1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) Maxime Coquelin 2015
   4 * Copyright (C) STMicroelectronics SA 2017
   5 * Authors:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
   6 *	     Gerald Baeza <gerald.baeza@foss.st.com>
   7 *	     Erwan Le Ray <erwan.leray@foss.st.com>
   8 *
   9 * Inspired by st-asc.c from STMicroelectronics (c)
  10 */
  11
  12#include <linux/clk.h>
  13#include <linux/console.h>
  14#include <linux/delay.h>
  15#include <linux/dma-direction.h>
  16#include <linux/dmaengine.h>
  17#include <linux/dma-mapping.h>
  18#include <linux/io.h>
  19#include <linux/iopoll.h>
  20#include <linux/irq.h>
  21#include <linux/module.h>
  22#include <linux/of.h>
  23#include <linux/of_platform.h>
  24#include <linux/pinctrl/consumer.h>
  25#include <linux/platform_device.h>
  26#include <linux/pm_runtime.h>
  27#include <linux/pm_wakeirq.h>
  28#include <linux/serial_core.h>
  29#include <linux/serial.h>
  30#include <linux/spinlock.h>
  31#include <linux/sysrq.h>
  32#include <linux/tty_flip.h>
  33#include <linux/tty.h>
  34
  35#include "serial_mctrl_gpio.h"
  36#include "stm32-usart.h"
  37
  38
  39/* Register offsets */
  40static struct stm32_usart_info __maybe_unused stm32f4_info = {
  41	.ofs = {
  42		.isr	= 0x00,
  43		.rdr	= 0x04,
  44		.tdr	= 0x04,
  45		.brr	= 0x08,
  46		.cr1	= 0x0c,
  47		.cr2	= 0x10,
  48		.cr3	= 0x14,
  49		.gtpr	= 0x18,
  50		.rtor	= UNDEF_REG,
  51		.rqr	= UNDEF_REG,
  52		.icr	= UNDEF_REG,
  53	},
  54	.cfg = {
  55		.uart_enable_bit = 13,
  56		.has_7bits_data = false,
  57		.fifosize = 1,
  58	}
  59};
  60
  61static struct stm32_usart_info __maybe_unused stm32f7_info = {
  62	.ofs = {
  63		.cr1	= 0x00,
  64		.cr2	= 0x04,
  65		.cr3	= 0x08,
  66		.brr	= 0x0c,
  67		.gtpr	= 0x10,
  68		.rtor	= 0x14,
  69		.rqr	= 0x18,
  70		.isr	= 0x1c,
  71		.icr	= 0x20,
  72		.rdr	= 0x24,
  73		.tdr	= 0x28,
  74	},
  75	.cfg = {
  76		.uart_enable_bit = 0,
  77		.has_7bits_data = true,
  78		.has_swap = true,
  79		.fifosize = 1,
  80	}
  81};
  82
  83static struct stm32_usart_info __maybe_unused stm32h7_info = {
  84	.ofs = {
  85		.cr1	= 0x00,
  86		.cr2	= 0x04,
  87		.cr3	= 0x08,
  88		.brr	= 0x0c,
  89		.gtpr	= 0x10,
  90		.rtor	= 0x14,
  91		.rqr	= 0x18,
  92		.isr	= 0x1c,
  93		.icr	= 0x20,
  94		.rdr	= 0x24,
  95		.tdr	= 0x28,
  96	},
  97	.cfg = {
  98		.uart_enable_bit = 0,
  99		.has_7bits_data = true,
 100		.has_swap = true,
 101		.has_wakeup = true,
 102		.has_fifo = true,
 103		.fifosize = 16,
 104	}
 105};
 106
 107static void stm32_usart_stop_tx(struct uart_port *port);
 108static void stm32_usart_transmit_chars(struct uart_port *port);
 109static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch);
 110
 111static inline struct stm32_port *to_stm32_port(struct uart_port *port)
 112{
 113	return container_of(port, struct stm32_port, port);
 114}
 115
 116static void stm32_usart_set_bits(struct uart_port *port, u32 reg, u32 bits)
 117{
 118	u32 val;
 119
 120	val = readl_relaxed(port->membase + reg);
 121	val |= bits;
 122	writel_relaxed(val, port->membase + reg);
 123}
 124
 125static void stm32_usart_clr_bits(struct uart_port *port, u32 reg, u32 bits)
 126{
 127	u32 val;
 128
 129	val = readl_relaxed(port->membase + reg);
 130	val &= ~bits;
 131	writel_relaxed(val, port->membase + reg);
 132}
 133
 134static unsigned int stm32_usart_tx_empty(struct uart_port *port)
 135{
 136	struct stm32_port *stm32_port = to_stm32_port(port);
 137	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 138
 139	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
 140		return TIOCSER_TEMT;
 141
 142	return 0;
 143}
 144
 145static void stm32_usart_rs485_rts_enable(struct uart_port *port)
 146{
 147	struct stm32_port *stm32_port = to_stm32_port(port);
 148	struct serial_rs485 *rs485conf = &port->rs485;
 149
 150	if (stm32_port->hw_flow_control ||
 151	    !(rs485conf->flags & SER_RS485_ENABLED))
 152		return;
 153
 154	if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 155		mctrl_gpio_set(stm32_port->gpios,
 156			       stm32_port->port.mctrl | TIOCM_RTS);
 157	} else {
 158		mctrl_gpio_set(stm32_port->gpios,
 159			       stm32_port->port.mctrl & ~TIOCM_RTS);
 160	}
 161}
 162
 163static void stm32_usart_rs485_rts_disable(struct uart_port *port)
 164{
 165	struct stm32_port *stm32_port = to_stm32_port(port);
 166	struct serial_rs485 *rs485conf = &port->rs485;
 167
 168	if (stm32_port->hw_flow_control ||
 169	    !(rs485conf->flags & SER_RS485_ENABLED))
 170		return;
 171
 172	if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
 173		mctrl_gpio_set(stm32_port->gpios,
 174			       stm32_port->port.mctrl & ~TIOCM_RTS);
 175	} else {
 176		mctrl_gpio_set(stm32_port->gpios,
 177			       stm32_port->port.mctrl | TIOCM_RTS);
 178	}
 179}
 180
 181static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
 182					 u32 delay_DDE, u32 baud)
 183{
 184	u32 rs485_deat_dedt;
 185	u32 rs485_deat_dedt_max = (USART_CR1_DEAT_MASK >> USART_CR1_DEAT_SHIFT);
 186	bool over8;
 187
 188	*cr3 |= USART_CR3_DEM;
 189	over8 = *cr1 & USART_CR1_OVER8;
 190
 191	*cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
 192
 193	if (over8)
 194		rs485_deat_dedt = delay_ADE * baud * 8;
 195	else
 196		rs485_deat_dedt = delay_ADE * baud * 16;
 197
 198	rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
 199	rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
 200			  rs485_deat_dedt_max : rs485_deat_dedt;
 201	rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEAT_SHIFT) &
 202			   USART_CR1_DEAT_MASK;
 203	*cr1 |= rs485_deat_dedt;
 204
 205	if (over8)
 206		rs485_deat_dedt = delay_DDE * baud * 8;
 207	else
 208		rs485_deat_dedt = delay_DDE * baud * 16;
 209
 210	rs485_deat_dedt = DIV_ROUND_CLOSEST(rs485_deat_dedt, 1000);
 211	rs485_deat_dedt = rs485_deat_dedt > rs485_deat_dedt_max ?
 212			  rs485_deat_dedt_max : rs485_deat_dedt;
 213	rs485_deat_dedt = (rs485_deat_dedt << USART_CR1_DEDT_SHIFT) &
 214			   USART_CR1_DEDT_MASK;
 215	*cr1 |= rs485_deat_dedt;
 216}
 217
 218static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios,
 219				    struct serial_rs485 *rs485conf)
 220{
 221	struct stm32_port *stm32_port = to_stm32_port(port);
 222	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 223	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 224	u32 usartdiv, baud, cr1, cr3;
 225	bool over8;
 226
 227	stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 228
 
