1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 8250-core based driver for the OMAP internal UART 4 * 5 * based on omap-serial.c, Copyright (C) 2010 Texas Instruments. 6 * 7 * Copyright (C) 2014 Sebastian Andrzej Siewior 8 * 9 */ 10 11 #include <linux/clk.h> 12 #include <linux/device.h> 13 #include <linux/io.h> 14 #include <linux/module.h> 15 #include <linux/serial_8250.h> 16 #include <linux/serial_reg.h> 17 #include <linux/tty_flip.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/of.h> 21 #include <linux/of_gpio.h> 22 #include <linux/of_irq.h> 23 #include <linux/delay.h> 24 #include <linux/pm_runtime.h> 25 #include <linux/console.h> 26 #include <linux/pm_qos.h> 27 #include <linux/pm_wakeirq.h> 28 #include <linux/dma-mapping.h> 29 #include <linux/sys_soc.h> 30 31 #include "8250.h" 32 33 #define DEFAULT_CLK_SPEED 48000000 34 #define OMAP_UART_REGSHIFT 2 35 36 #define UART_ERRATA_i202_MDR1_ACCESS (1 << 0) 37 #define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1) 38 #define OMAP_DMA_TX_KICK (1 << 2) 39 /* 40 * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015. 41 * The same errata is applicable to AM335x and DRA7x processors too. 42 */ 43 #define UART_ERRATA_CLOCK_DISABLE (1 << 3) 44 #define UART_HAS_EFR2 BIT(4) 45 #define UART_HAS_RHR_IT_DIS BIT(5) 46 #define UART_RX_TIMEOUT_QUIRK BIT(6) 47 #define UART_HAS_NATIVE_RS485 BIT(7) 48 49 #define OMAP_UART_FCR_RX_TRIG 6 50 #define OMAP_UART_FCR_TX_TRIG 4 51 52 /* SCR register bitmasks */ 53 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7) 54 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6) 55 #define OMAP_UART_SCR_TX_EMPTY (1 << 3) 56 #define OMAP_UART_SCR_DMAMODE_MASK (3 << 1) 57 #define OMAP_UART_SCR_DMAMODE_1 (1 << 1) 58 #define OMAP_UART_SCR_DMAMODE_CTL (1 << 0) 59 60 /* MVR register bitmasks */ 61 #define OMAP_UART_MVR_SCHEME_SHIFT 30 62 #define OMAP_UART_LEGACY_MVR_MAJ_MASK 0xf0 63 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT 4 64 #define OMAP_UART_LEGACY_MVR_MIN_MASK 0x0f 65 #define OMAP_UART_MVR_MAJ_MASK 0x700 66 #define OMAP_UART_MVR_MAJ_SHIFT 8 67 #define OMAP_UART_MVR_MIN_MASK 0x3f 68 69 /* SYSC register bitmasks */ 70 #define OMAP_UART_SYSC_SOFTRESET (1 << 1) 71 72 /* SYSS register bitmasks */ 73 #define OMAP_UART_SYSS_RESETDONE (1 << 0) 74 75 #define UART_TI752_TLR_TX 0 76 #define UART_TI752_TLR_RX 4 77 78 #define TRIGGER_TLR_MASK(x) ((x & 0x3c) >> 2) 79 #define TRIGGER_FCR_MASK(x) (x & 3) 80 81 /* Enable XON/XOFF flow control on output */ 82 #define OMAP_UART_SW_TX 0x08 83 /* Enable XON/XOFF flow control on input */ 84 #define OMAP_UART_SW_RX 0x02 85 86 #define OMAP_UART_WER_MOD_WKUP 0x7f 87 #define OMAP_UART_TX_WAKEUP_EN (1 << 7) 88 89 #define TX_TRIGGER 1 90 #define RX_TRIGGER 48 91 92 #define OMAP_UART_TCR_RESTORE(x) ((x / 4) << 4) 93 #define OMAP_UART_TCR_HALT(x) ((x / 4) << 0) 94 95 #define UART_BUILD_REVISION(x, y) (((x) << 8) | (y)) 96 97 #define OMAP_UART_REV_46 0x0406 98 #define OMAP_UART_REV_52 0x0502 99 #define OMAP_UART_REV_63 0x0603 100 101 /* Interrupt Enable Register 2 */ 102 #define UART_OMAP_IER2 0x1B 103 #define UART_OMAP_IER2_RHR_IT_DIS BIT(2) 104 105 /* Mode Definition Register 3 */ 106 #define UART_OMAP_MDR3 0x20 107 #define UART_OMAP_MDR3_DIR_POL BIT(3) 108 #define UART_OMAP_MDR3_DIR_EN BIT(4) 109 110 /* Enhanced features register 2 */ 111 #define UART_OMAP_EFR2 0x23 112 #define UART_OMAP_EFR2_TIMEOUT_BEHAVE BIT(6) 113 114 /* RX FIFO occupancy indicator */ 115 #define UART_OMAP_RX_LVL 0x19 116 117 struct omap8250_priv { 118 void __iomem *membase; 119 int line; 120 u8 habit; 121 u8 mdr1; 122 u8 mdr3; 123 u8 efr; 124 u8 scr; 125 u8 wer; 126 u8 xon; 127 u8 xoff; 128 u8 delayed_restore; 129 u16 quot; 130 131 u8 tx_trigger; 132 u8 rx_trigger; 133 bool is_suspending; 134 int wakeirq; 135 int wakeups_enabled; 136 u32 latency; 137 u32 calc_latency; 138 struct pm_qos_request pm_qos_request; 139 struct work_struct qos_work; 140 struct uart_8250_dma omap8250_dma; 141 spinlock_t rx_dma_lock; 142 bool rx_dma_broken; 143 bool throttled; 144 }; 145 146 struct omap8250_dma_params { 147 u32 rx_size; 148 u8 rx_trigger; 149 u8 tx_trigger; 150 }; 151 152 struct omap8250_platdata { 153 struct omap8250_dma_params *dma_params; 154 u8 habit; 155 }; 156 157 #ifdef CONFIG_SERIAL_8250_DMA 158 static void omap_8250_rx_dma_flush(struct uart_8250_port *p); 159 #else 160 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } 161 #endif 162 163 static u32 uart_read(struct omap8250_priv *priv, u32 reg) 164 { 165 return readl(priv->membase + (reg << OMAP_UART_REGSHIFT)); 166 } 167 168 /* Timeout low and High */ 169 #define UART_OMAP_TO_L 0x26 170 #define UART_OMAP_TO_H 0x27 171 172 /* 173 * Called on runtime PM resume path from omap8250_restore_regs(), and 174 * omap8250_set_mctrl(). 175 */ 176 static void __omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 177 { 178 struct uart_8250_port *up = up_to_u8250p(port); 179 struct omap8250_priv *priv = up->port.private_data; 180 u8 lcr; 181 182 serial8250_do_set_mctrl(port, mctrl); 183 184 if (!mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS)) { 185 /* 186 * Turn off autoRTS if RTS is lowered and restore autoRTS 187 * setting if RTS is raised 188 */ 189 lcr = serial_in(up, UART_LCR); 190 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 191 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) 192 priv->efr |= UART_EFR_RTS; 193 else 194 priv->efr &= ~UART_EFR_RTS; 195 serial_out(up, UART_EFR, priv->efr); 196 serial_out(up, UART_LCR, lcr); 197 } 198 } 199 200 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 201 { 202 int err; 203 204 err = pm_runtime_resume_and_get(port->dev); 205 if (err) 206 return; 207 208 __omap8250_set_mctrl(port, mctrl); 209 210 pm_runtime_mark_last_busy(port->dev); 211 pm_runtime_put_autosuspend(port->dev); 212 } 213 214 /* 215 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) 216 * The access to uart register after MDR1 Access 217 * causes UART to corrupt data. 218 * 219 * Need a delay = 220 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS) 221 * give 10 times as much 222 */ 223 static void omap_8250_mdr1_errataset(struct uart_8250_port *up, 224 struct omap8250_priv *priv) 225 { 226 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 227 udelay(2); 228 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT | 229 UART_FCR_CLEAR_RCVR); 230 } 231 232 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud, 233 struct omap8250_priv *priv) 234 { 235 unsigned int uartclk = port->uartclk; 236 unsigned int div_13, div_16; 237 unsigned int abs_d13, abs_d16; 238 239 /* 240 * Old custom speed handling. 