1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Driver for 8250/16550-type serial ports 4 * 5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. 6 * 7 * Copyright (C) 2001 Russell King. 8 */ 9 10 #include <linux/bits.h> 11 #include <linux/serial_8250.h> 12 #include <linux/serial_core.h> 13 #include <linux/dmaengine.h> 14 15 #include "../serial_mctrl_gpio.h" 16 17 struct uart_8250_dma { 18 int (*tx_dma)(struct uart_8250_port *p); 19 int (*rx_dma)(struct uart_8250_port *p); 20 void (*prepare_tx_dma)(struct uart_8250_port *p); 21 void (*prepare_rx_dma)(struct uart_8250_port *p); 22 23 /* Filter function */ 24 dma_filter_fn fn; 25 /* Parameter to the filter function */ 26 void *rx_param; 27 void *tx_param; 28 29 struct dma_slave_config rxconf; 30 struct dma_slave_config txconf; 31 32 struct dma_chan *rxchan; 33 struct dma_chan *txchan; 34 35 /* Device address base for DMA operations */ 36 phys_addr_t rx_dma_addr; 37 phys_addr_t tx_dma_addr; 38 39 /* DMA address of the buffer in memory */ 40 dma_addr_t rx_addr; 41 dma_addr_t tx_addr; 42 43 dma_cookie_t rx_cookie; 44 dma_cookie_t tx_cookie; 45 46 void *rx_buf; 47 48 size_t rx_size; 49 size_t tx_size; 50 51 unsigned char tx_running; 52 unsigned char tx_err; 53 unsigned char rx_running; 54 }; 55 56 struct old_serial_port { 57 unsigned int uart; 58 unsigned int baud_base; 59 unsigned int port; 60 unsigned int irq; 61 upf_t flags; 62 unsigned char io_type; 63 unsigned char __iomem *iomem_base; 64 unsigned short iomem_reg_shift; 65 }; 66 67 struct serial8250_config { 68 const char *name; 69 unsigned short fifo_size; 70 unsigned short tx_loadsz; 71 unsigned char fcr; 72 unsigned char rxtrig_bytes[UART_FCR_R_TRIG_MAX_STATE]; 73 unsigned int flags; 74 }; 75 76 #define UART_CAP_FIFO BIT(8) /* UART has FIFO */ 77 #define UART_CAP_EFR BIT(9) /* UART has EFR */ 78 #define UART_CAP_SLEEP BIT(10) /* UART has IER sleep */ 79 #define UART_CAP_AFE BIT(11) /* MCR-based hw flow control */ 80 #define UART_CAP_UUE BIT(12) /* UART needs IER bit 6 set (Xscale) */ 81 #define UART_CAP_RTOIE BIT(13) /* UART needs IER bit 4 set (Xscale, Tegra) */ 82 #define UART_CAP_HFIFO BIT(14) /* UART has a "hidden" FIFO */ 83 #define UART_CAP_RPM BIT(15) /* Runtime PM is active while idle */ 84 #define UART_CAP_IRDA BIT(16) /* UART supports IrDA line discipline */ 85 #define UART_CAP_MINI BIT(17) /* Mini UART on BCM283X family lacks: 86 * STOP PARITY EPAR SPAR WLEN5 WLEN6 87 */ 88 #define UART_CAP_NOTEMT BIT(18) /* UART without interrupt on TEMT available */ 89 90 #define UART_BUG_QUOT BIT(0) /* UART has buggy quot LSB */ 91 #define UART_BUG_TXEN BIT(1) /* UART has buggy TX IIR status */ 92 #define UART_BUG_NOMSR BIT(2) /* UART has buggy MSR status bits (Au1x00) */ 93 #define UART_BUG_THRE BIT(3) /* UART has buggy THRE reassertion */ 94 #define UART_BUG_TXRACE BIT(5) /* UART Tx fails to set remote DR */ 95 96 /* Module parameters */ 97 #define UART_NR CONFIG_SERIAL_8250_NR_UARTS 98 99 extern unsigned int nr_uarts; 100 101 #define SERIAL8250_PORT_FLAGS(_base, _irq, _flags) \ 102 { \ 103 .iobase = _base, \ 104 .irq = _irq, \ 105 .uartclk = 1843200, \ 106 .iotype = UPIO_PORT, \ 107 .flags = UPF_BOOT_AUTOCONF | (_flags), \ 108 } 109 110 #define SERIAL8250_PORT(_base, _irq) SERIAL8250_PORT_FLAGS(_base, _irq, 0) 111 112 extern struct uart_driver serial8250_reg; 113 void serial8250_register_ports(struct uart_driver *drv, struct device *dev); 114 115 /* Legacy ISA bus related