 
 229	if (rs485conf->flags & SER_RS485_ENABLED) {
 230		cr1 = readl_relaxed(port->membase + ofs->cr1);
 231		cr3 = readl_relaxed(port->membase + ofs->cr3);
 232		usartdiv = readl_relaxed(port->membase + ofs->brr);
 233		usartdiv = usartdiv & GENMASK(15, 0);
 234		over8 = cr1 & USART_CR1_OVER8;
 235
 236		if (over8)
 237			usartdiv = usartdiv | (usartdiv & GENMASK(4, 0))
 238				   << USART_BRR_04_R_SHIFT;
 239
 240		baud = DIV_ROUND_CLOSEST(port->uartclk, usartdiv);
 241		stm32_usart_config_reg_rs485(&cr1, &cr3,
 242					     rs485conf->delay_rts_before_send,
 243					     rs485conf->delay_rts_after_send,
 244					     baud);
 245
 246		if (rs485conf->flags & SER_RS485_RTS_ON_SEND)
 247			cr3 &= ~USART_CR3_DEP;
 248		else
 249			cr3 |= USART_CR3_DEP;
 250
 251		writel_relaxed(cr3, port->membase + ofs->cr3);
 252		writel_relaxed(cr1, port->membase + ofs->cr1);
 253
 254		if (!port->rs485_rx_during_tx_gpio)
 255			rs485conf->flags |= SER_RS485_RX_DURING_TX;
 256
 257	} else {
 258		stm32_usart_clr_bits(port, ofs->cr3,
 259				     USART_CR3_DEM | USART_CR3_DEP);
 260		stm32_usart_clr_bits(port, ofs->cr1,
 261				     USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
 262	}
 263
 264	stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 265
 266	/* Adjust RTS polarity in case it's driven in software */
 267	if (stm32_usart_tx_empty(port))
 268		stm32_usart_rs485_rts_disable(port);
 269	else
 270		stm32_usart_rs485_rts_enable(port);
 271
 272	return 0;
 273}
 274
 275static int stm32_usart_init_rs485(struct uart_port *port,
 276				  struct platform_device *pdev)
 277{
 278	struct serial_rs485 *rs485conf = &port->rs485;
 279
 280	rs485conf->flags = 0;
 281	rs485conf->delay_rts_before_send = 0;
 282	rs485conf->delay_rts_after_send = 0;
 283
 284	if (!pdev->dev.of_node)
 285		return -ENODEV;
 286
 287	return uart_get_rs485_mode(port);
 288}
 289
 290static bool stm32_usart_rx_dma_started(struct stm32_port *stm32_port)
 291{
 292	return stm32_port->rx_ch ? stm32_port->rx_dma_busy : false;
 293}
 294
 295static void stm32_usart_rx_dma_terminate(struct stm32_port *stm32_port)
 296{
 297	dmaengine_terminate_async(stm32_port->rx_ch);
 298	stm32_port->rx_dma_busy = false;
 299}
 300
 301static int stm32_usart_dma_pause_resume(struct stm32_port *stm32_port,
 302					struct dma_chan *chan,
 303					enum dma_status expected_status,
 304					int dmaengine_pause_or_resume(struct dma_chan *),
 305					bool stm32_usart_xx_dma_started(struct stm32_port *),
 306					void stm32_usart_xx_dma_terminate(struct stm32_port *))
 307{
 308	struct uart_port *port = &stm32_port->port;
 309	enum dma_status dma_status;
 310	int ret;
 311
 312	if (!stm32_usart_xx_dma_started(stm32_port))
 313		return -EPERM;
 314
 315	dma_status = dmaengine_tx_status(chan, chan->cookie, NULL);
 316	if (dma_status != expected_status)
 317		return -EAGAIN;
 318
 319	ret = dmaengine_pause_or_resume(chan);
 320	if (ret) {
 321		dev_err(port->dev, "DMA failed with error code: %d\n", ret);
 322		stm32_usart_xx_dma_terminate(stm32_port);
 323	}
 324	return ret;
 325}
 326
 327static int stm32_usart_rx_dma_pause(struct stm32_port *stm32_port)
 328{
 329	return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
 330					    DMA_IN_PROGRESS, dmaengine_pause,
 331					    stm32_usart_rx_dma_started,
 332					    stm32_usart_rx_dma_terminate);
 333}
 334
 335static int stm32_usart_rx_dma_resume(struct stm32_port *stm32_port)
 336{
 337	return stm32_usart_dma_pause_resume(stm32_port, stm32_port->rx_ch,
 338					    DMA_PAUSED, dmaengine_resume,
 339					    stm32_usart_rx_dma_started,
 340					    stm32_usart_rx_dma_terminate);
 341}
 342
 343/* Return true when data is pending (in pio mode), and false when no data is pending. */
 344static bool stm32_usart_pending_rx_pio(struct uart_port *port, u32 *sr)
 345{
 346	struct stm32_port *stm32_port = to_stm32_port(port);
 347	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 348
 349	*sr = readl_relaxed(port->membase + ofs->isr);
 350	/* Get pending characters in RDR or FIFO */
 351	if (*sr & USART_SR_RXNE) {
 352		/* Get all pending characters from the RDR or the FIFO when using interrupts */
 353		if (!stm32_usart_rx_dma_started(stm32_port))
 354			return true;
 355
 356		/* Handle only RX data errors when using DMA */
 357		if (*sr & USART_SR_ERR_MASK)
 358			return true;
 359	}
 360
 361	return false;
 362}
 363
 364static u8 stm32_usart_get_char_pio(struct uart_port *port)
 365{
 366	struct stm32_port *stm32_port = to_stm32_port(port);
 367	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 368	unsigned long c;
 369
 370	c = readl_relaxed(port->membase + ofs->rdr);
 371	/* Apply RDR data mask */
 372	c &= stm32_port->rdr_mask;
 373
 374	return c;
 375}
 376
 377static unsigned int stm32_usart_receive_chars_pio(struct uart_port *port)
 378{
 379	struct stm32_port *stm32_port = to_stm32_port(port);
 380	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
 381	unsigned int size = 0;
 382	u32 sr;
 383	u8 c, flag;
 384
 385	while (stm32_usart_pending_rx_pio(port, &sr)) {
 386		sr |= USART_SR_DUMMY_RX;
 387		flag = TTY_NORMAL;
 388
 389		/*
 390		 * Status bits has to be cleared before reading the RDR:
 391		 * In FIFO mode, reading the RDR will pop the next data
 392		 * (if any) along with its status bits into the SR.
 393		 * Not doing so leads to misalignement between RDR and SR,
 394		 * and clear status bits of the next rx data.
 395		 *
 396		 * Clear errors flags for stm32f7 and stm32h7 compatible
 397		 * devices. On stm32f4 compatible devices, the error bit is
 398		 * cleared by the sequence [read SR - read DR].
 399		 */
 400		if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
 401			writel_relaxed(sr & USART_SR_ERR_MASK,
 402				       port->membase + ofs->icr);
 403
 404		c = stm32_usart_get_char_pio(port);
 405		port->icount.rx++;
 406		size++;
 407		if (sr & USART_SR_ERR_MASK) {
 408			if (sr & USART_SR_ORE) {
 409				port->icount.overrun++;
 410			} else if (sr & USART_SR_PE) {
 411				port->icount.parity++;
 412			} else if (sr & USART_SR_FE) {
 413				/* Break detection if character is null */
 414				if (!c) {
 415					port->icount.brk++;
 416					if (uart_handle_break(port))
 417						continue;
 418				} else {
 419					port->icount.frame++;
 420				}
 421			}
 422
 423			sr &= port->read_status_mask;
 424
 425			if (sr & USART_SR_PE) {
 426				flag = TTY_PARITY;
 427			} else if (sr & USART_SR_FE) {
 428				if (!c)
 429					flag = TTY_BREAK;
 430				else
 431					flag = TTY_FRAME;
 432			}
 433		}
 434
 435		if (uart_prepare_sysrq_char(port, c))
 436			continue;
 437		uart_insert_char(port, sr, USART_SR_ORE, c, flag);
 438	}
 439
 440	return size;
 441}
 442
 443static void stm32_usart_push_buffer_dma(struct uart_port *port, unsigned int dma_size)
 444{
 445	struct stm32_port *stm32_port = to_stm32_port(port);
 446	struct tty_port *ttyport = &stm32_port->port.state->port;
 447	unsigned char *dma_start;
 448	int dma_count, i;
 449
 450	dma_start = stm32_port->rx_buf + (RX_BUF_L - stm32_port->last_res);
 451
 452	/*
 453	 * Apply rdr_mask on buffer in order to mask parity bit.
 454	 * This loop is useless in cs8 mode because DMA copies only
 455	 * 8 bits and already ignores parity bit.
 456	 */
 457	if (!(stm32_port->rdr_mask == (BIT(8) - 1)))
 458		for (i = 0; i < dma_size; i++)
 459			*(dma_start + i) &= stm32_port->rdr_mask;
 460
 461	dma_count = tty_insert_flip_string(ttyport, dma_start, dma_size);
 462	port->icount.rx += dma_count;
 463	if (dma_count != dma_size)
 464		port->icount.buf_overrun++;
 465	stm32_port->last_res -= dma_count;
 466	if (stm32_port->last_res == 0)
 467		stm32_port->last_res = RX_BUF_L;
 468}
 469
 470static unsigned int stm32_usart_receive_chars_dma(struct uart_port *port)
 471{
 472	struct stm32_port *stm32_port = to_stm32_port(port);
 473	unsigned int dma_size, size = 0;
 474
 475	/* DMA buffer is configured in cyclic mode and handles the rollback of the buffer. */
 476	if (stm32_port->rx_dma_state.residue > stm32_port->last_res) {
 477		/* Conditional first part: from last_res to end of DMA buffer */
 478		dma_size = stm32_port->last_res;
 479		stm32_usart_push_buffer_dma(port, dma_size);
 480		size = dma_size;
 481	}
 482
 483	dma_size = stm32_port->last_res - stm32_port->rx_dma_state.residue;
 484	stm32_usart_push_buffer_dma(port, dma_size);
 485	size += dma_size;
 486
 487	return size;
 488}
 489
 490static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force_dma_flush)
 491{
 492	struct stm32_port *stm32_port = to_stm32_port(port);
 493	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 494	enum dma_status rx_dma_status;
 495	u32 sr;
 496	unsigned int size = 0;
 497
 498	if (stm32_usart_rx_dma_started(stm32_port) || force_dma_flush) {
 499		rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
 500						    stm32_port->rx_ch->cookie,
 501						    &stm32_port->rx_dma_state);
 502		if (rx_dma_status == DMA_IN_PROGRESS ||
 503		    rx_dma_status == DMA_PAUSED) {
 504			/* Empty DMA buffer */
 505			size = stm32_usart_receive_chars_dma(port);
 506			sr = readl_relaxed(port->membase + ofs->isr);
 507			if (sr & USART_SR_ERR_MASK) {
 508				/* Disable DMA request line */
 509				stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 510
 511				/* Switch to PIO mode to handle the errors */
 512				size += stm32_usart_receive_chars_pio(port);
 513
 514				/* Switch back to DMA mode */
 515				stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAR);
 516			}
 517		} else {
 518			/* Disable RX DMA */
 519			stm32_usart_rx_dma_terminate(stm32_port);
 
