: /* Receive error */ 897 tegra_uart_decode_rx_error(tup, 898 tegra_uart_read(tup, UART_LSR)); 899 break; 900 901 case 5: /* break nothing to handle */ 902 case 7: /* break nothing to handle */ 903 break; 904 } 905 } 906 } 907 908 static void tegra_uart_stop_rx(struct uart_port *u) 909 { 910 struct tegra_uart_port *tup = to_tegra_uport(u); 911 struct tty_port *port = &tup->uport.state->port; 912 unsigned long ier; 913 914 if (tup->rts_active) 915 set_rts(tup, false); 916 917 if (!tup->rx_in_progress) 918 return; 919 920 tegra_uart_wait_sym_time(tup, 1); /* wait one character interval */ 921 922 ier = tup->ier_shadow; 923 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE | 924 TEGRA_UART_IER_EORD); 925 tup->ier_shadow = ier; 926 tegra_uart_write(tup, ier, UART_IER); 927 tup->rx_in_progress = 0; 928 929 if (!tup->use_rx_pio) 930 tegra_uart_terminate_rx_dma(tup); 931 else 932 tegra_uart_handle_rx_pio(tup, port); 933 } 934 935 static void tegra_uart_hw_deinit(struct tegra_uart_port *tup) 936 { 937 unsigned long flags; 938 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud); 939 unsigned long fifo_empty_time = tup->uport.fifosize * char_time; 940 unsigned long wait_time; 941 unsigned long lsr; 942 unsigned long msr; 943 unsigned long mcr; 944 945 /* Disable interrupts */ 946 tegra_uart_write(tup, 0, UART_IER); 947 948 lsr = tegra_uart_read(tup, UART_LSR); 949 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) { 950 msr = tegra_uart_read(tup, UART_MSR); 951 mcr = tegra_uart_read(tup, UART_MCR); 952 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS)) 953 dev_err(tup->uport.dev, 954 "Tx Fifo not empty, CTS disabled, waiting\n"); 955 956 /* Wait for Tx fifo to be empty */ 957 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) { 958 wait_time = min(fifo_empty_time, 100lu); 959 udelay(wait_time); 960 fifo_empty_time -= wait_time; 961 if (!fifo_empty_time) { 962 msr = tegra_uart_read(tup, UART_MSR); 963 mcr = tegra_uart_read(tup, UART_MCR); 964 if ((mcr & TEGRA_UART_MCR_CTS_EN) && 965 (msr & UART_MSR_CTS)) 966 dev_err(tup->uport.dev, 967 "Slave not ready\n"); 968 break; 969 } 970 lsr = tegra_uart_read(tup, UART_LSR); 971 } 972 } 973 974 spin_lock_irqsave(&tup->uport.lock, flags); 975 /* Reset the Rx and Tx FIFOs */ 976 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR); 977 tup->current_baud = 0; 978 spin_unlock_irqrestore(&tup->uport.lock, flags); 979 980 tup->rx_in_progress = 0; 981 tup->tx_in_progress = 0; 982 983 if (!tup->use_rx_pio) 984 tegra_uart_dma_channel_free(tup, true); 985 if (!tup->use_tx_pio) 986 tegra_uart_dma_channel_free(tup, false); 987 988 clk_disable_unprepare(tup->uart_clk); 989 } 990 991 static int tegra_uart_hw_init(struct tegra_uart_port *tup) 992 { 993 int ret; 994 995 tup->fcr_shadow = 0; 996 tup->mcr_shadow = 0; 997 tup->lcr_shadow = 0; 998 tup->ier_shadow = 0; 999 tup->current_baud = 0; 1000 1001 clk_prepare_enable(tup->uart_clk); 1002 1003 /* Reset the UART controller to clear all previous status.*/ 1004 reset_control_assert(tup->rst); 1005 udelay(10); 1006 reset_control_deassert(tup->rst); 1007 1008 tup->rx_in_progress = 0; 1009 tup->tx_in_progress = 0; 1010 1011 /* 1012 * Set the trigger level 1013 * 1014 * For PIO mode: 1015 * 1016 * For receive, this will interrupt the CPU after that many number of 1017 * bytes are received, for the remaining bytes the receive timeout 1018 * interrupt is received. Rx high watermark is set to 4. 