241 */ 242 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) { 243 priv->quot = port->custom_divisor & UART_DIV_MAX; 244 /* 245 * I assume that nobody is using this. But hey, if somebody 246 * would like to specify the divisor _and_ the mode then the 247 * driver is ready and waiting for it. 248 */ 249 if (port->custom_divisor & (1 << 16)) 250 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 251 else 252 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 253 return; 254 } 255 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud); 256 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud); 257 258 if (!div_13) 259 div_13 = 1; 260 if (!div_16) 261 div_16 = 1; 262 263 abs_d13 = abs(baud - uartclk / 13 / div_13); 264 abs_d16 = abs(baud - uartclk / 16 / div_16); 265 266 if (abs_d13 >= abs_d16) { 267 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 268 priv->quot = div_16; 269 } else { 270 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 271 priv->quot = div_13; 272 } 273 } 274 275 static void omap8250_update_scr(struct uart_8250_port *up, 276 struct omap8250_priv *priv) 277 { 278 u8 old_scr; 279 280 old_scr = serial_in(up, UART_OMAP_SCR); 281 if (old_scr == priv->scr) 282 return; 283 284 /* 285 * The manual recommends not to enable the DMA mode selector in the SCR 286 * (instead of the FCR) register _and_ selecting the DMA mode as one 287 * register write because this may lead to malfunction. 288 */ 289 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK) 290 serial_out(up, UART_OMAP_SCR, 291 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK); 292 serial_out(up, UART_OMAP_SCR, priv->scr); 293 } 294 295 static void omap8250_update_mdr1(struct uart_8250_port *up, 296 struct omap8250_priv *priv) 297 { 298 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS) 299 omap_8250_mdr1_errataset(up, priv); 300 else 301 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 302 } 303 304 static void omap8250_restore_regs(struct uart_8250_port *up) 305 { 306 struct omap8250_priv *priv = up->port.private_data; 307 struct uart_8250_dma *dma = up->dma; 308 u8 mcr = serial8250_in_MCR(up); 309 310 /* Port locked to synchronize UART_IER access against the console. */ 311 lockdep_assert_held_once(&up->port.lock); 312 313 if (dma && dma->tx_running) { 314 /* 315 * TCSANOW requests the change to occur immediately however if 316 * we have a TX-DMA operation in progress then it has been 317 * observed that it might stall and never complete. Therefore we 318 * delay DMA completes to prevent this hang from happen. 319 */ 320 priv->delayed_restore = 1; 321 return; 322 } 323 324 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 325 serial_out(up, UART_EFR, UART_EFR_ECB); 326 327 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); 328 serial8250_out_MCR(up, mcr | UART_MCR_TCRTLR); 329 serial_out(up, UART_FCR, up->fcr); 330 331 omap8250_update_scr(up, priv); 332 333 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 334 335 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) | 336 OMAP_UART_TCR_HALT(52)); 337 serial_out(up, UART_TI752_TLR, 338 TRIGGER_TLR_MASK(priv->tx_trigger) << UART_TI752_TLR_TX | 339 TRIGGER_TLR_MASK(priv->rx_trigger) << UART_TI752_TLR_RX); 340 341 serial_out(up, UART_LCR, 0); 342 343 /* drop TCR + TLR access, we setup XON/XOFF later */ 344 serial8250_out_MCR(up, mcr); 345 346 serial_out(up, UART_IER, up->ier); 347 348 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 349 serial_dl_write(up, priv->quot); 350 351 serial_out(up, UART_EFR, priv->efr); 352 353 /* Configure flow control */ 354 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 355 serial_out(up, UART_XON1, priv->xon); 356 serial_out(up, UART_XOFF1, priv->xoff); 357 358 serial_out(up, UART_LCR, up->lcr); 359 360 omap8250_update_mdr1(up, priv); 361 362 __omap8250_set_mctrl(&up->port, up->port.mctrl); 363 364 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 365 366 if (up->port.rs485.flags & SER_RS485_ENABLED && 367 up->port.rs485_config == serial8250_em485_config) 368 serial8250_em485_stop_tx(up); 369 } 370 371 /* 372 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have 373 * some differences in how we want to handle flow control. 374 */ 375 static void omap_8250_set_termios(struct uart_port *port, 376 struct ktermios *termios, 377 const struct ktermios *old) 378 { 379 struct uart_8250_port *up = up_to_u8250p(port); 380 struct omap8250_priv *priv = up->port.private_data; 381 unsigned char cval = 0; 382 unsigned int baud; 383 384 cval = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag)); 385 386 if (termios->c_cflag & CSTOPB) 387 cval |= UART_LCR_STOP; 388 if (termios->c_cflag & PARENB) 389 cval |= UART_LCR_PARITY; 390 if (!(termios->c_cflag & PARODD)) 391 cval |= UART_LCR_EPAR; 392 if (termios->c_cflag & CMSPAR) 393 cval |= UART_LCR_SPAR; 394 395 /* 396 * Ask the core to calculate the divisor for us. 397 */ 398 baud = uart_get_baud_rate(port, termios, old, 399 port->uartclk / 16 / UART_DIV_MAX, 400 port->uartclk / 13); 401 omap_8250_get_divisor(port, baud, priv); 402 403 /* 404 * Ok, we're now changing the port state. Do it with 405 * interrupts disabled. 406 */ 407 pm_runtime_get_sync(port->dev); 408 spin_lock_irq(&port->lock); 409 410 /* 411 * Update the per-port timeout. 412 */ 413 uart_update_timeout(port, termios->c_cflag, baud); 414 415 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR; 416 if (termios->c_iflag & INPCK) 417 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE; 418 if (termios->c_iflag & (IGNBRK | PARMRK)) 419 up->port.read_status_mask |= UART_LSR_BI; 420 421 /* 422 * Characters to ignore 423 */ 424 up->port.ignore_status_mask = 0; 425 if (termios->c_iflag & IGNPAR) 426 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE; 427 if (termios->c_iflag & IGNBRK) { 428 up->port.ignore_status_mask |= UART_LSR_BI; 429 /* 430 * If we're ignoring parity and break indicators, 431 * ignore overruns too (for real raw support). 432 */ 433 if (termios->c_iflag & IGNPAR) 434 up->port.ignore_status_mask |= UART_LSR_OE; 435 } 436 437 /* 438 * ignore all characters if CREAD is not set 439 */ 440 if ((termios->c_cflag & CREAD) == 0) 441 up->port.ignore_status_mask |= UART_LSR_DR; 442 443 /* 444 * Modem status interrupts 445 */ 446 up->ier &= ~UART_IER_MSI; 447 if (UART_ENABLE_MS(&up->port, termios->c_cflag)) 448 up->ier |= UART_IER_MSI; 449 450 up->lcr = cval; 451 /* Up to here it was mostly serial8250_do_set_termios() */ 452 453 /* 454 * We enable TRIG_GRANU for RX and TX and additionally we set 455 * SCR_TX_EMPTY bit. The result is the following: 456 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt. 457 * - less than RX_TRIGGER number of bytes will also cause an interrupt 458 * once the UART decides that there no new bytes arriving. 459 * - Once THRE is enabled, the interrupt will be fired once the FIFO is 460 * empty - the trigger level is ignored here. 461 * 462 * Once DMA is enabled: 463 * - UART will assert the TX DMA line once there is room for TX_TRIGGER 464 * bytes in the TX FIFO. On each assert the DMA engine will move 465 * TX_TRIGGER bytes into the FIFO. 466 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in 467 * the FIFO and move RX_TRIGGER bytes. 