 520			/* Fall back to interrupt mode */
 521			dev_dbg(port->dev, "DMA error, fallback to irq mode\n");
 522			size = stm32_usart_receive_chars_pio(port);
 523		}
 524	} else {
 525		size = stm32_usart_receive_chars_pio(port);
 526	}
 527
 528	return size;
 529}
 530
 531static void stm32_usart_rx_dma_complete(void *arg)
 532{
 533	struct uart_port *port = arg;
 534	struct tty_port *tport = &port->state->port;
 535	unsigned int size;
 536	unsigned long flags;
 537
 538	uart_port_lock_irqsave(port, &flags);
 539	size = stm32_usart_receive_chars(port, false);
 540	uart_unlock_and_check_sysrq_irqrestore(port, flags);
 541	if (size)
 542		tty_flip_buffer_push(tport);
 543}
 544
 545static int stm32_usart_rx_dma_start_or_resume(struct uart_port *port)
 546{
 547	struct stm32_port *stm32_port = to_stm32_port(port);
 548	struct dma_async_tx_descriptor *desc;
 549	enum dma_status rx_dma_status;
 550	int ret;
 551
 552	if (stm32_port->throttled)
 553		return 0;
 554
 555	if (stm32_port->rx_dma_busy) {
 556		rx_dma_status = dmaengine_tx_status(stm32_port->rx_ch,
 557						    stm32_port->rx_ch->cookie,
 558						    NULL);
 559		if (rx_dma_status == DMA_IN_PROGRESS)
 560			return 0;
 561
 562		if (rx_dma_status == DMA_PAUSED && !stm32_usart_rx_dma_resume(stm32_port))
 563			return 0;
 564
 565		dev_err(port->dev, "DMA failed : status error.\n");
 566		stm32_usart_rx_dma_terminate(stm32_port);
 567	}
 568
 569	stm32_port->rx_dma_busy = true;
 570
 571	stm32_port->last_res = RX_BUF_L;
 572	/* Prepare a DMA cyclic transaction */
 573	desc = dmaengine_prep_dma_cyclic(stm32_port->rx_ch,
 574					 stm32_port->rx_dma_buf,
 575					 RX_BUF_L, RX_BUF_P,
 576					 DMA_DEV_TO_MEM,
 577					 DMA_PREP_INTERRUPT);
 578	if (!desc) {
 579		dev_err(port->dev, "rx dma prep cyclic failed\n");
 580		stm32_port->rx_dma_busy = false;
 581		return -ENODEV;
 582	}
 583
 584	desc->callback = stm32_usart_rx_dma_complete;
 585	desc->callback_param = port;
 586
 587	/* Push current DMA transaction in the pending queue */
 588	ret = dma_submit_error(dmaengine_submit(desc));
 589	if (ret) {
 590		dmaengine_terminate_sync(stm32_port->rx_ch);
 591		stm32_port->rx_dma_busy = false;
 592		return ret;
 593	}
 594
 595	/* Issue pending DMA requests */
 596	dma_async_issue_pending(stm32_port->rx_ch);
 597
 598	return 0;
 599}
 600
 601static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port)
 602{
 603	dmaengine_terminate_async(stm32_port->tx_ch);
 604	stm32_port->tx_dma_busy = false;
 605}
 606
 607static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port)
 608{
 609	/*
 610	 * We cannot use the function "dmaengine_tx_status" to know the
 611	 * status of DMA. This function does not show if the "dma complete"
 612	 * callback of the DMA transaction has been called. So we prefer
 613	 * to use "tx_dma_busy" flag to prevent dual DMA transaction at the
 614	 * same time.
 615	 */
 616	return stm32_port->tx_dma_busy;
 617}
 618
 619static int stm32_usart_tx_dma_pause(struct stm32_port *stm32_port)
 620{
 621	return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
 622					    DMA_IN_PROGRESS, dmaengine_pause,
 623					    stm32_usart_tx_dma_started,
 624					    stm32_usart_tx_dma_terminate);
 625}
 626
 627static int stm32_usart_tx_dma_resume(struct stm32_port *stm32_port)
 628{
 629	return stm32_usart_dma_pause_resume(stm32_port, stm32_port->tx_ch,
 630					    DMA_PAUSED, dmaengine_resume,
 631					    stm32_usart_tx_dma_started,
 632					    stm32_usart_tx_dma_terminate);
 633}
 634
 635static void stm32_usart_tx_dma_complete(void *arg)
 636{
 637	struct uart_port *port = arg;
 638	struct stm32_port *stm32port = to_stm32_port(port);
 
 639	unsigned long flags;
 640
 
 641	stm32_usart_tx_dma_terminate(stm32port);
 642
 643	/* Let's see if we have pending data to send */
 644	uart_port_lock_irqsave(port, &flags);
 645	stm32_usart_transmit_chars(port);
 646	uart_port_unlock_irqrestore(port, flags);
 647}
 648
 649static void stm32_usart_tx_interrupt_enable(struct uart_port *port)
 650{
 651	struct stm32_port *stm32_port = to_stm32_port(port);
 652	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 653
 654	/*
 655	 * Enables TX FIFO threashold irq when FIFO is enabled,
 656	 * or TX empty irq when FIFO is disabled
 657	 */
 658	if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 659		stm32_usart_set_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 660	else
 661		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TXEIE);
 662}
 663
 664static void stm32_usart_tc_interrupt_enable(struct uart_port *port)
 665{
 666	struct stm32_port *stm32_port = to_stm32_port(port);
 667	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 668
 669	stm32_usart_set_bits(port, ofs->cr1, USART_CR1_TCIE);
 670}
 671
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 672static void stm32_usart_tx_interrupt_disable(struct uart_port *port)
 673{
 674	struct stm32_port *stm32_port = to_stm32_port(port);
 675	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 676
 677	if (stm32_port->fifoen && stm32_port->txftcfg >= 0)
 678		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_TXFTIE);
 679	else
 680		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TXEIE);
 681}
 682
 683static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
 684{
 685	struct stm32_port *stm32_port = to_stm32_port(port);
 686	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 687
 688	stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_TCIE);
 689}
 690
 691static void stm32_usart_transmit_chars_pio(struct uart_port *port)
 692{
 693	struct stm32_port *stm32_port = to_stm32_port(port);
 694	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 695	struct circ_buf *xmit = &port->state->xmit;
 696
 
 
 
 697	while (!uart_circ_empty(xmit)) {
 698		/* Check that TDR is empty before filling FIFO */
 699		if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE))
 700			break;
 701		writel_relaxed(xmit->buf[xmit->tail], port->membase + ofs->tdr);
 702		uart_xmit_advance(port, 1);
 703	}
 704
 705	/* rely on TXE irq (mask or unmask) for sending remaining data */
 706	if (uart_circ_empty(xmit))
 707		stm32_usart_tx_interrupt_disable(port);
 708	else
 709		stm32_usart_tx_interrupt_enable(port);
 710}
 711
 712static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 713{
 714	struct stm32_port *stm32port = to_stm32_port(port);
 
 715	struct circ_buf *xmit = &port->state->xmit;
 716	struct dma_async_tx_descriptor *desc = NULL;
 717	unsigned int count;
 718	int ret;
 719
 720	if (stm32_usart_tx_dma_started(stm32port)) {
 721		ret = stm32_usart_tx_dma_resume(stm32port);
 722		if (ret < 0 && ret != -EAGAIN)
 723			goto fallback_err;
 724		return;
 725	}
 726
 727	count = uart_circ_chars_pending(xmit);
 728
 729	if (count > TX_BUF_L)
 730		count = TX_BUF_L;
 731
 732	if (xmit->tail < xmit->head) {
 733		memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], count);
 734	} else {
 735		size_t one = UART_XMIT_SIZE - xmit->tail;
 736		size_t two;
 737
 738		if (one > count)
 739			one = count;
 740		two = count - one;
 741
 742		memcpy(&stm32port->tx_buf[0], &xmit->buf[xmit->tail], one);
 743		if (two)
 744			memcpy(&stm32port->tx_buf[one], &xmit->buf[0], two);
 745	}
 746
 747	desc = dmaengine_prep_slave_single(stm32port->tx_ch,
 748					   stm32port->tx_dma_buf,
 749					   count,
 750					   DMA_MEM_TO_DEV,
 751					   DMA_PREP_INTERRUPT);
 752
 753	if (!desc)
 754		goto fallback_err;
 755
 756	/*
 757	 * Set "tx_dma_busy" flag. This flag will be released when
 758	 * dmaengine_terminate_async will be called. This flag helps
 759	 * transmit_chars_dma not to start another DMA transaction
 760	 * if the callback of the previous is not yet called.
 761	 */
 762	stm32port->tx_dma_busy = true;
 763
 764	desc->callback = stm32_usart_tx_dma_complete;
 765	desc->callback_param = port;
 766
 767	/* Push current DMA TX transaction in the pending queue */
 768	/* DMA no yet started, safe to free resources */
 769	ret = dma_submit_error(dmaengine_submit(desc));
 770	if (ret) {
 771		dev_err(port->dev, "DMA failed with error code: %d\n", ret);
 772		stm32_usart_tx_dma_terminate(stm32port);
 773		goto fallback_err;
 774	}
 775
 776	/* Issue pending DMA TX requests */
 777	dma_async_issue_pending(stm32port->tx_ch);
 778
 
 
 779	uart_xmit_advance(port, count);
 780
 781	return;
 782
 783fallback_err:
 784	stm32_usart_transmit_chars_pio(port);
 785}
 786
 787static void stm32_usart_transmit_chars(struct uart_port *port)
 788{
 789	struct stm32_port *stm32_port = to_stm32_port(port);
 790	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 791	struct circ_buf *xmit = &port->state->xmit;
 792	u32 isr;
 793	int ret;
 794
 795	if (!stm32_port->hw_flow_control &&
 796	    port->rs485.flags & SER_RS485_ENABLED &&
 797	    (port->x_char ||
 798	     !(uart_circ_empty(xmit) || uart_tx_stopped(port)))) {
 799		stm32_usart_tc_interrupt_disable(port);
 800		stm32_usart_rs485_rts_enable(port);
 801	}
 802
 803	if (port->x_char) {
 804		/* dma terminate may have been called in case of dma pause failure */
 805		stm32_usart_tx_dma_pause(stm32_port);
 