APIs */ 116 typedef void (*serial8250_isa_config_fn)(int, struct uart_port *, u32 *); 117 extern serial8250_isa_config_fn serial8250_isa_config; 118 119 void serial8250_isa_init_ports(void); 120 121 extern struct platform_device *serial8250_isa_devs; 122 123 extern const struct uart_ops *univ8250_port_base_ops; 124 extern struct uart_ops univ8250_port_ops; 125 126 static inline int serial_in(struct uart_8250_port *up, int offset) 127 { 128 return up->port.serial_in(&up->port, offset); 129 } 130 131 static inline void serial_out(struct uart_8250_port *up, int offset, int value) 132 { 133 up->port.serial_out(&up->port, offset, value); 134 } 135 136 /** 137 * serial_lsr_in - Read LSR register and preserve flags across reads 138 * @up: uart 8250 port 139 * 140 * Read LSR register and handle saving non-preserved flags across reads. 141 * The flags that are not preserved across reads are stored into 142 * up->lsr_saved_flags. 143 * 144 * Returns LSR value or'ed with the preserved flags (if any). 145 */ 146 static inline u16 serial_lsr_in(struct uart_8250_port *up) 147 { 148 u16 lsr = up->lsr_saved_flags; 149 150 lsr |= serial_in(up, UART_LSR); 151 up->lsr_saved_flags = lsr & up->lsr_save_mask; 152 153 return lsr; 154 } 155 156 /* 157 * For the 16C950 158 */ 159 static void serial_icr_write(struct uart_8250_port *up, int offset, int value) 160 { 161 serial_out(up, UART_SCR, offset); 162 serial_out(up, UART_ICR, value); 163 } 164 165 static unsigned int __maybe_unused serial_icr_read(struct uart_8250_port *up, 166 int offset) 167 { 168 unsigned int value; 169 170 serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); 171 serial_out(up, UART_SCR, offset); 172 value = serial_in(up, UART_ICR); 173 serial_icr_write(up, UART_ACR, up->acr); 174 175 return value; 176 } 177 178 void serial8250_clear_fifos(struct uart_8250_port *p); 179 void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p); 180 void serial8250_fifo_wait_for_lsr_thre(struct uart_8250_port *up, 181 struct nbcon_write_context *wctxt, 182 unsigned int count); 183 184 void serial8250_rpm_get(struct uart_8250_port *p); 185 void serial8250_rpm_put(struct uart_8250_port *p); 186 DEFINE_GUARD(serial8250_rpm, struct uart_8250_port *, 187 serial8250_rpm_get(_T), serial8250_rpm_put(_T)); 188 189 static inline u32 serial_dl_read(struct uart_8250_port *up) 190 { 191 return up->dl_read(up); 192 } 193 194 static inline void serial_dl_write(struct uart_8250_port *up, u32 value) 195 { 196 up->dl_write(up, value); 197 } 198 199 static inline bool serial8250_set_THRI(struct uart_8250_port *up) 200 { 201 /* Port locked to synchronize UART_IER access against the console. */ 202 lockdep_assert_held_once(&up->port.lock); 203 204 if (up->ier & UART_IER_THRI) 205 return false; 206 up->ier |= UART_IER_THRI; 207 serial_out(up, UART_IER, up->ier); 208 return true; 209 } 210 211 static inline bool serial8250_clear_THRI(struct uart_8250_port *up) 212 { 213 /* Port locked to synchronize UART_IER access against the console. */ 214 lockdep_assert_held_once(&up->port.lock); 215 216 if (!