468 * This is because threshold and trigger values are the same. 469 */ 470 up->fcr = UART_FCR_ENABLE_FIFO; 471 up->fcr |= TRIGGER_FCR_MASK(priv->tx_trigger) << OMAP_UART_FCR_TX_TRIG; 472 up->fcr |= TRIGGER_FCR_MASK(priv->rx_trigger) << OMAP_UART_FCR_RX_TRIG; 473 474 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY | 475 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK; 476 477 if (up->dma) 478 priv->scr |= OMAP_UART_SCR_DMAMODE_1 | 479 OMAP_UART_SCR_DMAMODE_CTL; 480 481 priv->xon = termios->c_cc[VSTART]; 482 priv->xoff = termios->c_cc[VSTOP]; 483 484 priv->efr = 0; 485 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); 486 487 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && 488 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) && 489 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_CTS)) { 490 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ 491 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; 492 priv->efr |= UART_EFR_CTS; 493 } else if (up->port.flags & UPF_SOFT_FLOW) { 494 /* 495 * OMAP rx s/w flow control is borked; the transmitter remains 496 * stuck off even if rx flow control is subsequently disabled 497 */ 498 499 /* 500 * IXOFF Flag: 501 * Enable XON/XOFF flow control on output. 502 * Transmit XON1, XOFF1 503 */ 504 if (termios->c_iflag & IXOFF) { 505 up->port.status |= UPSTAT_AUTOXOFF; 506 priv->efr |= OMAP_UART_SW_TX; 507 } 508 } 509 omap8250_restore_regs(up); 510 511 spin_unlock_irq(&up->port.lock); 512 pm_runtime_mark_last_busy(port->dev); 513 pm_runtime_put_autosuspend(port->dev); 514 515 /* calculate wakeup latency constraint */ 516 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud; 517 priv->latency = priv->calc_latency; 518 519 schedule_work(&priv->qos_work); 520 521 /* Don't rewrite B0 */ 522 if (tty_termios_baud_rate(termios)) 523 tty_termios_encode_baud_rate(termios, baud, baud); 524 } 525 526 /* same as 8250 except that we may have extra flow bits set in EFR */ 527 static void omap_8250_pm(struct uart_port *port, unsigned int state, 528 unsigned int oldstate) 529 { 530 struct uart_8250_port *up = up_to_u8250p(port); 531 u8 efr; 532 533 pm_runtime_get_sync(port->dev); 534 535 /* Synchronize UART_IER access against the console. */ 536 spin_lock_irq(&port->lock); 537 538 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 539 efr = serial_in(up, UART_EFR); 540 serial_out(up, UART_EFR, efr | UART_EFR_ECB); 541 serial_out(up, UART_LCR, 0); 542 543 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0); 544 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 545 serial_out(up, UART_EFR, efr); 546 serial_out(up, UART_LCR, 0); 547 548 spin_unlock_irq(&port->lock); 549 550 pm_runtime_mark_last_busy(port->dev); 551 pm_runtime_put_autosuspend(port->dev); 552 } 553 554 static void omap_serial_fill_features_erratas(struct uart_8250_port *up, 555 struct omap8250_priv *priv) 556 { 557 static const struct soc_device_attribute k3_soc_devices[] = { 558 { .family = "AM65X", }, 559 { .family = "J721E", .revision = "SR1.0" }, 560 { /* sentinel */ } 561 }; 562 u32 mvr, scheme; 563 u16 revision, major, minor; 564 565 mvr = uart_read(priv, UART_OMAP_MVER); 566 567 /* Check revision register scheme */ 568 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT; 569 570 switch (scheme) { 571 case 0: /* Legacy Scheme: OMAP2/3 */ 572 /* MINOR_REV[0:4], MAJOR_REV[4:7] */ 573 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >> 574 OMAP_UART_LEGACY_MVR_MAJ_SHIFT; 575 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK); 576 break; 577 case 1: 578 /* New Scheme: OMAP4+ */ 579 /* MINOR_REV[0:5], MAJOR_REV[8:10] */ 580 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >> 581 OMAP_UART_MVR_MAJ_SHIFT; 582 minor = (mvr & OMAP_UART_MVR_MIN_MASK); 583 break; 584 default: 585 dev_warn(up->port.dev, 586 "Unknown revision, defaulting to highest\n"); 587 /* highest possible revision */ 588 major = 0xff; 589 minor = 0xff; 590 } 591 /* normalize revision for the driver */ 592 revision = UART_BUILD_REVISION(major, minor); 593 594 switch (revision) { 595 case OMAP_UART_REV_46: 596 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS; 597 break; 598 case OMAP_UART_REV_52: 599 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 600 OMAP_UART_WER_HAS_TX_WAKEUP; 601 break; 602 case OMAP_UART_REV_63: 603 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 604 OMAP_UART_WER_HAS_TX_WAKEUP; 605 break; 606 default: 607 break; 608 } 609 610 /* 611 * AM65x SR1.0, AM65x SR2.0 and J721e SR1.0 don't 612 * don't have RHR_IT_DIS bit in IER2 register. So drop to flag 613 * to enable errata workaround. 614 */ 615 if (soc_device_match(k3_soc_devices)) 616 priv->habit &= ~UART_HAS_RHR_IT_DIS; 617 } 618 619 static void omap8250_uart_qos_work(struct work_struct *work) 620 { 621 struct omap8250_priv *priv; 622 623 priv = container_of(work, struct omap8250_priv, qos_work); 624 cpu_latency_qos_update_request(&priv->pm_qos_request, priv->latency); 625 } 626 627 #ifdef CONFIG_SERIAL_8250_DMA 628 static int omap_8250_dma_handle_irq(struct uart_port *port); 629 #endif 630 631 static irqreturn_t omap8250_irq(int irq, void *dev_id) 632 { 633 struct omap8250_priv *priv = dev_id; 634 struct uart_8250_port *up = serial8250_get_port(priv->line); 635 struct uart_port *port = &up->port; 636 unsigned int iir, lsr; 637 int ret; 638 639 #ifdef CONFIG_SERIAL_8250_DMA 640 if (up->dma) { 641 ret = omap_8250_dma_handle_irq(port); 642 return IRQ_RETVAL(ret); 643 } 644 #endif 645 646 serial8250_rpm_get(up); 647 lsr = serial_port_in(port, UART_LSR); 648 iir = serial_port_in(port, UART_IIR); 649 ret = serial8250_handle_irq(port, iir); 650 651 /* 652 * On K3 SoCs, it is observed that RX TIMEOUT is signalled after 653 * FIFO has been drained or erroneously. 654 * So apply solution of Errata i2310 as mentioned in 655 * https://www.ti.com/lit/pdf/sprz536 656 */ 657 if (priv->habit & UART_RX_TIMEOUT_QUIRK && 658 (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT && 659 serial_port_in(port, UART_OMAP_RX_LVL) == 0) { 660 unsigned char efr2, timeout_h, timeout_l; 661 662 efr2 = serial_in(up, UART_OMAP_EFR2); 663 timeout_h = serial_in(up, UART_OMAP_TO_H); 664 timeout_l = serial_in(up, UART_OMAP_TO_L); 665 serial_out(up, UART_OMAP_TO_H, 0xFF); 666 serial_out(up, UART_OMAP_TO_L, 0xFF); 667 serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE); 668 serial_in(up, UART_IIR); 669 serial_out(up, UART_OMAP_EFR2, efr2); 670 serial_out(up, UART_OMAP_TO_H, timeout_h); 671 serial_out(up, UART_OMAP_TO_L, timeout_l); 672 } 673 674 /* Stop processing interrupts on input overrun */ 675 if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) { 676 unsigned long delay; 677 678 /* Synchronize UART_IER access against the console. */ 679 spin_lock(&port->lock); 680 up->ier = port->serial_in(port, UART_IER); 681 if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { 682 port->ops->stop_rx(port); 683 } else { 684 /* Keep restarting the timer until 685 * the input overrun subsides. 