 806
 807		/* Check that TDR is empty before filling FIFO */
 808		ret =
 809		readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
 810						  isr,
 811						  (isr & USART_SR_TXE),
 812						  10, 1000);
 813		if (ret)
 814			dev_warn(port->dev, "1 character may be erased\n");
 815
 816		writel_relaxed(port->x_char, port->membase + ofs->tdr);
 817		port->x_char = 0;
 818		port->icount.tx++;
 819
 820		/* dma terminate may have been called in case of dma resume failure */
 821		stm32_usart_tx_dma_resume(stm32_port);
 822		return;
 823	}
 824
 825	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 826		stm32_usart_tx_interrupt_disable(port);
 827		return;
 828	}
 829
 830	if (ofs->icr == UNDEF_REG)
 831		stm32_usart_clr_bits(port, ofs->isr, USART_SR_TC);
 832	else
 833		writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
 834
 835	if (stm32_port->tx_ch)
 836		stm32_usart_transmit_chars_dma(port);
 837	else
 838		stm32_usart_transmit_chars_pio(port);
 839
 840	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 841		uart_write_wakeup(port);
 842
 843	if (uart_circ_empty(xmit)) {
 844		stm32_usart_tx_interrupt_disable(port);
 845		if (!stm32_port->hw_flow_control &&
 846		    port->rs485.flags & SER_RS485_ENABLED) {
 
 847			stm32_usart_tc_interrupt_enable(port);
 848		}
 849	}
 850}
 851
 852static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 853{
 854	struct uart_port *port = ptr;
 855	struct tty_port *tport = &port->state->port;
 856	struct stm32_port *stm32_port = to_stm32_port(port);
 857	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 858	u32 sr;
 859	unsigned int size;
 860
 861	sr = readl_relaxed(port->membase + ofs->isr);
 862
 863	if (!stm32_port->hw_flow_control &&
 864	    port->rs485.flags & SER_RS485_ENABLED &&
 865	    (sr & USART_SR_TC)) {
 866		stm32_usart_tc_interrupt_disable(port);
 867		stm32_usart_rs485_rts_disable(port);
 868	}
 869
 870	if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
 871		writel_relaxed(USART_ICR_RTOCF,
 872			       port->membase + ofs->icr);
 873
 874	if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
 875		/* Clear wake up flag and disable wake up interrupt */
 876		writel_relaxed(USART_ICR_WUCF,
 877			       port->membase + ofs->icr);
 878		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
 879		if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
 880			pm_wakeup_event(tport->tty->dev, 0);
 881	}
 882
 883	/*
 884	 * rx errors in dma mode has to be handled ASAP to avoid overrun as the DMA request
 885	 * line has been masked by HW and rx data are stacking in FIFO.
 886	 */
 887	if (!stm32_port->throttled) {
 888		if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) ||
 889		    ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) {
 890			uart_port_lock(port);
 891			size = stm32_usart_receive_chars(port, false);
 892			uart_unlock_and_check_sysrq(port);
 893			if (size)
 894				tty_flip_buffer_push(tport);
 895		}
 896	}
 897
 898	if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) {
 899		uart_port_lock(port);
 900		stm32_usart_transmit_chars(port);
 901		uart_port_unlock(port);
 902	}
 903
 904	/* Receiver timeout irq for DMA RX */
 905	if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) {
 906		uart_port_lock(port);
 907		size = stm32_usart_receive_chars(port, false);
 908		uart_unlock_and_check_sysrq(port);
 909		if (size)
 910			tty_flip_buffer_push(tport);
 911	}
 912
 913	return IRQ_HANDLED;
 914}
 915
 916static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 917{
 918	struct stm32_port *stm32_port = to_stm32_port(port);
 919	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 920
 921	if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
 922		stm32_usart_set_bits(port, ofs->cr3, USART_CR3_RTSE);
 923	else
 924		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
 925
 926	mctrl_gpio_set(stm32_port->gpios, mctrl);
 927}
 928
 929static unsigned int stm32_usart_get_mctrl(struct uart_port *port)
 930{
 931	struct stm32_port *stm32_port = to_stm32_port(port);
 932	unsigned int ret;
 933
 934	/* This routine is used to get signals of: DCD, DSR, RI, and CTS */
 935	ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 936
 937	return mctrl_gpio_get(stm32_port->gpios, &ret);
 938}
 939
 940static void stm32_usart_enable_ms(struct uart_port *port)
 941{
 942	mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
 943}
 944
 945static void stm32_usart_disable_ms(struct uart_port *port)
 946{
 947	mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
 948}
 949
 950/* Transmit stop */
 951static void stm32_usart_stop_tx(struct uart_port *port)
 952{
 953	struct stm32_port *stm32_port = to_stm32_port(port);
 
 954
 955	stm32_usart_tx_interrupt_disable(port);
 956
 957	/* dma terminate may have been called in case of dma pause failure */
 958	stm32_usart_tx_dma_pause(stm32_port);
 959
 960	stm32_usart_rs485_rts_disable(port);
 961}
 962
 963/* There are probably characters waiting to be transmitted. */
 964static void stm32_usart_start_tx(struct uart_port *port)
 965{
 966	struct circ_buf *xmit = &port->state->xmit;
 967
 968	if (uart_circ_empty(xmit) && !port->x_char) {
 969		stm32_usart_rs485_rts_disable(port);
 970		return;
 971	}
 972
 973	stm32_usart_rs485_rts_enable(port);
 974
 975	stm32_usart_transmit_chars(port);
 976}
 977
 978/* Flush the transmit buffer. */
 979static void stm32_usart_flush_buffer(struct uart_port *port)
 980{
 981	struct stm32_port *stm32_port = to_stm32_port(port);
 
 982
 983	if (stm32_port->tx_ch)
 984		stm32_usart_tx_dma_terminate(stm32_port);
 
 
 985}
 986
 987/* Throttle the remote when input buffer is about to overflow. */
 988static void stm32_usart_throttle(struct uart_port *port)
 989{
 990	struct stm32_port *stm32_port = to_stm32_port(port);
 991	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 992	unsigned long flags;
 993
 994	uart_port_lock_irqsave(port, &flags);
 995
 996	/*
 997	 * Pause DMA transfer, so the RX data gets queued into the FIFO.
 998	 * Hardware flow control is triggered when RX FIFO is full.
 999	 */
1000	stm32_usart_rx_dma_pause(stm32_port);
 
1001
1002	stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1003	if (stm32_port->cr3_irq)
1004		stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1005
1006	stm32_port->throttled = true;
1007	uart_port_unlock_irqrestore(port, flags);
1008}
1009
1010/* Unthrottle the remote, the input buffer can now accept data. */
1011static void stm32_usart_unthrottle(struct uart_port *port)
1012{
1013	struct stm32_port *stm32_port = to_stm32_port(port);
1014	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1015	unsigned long flags;
1016
1017	uart_port_lock_irqsave(port, &flags);
1018	stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq);
1019	if (stm32_port->cr3_irq)
1020		stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq);
1021
1022	stm32_port->throttled = false;
1023
1024	/*
1025	 * Switch back to DMA mode (resume DMA).
1026	 * Hardware flow control is stopped when FIFO is not full any more.
1027	 */
1028	if (stm32_port->rx_ch)
1029		stm32_usart_rx_dma_start_or_resume(port);
1030
1031	uart_port_unlock_irqrestore(port, flags);
 
1032}
1033
1034/* Receive stop */
1035static void stm32_usart_stop_rx(struct uart_port *port)
1036{
1037	struct stm32_port *stm32_port = to_stm32_port(port);
1038	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1039
1040	/* Disable DMA request line. */
1041	stm32_usart_rx_dma_pause(stm32_port);
 
1042
1043	stm32_usart_clr_bits(port, ofs->cr1, stm32_port->cr1_irq);
1044	if (stm32_port->cr3_irq)
1045		stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq);
1046}
1047
 
1048static void stm32_usart_break_ctl(struct uart_port *port, int break_state)
1049{
 
 
 
 
1050	struct stm32_port *stm32_port = to_stm32_port(port);
1051	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1052	unsigned long flags;
 
1053
1054	spin_lock_irqsave(&port->lock, flags);
 
 
 
 
 
 
 
 
 
 
1055
1056	if (break_state)
1057		stm32_usart_set_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1058	else
1059		stm32_usart_clr_bits(port, ofs->rqr, USART_RQR_SBKRQ);
1060
1061	spin_unlock_irqrestore(&port->lock, flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1062}
1063
1064static int stm32_usart_startup(struct uart_port *port)
1065{
1066	struct stm32_port *stm32_port = to_stm32_port(port);
1067	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1068	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1069	const char *name = to_platform_device(port->dev)->name;
1070	u32 val;
1071	int ret;
1072
1073	ret = request_irq(port->irq, stm32_usart_interrupt,
1074			  IRQF_NO_SUSPEND, name, port);
1075	if (ret)
1076		return ret;
1077
1078	if (stm32_port->swap) {
1079		val = readl_relaxed(port->membase + ofs->cr2);
1080		val |= USART_CR2_SWAP;
1081		writel_relaxed(val, port->membase + ofs->cr2);
1082	}
1083
1084	/* RX FIFO Flush */
1085	if (ofs->rqr != UNDEF_REG)
1086		writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
1087
1088	if (stm32_port->rx_ch) {
1089		ret = stm32_usart_rx_dma_start_or_resume(port);
1090		if (ret) {
1091			free_irq(port->irq, port);
1092			return ret;
1093		}
1094	}
1095
1096	/* RX enabling */
1097	val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit);
1098	stm32_usart_set_bits(port, ofs->cr1, val);
1099
1100	return 0;
1101}
1102
1103static void stm32_usart_shutdown(struct uart_port *port)
1104{
1105	struct stm32_port *stm32_port = to_stm32_port(port);
1106	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1107	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1108	u32 val, isr;
1109	int ret;
1110
 