1019 * 1020 * For transmit, if the trasnmit interrupt is enabled, this will 1021 * interrupt the CPU when the number of entries in the FIFO reaches the 1022 * low watermark. Tx low watermark is set to 16 bytes. 1023 * 1024 * For DMA mode: 1025 * 1026 * Set the Tx trigger to 16. This should match the DMA burst size that 1027 * programmed in the DMA registers. 1028 */ 1029 tup->fcr_shadow = UART_FCR_ENABLE_FIFO; 1030 1031 if (tup->use_rx_pio) { 1032 tup->fcr_shadow |= UART_FCR_R_TRIG_11; 1033 } else { 1034 if (tup->cdata->max_dma_burst_bytes == 8) 1035 tup->fcr_shadow |= UART_FCR_R_TRIG_10; 1036 else 1037 tup->fcr_shadow |= UART_FCR_R_TRIG_01; 1038 } 1039 1040 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B; 1041 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1042 1043 /* Dummy read to ensure the write is posted */ 1044 tegra_uart_read(tup, UART_SCR); 1045 1046 if (tup->cdata->fifo_mode_enable_status) { 1047 ret = tegra_uart_wait_fifo_mode_enabled(tup); 1048 if (ret < 0) { 1049 dev_err(tup->uport.dev, 1050 "Failed to enable FIFO mode: %d\n", ret); 1051 return ret; 1052 } 1053 } else { 1054 /* 1055 * For all tegra devices (up to t210), there is a hardware 1056 * issue that requires software to wait for 3 UART clock 1057 * periods after enabling the TX fifo, otherwise data could 1058 * be lost. 1059 */ 1060 tegra_uart_wait_cycle_time(tup, 3); 1061 } 1062 1063 /* 1064 * Initialize the UART with default configuration 1065 * (115200, N, 8, 1) so that the receive DMA buffer may be 1066 * enqueued 1067 */ 1068 ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD); 1069 if (ret < 0) { 1070 dev_err(tup->uport.dev, "Failed to set baud rate\n"); 1071 return ret; 1072 } 1073 if (!tup->use_rx_pio) { 1074 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR; 1075 tup->fcr_shadow |= UART_FCR_DMA_SELECT; 1076 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1077 } else { 1078 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1079 } 1080 tup->rx_in_progress = 1; 1081 1082 /* 1083 * Enable IE_RXS for the receive status interrupts like line errros. 1084 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd. 1085 * 1086 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when 1087 * the DATA is sitting in the FIFO and couldn't be transferred to the 1088 * DMA as the DMA size alignment (4 bytes) is not met. EORD will be 1089 * triggered when there is a pause of the incomming data stream for 4 1090 * characters long. 1091 * 1092 * For pauses in the data which is not aligned to 4 bytes, we get 1093 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first 1094 * then the EORD. 1095 */ 1096 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI; 1097 1098 /* 1099 * If using DMA mode, enable EORD interrupt to notify about RX 1100 * completion. 1101 */ 1102 if (!tup->use_rx_pio) 1103 tup->ier_shadow |= TEGRA_UART_IER_EORD; 1104 1105 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1106 return 0; 1107 } 1108 1109 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup, 1110 bool dma_to_memory) 1111 { 1112 if (dma_to_memory) { 1113 dmaengine_terminate_all(tup->rx_dma_chan); 1114 dma_release_channel(tup->rx_dma_chan); 1115 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE, 1116 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys); 1117 tup->rx_dma_chan = NULL; 1118 tup->rx_dma_buf_phys = 0; 1119 tup->rx_dma_buf_virt = NULL; 1120 } else { 1121 dmaengine_terminate_all(tup->tx_dma_chan); 1122 dma_release_channel(tup->tx_dma_chan); 1123 