686 */ 687 cancel_delayed_work(&up->overrun_backoff); 688 } 689 spin_unlock(&port->lock); 690 691 delay = msecs_to_jiffies(up->overrun_backoff_time_ms); 692 schedule_delayed_work(&up->overrun_backoff, delay); 693 } 694 695 serial8250_rpm_put(up); 696 697 return IRQ_RETVAL(ret); 698 } 699 700 static int omap_8250_startup(struct uart_port *port) 701 { 702 struct uart_8250_port *up = up_to_u8250p(port); 703 struct omap8250_priv *priv = port->private_data; 704 struct uart_8250_dma *dma = &priv->omap8250_dma; 705 int ret; 706 707 if (priv->wakeirq) { 708 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq); 709 if (ret) 710 return ret; 711 } 712 713 pm_runtime_get_sync(port->dev); 714 715 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 716 717 serial_out(up, UART_LCR, UART_LCR_WLEN8); 718 719 up->lsr_saved_flags = 0; 720 up->msr_saved_flags = 0; 721 722 /* Disable DMA for console UART */ 723 if (dma->fn && !uart_console(port)) { 724 up->dma = &priv->omap8250_dma; 725 ret = serial8250_request_dma(up); 726 if (ret) { 727 dev_warn_ratelimited(port->dev, 728 "failed to request DMA\n"); 729 up->dma = NULL; 730 } 731 } else { 732 up->dma = NULL; 733 } 734 735 /* Synchronize UART_IER access against the console. */ 736 spin_lock_irq(&port->lock); 737 up->ier = UART_IER_RLSI | UART_IER_RDI; 738 serial_out(up, UART_IER, up->ier); 739 spin_unlock_irq(&port->lock); 740 741 #ifdef CONFIG_PM 742 up->capabilities |= UART_CAP_RPM; 743 #endif 744 745 /* Enable module level wake up */ 746 priv->wer = OMAP_UART_WER_MOD_WKUP; 747 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP) 748 priv->wer |= OMAP_UART_TX_WAKEUP_EN; 749 serial_out(up, UART_OMAP_WER, priv->wer); 750 751 if (up->dma && !(priv->habit & UART_HAS_EFR2)) { 752 spin_lock_irq(&port->lock); 753 up->dma->rx_dma(up); 754 spin_unlock_irq(&port->lock); 755 } 756 757 enable_irq(up->port.irq); 758 759 pm_runtime_mark_last_busy(port->dev); 760 pm_runtime_put_autosuspend(port->dev); 761 return 0; 762 } 763 764 static void omap_8250_shutdown(struct uart_port *port) 765 { 766 struct uart_8250_port *up = up_to_u8250p(port); 767 struct omap8250_priv *priv = port->private_data; 768 769 flush_work(&priv->qos_work); 770 if (up->dma) 771 omap_8250_rx_dma_flush(up); 772 773 pm_runtime_get_sync(port->dev); 774 775 serial_out(up, UART_OMAP_WER, 0); 776 if (priv->habit & UART_HAS_EFR2) 777 serial_out(up, UART_OMAP_EFR2, 0x0); 778 779 /* Synchronize UART_IER access against the console. */ 780 spin_lock_irq(&port->lock); 781 up->ier = 0; 782 serial_out(up, UART_IER, 0); 783 spin_unlock_irq(&port->lock); 784 disable_irq_nosync(up->port.irq); 785 dev_pm_clear_wake_irq(port->dev); 786 787 serial8250_release_dma(up); 788 up->dma = NULL; 789 790 /* 791 * Disable break condition and FIFOs 792 */ 793 if (up->lcr & UART_LCR_SBC) 794 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC); 795 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 796 797 pm_runtime_mark_last_busy(port->dev); 798 pm_runtime_put_autosuspend(port->dev); 799 } 800 801 static void omap_8250_throttle(struct uart_port *port) 802 { 803 struct omap8250_priv *priv = port->private_data; 804 unsigned long flags; 805 806 pm_runtime_get_sync(port->dev); 807 808 spin_lock_irqsave(&port->lock, flags); 809 port->ops->stop_rx(port); 810 priv->throttled = true; 811 spin_unlock_irqrestore(&port->lock, flags); 812 813 pm_runtime_mark_last_busy(port->dev); 814 pm_runtime_put_autosuspend(port->dev); 815 } 816 817 static void omap_8250_unthrottle(struct uart_port *port) 818 { 819 struct omap8250_priv *priv = port->private_data; 820 struct uart_8250_port *up = up_to_u8250p(port); 821 unsigned long flags; 822 823 pm_runtime_get_sync(port->dev); 824 825 /* Synchronize UART_IER access against the console. */ 826 spin_lock_irqsave(&port->lock, flags); 827 priv->throttled = false; 828 if (up->dma) 829 up->dma->rx_dma(up); 830 up->ier |= UART_IER_RLSI | UART_IER_RDI; 831 port->read_status_mask |= UART_LSR_DR; 832 serial_out(up, UART_IER, up->ier); 833 spin_unlock_irqrestore(&port->lock, flags); 834 835 pm_runtime_mark_last_busy(port->dev); 836 pm_runtime_put_autosuspend(port->dev); 837 } 838 839 static int omap8250_rs485_config(struct uart_port *port, 840 struct ktermios *termios, 841 struct serial_rs485 *rs485) 842 { 843 struct omap8250_priv *priv = port->private_data; 844 struct uart_8250_port *up = up_to_u8250p(port); 845 u32 fixed_delay_rts_before_send = 0; 846 u32 fixed_delay_rts_after_send = 0; 847 unsigned int baud; 848 849 /* 850 * There is a fixed delay of 3 bit clock cycles after the TX shift 851 * register is going empty to allow time for the stop bit to transition 852 * through the transceiver before direction is changed to receive. 853 * 854 * Additionally there appears to be a 1 bit clock delay between writing 855 * to the THR register and transmission of the start bit, per page 8783 856 * of the AM65 TRM: https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf 857 */ 858 if (priv->quot) { 859 if (priv->mdr1 == UART_OMAP_MDR1_16X_MODE) 860 baud = port->uartclk / (16 * priv->quot); 861 else 862 baud = port->uartclk / (13 * priv->quot); 863 864 fixed_delay_rts_after_send = 3 * MSEC_PER_SEC / baud; 865 fixed_delay_rts_before_send = 1 * MSEC_PER_SEC / baud; 866 } 867 868 /* 869 * Fall back to RS485 software emulation if the UART is missing 870 * hardware support, if the device tree specifies an mctrl_gpio 871 * (indicates that RTS is unavailable due to a pinmux conflict) 872 * or if the requested delays exceed the fixed hardware delays. 873 */ 874 if (!(priv->habit & UART_HAS_NATIVE_RS485) || 875 mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) || 876 rs485->delay_rts_after_send > fixed_delay_rts_after_send || 877 rs485->delay_rts_before_send > fixed_delay_rts_before_send) { 878 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN; 879 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 880 881 port->rs485_config = serial8250_em485_config; 882 return serial8250_em485_config(port, termios, rs485); 883 } 884 885 rs485->delay_rts_after_send = fixed_delay_rts_after_send; 886 rs485->delay_rts_before_send = fixed_delay_rts_before_send; 887 888 if (rs485->flags & SER_RS485_ENABLED) 889 priv->mdr3 |= UART_OMAP_MDR3_DIR_EN; 890 else 891 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN; 892 893 /* 894 * Retain same polarity semantics as RS485 software emulation, 895 * i.e. SER_RS485_RTS_ON_SEND means driving RTS low on send. 896 */ 897 if (rs485->flags & SER_RS485_RTS_ON_SEND) 898 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_POL; 899 else 900 priv->mdr3 |= UART_OMAP_MDR3_DIR_POL; 901 902 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 903 904 return 0; 905 } 906 907 #ifdef CONFIG_SERIAL_8250_DMA 908 static int omap_8250_rx_dma(struct uart_8250_port *p); 909 910 /* Must be called while priv->rx_dma_lock is held */ 911 static void __dma_rx_do_complete(struct uart_8250_port *p) 912 { 913 struct uart_8250_dma *dma = p->dma; 914 struct tty_port *tty_port = &p->port.state->port; 915 struct omap8250_priv *priv = p->port.private_data; 916 struct dma_chan *rxchan = dma->rxchan; 917 dma_cookie_t cookie; 918 struct dma_tx_state state; 919 int count; 920 int ret; 921 u32 reg; 922 923 if (!dma->rx_running) 924 goto out; 925 926 cookie = dma->rx_cookie; 927 dma->rx_running = 0; 928 929 /* Re-enable RX FIFO interrupt now that transfer is complete */ 930 if (priv->habit & UART_HAS_RHR_IT_DIS) { 931 reg = serial_in(p, UART_OMAP_IER2); 932 reg &= ~UART_OMAP_IER2_RHR_IT_DIS; 933 serial_out(p, UART_OMAP_IER2, reg); 934 } 935 936 dmaengine_tx_status(rxchan, cookie, &state); 937 938 count = dma->rx_size - state.residue + state.in_flight_bytes; 939 if (count < dma->rx_size) { 940 dmaengine_terminate_async(rxchan); 941 942 /* 943 * Poll for teardown to complete which guarantees in 944 * flight data is drained. 