 
 
1111	if (stm32_usart_tx_dma_started(stm32_port))
1112		stm32_usart_tx_dma_terminate(stm32_port);
1113
1114	if (stm32_port->tx_ch)
1115		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
1116
1117	/* Disable modem control interrupts */
1118	stm32_usart_disable_ms(port);
1119
1120	val = USART_CR1_TXEIE | USART_CR1_TE;
1121	val |= stm32_port->cr1_irq | USART_CR1_RE;
1122	val |= BIT(cfg->uart_enable_bit);
1123	if (stm32_port->fifoen)
1124		val |= USART_CR1_FIFOEN;
1125
1126	ret = readl_relaxed_poll_timeout(port->membase + ofs->isr,
1127					 isr, (isr & USART_SR_TC),
1128					 10, 100000);
1129
1130	/* Send the TC error message only when ISR_TC is not set */
1131	if (ret)
1132		dev_err(port->dev, "Transmission is not complete\n");
1133
1134	/* Disable RX DMA. */
1135	if (stm32_port->rx_ch) {
1136		stm32_usart_rx_dma_terminate(stm32_port);
1137		dmaengine_synchronize(stm32_port->rx_ch);
1138	}
1139
1140	/* flush RX & TX FIFO */
1141	if (ofs->rqr != UNDEF_REG)
1142		writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1143			       port->membase + ofs->rqr);
1144
1145	stm32_usart_clr_bits(port, ofs->cr1, val);
1146
1147	free_irq(port->irq, port);
1148}
1149
1150static void stm32_usart_set_termios(struct uart_port *port,
1151				    struct ktermios *termios,
1152				    const struct ktermios *old)
1153{
1154	struct stm32_port *stm32_port = to_stm32_port(port);
1155	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1156	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1157	struct serial_rs485 *rs485conf = &port->rs485;
1158	unsigned int baud, bits;
1159	u32 usartdiv, mantissa, fraction, oversampling;
1160	tcflag_t cflag = termios->c_cflag;
1161	u32 cr1, cr2, cr3, isr;
1162	unsigned long flags;
1163	int ret;
1164
1165	if (!stm32_port->hw_flow_control)
1166		cflag &= ~CRTSCTS;
1167
1168	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8);
1169
1170	uart_port_lock_irqsave(port, &flags);
1171
1172	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
1173						isr,
1174						(isr & USART_SR_TC),
1175						10, 100000);
1176
1177	/* Send the TC error message only when ISR_TC is not set. */
1178	if (ret)
1179		dev_err(port->dev, "Transmission is not complete\n");
1180
1181	/* Stop serial port and reset value */
1182	writel_relaxed(0, port->membase + ofs->cr1);
1183
1184	/* flush RX & TX FIFO */
1185	if (ofs->rqr != UNDEF_REG)
1186		writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,
1187			       port->membase + ofs->rqr);
1188
1189	cr1 = USART_CR1_TE | USART_CR1_RE;
1190	if (stm32_port->fifoen)
1191		cr1 |= USART_CR1_FIFOEN;
1192	cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
1193
1194	/* Tx and RX FIFO configuration */
1195	cr3 = readl_relaxed(port->membase + ofs->cr3);
1196	cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE;
1197	if (stm32_port->fifoen) {
1198		if (stm32_port->txftcfg >= 0)
1199			cr3 |= stm32_port->txftcfg << USART_CR3_TXFTCFG_SHIFT;
1200		if (stm32_port->rxftcfg >= 0)
1201			cr3 |= stm32_port->rxftcfg << USART_CR3_RXFTCFG_SHIFT;
1202	}
1203
1204	if (cflag & CSTOPB)
1205		cr2 |= USART_CR2_STOP_2B;
1206
1207	bits = tty_get_char_size(cflag);
1208	stm32_port->rdr_mask = (BIT(bits) - 1);
1209
1210	if (cflag & PARENB) {
1211		bits++;
1212		cr1 |= USART_CR1_PCE;
1213	}
1214
1215	/*
1216	 * Word length configuration:
1217	 * CS8 + parity, 9 bits word aka [M1:M0] = 0b01
1218	 * CS7 or (CS6 + parity), 7 bits word aka [M1:M0] = 0b10
1219	 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
1220	 * M0 and M1 already cleared by cr1 initialization.
1221	 */
1222	if (bits == 9) {
1223		cr1 |= USART_CR1_M0;
1224	} else if ((bits == 7) && cfg->has_7bits_data) {
1225		cr1 |= USART_CR1_M1;
1226	} else if (bits != 8) {
1227		dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
1228			, bits);
1229		cflag &= ~CSIZE;
1230		cflag |= CS8;
1231		termios->c_cflag = cflag;
1232		bits = 8;
1233		if (cflag & PARENB) {
1234			bits++;
1235			cr1 |= USART_CR1_M0;
1236		}
1237	}
1238
1239	if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch ||
1240				       (stm32_port->fifoen &&
1241					stm32_port->rxftcfg >= 0))) {
1242		if (cflag & CSTOPB)
1243			bits = bits + 3; /* 1 start bit + 2 stop bits */
1244		else
1245			bits = bits + 2; /* 1 start bit + 1 stop bit */
1246
1247		/* RX timeout irq to occur after last stop bit + bits */
1248		stm32_port->cr1_irq = USART_CR1_RTOIE;
1249		writel_relaxed(bits, port->membase + ofs->rtor);
1250		cr2 |= USART_CR2_RTOEN;
1251		/*
1252		 * Enable fifo threshold irq in two cases, either when there is no DMA, or when
1253		 * wake up over usart, from low power until the DMA gets re-enabled by resume.
1254		 */
1255		stm32_port->cr3_irq =  USART_CR3_RXFTIE;
1256	}
1257
1258	cr1 |= stm32_port->cr1_irq;
1259	cr3 |= stm32_port->cr3_irq;
1260
1261	if (cflag & PARODD)
1262		cr1 |= USART_CR1_PS;
1263
1264	port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
1265	if (cflag & CRTSCTS) {
1266		port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
1267		cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
1268	}
1269
1270	usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
1271
1272	/*
1273	 * The USART supports 16 or 8 times oversampling.
1274	 * By default we prefer 16 times oversampling, so that the receiver
1275	 * has a better tolerance to clock deviations.
1276	 * 8 times oversampling is only used to achieve higher speeds.
1277	 */
1278	if (usartdiv < 16) {
1279		oversampling = 8;
1280		cr1 |= USART_CR1_OVER8;
1281		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8);
1282	} else {
1283		oversampling = 16;
1284		cr1 &= ~USART_CR1_OVER8;
1285		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8);
1286	}
1287
1288	mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT;
1289	fraction = usartdiv % oversampling;
1290	writel_relaxed(mantissa | fraction, port->membase + ofs->brr);
1291
1292	uart_update_timeout(port, cflag, baud);
1293
1294	port->read_status_mask = USART_SR_ORE;
1295	if (termios->c_iflag & INPCK)
1296		port->read_status_mask |= USART_SR_PE | USART_SR_FE;
1297	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1298		port->read_status_mask |= USART_SR_FE;
1299
1300	/* Characters to ignore */
1301	port->ignore_status_mask = 0;
1302	if (termios->c_iflag & IGNPAR)
1303		port->ignore_status_mask = USART_SR_PE | USART_SR_FE;
1304	if (termios->c_iflag & IGNBRK) {
1305		port->ignore_status_mask |= USART_SR_FE;
1306		/*
1307		 * If we're ignoring parity and break indicators,
1308		 * ignore overruns too (for real raw support).
1309		 */
1310		if (termios->c_iflag & IGNPAR)
1311			port->ignore_status_mask |= USART_SR_ORE;
1312	}
1313
1314	/* Ignore all characters if CREAD is not set */
1315	if ((termios->c_cflag & CREAD) == 0)
1316		port->ignore_status_mask |= USART_SR_DUMMY_RX;
1317
1318	if (stm32_port->rx_ch) {
1319		/*
1320		 * Setup DMA to collect only valid data and enable error irqs.
1321		 * This also enables break reception when using DMA.
1322		 */
1323		cr1 |= USART_CR1_PEIE;
1324		cr3 |= USART_CR3_EIE;
1325		cr3 |= USART_CR3_DMAR;
1326		cr3 |= USART_CR3_DDRE;
1327	}
1328
1329	if (stm32_port->tx_ch)
1330		cr3 |= USART_CR3_DMAT;
1331
1332	if (rs485conf->flags & SER_RS485_ENABLED) {
1333		stm32_usart_config_reg_rs485(&cr1, &cr3,
1334					     rs485conf->delay_rts_before_send,
1335					     rs485conf->delay_rts_after_send,
1336					     baud);
1337		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
1338			cr3 &= ~USART_CR3_DEP;
1339			rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
1340		} else {
1341			cr3 |= USART_CR3_DEP;
1342			rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
1343		}
1344
1345	} else {
1346		cr3 &= ~(USART_CR3_DEM | USART_CR3_DEP);
1347		cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
1348	}
1349
1350	/* Configure wake up from low power on start bit detection */
1351	if (stm32_port->wakeup_src) {
1352		cr3 &= ~USART_CR3_WUS_MASK;
1353		cr3 |= USART_CR3_WUS_START_BIT;
1354	}
1355
1356	writel_relaxed(cr3, port->membase + ofs->cr3);
1357	writel_relaxed(cr2, port->membase + ofs->cr2);
1358	writel_relaxed(cr1, port->membase + ofs->cr1);
1359
1360	stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1361	uart_port_unlock_irqrestore(port, flags);
1362
1363	/* Handle modem control interrupts */
1364	if (UART_ENABLE_MS(port, termios->c_cflag))
1365		stm32_usart_enable_ms(port);
1366	else
1367		stm32_usart_disable_ms(port);
1368}
1369
1370static const char *stm32_usart_type(struct uart_port *port)
1371{
1372	return (port->type == PORT_STM32) ? DRIVER_NAME : NULL;
1373}
1374
1375static void stm32_usart_release_port(struct uart_port *port)
1376{
1377}
1378
1379static int stm32_usart_request_port(struct uart_port *port)
1380{
1381	return 0;
1382}
1383
1384static void stm32_usart_config_port(struct uart_port *port, int flags)
1385{
1386	if (flags & UART_CONFIG_TYPE)
1387		port->type = PORT_STM32;
1388}
1389
1390static int
1391stm32_usart_verify_port(struct uart_port *port, struct serial_struct *ser)
1392{
1393	/* No user changeable parameters */
1394	return -EINVAL;
1395}
1396
1397static void stm32_usart_pm(struct uart_port *port, unsigned int state,
1398			   unsigned int oldstate)
1399{
1400	struct stm32_port *stm32port = container_of(port,
1401			struct stm32_port, port);
1402	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1403	const struct stm32_usart_config *cfg = &stm32port->info->cfg;
1404	unsigned long flags;
1405
1406	switch (state) {
1407	case UART_PM_STATE_ON:
1408		pm_runtime_get_sync(port->dev);
1409		break;
1410	case UART_PM_STATE_OFF:
1411		uart_port_lock_irqsave(port, &flags);
1412		stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
1413		uart_port_unlock_irqrestore(port, flags);
1414		pm_runtime_put_sync(port->dev);
1415		break;
1416	}
1417}
1418
1419#if defined(CONFIG_CONSOLE_POLL)
1420
1421 /* Callbacks for characters polling in debug context (i.e. KGDB). */
1422static int stm32_usart_poll_init(struct uart_port *port)
1423{
1424	struct stm32_port *stm32_port = to_stm32_port(port);
1425
1426	return clk_prepare_enable(stm32_port->clk);
1427}
1428
1429static int stm32_usart_poll_get_char(struct uart_port *port)
1430{
1431	struct stm32_port *stm32_port = to_stm32_port(port);
1432	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1433
1434	if (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_RXNE))
1435		return NO_POLL_CHAR;
1436
1437	return readl_relaxed(port->membase + ofs->rdr) & stm32_port->rdr_mask;
1438}
1439
1440static void stm32_usart_poll_put_char(struct uart_port *port, unsigned char ch)
1441{
1442	stm32_usart_console_putchar(port, ch);
1443}
1444#endif /* CONFIG_CONSOLE_POLL */
1445
1446static const struct uart_ops stm32_uart_ops = {
1447	.tx_empty	= stm32_usart_tx_empty,
1448	.set_mctrl	= stm32_usart_set_mctrl,
1449	.get_mctrl	= stm32_usart_get_mctrl,
1450	.stop_tx	= stm32_usart_stop_tx,
1451	.start_tx	= stm32_usart_start_tx,
1452	.throttle	= stm32_usart_throttle,
1453	.unthrottle	= stm32_usart_unthrottle,
1454	.stop_rx	= stm32_usart_stop_rx,
1455	.enable_ms	= stm32_usart_enable_ms,
1456	.break_ctl	= stm32_usart_break_ctl,
1457	.startup	= stm32_usart_startup,
1458	.shutdown	= stm32_usart_shutdown,
1459	.flush_buffer	= stm32_usart_flush_buffer,
1460	.set_termios	= stm32_usart_set_termios,
1461	.pm		= stm32_usart_pm,
