[linux-2.6-block.git] / drivers / tty / serial / sprd_serial.c

/*
 * Copyright (C) 2012-2015 Spreadtrum Communications Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/clk.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>

/* device name */
#define UART_NR_MAX		8
#define SPRD_TTY_NAME		"ttyS"
#define SPRD_FIFO_SIZE		128
#define SPRD_DEF_RATE		26000000
#define SPRD_BAUD_IO_LIMIT	3000000
#define SPRD_TIMEOUT		256

/* the offset of serial registers and BITs for them */
/* data registers */
#define SPRD_TXD		0x0000
#define SPRD_RXD		0x0004

/* line status register and its BITs  */
#define SPRD_LSR		0x0008
#define SPRD_LSR_OE		BIT(4)
#define SPRD_LSR_FE		BIT(3)
#define SPRD_LSR_PE		BIT(2)
#define SPRD_LSR_BI		BIT(7)
#define SPRD_LSR_TX_OVER	BIT(15)

/* data number in TX and RX fifo */
#define SPRD_STS1		0x000C

/* interrupt enable register and its BITs */
#define SPRD_IEN		0x0010
#define SPRD_IEN_RX_FULL	BIT(0)
#define SPRD_IEN_TX_EMPTY	BIT(1)
#define SPRD_IEN_BREAK_DETECT	BIT(7)
#define SPRD_IEN_TIMEOUT	BIT(13)

/* interrupt clear register */
#define SPRD_ICLR		0x0014

/* line control register */
#define SPRD_LCR		0x0018
#define SPRD_LCR_STOP_1BIT	0x10
#define SPRD_LCR_STOP_2BIT	0x30
#define SPRD_LCR_DATA_LEN	(BIT(2) | BIT(3))
#define SPRD_LCR_DATA_LEN5	0x0
#define SPRD_LCR_DATA_LEN6	0x4
#define SPRD_LCR_DATA_LEN7	0x8
#define SPRD_LCR_DATA_LEN8	0xc
#define SPRD_LCR_PARITY	(BIT(0) | BIT(1))
#define SPRD_LCR_PARITY_EN	0x2
#define SPRD_LCR_EVEN_PAR	0x0
#define SPRD_LCR_ODD_PAR	0x1

/* control register 1 */
#define SPRD_CTL1			0x001C
#define RX_HW_FLOW_CTL_THLD	BIT(6)
#define RX_HW_FLOW_CTL_EN	BIT(7)
#define TX_HW_FLOW_CTL_EN	BIT(8)
#define RX_TOUT_THLD_DEF	0x3E00
#define RX_HFC_THLD_DEF	0x40

/* fifo threshold register */
#define SPRD_CTL2		0x0020
#define THLD_TX_EMPTY	0x40
#define THLD_RX_FULL	0x40

/* config baud rate register */
#define SPRD_CLKD0		0x0024
#define SPRD_CLKD1		0x0028

/* interrupt mask status register */
#define SPRD_IMSR			0x002C
#define SPRD_IMSR_RX_FIFO_FULL		BIT(0)
#define SPRD_IMSR_TX_FIFO_EMPTY	BIT(1)
#define SPRD_IMSR_BREAK_DETECT		BIT(7)
#define SPRD_IMSR_TIMEOUT		BIT(13)

struct reg_backup {
	u32 ien;
	u32 ctrl0;
	u32 ctrl1;
	u32 ctrl2;
	u32 clkd0;
	u32 clkd1;
	u32 dspwait;
};

struct sprd_uart_port {
	struct uart_port port;
	struct reg_backup reg_bak;
	char name[16];
};

static struct sprd_uart_port *sprd_port[UART_NR_MAX];
static int sprd_ports_num;

static inline unsigned int serial_in(struct uart_port *port, int offset)
{
	return readl_relaxed(port->membase + offset);
}

static inline void serial_out(struct uart_port *port, int offset, int value)
{
	writel_relaxed(value, port->membase + offset);
}

static unsigned int sprd_tx_empty(struct uart_port *port)
{
	if (serial_in(port, SPRD_STS1) & 0xff00)
		return 0;
	else
		return TIOCSER_TEMT;
}

static unsigned int sprd_get_mctrl(struct uart_port *port)
{
	return TIOCM_DSR | TIOCM_CTS;
}