945 */ 946 if (state.in_flight_bytes) { 947 int poll_count = 25; 948 949 while (dmaengine_tx_status(rxchan, cookie, NULL) && 950 poll_count--) 951 cpu_relax(); 952 953 if (poll_count == -1) 954 dev_err(p->port.dev, "teardown incomplete\n"); 955 } 956 } 957 if (!count) 958 goto out; 959 ret = tty_insert_flip_string(tty_port, dma->rx_buf, count); 960 961 p->port.icount.rx += ret; 962 p->port.icount.buf_overrun += count - ret; 963 out: 964 965 tty_flip_buffer_push(tty_port); 966 } 967 968 static void __dma_rx_complete(void *param) 969 { 970 struct uart_8250_port *p = param; 971 struct omap8250_priv *priv = p->port.private_data; 972 struct uart_8250_dma *dma = p->dma; 973 struct dma_tx_state state; 974 unsigned long flags; 975 976 /* Synchronize UART_IER access against the console. */ 977 spin_lock_irqsave(&p->port.lock, flags); 978 979 /* 980 * If the tx status is not DMA_COMPLETE, then this is a delayed 981 * completion callback. A previous RX timeout flush would have 982 * already pushed the data, so exit. 983 */ 984 if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) != 985 DMA_COMPLETE) { 986 spin_unlock_irqrestore(&p->port.lock, flags); 987 return; 988 } 989 __dma_rx_do_complete(p); 990 if (!priv->throttled) { 991 p->ier |= UART_IER_RLSI | UART_IER_RDI; 992 serial_out(p, UART_IER, p->ier); 993 if (!(priv->habit & UART_HAS_EFR2)) 994 omap_8250_rx_dma(p); 995 } 996 997 spin_unlock_irqrestore(&p->port.lock, flags); 998 } 999 1000 static void omap_8250_rx_dma_flush(struct uart_8250_port *p) 1001 { 1002 struct omap8250_priv *priv = p->port.private_data; 1003 struct uart_8250_dma *dma = p->dma; 1004 struct dma_tx_state state; 1005 unsigned long flags; 1006 int ret; 1007 1008 spin_lock_irqsave(&priv->rx_dma_lock, flags); 1009 1010 if (!dma->rx_running) { 1011 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1012 return; 1013 } 1014 1015 ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); 1016 if (ret == DMA_IN_PROGRESS) { 1017 ret = dmaengine_pause(dma->rxchan); 1018 if (WARN_ON_ONCE(ret)) 1019 priv->rx_dma_broken = true; 1020 } 1021 __dma_rx_do_complete(p); 1022 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1023 } 1024 1025 static int omap_8250_rx_dma(struct uart_8250_port *p) 1026 { 1027 struct omap8250_priv *priv = p->port.private_data; 1028 struct uart_8250_dma *dma = p->dma; 1029 int err = 0; 1030 struct dma_async_tx_descriptor *desc; 1031 unsigned long flags; 1032 u32 reg; 1033 1034 /* Port locked to synchronize UART_IER access against the console. */ 1035 lockdep_assert_held_once(&p->port.lock); 1036 1037 if (priv->rx_dma_broken) 1038 return -EINVAL; 1039 1040 spin_lock_irqsave(&priv->rx_dma_lock, flags); 1041 1042 if (dma->rx_running) { 1043 enum dma_status state; 1044 1045 state = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, NULL); 1046 if (state == DMA_COMPLETE) { 1047 /* 1048 * Disable RX interrupts to allow RX DMA completion 1049 * callback to run. 1050 */ 1051 p->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 1052 serial_out(p, UART_IER, p->ier); 1053 } 1054 goto out; 1055 } 1056 1057 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, 1058 dma->rx_size, DMA_DEV_TO_MEM, 1059 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1060 if (!desc) { 1061 err = -EBUSY; 1062 goto out; 1063 } 1064 1065 dma->rx_running = 1; 1066 desc->callback = __dma_rx_complete; 1067 desc->callback_param = p; 1068 1069 dma->rx_cookie = dmaengine_submit(desc); 1070 1071 /* 1072 * Disable RX FIFO interrupt while RX DMA is enabled, else 1073 * spurious interrupt may be raised when data is in the RX FIFO 1074 * but is yet to be drained by DMA. 1075 */ 1076 if (priv->habit & UART_HAS_RHR_IT_DIS) { 1077 reg = serial_in(p, UART_OMAP_IER2); 1078 reg |= UART_OMAP_IER2_RHR_IT_DIS; 1079 serial_out(p, UART_OMAP_IER2, reg); 1080 } 1081 1082 dma_async_issue_pending(dma->rxchan); 1083 out: 1084 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1085 return err; 1086 } 1087 1088 static int omap_8250_tx_dma(struct uart_8250_port *p); 1089 1090 static void omap_8250_dma_tx_complete(void *param) 1091 { 1092 struct uart_8250_port *p = param; 1093 struct uart_8250_dma *dma = p->dma; 1094 struct circ_buf *xmit = &p->port.state->xmit; 1095 unsigned long flags; 1096 bool en_thri = false; 1097 struct omap8250_priv *priv = p->port.private_data; 1098 1099 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, 1100 UART_XMIT_SIZE, DMA_TO_DEVICE); 1101 1102 spin_lock_irqsave(&p->port.lock, flags); 1103 1104 dma->tx_running = 0; 1105 1106 uart_xmit_advance(&p->port, dma->tx_size); 1107 1108 if (priv->delayed_restore) { 1109 priv->delayed_restore = 0; 1110 omap8250_restore_regs(p); 1111 } 1112 1113 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 1114 uart_write_wakeup(&p->port); 1115 1116 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { 1117 int ret; 1118 1119 ret = omap_8250_tx_dma(p); 1120 if (ret) 1121 en_thri = true; 1122 } else if (p->capabilities & UART_CAP_RPM) { 1123 en_thri = true; 1124 } 1125 1126 if (en_thri) { 1127 dma->tx_err = 1; 1128 serial8250_set_THRI(p); 1129 } 1130 1131 spin_unlock_irqrestore(&p->port.lock, flags); 1132 } 1133 1134 static int omap_8250_tx_dma(struct uart_8250_port *p) 1135 { 1136 struct uart_8250_dma *dma = p->dma; 1137 struct omap8250_priv *priv = p->port.private_data; 1138 struct circ_buf *xmit = &p->port.state->xmit; 1139 struct dma_async_tx_descriptor *desc; 1140 unsigned int skip_byte = 0; 1141 int ret; 1142 1143 if (dma->tx_running) 1144 return 0; 1145 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) { 1146 1147 /* 1148 * Even if no data, we need to return an error for the two cases 1149 * below so serial8250_tx_chars() is invoked and properly clears 1150 * THRI and/or runtime suspend. 