1462	.type		= stm32_usart_type,
1463	.release_port	= stm32_usart_release_port,
1464	.request_port	= stm32_usart_request_port,
1465	.config_port	= stm32_usart_config_port,
1466	.verify_port	= stm32_usart_verify_port,
1467#if defined(CONFIG_CONSOLE_POLL)
1468	.poll_init      = stm32_usart_poll_init,
1469	.poll_get_char	= stm32_usart_poll_get_char,
1470	.poll_put_char	= stm32_usart_poll_put_char,
1471#endif /* CONFIG_CONSOLE_POLL */
1472};
1473
1474/*
1475 * STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG)
1476 * Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case,
1477 * RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE.
1478 * So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1.
1479 */
1480static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 };
1481
1482static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p,
1483				  int *ftcfg)
1484{
1485	u32 bytes, i;
1486
1487	/* DT option to get RX & TX FIFO threshold (default to 8 bytes) */
1488	if (of_property_read_u32(pdev->dev.of_node, p, &bytes))
1489		bytes = 8;
1490
1491	for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++)
1492		if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes)
1493			break;
1494	if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg))
1495		i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1;
1496
1497	dev_dbg(&pdev->dev, "%s set to %d bytes\n", p,
1498		stm32h7_usart_fifo_thresh_cfg[i]);
1499
1500	/* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */
1501	if (i)
1502		*ftcfg = i - 1;
1503	else
1504		*ftcfg = -EINVAL;
1505}
1506
1507static void stm32_usart_deinit_port(struct stm32_port *stm32port)
1508{
1509	clk_disable_unprepare(stm32port->clk);
1510}
1511
1512static const struct serial_rs485 stm32_rs485_supported = {
1513	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
1514		 SER_RS485_RX_DURING_TX,
1515	.delay_rts_before_send = 1,
1516	.delay_rts_after_send = 1,
1517};
1518
1519static int stm32_usart_init_port(struct stm32_port *stm32port,
1520				 struct platform_device *pdev)
1521{
1522	struct uart_port *port = &stm32port->port;
1523	struct resource *res;
1524	int ret, irq;
1525
1526	irq = platform_get_irq(pdev, 0);
1527	if (irq < 0)
1528		return irq;
1529
1530	port->iotype	= UPIO_MEM;
1531	port->flags	= UPF_BOOT_AUTOCONF;
1532	port->ops	= &stm32_uart_ops;
1533	port->dev	= &pdev->dev;
1534	port->fifosize	= stm32port->info->cfg.fifosize;
1535	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE);
1536	port->irq = irq;
1537	port->rs485_config = stm32_usart_config_rs485;
1538	port->rs485_supported = stm32_rs485_supported;
1539
1540	ret = stm32_usart_init_rs485(port, pdev);
1541	if (ret)
1542		return ret;
1543
1544	stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&
1545		of_property_read_bool(pdev->dev.of_node, "wakeup-source");
1546
1547	stm32port->swap = stm32port->info->cfg.has_swap &&
1548		of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");
1549
1550	stm32port->fifoen = stm32port->info->cfg.has_fifo;
1551	if (stm32port->fifoen) {
1552		stm32_usart_get_ftcfg(pdev, "rx-threshold",
1553				      &stm32port->rxftcfg);
1554		stm32_usart_get_ftcfg(pdev, "tx-threshold",
1555				      &stm32port->txftcfg);
1556	}
1557
1558	port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
1559	if (IS_ERR(port->membase))
1560		return PTR_ERR(port->membase);
1561	port->mapbase = res->start;
1562
1563	spin_lock_init(&port->lock);
1564
1565	stm32port->clk = devm_clk_get(&pdev->dev, NULL);
1566	if (IS_ERR(stm32port->clk))
1567		return PTR_ERR(stm32port->clk);
1568
1569	/* Ensure that clk rate is correct by enabling the clk */
1570	ret = clk_prepare_enable(stm32port->clk);
1571	if (ret)
1572		return ret;
1573
1574	stm32port->port.uartclk = clk_get_rate(stm32port->clk);
1575	if (!stm32port->port.uartclk) {
1576		ret = -EINVAL;
1577		goto err_clk;
1578	}
1579
1580	stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
1581	if (IS_ERR(stm32port->gpios)) {
1582		ret = PTR_ERR(stm32port->gpios);
1583		goto err_clk;
1584	}
1585
1586	/*
1587	 * Both CTS/RTS gpios and "st,hw-flow-ctrl" (deprecated) or "uart-has-rtscts"
1588	 * properties should not be specified.
1589	 */
1590	if (stm32port->hw_flow_control) {
1591		if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
1592		    mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
1593			dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
1594			ret = -EINVAL;
1595			goto err_clk;
1596		}
1597	}
1598
1599	return ret;
1600
1601err_clk:
1602	clk_disable_unprepare(stm32port->clk);
1603
1604	return ret;
1605}
1606
1607static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
1608{
1609	struct device_node *np = pdev->dev.of_node;
1610	int id;
1611
1612	if (!np)
1613		return NULL;
1614
1615	id = of_alias_get_id(np, "serial");
1616	if (id < 0) {
1617		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", id);
1618		return NULL;
1619	}
1620
1621	if (WARN_ON(id >= STM32_MAX_PORTS))
1622		return NULL;
1623
1624	stm32_ports[id].hw_flow_control =
1625		of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
1626		of_property_read_bool (np, "uart-has-rtscts");
1627	stm32_ports[id].port.line = id;
1628	stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
1629	stm32_ports[id].cr3_irq = 0;
1630	stm32_ports[id].last_res = RX_BUF_L;
1631	return &stm32_ports[id];
1632}
1633
1634#ifdef CONFIG_OF
1635static const struct of_device_id stm32_match[] = {
1636	{ .compatible = "st,stm32-uart", .data = &stm32f4_info},
1637	{ .compatible = "st,stm32f7-uart", .data = &stm32f7_info},
1638	{ .compatible = "st,stm32h7-uart", .data = &stm32h7_info},
1639	{},
1640};
1641
1642MODULE_DEVICE_TABLE(of, stm32_match);
1643#endif
1644
1645static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
1646					 struct platform_device *pdev)
1647{
1648	if (stm32port->rx_buf)
1649		dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
1650				  stm32port->rx_dma_buf);
1651}
1652
1653static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
1654				       struct platform_device *pdev)
1655{
1656	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1657	struct uart_port *port = &stm32port->port;
1658	struct device *dev = &pdev->dev;
1659	struct dma_slave_config config;
1660	int ret;
1661
1662	stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
1663					       &stm32port->rx_dma_buf,
1664					       GFP_KERNEL);
1665	if (!stm32port->rx_buf)
1666		return -ENOMEM;
1667
1668	/* Configure DMA channel */
1669	memset(&config, 0, sizeof(config));
1670	config.src_addr = port->mapbase + ofs->rdr;
1671	config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1672
1673	ret = dmaengine_slave_config(stm32port->rx_ch, &config);
1674	if (ret < 0) {
1675		dev_err(dev, "rx dma channel config failed\n");
1676		stm32_usart_of_dma_rx_remove(stm32port, pdev);
1677		return ret;
1678	}
1679
1680	return 0;
1681}
1682
1683static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
1684					 struct platform_device *pdev)
1685{
1686	if (stm32port->tx_buf)
1687		dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
1688				  stm32port->tx_dma_buf);
1689}
1690
1691static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
1692				       struct platform_device *pdev)
1693{
1694	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
1695	struct uart_port *port = &stm32port->port;
1696	struct device *dev = &pdev->dev;
1697	struct dma_slave_config config;
1698	int ret;
1699
1700	stm32port->tx_buf = dma_alloc_coherent(dev, TX_BUF_L,
1701					       &stm32port->tx_dma_buf,
1702					       GFP_KERNEL);
1703	if (!stm32port->tx_buf)
1704		return -ENOMEM;
1705
1706	/* Configure DMA channel */
1707	memset(&config, 0, sizeof(config));
1708	config.dst_addr = port->mapbase + ofs->tdr;
1709	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1710
1711	ret = dmaengine_slave_config(stm32port->tx_ch, &config);
1712	if (ret < 0) {
1713		dev_err(dev, "tx dma channel config failed\n");
1714		stm32_usart_of_dma_tx_remove(stm32port, pdev);
1715		return ret;
1716	}
1717
1718	return 0;
1719}
1720
1721static int stm32_usart_serial_probe(struct platform_device *pdev)
1722{
1723	struct stm32_port *stm32port;
1724	int ret;
1725
1726	stm32port = stm32_usart_of_get_port(pdev);
1727	if (!stm32port)
1728		return -ENODEV;
1729
1730	stm32port->info = of_device_get_match_data(&pdev->dev);
1731	if (!stm32port->info)
1732		return -EINVAL;
1733
1734	stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
1735	if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER)
1736		return -EPROBE_DEFER;
1737
1738	/* Fall back in interrupt mode for any non-deferral error */
1739	if (IS_ERR(stm32port->rx_ch))
1740		stm32port->rx_ch = NULL;
1741
1742	stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
1743	if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
1744		ret = -EPROBE_DEFER;
1745		goto err_dma_rx;
1746	}
1747	/* Fall back in interrupt mode for any non-deferral error */
1748	if (IS_ERR(stm32port->tx_ch))
1749		stm32port->tx_ch = NULL;
1750
1751	ret = stm32_usart_init_port(stm32port, pdev);
1752	if (ret)
1753		goto err_dma_tx;
1754
1755	if (stm32port->wakeup_src) {
1756		device_set_wakeup_capable(&pdev->dev, true);
1757		ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
1758		if (ret)
1759			goto err_deinit_port;
1760	}
1761
1762	if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
1763		/* Fall back in interrupt mode */
1764		dma_release_channel(stm32port->rx_ch);
1765		stm32port->rx_ch = NULL;
1766	}
1767
1768	if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
1769		/* Fall back in interrupt mode */
1770		dma_release_channel(stm32port->tx_ch);
1771		stm32port->tx_ch = NULL;
1772	}
1773
1774	if (!stm32port->rx_ch)
1775		dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
1776	if (!stm32port->tx_ch)
1777		dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
1778
1779	platform_set_drvdata(pdev, &stm32port->port);
1780
1781	pm_runtime_get_noresume(&pdev->dev);
1782	pm_runtime_set_active(&pdev->dev);
1783	pm_runtime_enable(&pdev->dev);
1784
1785	ret = uart_add_one_port(&stm32_usart_driver, &stm32port->port);
1786	if (ret)
1787		goto err_port;
1788
1789	pm_runtime_put_sync(&pdev->dev);
1790
1791	return 0;
1792
1793err_port:
1794	pm_runtime_disable(&pdev->dev);
1795	pm_runtime_set_suspended(&pdev->dev);
1796	pm_runtime_put_noidle(&pdev->dev);
1797
1798	if (stm32port->tx_ch)
1799		stm32_usart_of_dma_tx_remove(stm32port, pdev);
1800	if (stm32port->rx_ch)
1801		stm32_usart_of_dma_rx_remove(stm32port, pdev);
1802
1803	if (stm32port->wakeup_src)
1804		dev_pm_clear_wake_irq(&pdev->dev);
1805
1806err_deinit_port:
1807	if (stm32port->wakeup_src)
1808		device_set_wakeup_capable(&pdev->dev, false);
1809
1810	stm32_usart_deinit_port(stm32port);
1811
1812err_dma_tx:
1813	if (stm32port->tx_ch)
1814		dma_release_channel(stm32port->tx_ch);
1815
1816err_dma_rx:
1817	if (stm32port->rx_ch)
1818		dma_release_channel(stm32port->rx_ch);
1819
1820	return ret;
1821}
1822
1823static void stm32_usart_serial_remove(struct platform_device *pdev)
1824{
1825	struct uart_port *port = platform_get_drvdata(pdev);
1826	struct stm32_port *stm32_port = to_stm32_port(port);
1827	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
1828	u32 cr3;
1829
1830	pm_runtime_get_sync(&pdev->dev);
1831	uart_remove_one_port(&stm32_usart_driver, port);
 