(up->ier & UART_IER_THRI)) 217 return false; 218 up->ier &= ~UART_IER_THRI; 219 serial_out(up, UART_IER, up->ier); 220 return true; 221 } 222 223 struct uart_8250_port *serial8250_setup_port(int index); 224 struct uart_8250_port *serial8250_get_port(int line); 225 226 int serial8250_em485_config(struct uart_port *port, struct ktermios *termios, 227 struct serial_rs485 *rs485); 228 void serial8250_em485_start_tx(struct uart_8250_port *p, bool toggle_ier); 229 void serial8250_em485_stop_tx(struct uart_8250_port *p, bool toggle_ier); 230 void serial8250_em485_destroy(struct uart_8250_port *p); 231 extern struct serial_rs485 serial8250_em485_supported; 232 233 /* MCR <-> TIOCM conversion */ 234 static inline int serial8250_TIOCM_to_MCR(int tiocm) 235 { 236 int mcr = 0; 237 238 if (tiocm & TIOCM_RTS) 239 mcr |= UART_MCR_RTS; 240 if (tiocm & TIOCM_DTR) 241 mcr |= UART_MCR_DTR; 242 if (tiocm & TIOCM_OUT1) 243 mcr |= UART_MCR_OUT1; 244 if (tiocm & TIOCM_OUT2) 245 mcr |= UART_MCR_OUT2; 246 if (tiocm & TIOCM_LOOP) 247 mcr |= UART_MCR_LOOP; 248 249 return mcr; 250 } 251 252 static inline int serial8250_MCR_to_TIOCM(int mcr) 253 { 254 int tiocm = 0; 255 256 if (mcr & UART_MCR_RTS) 257 tiocm |= TIOCM_RTS; 258 if (mcr & UART_MCR_DTR) 259 tiocm |= TIOCM_DTR; 260 if (mcr & UART_MCR_OUT1) 261 tiocm |= TIOCM_OUT1; 262 if (mcr & UART_MCR_OUT2) 263 tiocm |= TIOCM_OUT2; 264 if (mcr & UART_MCR_LOOP) 265 tiocm |= TIOCM_LOOP; 266 267 return tiocm; 268 } 269 270 /* MSR <-> TIOCM conversion */ 271 static inline int serial8250_MSR_to_TIOCM(int msr) 272 { 273 int tiocm = 0; 274 275 if (msr & UART_MSR_DCD) 276 tiocm |= TIOCM_CAR; 277 if (msr & UART_MSR_RI) 278 tiocm |= TIOCM_RNG; 279 if (msr & UART_MSR_DSR) 280 tiocm |= TIOCM_DSR; 281 if (msr & UART_MSR_CTS) 282 tiocm |= TIOCM_CTS; 283 284 return tiocm; 285 } 286 287 static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) 288 { 289 serial_out(up, UART_MCR, value); 290 291 if (up->gpios) 292 mctrl_gpio_set(up->gpios, serial8250_MCR_to_TIOCM(value)); 293 } 294 295 static inline int serial8250_in_MCR(struct uart_8250_port *up) 296 { 297 int mctrl; 298 299 mctrl = serial_in(up, UART_MCR); 300 301 if (up->gpios) { 302 unsigned int mctrl_gpio = 0; 303 304 mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); 305 mctrl |= serial8250_TIOCM_to_MCR(mctrl_gpio); 306 } 307 308 return mctrl; 309 } 310 311 #ifdef CONFIG_SERIAL_8250_PNP 312 int serial8250_pnp_init(void); 313 void serial8250_pnp_exit(void); 314 #else 315 static inline int serial8250_pnp_init(void) { return 0; } 316 static inline void serial8250_pnp_exit(void) { } 317 #endif 318 319 #ifdef CONFIG_SERIAL_8250_RSA 320 void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops); 321 void rsa_enable(struct uart_8250_port *up); 322 void rsa_disable(struct uart_8250_port *up); 323 void rsa_autoconfig(struct uart_8250_port *up); 324 void rsa_reset(struct uart_8250_port *up); 325 #else 326 static inline void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops) { } 327 static inline void rsa_enable(struct uart_8250_port *up) {} 328 static inline void rsa_disable(struct uart_8250_port *up) {} 329 static inline void rsa_autoconfig(struct uart_8250_port *up) {} 330 static inline void rsa_reset(struct uart_8250_port *up) {} 331 #endif 332 333 #ifdef CONFIG_SERIAL_8250_FINTEK 334 int fintek_8250_probe(struct uart_8250_port *uart); 335 #else 336 static inline int fintek_8250_probe(struct uart_8250_port *uart) { return 0; } 337 #endif 338 339 #if IS_REACHABLE(CONFIG_SERIAL_8250_HUB6) 340 bool hub6_match_port(const struct uart_port *port1, const struct uart_port *port2); 341 #else 342 static inline bool hub6_match_port(const struct uart_port *port1, const struct uart_port *port2) 343 { return false; } 344 #endif 345 346 #ifdef CONFIG_ARCH_OMAP1 347 #include <linux/soc/ti/omap1-soc.h> 