1151 */ 1152 if (dma->tx_err || p->capabilities & UART_CAP_RPM) { 1153 ret = -EBUSY; 1154 goto err; 1155 } 1156 serial8250_clear_THRI(p); 1157 return 0; 1158 } 1159 1160 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 1161 if (priv->habit & OMAP_DMA_TX_KICK) { 1162 u8 tx_lvl; 1163 1164 /* 1165 * We need to put the first byte into the FIFO in order to start 1166 * the DMA transfer. For transfers smaller than four bytes we 1167 * don't bother doing DMA at all. It seem not matter if there 1168 * are still bytes in the FIFO from the last transfer (in case 1169 * we got here directly from omap_8250_dma_tx_complete()). Bytes 1170 * leaving the FIFO seem not to trigger the DMA transfer. It is 1171 * really the byte that we put into the FIFO. 1172 * If the FIFO is already full then we most likely got here from 1173 * omap_8250_dma_tx_complete(). And this means the DMA engine 1174 * just completed its work. We don't have to wait the complete 1175 * 86us at 115200,8n1 but around 60us (not to mention lower 1176 * baudrates). So in that case we take the interrupt and try 1177 * again with an empty FIFO. 1178 */ 1179 tx_lvl = serial_in(p, UART_OMAP_TX_LVL); 1180 if (tx_lvl == p->tx_loadsz) { 1181 ret = -EBUSY; 1182 goto err; 1183 } 1184 if (dma->tx_size < 4) { 1185 ret = -EINVAL; 1186 goto err; 1187 } 1188 skip_byte = 1; 1189 } 1190 1191 desc = dmaengine_prep_slave_single(dma->txchan, 1192 dma->tx_addr + xmit->tail + skip_byte, 1193 dma->tx_size - skip_byte, DMA_MEM_TO_DEV, 1194 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1195 if (!desc) { 1196 ret = -EBUSY; 1197 goto err; 1198 } 1199 1200 dma->tx_running = 1; 1201 1202 desc->callback = omap_8250_dma_tx_complete; 1203 desc->callback_param = p; 1204 1205 dma->tx_cookie = dmaengine_submit(desc); 1206 1207 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr, 1208 UART_XMIT_SIZE, DMA_TO_DEVICE); 1209 1210 dma_async_issue_pending(dma->txchan); 1211 if (dma->tx_err) 1212 dma->tx_err = 0; 1213 1214 serial8250_clear_THRI(p); 1215 if (skip_byte) 1216 serial_out(p, UART_TX, xmit->buf[xmit->tail]); 1217 return 0; 1218 err: 1219 dma->tx_err = 1; 1220 return ret; 1221 } 1222 1223 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) 1224 { 1225 switch (iir & 0x3f) { 1226 case UART_IIR_RLSI: 1227 case UART_IIR_RX_TIMEOUT: 1228 case UART_IIR_RDI: 1229 omap_8250_rx_dma_flush(up); 1230 return true; 1231 } 1232 return omap_8250_rx_dma(up); 1233 } 1234 1235 static u16 omap_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, u16 status) 1236 { 1237 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1238 (iir & UART_IIR_RDI)) { 1239 if (handle_rx_dma(up, iir)) { 1240 status = serial8250_rx_chars(up, status); 1241 omap_8250_rx_dma(up); 1242 } 1243 } 1244 1245 return status; 1246 } 1247 1248 static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, 1249 u16 status) 1250 { 1251 /* Port locked to synchronize UART_IER access against the console. */ 1252 lockdep_assert_held_once(&up->port.lock); 1253 1254 /* 1255 * Queue a new transfer if FIFO has data. 1256 */ 1257 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1258 (up->ier & UART_IER_RDI)) { 1259 omap_8250_rx_dma(up); 1260 serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE); 1261 } else if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) { 1262 /* 1263 * Disable RX timeout, read IIR to clear 1264 * current timeout condition, clear EFR2 to 1265 * periodic timeouts, re-enable interrupts. 1266 */ 1267 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 1268 serial_out(up, UART_IER, up->ier); 1269 omap_8250_rx_dma_flush(up); 1270 serial_in(up, UART_IIR); 1271 serial_out(up, UART_OMAP_EFR2, 0x0); 1272 up->ier |= UART_IER_RLSI | UART_IER_RDI; 1273 serial_out(up, UART_IER, up->ier); 1274 } 1275 } 1276 1277 /* 1278 * This is mostly serial8250_handle_irq(). We have a slightly different DMA 1279 * hoook for RX/TX and need different logic for them in the ISR. Therefore we 1280 * use the default routine in the non-DMA case and this one for with DMA. 1281 */ 1282 static int omap_8250_dma_handle_irq(struct uart_port *port) 1283 { 1284 struct uart_8250_port *up = up_to_u8250p(port); 1285 struct omap8250_priv *priv = up->port.private_data; 1286 u16 status; 1287 u8 iir; 1288 1289 serial8250_rpm_get(up); 1290 1291 iir = serial_port_in(port, UART_IIR); 1292 if (iir & UART_IIR_NO_INT) { 1293 serial8250_rpm_put(up); 1294 return IRQ_HANDLED; 1295 } 1296 1297 spin_lock(&port->lock); 1298 1299 status = serial_port_in(port, UART_LSR); 1300 1301 if ((iir & 0x3f) != UART_IIR_THRI) { 1302 if (priv->habit & UART_HAS_EFR2) 1303 am654_8250_handle_rx_dma(up, iir, status); 1304 else 1305 status = omap_8250_handle_rx_dma(up, iir, status); 1306 } 1307 1308 serial8250_modem_status(up); 1309 if (status & UART_LSR_THRE && up->dma->tx_err) { 1310 if (uart_tx_stopped(&up->port) || 1311 uart_circ_empty(&up->port.state->xmit)) { 1312 up->dma->tx_err = 0; 1313 serial8250_tx_chars(up); 1314 } else { 1315 /* 1316 * try again due to an earlier failer which 1317 * might have been resolved by now. 1318 */ 1319 if (omap_8250_tx_dma(up)) 1320 serial8250_tx_chars(up); 1321 } 1322 } 1323 1324 uart_unlock_and_check_sysrq(port); 1325 1326 serial8250_rpm_put(up); 1327 return 1; 1328 } 1329 1330 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param) 1331 { 1332 return false; 1333 } 1334 1335 #else 1336 1337 static inline int omap_8250_rx_dma(struct uart_8250_port *p) 1338 { 1339 return -EINVAL; 1340 } 1341 #endif 1342 1343 static int omap8250_no_handle_irq(struct uart_port *port) 1344 { 1345 /* IRQ has not been requested but handling irq? */ 1346 WARN_ONCE(1, "Unexpected irq handling before port startup\n"); 1347 return 0; 1348 } 1349 1350 static struct omap8250_dma_params am654_dma = { 1351 .rx_size = SZ_2K, 1352 .rx_trigger = 1, 1353 .tx_trigger = TX_TRIGGER, 1354 }; 1355 1356 static struct omap8250_dma_params am33xx_dma = { 1357 .rx_size = RX_TRIGGER, 1358 .rx_trigger = RX_TRIGGER, 1359 .tx_trigger = TX_TRIGGER, 1360 }; 1361 1362 static struct omap8250_platdata am654_platdata = { 1363 .dma_params = &am654_dma, 1364 .habit = UART_HAS_EFR2 | UART_HAS_RHR_IT_DIS | 1365 UART_RX_TIMEOUT_QUIRK | UART_HAS_NATIVE_RS485, 1366 }; 1367 1368 static struct omap8250_platdata am33xx_platdata = { 1369 .dma_params = &am33xx_dma, 1370 .habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE, 1371 }; 1372 1373 static struct omap8250_platdata omap4_platdata = { 1374 .dma_params = &am33xx_dma, 1375 .habit = UART_ERRATA_CLOCK_DISABLE, 1376 }; 1377 1378 static const struct of_device_id omap8250_dt_ids[] = { 1379 { .compatible = "ti,am654-uart", .data = &am654_platdata, }, 1380 { .compatible = "ti,omap2-uart" }, 1381 { .compatible = "ti,omap3-uart" }, 1382 { .compatible = "ti,omap4-uart", .data = &omap4_platdata, }, 1383 { .compatible = "ti,am3352-uart", .data = &am33xx_platdata, }, 1384 { .compatible = "ti,am4372-uart", .data = &am33xx_platdata, }, 1385 { .compatible = "ti,dra742-uart", .data = &omap4_platdata, }, 1386 {}, 1387 }; 1388 MODULE_DEVICE_TABLE(of, omap8250_dt_ids); 1389 1390 static int omap8250_probe(struct platform_device *pdev) 1391 { 1392 struct device_node *np = pdev->dev.of_node; 1393 struct omap8250_priv *priv; 1394 const struct omap8250_platdata *pdata; 1395 struct uart_8250_port up; 1396 struct resource *regs; 1397 void __iomem *membase; 1398 int irq, ret; 1399 1400 irq = platform_get_irq(pdev, 0); 1401 if (irq < 0) 1402 return irq; 1403 1404 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1405 if (!regs) { 1406 dev_err(&pdev->dev, "missing registers\n"); 1407 return -EINVAL; 1408 } 1409 1410 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 1411 if (!priv) 1412 return -ENOMEM; 1413 1414 membase = devm_ioremap(&pdev->dev, regs->start, 1415 resource_size(regs)); 1416 if (!membase) 1417 return -ENODEV; 1418 1419 memset(&up, 0, sizeof(up)); 1420 up.port.dev = &pdev->dev; 1421 up.port.mapbase = regs->start; 1422 up.port.membase = membase; 1423 up.port.irq = irq; 1424 /* 1425 * It claims to be 16C750 compatible however it is a little different. 