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys, 1124 UART_XMIT_SIZE, DMA_TO_DEVICE); 1125 tup->tx_dma_chan = NULL; 1126 tup->tx_dma_buf_phys = 0; 1127 tup->tx_dma_buf_virt = NULL; 1128 } 1129 } 1130 1131 static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup, 1132 bool dma_to_memory) 1133 { 1134 struct dma_chan *dma_chan; 1135 unsigned char *dma_buf; 1136 dma_addr_t dma_phys; 1137 int ret; 1138 struct dma_slave_config dma_sconfig; 1139 1140 dma_chan = dma_request_chan(tup->uport.dev, dma_to_memory ? "rx" : "tx"); 1141 if (IS_ERR(dma_chan)) { 1142 ret = PTR_ERR(dma_chan); 1143 dev_err(tup->uport.dev, 1144 "DMA channel alloc failed: %d\n", ret); 1145 return ret; 1146 } 1147 1148 if (dma_to_memory) { 1149 dma_buf = dma_alloc_coherent(tup->uport.dev, 1150 TEGRA_UART_RX_DMA_BUFFER_SIZE, 1151 &dma_phys, GFP_KERNEL); 1152 if (!dma_buf) { 1153 dev_err(tup->uport.dev, 1154 "Not able to allocate the dma buffer\n"); 1155 dma_release_channel(dma_chan); 1156 return -ENOMEM; 1157 } 1158 dma_sync_single_for_device(tup->uport.dev, dma_phys, 1159 TEGRA_UART_RX_DMA_BUFFER_SIZE, 1160 DMA_TO_DEVICE); 1161 dma_sconfig.src_addr = tup->uport.mapbase; 1162 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 1163 dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes; 1164 tup->rx_dma_chan = dma_chan; 1165 tup->rx_dma_buf_virt = dma_buf; 1166 tup->rx_dma_buf_phys = dma_phys; 1167 } else { 1168 dma_phys = dma_map_single(tup->uport.dev, 1169 tup->uport.state->xmit.buf, UART_XMIT_SIZE, 1170 DMA_TO_DEVICE); 1171 if (dma_mapping_error(tup->uport.dev, dma_phys)) { 1172 dev_err(tup->uport.dev, "dma_map_single tx failed\n"); 1173 dma_release_channel(dma_chan); 1174 return -ENOMEM; 1175 } 1176 dma_buf = tup->uport.state->xmit.buf; 1177 dma_sconfig.dst_addr = tup->uport.mapbase; 1178 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 1179 dma_sconfig.dst_maxburst = 16; 1180 tup->tx_dma_chan = dma_chan; 1181 tup->tx_dma_buf_virt = dma_buf; 1182 tup->tx_dma_buf_phys = dma_phys; 1183 } 1184 1185 ret = dmaengine_slave_config(dma_chan, &dma_sconfig); 1186 if (ret < 0) { 1187 dev_err(tup->uport.dev, 1188 "Dma slave config failed, err = %d\n", ret); 1189 tegra_uart_dma_channel_free(tup, dma_to_memory); 1190 return ret; 1191 } 1192 1193 return 0; 1194 } 1195 1196 static int tegra_uart_startup(struct uart_port *u) 1197 { 1198 struct tegra_uart_port *tup = to_tegra_uport(u); 1199 int ret; 1200 1201 if (!tup->use_tx_pio) { 1202 ret = tegra_uart_dma_channel_allocate(tup, false); 1203 if (ret < 0) { 1204 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", 1205 ret); 1206 return ret; 1207 } 1208 } 1209 1210 if (!tup->use_rx_pio) { 1211 ret = tegra_uart_dma_channel_allocate(tup, true); 1212 if (ret < 0) { 1213 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", 1214 ret); 1215 goto fail_rx_dma; 1216 } 1217 } 1218 1219 ret = tegra_uart_hw_init(tup); 1220 if (ret < 0) { 1221 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret); 1222 goto fail_hw_init; 1223 } 1224 1225 ret = request_irq(u->irq, tegra_uart_isr, 0, 1226 dev_name(u->dev), tup); 1227 if (ret < 0) { 1228 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq); 1229 goto fail_hw_init; 1230 } 1231 return 0; 1232 1233 fail_hw_init: 1234 if (!tup->use_rx_pio) 1235 tegra_uart_dma_channel_free(tup, true); 1236 fail_rx_dma: 1237 if (!tup->use_tx_pio) 1238 tegra_uart_dma_channel_free(tup, false); 1239 return ret; 1240 } 1241 1242 /* 1243 * Flush any TX data submitted for DMA and PIO. Called when the 1244 * TX circular buffer is reset. 