348 static inline int is_omap1_8250(struct uart_8250_port *pt) 349 { 350 int res; 351 352 switch (pt->port.mapbase) { 353 case OMAP1_UART1_BASE: 354 case OMAP1_UART2_BASE: 355 case OMAP1_UART3_BASE: 356 res = 1; 357 break; 358 default: 359 res = 0; 360 break; 361 } 362 363 return res; 364 } 365 366 static inline int is_omap1510_8250(struct uart_8250_port *pt) 367 { 368 if (!cpu_is_omap1510()) 369 return 0; 370 371 return is_omap1_8250(pt); 372 } 373 #else 374 static inline int is_omap1_8250(struct uart_8250_port *pt) 375 { 376 return 0; 377 } 378 static inline int is_omap1510_8250(struct uart_8250_port *pt) 379 { 380 return 0; 381 } 382 #endif 383 384 #ifdef CONFIG_SERIAL_8250_DMA 385 extern int serial8250_tx_dma(struct uart_8250_port *); 386 extern void serial8250_tx_dma_flush(struct uart_8250_port *); 387 extern int serial8250_rx_dma(struct uart_8250_port *); 388 extern void serial8250_rx_dma_flush(struct uart_8250_port *); 389 extern int serial8250_request_dma(struct uart_8250_port *); 390 extern void serial8250_release_dma(struct uart_8250_port *); 391 392 static inline void serial8250_do_prepare_tx_dma(struct uart_8250_port *p) 393 { 394 struct uart_8250_dma *dma = p->dma; 395 396 if (dma->prepare_tx_dma) 397 dma->prepare_tx_dma(p); 398 } 399 400 static inline void serial8250_do_prepare_rx_dma(struct uart_8250_port *p) 401 { 402 struct uart_8250_dma *dma = p->dma; 403 404 if (dma->prepare_rx_dma) 405 dma->prepare_rx_dma(p); 406 } 407 408 static inline bool serial8250_tx_dma_running(struct uart_8250_port *p) 409 { 410 struct uart_8250_dma *dma = p->dma; 411 412 return dma && dma->tx_running; 413 } 414 415 static inline void serial8250_tx_dma_pause(struct uart_8250_port *p) 416 { 417 struct uart_8250_dma *dma = p->dma; 418 419 if (!dma->tx_running) 420 return; 421 422 dmaengine_pause(dma->txchan); 423 } 424 425 static inline void serial8250_tx_dma_resume(struct uart_8250_port *p) 426 { 427 struct uart_8250_dma *dma = p->dma; 428 429 if (!dma->tx_running) 430 return; 431 432 dmaengine_resume(dma->txchan); 433 } 434 #else 435 static inline int serial8250_tx_dma(struct uart_8250_port *p) 436 { 437 return -1; 438 } 439 static inline void serial8250_tx_dma_flush(struct uart_8250_port *p) { } 440 static inline int serial8250_rx_dma(struct uart_8250_port *p) 441 { 442 return -1; 443 } 444 static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { } 445 static inline int serial8250_request_dma(struct uart_8250_port *p) 446 { 447 return -1; 448 } 449 static inline void serial8250_release_dma(struct uart_8250_port *p) { } 450 451 static inline bool serial8250_tx_dma_running(struct uart_8250_port *p) 452 { 453 return false; 454 } 455 456 static inline void serial8250_tx_dma_pause(struct uart_8250_port *p) { } 457 static inline void serial8250_tx_dma_resume(struct uart_8250_port *p) { } 458 #endif 459 460 static inline int ns16550a_goto_highspeed(struct uart_8250_port *up) 461 { 462 unsigned char status; 463 464 status = serial_in(up, 0x04); /* EXCR2 */ 465 #define PRESL(x) ((x) & 0x30) 466 if (PRESL(status) == 0x10) { 467 /* already in high speed mode */ 468 return 0; 469 } else { 470 status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */ 471 status |= 0x10; /* 1.625 divisor for baud_base --> 921600 */ 472 serial_out(up, 0x04, status); 473 } 474 return 1; 475 } 476 477 static inline int serial_index(struct uart_port *port) 478 { 479 return port->minor - 64; 480 } 481