static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	/* nothing to do */
}

static void sprd_stop_tx(struct uart_port *port)
{
	unsigned int ien, iclr;

	iclr = serial_in(port, SPRD_ICLR);
	ien = serial_in(port, SPRD_IEN);

	iclr |= SPRD_IEN_TX_EMPTY;
	ien &= ~SPRD_IEN_TX_EMPTY;

	serial_out(port, SPRD_ICLR, iclr);
	serial_out(port, SPRD_IEN, ien);
}

static void sprd_start_tx(struct uart_port *port)
{
	unsigned int ien;

	ien = serial_in(port, SPRD_IEN);
	if (!(ien & SPRD_IEN_TX_EMPTY)) {
		ien |= SPRD_IEN_TX_EMPTY;
		serial_out(port, SPRD_IEN, ien);
	}
}

static void sprd_stop_rx(struct uart_port *port)
{
	unsigned int ien, iclr;

	iclr = serial_in(port, SPRD_ICLR);
	ien = serial_in(port, SPRD_IEN);

	ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
	iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;

	serial_out(port, SPRD_IEN, ien);
	serial_out(port, SPRD_ICLR, iclr);
}

/* The Sprd serial does not support this function. */
static void sprd_break_ctl(struct uart_port *port, int break_state)
{
	/* nothing to do */
}

static int handle_lsr_errors(struct uart_port *port,
			     unsigned int *flag,
			     unsigned int *lsr)
{
	int ret = 0;

	/* statistics */
	if (*lsr & SPRD_LSR_BI) {
		*lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE);
		port->icount.brk++;
		ret = uart_handle_break(port);
		if (ret)
			return ret;
	} else if (*lsr & SPRD_LSR_PE)
		port->icount.parity++;
	else if (*lsr & SPRD_LSR_FE)
		port->icount.frame++;
	if (*lsr & SPRD_LSR_OE)
		port->icount.overrun++;

	/* mask off conditions which should be ignored */
	*lsr &= port->read_status_mask;
	if (*lsr & SPRD_LSR_BI)
		*flag = TTY_BREAK;
	else if (*lsr & SPRD_LSR_PE)
		*flag = TTY_PARITY;
	else if (*lsr & SPRD_LSR_FE)
		*flag = TTY_FRAME;

	return ret;
}

static inline void sprd_rx(struct uart_port *port)
{
	struct tty_port *tty = &port->state->port;
	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;

	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
		lsr = serial_in(port, SPRD_LSR);
		ch = serial_in(port, SPRD_RXD);
		flag = TTY_NORMAL;
		port->icount.rx++;

		if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE |
			SPRD_LSR_FE | SPRD_LSR_OE))
			if (handle_lsr_errors(port, &lsr, &flag))
				continue;
		if (uart_handle_sysrq_char(port, ch))
			continue;

		uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
	}

	tty_flip_buffer_push(tty);
}

static inline void sprd_tx(struct uart_port *port)
{
	struct circ_buf *xmit = &port->state->xmit;
	int count;

	if (port->x_char) {
		serial_out(port, SPRD_TXD, port->x_char);
		port->icount.tx++;
		port->x_char = 0;
		return;
	}

	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		sprd_stop_tx(port);
		return;
	}

	count = THLD_TX_EMPTY;
	do {
		serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	} while (--count > 0);

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	if (uart_circ_empty(xmit))
		sprd_stop_tx(port);
}

/* this handles the interrupt from one port */
static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
{
	struct uart_port *port = dev_id;
	unsigned int ims;

	spin_lock(&port->lock);

	ims = serial_in(port, SPRD_IMSR);

	if (!ims) {
		spin_unlock(&port->lock);
		return IRQ_NONE;
	}

	serial_out(port, SPRD_ICLR, ~0);

	if (ims & (SPRD_IMSR_RX_FIFO_FULL |
		SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
		sprd_rx(port);

	if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
		sprd_tx(port);

	spin_unlock(&port->lock);

	return IRQ_HANDLED;
}

static int sprd_startup(struct uart_port *port)
{
	int ret = 0;
	unsigned int ien, fc;
	unsigned int timeout;
	struct sprd_uart_port *sp;
	unsigned long flags;

	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));