1245 */ 1246 static void tegra_uart_flush_buffer(struct uart_port *u) 1247 { 1248 struct tegra_uart_port *tup = to_tegra_uport(u); 1249 1250 tup->tx_bytes = 0; 1251 if (tup->tx_dma_chan) 1252 dmaengine_terminate_all(tup->tx_dma_chan); 1253 } 1254 1255 static void tegra_uart_shutdown(struct uart_port *u) 1256 { 1257 struct tegra_uart_port *tup = to_tegra_uport(u); 1258 1259 tegra_uart_hw_deinit(tup); 1260 free_irq(u->irq, tup); 1261 } 1262 1263 static void tegra_uart_enable_ms(struct uart_port *u) 1264 { 1265 struct tegra_uart_port *tup = to_tegra_uport(u); 1266 1267 if (tup->enable_modem_interrupt) { 1268 tup->ier_shadow |= UART_IER_MSI; 1269 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1270 } 1271 } 1272 1273 static void tegra_uart_set_termios(struct uart_port *u, 1274 struct ktermios *termios, struct ktermios *oldtermios) 1275 { 1276 struct tegra_uart_port *tup = to_tegra_uport(u); 1277 unsigned int baud; 1278 unsigned long flags; 1279 unsigned int lcr; 1280 int symb_bit = 1; 1281 struct clk *parent_clk = clk_get_parent(tup->uart_clk); 1282 unsigned long parent_clk_rate = clk_get_rate(parent_clk); 1283 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF; 1284 int ret; 1285 1286 max_divider *= 16; 1287 spin_lock_irqsave(&u->lock, flags); 1288 1289 /* Changing configuration, it is safe to stop any rx now */ 1290 if (tup->rts_active) 1291 set_rts(tup, false); 1292 1293 /* Clear all interrupts as configuration is going to be changed */ 1294 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER); 1295 tegra_uart_read(tup, UART_IER); 1296 tegra_uart_write(tup, 0, UART_IER); 1297 tegra_uart_read(tup, UART_IER); 1298 1299 /* Parity */ 1300 lcr = tup->lcr_shadow; 1301 lcr &= ~UART_LCR_PARITY; 1302 1303 /* CMSPAR isn't supported by this driver */ 1304 termios->c_cflag &= ~CMSPAR; 1305 1306 if ((termios->c_cflag & PARENB) == PARENB) { 1307 symb_bit++; 1308 if (termios->c_cflag & PARODD) { 1309 lcr |= UART_LCR_PARITY; 1310 lcr &= ~UART_LCR_EPAR; 1311 lcr &= ~UART_LCR_SPAR; 1312 } else { 1313 lcr |= UART_LCR_PARITY; 1314 lcr |= UART_LCR_EPAR; 1315 lcr &= ~UART_LCR_SPAR; 1316 } 1317 } 1318 1319 lcr &= ~UART_LCR_WLEN8; 1320 switch (termios->c_cflag & CSIZE) { 1321 case CS5: 1322 lcr |= UART_LCR_WLEN5; 1323 symb_bit += 5; 1324 break; 1325 case CS6: 1326 lcr |= UART_LCR_WLEN6; 1327 symb_bit += 6; 1328 break; 1329 case CS7: 1330 lcr |= UART_LCR_WLEN7; 1331 symb_bit += 7; 1332 break; 1333 default: 1334 lcr |= UART_LCR_WLEN8; 1335 symb_bit += 8; 1336 break; 1337 } 1338 1339 /* Stop bits */ 1340 if (termios->c_cflag & CSTOPB) { 1341 lcr |= UART_LCR_STOP; 1342 symb_bit += 2; 1343 } else { 1344 lcr &= ~UART_LCR_STOP; 1345 symb_bit++; 1346 } 1347 1348 tegra_uart_write(tup, lcr, UART_LCR); 1349 tup->lcr_shadow = lcr; 1350 tup->symb_bit = symb_bit; 1351 1352 /* Baud rate. */ 1353 baud = uart_get_baud_rate(u, termios, oldtermios, 1354 parent_clk_rate/max_divider, 1355 parent_clk_rate/16); 1356 spin_unlock_irqrestore(&u->lock, flags); 1357 ret = tegra_set_baudrate(tup, baud); 1358 if (ret < 0) { 1359 dev_err(tup->uport.dev, "Failed to set baud rate\n"); 1360 return; 1361 } 1362 if (tty_termios_baud_rate(termios)) 1363 tty_termios_encode_baud_rate(termios, baud, baud); 1364 spin_lock_irqsave(&u->lock, flags); 1365 1366 /* Flow control */ 1367 if (termios->c_cflag & CRTSCTS) { 1368 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN; 1369 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN; 