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_reg.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 97 #ifdef CONFIG_SERIAL_8250_SHARE_IRQ 98 #define SERIAL8250_SHARE_IRQS 1 99 #else 100 #define SERIAL8250_SHARE_IRQS 0 101 #endif 102 103 #define SERIAL8250_PORT_FLAGS(_base, _irq, _flags) \ 104 { \ 105 .iobase = _base, \ 106 .irq = _irq, \ 107 .uartclk = 1843200, \ 108 .iotype = UPIO_PORT, \ 109 .flags = UPF_BOOT_AUTOCONF | (_flags), \ 110 } 111 112 #define SERIAL8250_PORT(_base, _irq) SERIAL8250_PORT_FLAGS(_base, _irq, 0) 113 114 115 static inline int serial_in(struct uart_8250_port *up, int offset) 116 { 117 return up->port.serial_in(&up->port, offset); 118 } 119 120 static inline void serial_out(struct uart_8250_port *up, int offset, int value) 121 { 122 up->port.serial_out(&up->port, offset, value); 123 } 124 125 /** 126 * serial_lsr_in - Read LSR register and preserve flags across reads 127 * @up: uart 8250 port 128 * 129 * Read LSR register and handle saving non-preserved flags across reads. 130 * The flags that are not preserved across reads are stored into 131 * up->lsr_saved_flags. 132 * 133 * Returns LSR value or'ed with the preserved flags (if any). 134 */ 135 static inline u16 serial_lsr_in(struct uart_8250_port *up) 136 { 137 u16 lsr = up->lsr_saved_flags; 138 139 lsr |= serial_in(up, UART_LSR); 140 up->lsr_saved_flags = lsr & up->lsr_save_mask; 141 142 return lsr; 143 } 144 145 /* 146 * For the 16C950 147 */ 148 static void serial_icr_write(struct uart_8250_port *up, int offset, int value) 149 { 150 serial_out(up, UART_SCR, offset); 151 serial_out(up, UART_ICR, value); 152 } 153 154 static unsigned int __maybe_unused serial_icr_read(struct uart_8250_port *up, 155 int offset) 156 { 157 unsigned int value; 158 159 serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); 160 serial_out(up, UART_SCR, offset); 161 value = serial_in(up, UART_ICR); 162 serial_icr_write(up, UART_ACR, up->acr); 163 164 return value; 165 } 166 167 void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p); 168 169 static inline u32 serial_dl_read(struct uart_8250_port *up) 170 { 171 return up->dl_read(up); 172 } 173 174 static inline void serial_dl_write(struct uart_8250_port *up, u32 value) 175 { 176 up->dl_write(up, value); 177 } 178 179 static inline bool serial8250_set_THRI(struct uart_8250_port *up) 180 { 181 /* Port locked to synchronize UART_IER access against the console. */ 182 lockdep_assert_held_once(&up->port.lock); 183 184 if (up->ier & UART_IER_THRI) 185 return false; 186 up->ier |= UART_IER_THRI; 187 serial_out(up, UART_IER, up->ier); 188 return true; 189 } 190 191 static inline bool serial8250_clear_THRI(struct uart_8250_port *up) 192 { 193 /* Port locked to synchronize UART_IER access against the console. */ 194 lockdep_assert_held_once(&up->port.lock); 195 196 if (!(up->ier & UART_IER_THRI)) 197 return false; 198 up->ier &= ~UART_IER_THRI; 199 serial_out(up, UART_IER, up->ier); 200 return true; 201 } 202 203 struct uart_8250_port *serial8250_get_port(int line); 204 205 void serial8250_rpm_get(struct uart_8250_port *p); 206 void serial8250_rpm_put(struct uart_8250_port *p); 207 208 void serial8250_rpm_get_tx(struct uart_8250_port *p); 209 void serial8250_rpm_put_tx(struct uart_8250_port *p); 210 211 int serial8250_em485_config(struct uart_port *port, struct ktermios *termios, 212 struct serial_rs485 *rs485); 213 void serial8250_em485_start_tx(struct uart_8250_port *p); 214 void serial8250_em485_stop_tx(struct uart_8250_port *p); 215 void serial8250_em485_destroy(struct uart_8250_port *p); 216 extern struct serial_rs485 serial8250_em485_supported; 217 218 /* MCR <-> TIOCM conversion */ 219 static inline int serial8250_TIOCM_to_MCR(int tiocm) 220 { 221 int mcr = 0; 222 223 if (tiocm & TIOCM_RTS) 224 mcr |= UART_MCR_RTS; 225 if (tiocm & TIOCM_DTR) 226 mcr |= UART_MCR_DTR; 227 if (tiocm & TIOCM_OUT1) 228 mcr |= UART_MCR_OUT1; 229 if (tiocm & TIOCM_OUT2) 230 mcr |= UART_MCR_OUT2; 231 if (tiocm & TIOCM_LOOP) 232 mcr |= UART_MCR_LOOP; 233 234 return mcr; 235 } 236 237 static inline int serial8250_MCR_to_TIOCM(int mcr) 238 { 239 int tiocm = 0; 240 241 if (mcr & UART_MCR_RTS) 242 tiocm |= TIOCM_RTS; 243 if (mcr & UART_MCR_DTR) 244 tiocm |= TIOCM_DTR; 245 if (mcr & UART_MCR_OUT1) 246 tiocm |= TIOCM_OUT1; 247 if (mcr & UART_MCR_OUT2) 248 tiocm |= TIOCM_OUT2; 249 if (mcr & UART_MCR_LOOP) 250 tiocm |= TIOCM_LOOP; 251 252 return tiocm; 253 } 254 255 /* MSR <-> TIOCM conversion */ 256 static inline int serial8250_MSR_to_TIOCM(int msr) 257 { 258 int tiocm = 0; 259 260 if (msr & UART_MSR_DCD) 261 tiocm |= TIOCM_CAR; 262 if (msr & UART_MSR_RI) 263 tiocm |= TIOCM_RNG; 264 if (msr & UART_MSR_DSR) 265 tiocm |= TIOCM_DSR; 266 if (msr & UART_MSR_CTS) 267 tiocm |= TIOCM_CTS; 268 269 return tiocm; 270 } 271 272 static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) 273 { 274 serial_out(up, UART_MCR, value); 275 276 if (up->gpios) 277 mctrl_gpio_set(up->gpios, serial8250_MCR_to_TIOCM(value)); 278 } 279 280 static inline int serial8250_in_MCR(struct uart_8250_port *up) 281 { 282 int mctrl; 283 284 mctrl = serial_in(up, UART_MCR); 285 286 if (up->gpios) { 287 unsigned int mctrl_gpio = 0; 288 289 mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); 290 mctrl |= serial8250_TIOCM_to_MCR(mctrl_gpio); 291 } 292 293 return mctrl; 294 } 295 296 #ifdef CONFIG_SERIAL_8250_PNP 297 int serial8250_pnp_init(void); 298 void serial8250_pnp_exit(void); 299 #else 300 static inline int serial8250_pnp_init(void) { return 0; } 301 static inline void serial8250_pnp_exit(void) { } 302 #endif 303 304 #ifdef CONFIG_SERIAL_8250_FINTEK 305 int fintek_8250_probe(struct uart_8250_port *uart); 306 #else 307 static inline int fintek_8250_probe(struct uart_8250_port *uart) { return 0; } 308 #endif 309 310 #ifdef CONFIG_ARCH_OMAP1 311 #include <linux/soc/ti/omap1-soc.h> 312 static inline int is_omap1_8250(struct uart_8250_port *pt) 313 { 314 int res; 315 316 switch (pt->port.mapbase) { 317 case OMAP1_UART1_BASE: 318 case OMAP1_UART2_BASE: 319 case OMAP1_UART3_BASE: 320 res = 1; 321 break; 322 default: 323 res = 0; 324 break; 325 } 326 327 return res; 328 } 329 330 static inline int is_omap1510_8250(struct uart_8250_port *pt) 331 { 332 if (!cpu_is_omap1510()) 333 return 0; 334 335 return is_omap1_8250(pt); 336 } 337 #else 338 static inline int is_omap1_8250(struct uart_8250_port *pt) 339 { 340 return 0; 341 } 342 static inline int is_omap1510_8250(struct uart_8250_port *pt) 343 { 344 return 0; 345 } 346 #endif 347 348 #ifdef CONFIG_SERIAL_8250_DMA 349 extern int serial8250_tx_dma(struct uart_8250_port *); 350 extern int serial8250_rx_dma(struct uart_8250_port *); 351 extern void serial8250_rx_dma_flush(struct uart_8250_port *); 352 extern int serial8250_request_dma(struct uart_8250_port *); 353 extern void serial8250_release_dma(struct uart_8250_port *); 354 355 static inline void serial8250_do_prepare_tx_dma(struct uart_8250_port *p) 356 { 357 struct uart_8250_dma *dma = p->dma; 358 359 if (dma->prepare_tx_dma) 360 dma->prepare_tx_dma(p); 361 } 362 363 static inline void serial8250_do_prepare_rx_dma(struct uart_8250_port *p) 364 { 365 struct uart_8250_dma *dma = p->dma; 366 367 if (dma->prepare_rx_dma) 368 dma->prepare_rx_dma(p); 369 } 370 371 static inline bool serial8250_tx_dma_running(struct uart_8250_port *p) 372 { 373 struct uart_8250_dma *dma = p->dma; 374 375 return dma && dma->tx_running; 376 } 377 #else 378 static inline int serial8250_tx_dma(struct uart_8250_port *p) 379 { 380 return -1; 381 } 382 static inline int serial8250_rx_dma(struct uart_8250_port *p) 383 { 384 return -1; 385 } 386 static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { } 387 static inline int serial8250_request_dma(struct uart_8250_port *p) 388 { 389 return -1; 390 } 391 static inline void serial8250_release_dma(struct uart_8250_port *p) { } 392 393 static inline bool serial8250_tx_dma_running(struct uart_8250_port *p) 394 { 395 return false; 396 } 397 #endif 398 399 static inline int ns16550a_goto_highspeed(struct uart_8250_port *up) 400 { 401 unsigned char status; 402 403 status = serial_in(up, 0x04); /* EXCR2 */ 404 #define PRESL(x) ((x) & 0x30) 405 if (PRESL(status) == 0x10) { 406 /* already in high speed mode */ 407 return 0; 408 } else { 409 status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */ 410 status |= 0x10; /* 1.625 divisor for baud_base --> 921600 */ 411 serial_out(up, 0x04, status); 412 } 413 return 1; 414 } 415 416 static inline int serial_index(struct uart_port *port) 417 { 418 return port->minor - 64; 419 } 420