1426 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to 1427 * have) is enabled via EFR instead of MCR. The type is set here 8250 1428 * just to get things going. UNKNOWN does not work for a few reasons and 1429 * we don't need our own type since we don't use 8250's set_termios() 1430 * or pm callback. 1431 */ 1432 up.port.type = PORT_8250; 1433 up.port.iotype = UPIO_MEM; 1434 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW | 1435 UPF_HARD_FLOW; 1436 up.port.private_data = priv; 1437 1438 up.port.regshift = OMAP_UART_REGSHIFT; 1439 up.port.fifosize = 64; 1440 up.tx_loadsz = 64; 1441 up.capabilities = UART_CAP_FIFO; 1442 #ifdef CONFIG_PM 1443 /* 1444 * Runtime PM is mostly transparent. However to do it right we need to a 1445 * TX empty interrupt before we can put the device to auto idle. So if 1446 * PM is not enabled we don't add that flag and can spare that one extra 1447 * interrupt in the TX path. 1448 */ 1449 up.capabilities |= UART_CAP_RPM; 1450 #endif 1451 up.port.set_termios = omap_8250_set_termios; 1452 up.port.set_mctrl = omap8250_set_mctrl; 1453 up.port.pm = omap_8250_pm; 1454 up.port.startup = omap_8250_startup; 1455 up.port.shutdown = omap_8250_shutdown; 1456 up.port.throttle = omap_8250_throttle; 1457 up.port.unthrottle = omap_8250_unthrottle; 1458 up.port.rs485_config = omap8250_rs485_config; 1459 /* same rs485_supported for software emulation and native RS485 */ 1460 up.port.rs485_supported = serial8250_em485_supported; 1461 up.rs485_start_tx = serial8250_em485_start_tx; 1462 up.rs485_stop_tx = serial8250_em485_stop_tx; 1463 up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); 1464 1465 ret = of_alias_get_id(np, "serial"); 1466 if (ret < 0) { 1467 dev_err(&pdev->dev, "failed to get alias\n"); 1468 return ret; 1469 } 1470 up.port.line = ret; 1471 1472 if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) { 1473 struct clk *clk; 1474 1475 clk = devm_clk_get(&pdev->dev, NULL); 1476 if (IS_ERR(clk)) { 1477 if (PTR_ERR(clk) == -EPROBE_DEFER) 1478 return -EPROBE_DEFER; 1479 } else { 1480 up.port.uartclk = clk_get_rate(clk); 1481 } 1482 } 1483 1484 if (of_property_read_u32(np, "overrun-throttle-ms", 1485 &up.overrun_backoff_time_ms) != 0) 1486 up.overrun_backoff_time_ms = 0; 1487 1488 pdata = of_device_get_match_data(&pdev->dev); 1489 if (pdata) 1490 priv->habit |= pdata->habit; 1491 1492 if (!up.port.uartclk) { 1493 up.port.uartclk = DEFAULT_CLK_SPEED; 1494 dev_warn(&pdev->dev, 1495 "No clock speed specified: using default: %d\n", 1496 DEFAULT_CLK_SPEED); 1497 } 1498 1499 priv->membase = membase; 1500 priv->line = -ENODEV; 1501 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1502 priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1503 cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency); 1504 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work); 1505 1506 spin_lock_init(&priv->rx_dma_lock); 1507 1508 platform_set_drvdata(pdev, priv); 1509 1510 device_init_wakeup(&pdev->dev, true); 1511 pm_runtime_enable(&pdev->dev); 1512 pm_runtime_use_autosuspend(&pdev->dev); 1513 1514 /* 1515 * Disable runtime PM until autosuspend delay unless specifically 1516 * enabled by the user via sysfs. This is the historic way to 1517 * prevent an unsafe default policy with lossy characters on wake-up. 1518 * For serdev devices this is not needed, the policy can be managed by 1519 * the serdev driver. 1520 */ 1521 if (!of_get_available_child_count(pdev->dev.of_node)) 1522 pm_runtime_set_autosuspend_delay(&pdev->dev, -1); 1523 1524 pm_runtime_irq_safe(&pdev->dev); 1525 1526 pm_runtime_get_sync(&pdev->dev); 1527 1528 omap_serial_fill_features_erratas(&up, priv); 1529 up.port.handle_irq = omap8250_no_handle_irq; 1530 priv->rx_trigger = RX_TRIGGER; 1531 priv->tx_trigger = TX_TRIGGER; 1532 #ifdef CONFIG_SERIAL_8250_DMA 1533 /* 1534 * Oh DMA support. If there are no DMA properties in the DT then 1535 * we will fall back to a generic DMA channel which does not 1536 * really work here. To ensure that we do not get a generic DMA 1537 * channel assigned, we have the the_no_dma_filter_fn() here. 1538 * To avoid "failed to request DMA" messages we check for DMA 1539 * properties in DT. 1540 */ 1541 ret = of_property_count_strings(np, "dma-names"); 1542 if (ret == 2) { 1543 struct omap8250_dma_params *dma_params = NULL; 1544 struct uart_8250_dma *dma = &priv->omap8250_dma; 1545 1546 dma->fn = the_no_dma_filter_fn; 1547 dma->tx_dma = omap_8250_tx_dma; 1548 dma->rx_dma = omap_8250_rx_dma; 1549 if (pdata) 1550 dma_params = pdata->dma_params; 1551 1552 if (dma_params) { 1553 dma->rx_size = dma_params->rx_size; 1554 dma->rxconf.src_maxburst = dma_params->rx_trigger; 1555 dma->txconf.dst_maxburst = dma_params->tx_trigger; 1556 priv->rx_trigger = dma_params->rx_trigger; 1557 priv->tx_trigger = dma_params->tx_trigger; 1558 } else { 1559 dma->rx_size = RX_TRIGGER; 1560 dma->rxconf.src_maxburst = RX_TRIGGER; 1561 dma->txconf.dst_maxburst = TX_TRIGGER; 1562 } 1563 } 1564 #endif 1565 1566 irq_set_status_flags(irq, IRQ_NOAUTOEN); 1567 ret = devm_request_irq(&pdev->dev, irq, omap8250_irq, 0, 1568 dev_name(&pdev->dev), priv); 1569 if (ret < 0) 1570 goto err; 1571 1572 priv->wakeirq = irq_of_parse_and_map(np, 1); 1573 1574 ret = serial8250_register_8250_port(&up); 1575 if (ret < 0) { 1576 dev_err(&pdev->dev, "unable to register 8250 port\n"); 1577 goto err; 1578 } 1579 priv->line = ret; 1580 pm_runtime_mark_last_busy(&pdev->dev); 1581 pm_runtime_put_autosuspend(&pdev->dev); 1582 return 0; 1583 err: 1584 pm_runtime_dont_use_autosuspend(&pdev->dev); 1585 pm_runtime_put_sync(&pdev->dev); 1586 flush_work(&priv->qos_work); 1587 pm_runtime_disable(&pdev->dev); 1588 cpu_latency_qos_remove_request(&priv->pm_qos_request); 1589 return ret; 1590 } 1591 1592 static int omap8250_remove(struct platform_device *pdev) 1593 { 1594 struct omap8250_priv *priv = platform_get_drvdata(pdev); 1595 struct uart_8250_port *up; 1596 int err; 1597 1598 err = pm_runtime_resume_and_get(&pdev->dev); 1599 if (err) 1600 dev_err(&pdev->dev, "Failed to resume hardware\n"); 1601 1602 up = serial8250_get_port(priv->line); 1603 omap_8250_shutdown(&up->port); 1604 serial8250_unregister_port(priv->line); 1605 priv->line = -ENODEV; 1606 pm_runtime_dont_use_autosuspend(&pdev->dev); 1607 pm_runtime_put_sync(&pdev->dev); 1608 flush_work(&priv->qos_work); 1609 pm_runtime_disable(&pdev->dev); 1610 cpu_latency_qos_remove_request(&priv->pm_qos_request); 