1370 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR); 1371 /* if top layer has asked to set rts active then do so here */ 1372 if (tup->rts_active) 1373 set_rts(tup, true); 1374 } else { 1375 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN; 1376 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN; 1377 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR); 1378 } 1379 1380 /* update the port timeout based on new settings */ 1381 uart_update_timeout(u, termios->c_cflag, baud); 1382 1383 /* Make sure all writes have completed */ 1384 tegra_uart_read(tup, UART_IER); 1385 1386 /* Re-enable interrupt */ 1387 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1388 tegra_uart_read(tup, UART_IER); 1389 1390 tup->uport.ignore_status_mask = 0; 1391 /* Ignore all characters if CREAD is not set */ 1392 if ((termios->c_cflag & CREAD) == 0) 1393 tup->uport.ignore_status_mask |= UART_LSR_DR; 1394 if (termios->c_iflag & IGNBRK) 1395 tup->uport.ignore_status_mask |= UART_LSR_BI; 1396 1397 spin_unlock_irqrestore(&u->lock, flags); 1398 } 1399 1400 static const char *tegra_uart_type(struct uart_port *u) 1401 { 1402 return TEGRA_UART_TYPE; 1403 } 1404 1405 static const struct uart_ops tegra_uart_ops = { 1406 .tx_empty = tegra_uart_tx_empty, 1407 .set_mctrl = tegra_uart_set_mctrl, 1408 .get_mctrl = tegra_uart_get_mctrl, 1409 .stop_tx = tegra_uart_stop_tx, 1410 .start_tx = tegra_uart_start_tx, 1411 .stop_rx = tegra_uart_stop_rx, 1412 .flush_buffer = tegra_uart_flush_buffer, 1413 .enable_ms = tegra_uart_enable_ms, 1414 .break_ctl = tegra_uart_break_ctl, 1415 .startup = tegra_uart_startup, 1416 .shutdown = tegra_uart_shutdown, 1417 .set_termios = tegra_uart_set_termios, 1418 .type = tegra_uart_type, 1419 .request_port = tegra_uart_request_port, 1420 .release_port = tegra_uart_release_port, 1421 }; 1422 1423 static struct uart_driver tegra_uart_driver = { 1424 .owner = THIS_MODULE, 1425 .driver_name = "tegra_hsuart", 1426 .dev_name = "ttyTHS", 1427 .cons = NULL, 1428 .nr = TEGRA_UART_MAXIMUM, 1429 }; 1430 1431 static int tegra_uart_parse_dt(struct platform_device *pdev, 1432 struct tegra_uart_port *tup) 1433 { 1434 struct device_node *np = pdev->dev.of_node; 1435 int port; 1436 int ret; 1437 int index; 1438 u32 pval; 1439 int count; 1440 int n_entries; 1441 1442 port = of_alias_get_id(np, "serial"); 1443 if (port < 0) { 1444 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port); 1445 return port; 1446 } 1447 tup->uport.line = port; 1448 1449 tup->enable_modem_interrupt = of_property_read_bool(np, 1450 "nvidia,enable-modem-interrupt"); 1451 1452 index = of_property_match_string(np, "dma-names", "rx"); 1453 if (index < 0) { 1454 tup->use_rx_pio = true; 1455 dev_info(&pdev->dev, "RX in PIO mode\n"); 1456 } 1457 index = of_property_match_string(np, "dma-names", "tx"); 1458 if (index < 0) { 1459 tup->use_tx_pio = true; 1460 dev_info(&pdev->dev, "TX in PIO mode\n"); 1461 } 1462 1463 n_entries = of_property_count_u32_elems(np, "nvidia,adjust-baud-rates"); 1464 if (n_entries > 0) { 1465 tup->n_adjustable_baud_rates = n_entries / 3; 1466 tup->baud_tolerance = 1467 devm_kzalloc(&pdev->dev, (tup->n_adjustable_baud_rates) * 1468 sizeof(*tup->baud_tolerance), GFP_KERNEL); 1469 if (!tup->baud_tolerance) 1470 return -ENOMEM; 1471 for (count = 0, index = 0; count < n_entries; count += 3, 1472 index++) { 1473 ret = 1474 of_property_read_u32_index(np, 1475 "nvidia,adjust-baud-rates", 1476 count, &pval); 