 
1832
1833	pm_runtime_disable(&pdev->dev);
1834	pm_runtime_set_suspended(&pdev->dev);
1835	pm_runtime_put_noidle(&pdev->dev);
1836
1837	stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_PEIE);
 
 
 
 
 
1838
1839	if (stm32_port->tx_ch) {
1840		stm32_usart_of_dma_tx_remove(stm32_port, pdev);
1841		dma_release_channel(stm32_port->tx_ch);
1842	}
1843
1844	if (stm32_port->rx_ch) {
1845		stm32_usart_of_dma_rx_remove(stm32_port, pdev);
1846		dma_release_channel(stm32_port->rx_ch);
1847	}
1848
1849	cr3 = readl_relaxed(port->membase + ofs->cr3);
1850	cr3 &= ~USART_CR3_EIE;
1851	cr3 &= ~USART_CR3_DMAR;
1852	cr3 &= ~USART_CR3_DMAT;
1853	cr3 &= ~USART_CR3_DDRE;
1854	writel_relaxed(cr3, port->membase + ofs->cr3);
1855
1856	if (stm32_port->wakeup_src) {
1857		dev_pm_clear_wake_irq(&pdev->dev);
1858		device_init_wakeup(&pdev->dev, false);
1859	}
1860
1861	stm32_usart_deinit_port(stm32_port);
 