1611 device_init_wakeup(&pdev->dev, false); 1612 return 0; 1613 } 1614 1615 static int omap8250_prepare(struct device *dev) 1616 { 1617 struct omap8250_priv *priv = dev_get_drvdata(dev); 1618 1619 if (!priv) 1620 return 0; 1621 priv->is_suspending = true; 1622 return 0; 1623 } 1624 1625 static void omap8250_complete(struct device *dev) 1626 { 1627 struct omap8250_priv *priv = dev_get_drvdata(dev); 1628 1629 if (!priv) 1630 return; 1631 priv->is_suspending = false; 1632 } 1633 1634 static int omap8250_suspend(struct device *dev) 1635 { 1636 struct omap8250_priv *priv = dev_get_drvdata(dev); 1637 struct uart_8250_port *up = serial8250_get_port(priv->line); 1638 int err = 0; 1639 1640 serial8250_suspend_port(priv->line); 1641 1642 err = pm_runtime_resume_and_get(dev); 1643 if (err) 1644 return err; 1645 if (!device_may_wakeup(dev)) 1646 priv->wer = 0; 1647 serial_out(up, UART_OMAP_WER, priv->wer); 1648 if (uart_console(&up->port) && console_suspend_enabled) 1649 err = pm_runtime_force_suspend(dev); 1650 flush_work(&priv->qos_work); 1651 1652 return err; 1653 } 1654 1655 static int omap8250_resume(struct device *dev) 1656 { 1657 struct omap8250_priv *priv = dev_get_drvdata(dev); 1658 struct uart_8250_port *up = serial8250_get_port(priv->line); 1659 int err; 1660 1661 if (uart_console(&up->port) && console_suspend_enabled) { 1662 err = pm_runtime_force_resume(dev); 1663 if (err) 1664 return err; 1665 } 1666 1667 serial8250_resume_port(priv->line); 1668 /* Paired with pm_runtime_resume_and_get() in omap8250_suspend() */ 1669 pm_runtime_mark_last_busy(dev); 1670 pm_runtime_put_autosuspend(dev); 1671 1672 return 0; 1673 } 1674 1675 static int omap8250_lost_context(struct uart_8250_port *up) 1676 { 1677 u32 val; 1678 1679 val = serial_in(up, UART_OMAP_SCR); 1680 /* 1681 * If we lose context, then SCR is set to its reset value of zero. 1682 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1, 1683 * among other bits, to never set the register back to zero again. 1684 */ 1685 if (!val) 1686 return 1; 1687 return 0; 1688 } 1689 1690 static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val) 1691 { 1692 writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT)); 1693 } 1694 1695 /* TODO: in future, this should happen via API in drivers/reset/ */ 1696 static int omap8250_soft_reset(struct device *dev) 1697 { 1698 struct omap8250_priv *priv = dev_get_drvdata(dev); 1699 int timeout = 100; 1700 int sysc; 1701 int syss; 1702 1703 /* 1704 * At least on omap4, unused uarts may not idle after reset without 1705 * a basic scr dma configuration even with no dma in use. The 1706 * module clkctrl status bits will be 1 instead of 3 blocking idle 1707 * for the whole clockdomain. The softreset below will clear scr, 1708 * and we restore it on resume so this is safe to do on all SoCs 1709 * needing omap8250_soft_reset() quirk. Do it in two writes as 1710 * recommended in the comment for omap8250_update_scr(). 1711 */ 1712 uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); 1713 uart_write(priv, UART_OMAP_SCR, 1714 OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL); 1715 1716 sysc = uart_read(priv, UART_OMAP_SYSC); 1717 1718 /* softreset the UART */ 1719 sysc |= OMAP_UART_SYSC_SOFTRESET; 1720 uart_write(priv, UART_OMAP_SYSC, sysc); 1721 1722 /* By experiments, 1us enough for reset complete on AM335x */ 1723 do { 1724 udelay(1); 1725 syss = uart_read(priv, UART_OMAP_SYSS); 1726 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE)); 1727 1728 if (!timeout) { 1729 dev_err(dev, "timed out waiting for reset done\n"); 1730 return -ETIMEDOUT; 1731 } 1732 1733 return 0; 1734 } 1735 1736 static int omap8250_runtime_suspend(struct device *dev) 1737 { 1738 struct omap8250_priv *priv = dev_get_drvdata(dev); 1739 struct uart_8250_port *up = NULL; 1740 1741 if (priv->line >= 0) 1742 up = serial8250_get_port(priv->line); 1743 1744 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) { 1745 int ret; 1746 1747 ret = omap8250_soft_reset(dev); 1748 if (ret) 1749 return ret; 1750 1751 if (up) { 1752 /* Restore to UART mode after reset (for wakeup) */ 1753 omap8250_update_mdr1(up, priv); 1754 /* Restore wakeup enable register */ 1755 serial_out(up, UART_OMAP_WER, priv->wer); 1756 } 1757 } 1758 1759 if (up && up->dma && up->dma->rxchan) 1760 omap_8250_rx_dma_flush(up); 1761 1762 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1763 schedule_work(&priv->qos_work); 1764 1765 return 0; 1766 } 1767 1768 static int omap8250_runtime_resume(struct device *dev) 1769 { 1770 struct omap8250_priv *priv = dev_get_drvdata(dev); 1771 struct uart_8250_port *up = NULL; 1772 1773 if (priv->line >= 0) 1774 up = serial8250_get_port(priv->line); 1775 1776 if (up && omap8250_lost_context(up)) { 1777 spin_lock_irq(&up->port.lock); 1778 omap8250_restore_regs(up); 1779 spin_unlock_irq(&up->port.lock); 1780 } 1781 1782 if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) { 1783 spin_lock_irq(&up->port.lock); 1784 omap_8250_rx_dma(up); 1785 spin_unlock_irq(&up->port.lock); 1786 } 1787 1788 priv->latency = priv->calc_latency; 1789 schedule_work(&priv->qos_work); 1790 return 0; 1791 } 1792 1793 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP 1794 static int __init omap8250_console_fixup(void) 1795 { 1796 char *omap_str; 1797 char *options; 1798 u8 idx; 1799 1800 if (strstr(boot_command_line, "console=ttyS")) 1801 /* user set a ttyS based name for the console */ 1802 return 0; 1803 1804 omap_str = strstr(boot_command_line, "console=ttyO"); 1805 if (!omap_str) 1806 /* user did not set ttyO based console, so we don't care */ 1807 return 0; 1808 1809 omap_str += 12; 1810 if ('0' <= *omap_str && *omap_str <= '9') 1811 idx = *omap_str - '0'; 1812 else 1813 return 0; 1814 1815 omap_str++; 1816 if (omap_str[0] == ',') { 1817 omap_str++; 1818 options = omap_str; 1819 } else { 1820 options = NULL; 1821 } 1822 1823 add_preferred_console("ttyS", idx, options); 1824 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n", 1825 idx, idx); 1826 pr_err("This ensures that you still see kernel messages. Please\n"); 1827 pr_err("update your kernel commandline.\n"); 1828 return 0; 1829 } 1830 console_initcall(omap8250_console_fixup); 1831 #endif 1832 1833 static const struct dev_pm_ops omap8250_dev_pm_ops = { 1834 SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume) 1835 RUNTIME_PM_OPS(omap8250_runtime_suspend, 1836 omap8250_runtime_resume, NULL) 1837 .prepare = pm_sleep_ptr(omap8250_prepare), 1838 .complete = pm_sleep_ptr(omap8250_complete), 1839 }; 1840 1841 static struct platform_driver omap8250_platform_driver = { 1842 .driver = { 1843 .name = "omap8250", 1844 .pm = pm_ptr(&omap8250_dev_pm_ops), 1845 .of_match_table = omap8250_dt_ids, 1846 }, 1847 .probe = omap8250_probe, 1848 .remove = omap8250_remove, 1849 }; 1850 module_platform_driver(omap8250_platform_driver); 1851 1852 MODULE_AUTHOR("Sebastian Andrzej Siewior"); 1853 MODULE_DESCRIPTION("OMAP 8250 Driver"); 1854 MODULE_LICENSE("GPL v2"); 1855