1477 if (!ret) 1478 tup->baud_tolerance[index].lower_range_baud = 1479 pval; 1480 ret = 1481 of_property_read_u32_index(np, 1482 "nvidia,adjust-baud-rates", 1483 count + 1, &pval); 1484 if (!ret) 1485 tup->baud_tolerance[index].upper_range_baud = 1486 pval; 1487 ret = 1488 of_property_read_u32_index(np, 1489 "nvidia,adjust-baud-rates", 1490 count + 2, &pval); 1491 if (!ret) 1492 tup->baud_tolerance[index].tolerance = 1493 (s32)pval; 1494 } 1495 } else { 1496 tup->n_adjustable_baud_rates = 0; 1497 } 1498 1499 return 0; 1500 } 1501 1502 static struct tegra_uart_chip_data tegra20_uart_chip_data = { 1503 .tx_fifo_full_status = false, 1504 .allow_txfifo_reset_fifo_mode = true, 1505 .support_clk_src_div = false, 1506 .fifo_mode_enable_status = false, 1507 .uart_max_port = 5, 1508 .max_dma_burst_bytes = 4, 1509 .error_tolerance_low_range = 0, 1510 .error_tolerance_high_range = 4, 1511 }; 1512 1513 static struct tegra_uart_chip_data tegra30_uart_chip_data = { 1514 .tx_fifo_full_status = true, 1515 .allow_txfifo_reset_fifo_mode = false, 1516 .support_clk_src_div = true, 1517 .fifo_mode_enable_status = false, 1518 .uart_max_port = 5, 1519 .max_dma_burst_bytes = 4, 1520 .error_tolerance_low_range = 0, 1521 .error_tolerance_high_range = 4, 1522 }; 1523 1524 static struct tegra_uart_chip_data tegra186_uart_chip_data = { 1525 .tx_fifo_full_status = true, 1526 .allow_txfifo_reset_fifo_mode = false, 1527 .support_clk_src_div = true, 1528 .fifo_mode_enable_status = true, 1529 .uart_max_port = 8, 1530 .max_dma_burst_bytes = 8, 1531 .error_tolerance_low_range = 0, 1532 .error_tolerance_high_range = 4, 1533 }; 1534 1535 static struct tegra_uart_chip_data tegra194_uart_chip_data = { 1536 .tx_fifo_full_status = true, 1537 .allow_txfifo_reset_fifo_mode = false, 1538 .support_clk_src_div = true, 1539 .fifo_mode_enable_status = true, 1540 .uart_max_port = 8, 1541 .max_dma_burst_bytes = 8, 1542 .error_tolerance_low_range = -2, 1543 .error_tolerance_high_range = 2, 1544 }; 1545 1546 static const struct of_device_id tegra_uart_of_match[] = { 1547 { 1548 .compatible = "nvidia,tegra30-hsuart", 1549 .data = &tegra30_uart_chip_data, 1550 }, { 1551 .compatible = "nvidia,tegra20-hsuart", 1552 .data = &tegra20_uart_chip_data, 1553 }, { 1554 .compatible = "nvidia,tegra186-hsuart", 1555 .data = &tegra186_uart_chip_data, 1556 }, { 1557 .compatible = "nvidia,tegra194-hsuart", 1558 .data = &tegra194_uart_chip_data, 1559 }, { 1560 }, 1561 }; 1562 MODULE_DEVICE_TABLE(of, tegra_uart_of_match); 1563 1564 static int tegra_uart_probe(struct platform_device *pdev) 1565 { 1566 struct tegra_uart_port *tup; 1567 struct uart_port *u; 1568 struct resource *resource; 1569 int ret; 1570 const struct tegra_uart_chip_data *cdata; 1571 1572 cdata = of_device_get_match_data(&pdev->dev); 1573 if (!cdata) { 1574 dev_err(&pdev->dev, "Error: No device match found\n"); 1575 return -ENODEV; 1576 } 1577 1578 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL); 1579 if (!tup) { 1580 dev_err(&pdev->dev, "Failed to allocate memory for tup\n"); 1581 return -ENOMEM; 1582 } 1583 1584 ret = tegra_uart_parse_dt(pdev, tup); 1585 if (ret < 0) 1586 return ret; 1587 1588 u = &tup->uport; 1589 u->dev = &pdev->dev; 1590 u->ops = &tegra_uart_ops; 1591 u->type = PORT_TEGRA; 1592 u->fifosize = 32; 1593 tup->cdata = cdata; 1594 1595 platform_set_drvdata(pdev, tup); 1596 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1597 if (!resource) { 1598 dev_err(&pdev->dev, "No IO memory