 
1862}
1863
1864static void __maybe_unused stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
1865{
1866	struct stm32_port *stm32_port = to_stm32_port(port);
1867	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1868	u32 isr;
1869	int ret;
1870
1871	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr,
1872						(isr & USART_SR_TXE), 100,
1873						STM32_USART_TIMEOUT_USEC);
1874	if (ret != 0) {
1875		dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret);
1876		return;
1877	}
1878	writel_relaxed(ch, port->membase + ofs->tdr);
1879}
1880
1881#ifdef CONFIG_SERIAL_STM32_CONSOLE
1882static void stm32_usart_console_write(struct console *co, const char *s,
1883				      unsigned int cnt)
1884{
1885	struct uart_port *port = &stm32_ports[co->index].port;
1886	struct stm32_port *stm32_port = to_stm32_port(port);
1887	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
1888	const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
1889	unsigned long flags;
1890	u32 old_cr1, new_cr1;
1891	int locked = 1;
1892
1893	if (oops_in_progress)
1894		locked = uart_port_trylock_irqsave(port, &flags);
1895	else
1896		uart_port_lock_irqsave(port, &flags);
1897
1898	/* Save and disable interrupts, enable the transmitter */
1899	old_cr1 = readl_relaxed(port->membase + ofs->cr1);
1900	new_cr1 = old_cr1 & ~USART_CR1_IE_MASK;
1901	new_cr1 |=  USART_CR1_TE | BIT(cfg->uart_enable_bit);
1902	writel_relaxed(new_cr1, port->membase + ofs->cr1);
1903
1904	uart_console_write(port, s, cnt, stm32_usart_console_putchar);
1905
1906	/* Restore interrupt state */
1907	writel_relaxed(old_cr1, port->membase + ofs->cr1);
1908
1909	if (locked)
1910		uart_port_unlock_irqrestore(port, flags);
1911}
1912
1913static int stm32_usart_console_setup(struct console *co, char *options)
1914{
1915	struct stm32_port *stm32port;
1916	int baud = 9600;
1917	int bits = 8;
1918	int parity = 'n';
1919	int flow = 'n';
1920
1921	if (co->index >= STM32_MAX_PORTS)
1922		return -ENODEV;
1923
1924	stm32port = &stm32_ports[co->index];
1925
1926	/*
1927	 * This driver does not support early console initialization
1928	 * (use ARM early printk support instead), so we only expect
1929	 * this to be called during the uart port registration when the
1930	 * driver gets probed and the port should be mapped at that point.
1931	 */
1932	if (stm32port->port.mapbase == 0 || !stm32port->port.membase)
1933		return -ENXIO;
1934
1935	if (options)
1936		uart_parse_options(options, &baud, &parity, &bits, &flow);
1937
1938	return uart_set_options(&stm32port->port, co, baud, parity, bits, flow);
1939}
1940
1941static struct console stm32_console = {
1942	.name		= STM32_SERIAL_NAME,
1943	.device		= uart_console_device,
1944	.write		= stm32_usart_console_write,
1945	.setup		= stm32_usart_console_setup,
1946	.flags		= CON_PRINTBUFFER,
1947	.index		= -1,
1948	.data		= &stm32_usart_driver,
1949};
1950
1951#define STM32_SERIAL_CONSOLE (&stm32_console)
1952
1953#else
1954#define STM32_SERIAL_CONSOLE NULL
1955#endif /* CONFIG_SERIAL_STM32_CONSOLE */
1956
1957#ifdef CONFIG_SERIAL_EARLYCON
1958static void early_stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
1959{
1960	struct stm32_usart_info *info = port->private_data;
1961
1962	while (!(readl_relaxed(port->membase + info->ofs.isr) & USART_SR_TXE))
1963		cpu_relax();
1964
1965	writel_relaxed(ch, port->membase + info->ofs.tdr);
1966}
1967
1968static void early_stm32_serial_write(struct console *console, const char *s, unsigned int count)
1969{
1970	struct earlycon_device *device = console->data;
1971	struct uart_port *port = &device->port;
1972
1973	uart_console_write(port, s, count, early_stm32_usart_console_putchar);
1974}
1975
1976static int __init early_stm32_h7_serial_setup(struct earlycon_device *device, const char *options)
1977{
1978	if (!(device->port.membase || device->port.iobase))
1979		return -ENODEV;
1980	device->port.private_data = &stm32h7_info;
1981	device->con->write = early_stm32_serial_write;
1982	return 0;
1983}
1984
1985static int __init early_stm32_f7_serial_setup(struct earlycon_device *device, const char *options)
1986{
1987	if (!(device->port.membase || device->port.iobase))
1988		return -ENODEV;
1989	device->port.private_data = &stm32f7_info;
1990	device->con->write = early_stm32_serial_write;
1991	return 0;
1992}
1993
1994static int __init early_stm32_f4_serial_setup(struct earlycon_device *device, const char *options)
1995{
1996	if (!(device->port.membase || device->port.iobase))
1997		return -ENODEV;
1998	device->port.private_data = &stm32f4_info;
1999	device->con->write = early_stm32_serial_write;
2000	return 0;
2001}
2002
2003OF_EARLYCON_DECLARE(stm32, "st,stm32h7-uart", early_stm32_h7_serial_setup);
2004OF_EARLYCON_DECLARE(stm32, "st,stm32f7-uart", early_stm32_f7_serial_setup);
2005OF_EARLYCON_DECLARE(stm32, "st,stm32-uart", early_stm32_f4_serial_setup);
2006#endif /* CONFIG_SERIAL_EARLYCON */
2007
2008static struct uart_driver stm32_usart_driver = {
2009	.driver_name	= DRIVER_NAME,
2010	.dev_name	= STM32_SERIAL_NAME,
2011	.major		= 0,
2012	.minor		= 0,
2013	.nr		= STM32_MAX_PORTS,
2014	.cons		= STM32_SERIAL_CONSOLE,
2015};
2016
2017static int __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port,
2018						       bool enable)
2019{
2020	struct stm32_port *stm32_port = to_stm32_port(port);
2021	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
2022	struct tty_port *tport = &port->state->port;
2023	int ret;
2024	unsigned int size = 0;
2025	unsigned long flags;
2026
2027	if (!stm32_port->wakeup_src || !tty_port_initialized(tport))
2028		return 0;
2029
2030	/*
2031	 * Enable low-power wake-up and wake-up irq if argument is set to
2032	 * "enable", disable low-power wake-up and wake-up irq otherwise
2033	 */
2034	if (enable) {
2035		stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM);
2036		stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE);
2037		mctrl_gpio_enable_irq_wake(stm32_port->gpios);
2038
2039		/*
2040		 * When DMA is used for reception, it must be disabled before
2041		 * entering low-power mode and re-enabled when exiting from
2042		 * low-power mode.
2043		 */
2044		if (stm32_port->rx_ch) {
2045			uart_port_lock_irqsave(port, &flags);
 
 
2046			/* Poll data from DMA RX buffer if any */
2047			if (!stm32_usart_rx_dma_pause(stm32_port))
2048				size += stm32_usart_receive_chars(port, true);
2049			stm32_usart_rx_dma_terminate(stm32_port);
2050			uart_unlock_and_check_sysrq_irqrestore(port, flags);
2051			if (size)
2052				tty_flip_buffer_push(tport);
2053		}
2054
2055		/* Poll data from RX FIFO if any */
2056		stm32_usart_receive_chars(port, false);
2057	} else {
2058		if (stm32_port->rx_ch) {
2059			ret = stm32_usart_rx_dma_start_or_resume(port);
2060			if (ret)
2061				return ret;
2062		}
2063		mctrl_gpio_disable_irq_wake(stm32_port->gpios);
2064		stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM);
2065		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
2066	}
2067
2068	return 0;
2069}
2070
2071static int __maybe_unused stm32_usart_serial_suspend(struct device *dev)
2072{
2073	struct uart_port *port = dev_get_drvdata(dev);
2074	int ret;
2075
2076	uart_suspend_port(&stm32_usart_driver, port);
2077
2078	if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2079		ret = stm32_usart_serial_en_wakeup(port, true);
2080		if (ret)
2081			return ret;
2082	}
2083
2084	/*
2085	 * When "no_console_suspend" is enabled, keep the pinctrl default state
2086	 * and rely on bootloader stage to restore this state upon resume.
2087	 * Otherwise, apply the idle or sleep states depending on wakeup
2088	 * capabilities.
2089	 */
2090	if (console_suspend_enabled || !uart_console(port)) {
2091		if (device_may_wakeup(dev) || device_wakeup_path(dev))
2092			pinctrl_pm_select_idle_state(dev);
2093		else
2094			pinctrl_pm_select_sleep_state(dev);
2095	}
2096
2097	return 0;
2098}
2099
2100static int __maybe_unused stm32_usart_serial_resume(struct device *dev)
2101{
2102	struct uart_port *port = dev_get_drvdata(dev);
2103	int ret;
2104
2105	pinctrl_pm_select_default_state(dev);
2106
2107	if (device_may_wakeup(dev) || device_wakeup_path(dev)) {
2108		ret = stm32_usart_serial_en_wakeup(port, false);
2109		if (ret)
2110			return ret;
2111	}
2112
2113	return uart_resume_port(&stm32_usart_driver, port);
2114}
2115
2116static int __maybe_unused stm32_usart_runtime_suspend(struct device *dev)
2117{
2118	struct uart_port *port = dev_get_drvdata(dev);
2119	struct stm32_port *stm32port = container_of(port,
2120			struct stm32_port, port);
2121
2122	clk_disable_unprepare(stm32port->clk);
2123
2124	return 0;
2125}
2126
2127static int __maybe_unused stm32_usart_runtime_resume(struct device *dev)
2128{
2129	struct uart_port *port = dev_get_drvdata(dev);
2130	struct stm32_port *stm32port = container_of(port,
2131			struct stm32_port, port);
2132
2133	return clk_prepare_enable(stm32port->clk);
2134}
2135
2136static const struct dev_pm_ops stm32_serial_pm_ops = {
2137	SET_RUNTIME_PM_OPS(stm32_usart_runtime_suspend,
2138			   stm32_usart_runtime_resume, NULL)
2139	SET_SYSTEM_SLEEP_PM_OPS(stm32_usart_serial_suspend,
2140				stm32_usart_serial_resume)
2141};
2142
2143static struct platform_driver stm32_serial_driver = {
2144	.probe		= stm32_usart_serial_probe,
2145	.remove_new	= stm32_usart_serial_remove,
2146	.driver	= {
2147		.name	= DRIVER_NAME,
2148		.pm	= &stm32_serial_pm_ops,
2149		.of_match_table = of_match_ptr(stm32_match),
2150	},
2151};
2152
2153static int __init stm32_usart_init(void)
2154{
2155	static char banner[] __initdata = "STM32 USART driver initialized";
2156	int ret;
2157
2158	pr_info("%s\n", banner);
2159
2160	ret = uart_register_driver(&stm32_usart_driver);
2161	if (ret)
2162		return ret;
2163
2164	ret = platform_driver_register(&stm32_serial_driver);
2165	if (ret)
2166		uart_unregister_driver(&stm32_usart_driver);
2167
2168	return ret;
2169}
2170
2171static void __exit stm32_usart_exit(void)
2172{
2173	platform_driver_unregister(&stm32_serial_driver);
2174	uart_unregister_driver(&stm32_usart_driver);
2175}
2176
2177module_init(stm32_usart_init);
2178module_exit(stm32_usart_exit);
2179
2180MODULE_ALIAS("platform:" DRIVER_NAME);
2181MODULE_DESCRIPTION("STMicroelectronics STM32 serial port driver");
2182MODULE_LICENSE("GPL v2");