resource\n"); 1599 return -ENODEV; 1600 } 1601 1602 u->mapbase = resource->start; 1603 u->membase = devm_ioremap_resource(&pdev->dev, resource); 1604 if (IS_ERR(u->membase)) 1605 return PTR_ERR(u->membase); 1606 1607 tup->uart_clk = devm_clk_get(&pdev->dev, NULL); 1608 if (IS_ERR(tup->uart_clk)) { 1609 dev_err(&pdev->dev, "Couldn't get the clock\n"); 1610 return PTR_ERR(tup->uart_clk); 1611 } 1612 1613 tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial"); 1614 if (IS_ERR(tup->rst)) { 1615 dev_err(&pdev->dev, "Couldn't get the reset\n"); 1616 return PTR_ERR(tup->rst); 1617 } 1618 1619 u->iotype = UPIO_MEM32; 1620 ret = platform_get_irq(pdev, 0); 1621 if (ret < 0) 1622 return ret; 1623 u->irq = ret; 1624 u->regshift = 2; 1625 ret = uart_add_one_port(&tegra_uart_driver, u); 1626 if (ret < 0) { 1627 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret); 1628 return ret; 1629 } 1630 return ret; 1631 } 1632 1633 static int tegra_uart_remove(struct platform_device *pdev) 1634 { 1635 struct tegra_uart_port *tup = platform_get_drvdata(pdev); 1636 struct uart_port *u = &tup->uport; 1637 1638 uart_remove_one_port(&tegra_uart_driver, u); 1639 return 0; 1640 } 1641 1642 #ifdef CONFIG_PM_SLEEP 1643 static int tegra_uart_suspend(struct device *dev) 1644 { 1645 struct tegra_uart_port *tup = dev_get_drvdata(dev); 1646 struct uart_port *u = &tup->uport; 1647 1648 return uart_suspend_port(&tegra_uart_driver, u); 1649 } 1650 1651 static int tegra_uart_resume(struct device *dev) 1652 { 1653 struct tegra_uart_port *tup = dev_get_drvdata(dev); 1654 struct uart_port *u = &tup->uport; 1655 1656 return uart_resume_port(&tegra_uart_driver, u); 1657 } 1658 #endif 1659 1660 static const struct dev_pm_ops tegra_uart_pm_ops = { 1661 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume) 1662 }; 1663 1664 static struct platform_driver tegra_uart_platform_driver = { 1665 .probe = tegra_uart_probe, 1666 .remove = tegra_uart_remove, 1667 .driver = { 1668 .name = "serial-tegra", 1669 .of_match_table = tegra_uart_of_match, 1670 .pm = &tegra_uart_pm_ops, 1671 }, 1672 }; 1673 1674 static int __init tegra_uart_init(void) 1675 { 1676 int ret; 1677 struct device_node *node; 1678 const struct of_device_id *match = NULL; 1679 const struct tegra_uart_chip_data *cdata = NULL; 1680 1681 node = of_find_matching_node(NULL, tegra_uart_of_match); 1682 if (node) 1683 match = of_match_node(tegra_uart_of_match, node); 1684 if (match) 1685 cdata = match->data; 1686 if (cdata) 1687 tegra_uart_driver.nr = cdata->uart_max_port; 1688 1689 ret = uart_register_driver(&tegra_uart_driver); 1690 if (ret < 0) { 1691 pr_err("Could not register %s driver\n", 1692 tegra_uart_driver.driver_name); 1693 return ret; 1694 } 1695 1696 ret = platform_driver_register(&tegra_uart_platform_driver); 1697 if (ret < 0) { 1698 pr_err("Uart platform driver register failed, e = %d\n", ret); 1699 uart_unregister_driver(&tegra_uart_driver); 1700 return ret; 1701 } 1702 return 0; 1703 } 1704 1705 static void __exit tegra_uart_exit(void) 1706 { 1707 pr_info("Unloading tegra uart driver\n"); 1708 platform_driver_unregister(&tegra_uart_platform_driver); 1709 uart_unregister_driver(&tegra_uart_driver); 1710 } 1711 1712 module_init(tegra_uart_init); 1713 module_exit(tegra_uart_exit); 1714 1715 MODULE_ALIAS("platform:serial-tegra"); 1716 MODULE_DESCRIPTION("High speed UART driver for tegra chipset"); 1717 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); 1718 MODULE_LICENSE("GPL v2"); 1719