	/* clear rx fifo */
	timeout = SPRD_TIMEOUT;
	while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
		serial_in(port, SPRD_RXD);

	/* clear tx fifo */
	timeout = SPRD_TIMEOUT;
	while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
		cpu_relax();

	/* clear interrupt */
	serial_out(port, SPRD_IEN, 0);
	serial_out(port, SPRD_ICLR, ~0);

	/* allocate irq */
	sp = container_of(port, struct sprd_uart_port, port);
	snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
	ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
				IRQF_SHARED, sp->name, port);
	if (ret) {
		dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
			port->irq, ret);
		return ret;
	}
	fc = serial_in(port, SPRD_CTL1);
	fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
	serial_out(port, SPRD_CTL1, fc);

	/* enable interrupt */
	spin_lock_irqsave(&port->lock, flags);
	ien = serial_in(port, SPRD_IEN);
	ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
	serial_out(port, SPRD_IEN, ien);
	spin_unlock_irqrestore(&port->lock, flags);

	return 0;
}

static void sprd_shutdown(struct uart_port *port)
{
	serial_out(port, SPRD_IEN, 0);
	serial_out(port, SPRD_ICLR, ~0);
	devm_free_irq(port->dev, port->irq, port);
}

static void sprd_set_termios(struct uart_port *port,
				    struct ktermios *termios,
				    struct ktermios *old)
{
	unsigned int baud, quot;
	unsigned int lcr = 0, fc;
	unsigned long flags;

	/* ask the core to calculate the divisor for us */
	baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);

	quot = (unsigned int)((port->uartclk + baud / 2) / baud);

	/* set data length */
	switch (termios->c_cflag & CSIZE) {
	case CS5:
		lcr |= SPRD_LCR_DATA_LEN5;
		break;
	case CS6:
		lcr |= SPRD_LCR_DATA_LEN6;
		break;
	case CS7:
		lcr |= SPRD_LCR_DATA_LEN7;
		break;
	case CS8:
	default:
		lcr |= SPRD_LCR_DATA_LEN8;
		break;
	}

	/* calculate stop bits */
	lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
	if (termios->c_cflag & CSTOPB)
		lcr |= SPRD_LCR_STOP_2BIT;
	else
		lcr |= SPRD_LCR_STOP_1BIT;

	/* calculate parity */
	lcr &= ~SPRD_LCR_PARITY;
	termios->c_cflag &= ~CMSPAR;	/* no support mark/space */
	if (termios->c_cflag & PARENB) {
		lcr |= SPRD_LCR_PARITY_EN;
		if (termios->c_cflag & PARODD)
			lcr |= SPRD_LCR_ODD_PAR;
		else
			lcr |= SPRD_LCR_EVEN_PAR;
	}

	spin_lock_irqsave(&port->lock, flags);

	/* update the per-port timeout */
	uart_update_timeout(port, termios->c_cflag, baud);

	port->read_status_mask = SPRD_LSR_OE;
	if (termios->c_iflag & INPCK)
		port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
		port->read_status_mask |= SPRD_LSR_BI;

	/* characters to ignore */
	port->ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
	if (termios->c_iflag & IGNBRK) {
		port->ignore_status_mask |= SPRD_LSR_BI;
		/*
		 * If we're ignoring parity and break indicators,
		 * ignore overruns too (for real raw support).
		 */
		if (termios->c_iflag & IGNPAR)
			port->ignore_status_mask |= SPRD_LSR_OE;
	}

	/* flow control */
	fc = serial_in(port, SPRD_CTL1);
	fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
	if (termios->c_cflag & CRTSCTS) {
		fc |= RX_HW_FLOW_CTL_THLD;
		fc |= RX_HW_FLOW_CTL_EN;
		fc |= TX_HW_FLOW_CTL_EN;
	}

	/* clock divider bit0~bit15 */
	serial_out(port, SPRD_CLKD0, quot & 0xffff);

	/* clock divider bit16~bit20 */
	serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
	serial_out(port, SPRD_LCR, lcr);
	fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
	serial_out(port, SPRD_CTL1, fc);

	spin_unlock_irqrestore(&port->lock, flags);

	/* Don't rewrite B0 */
	if (tty_termios_baud_rate(termios))
		tty_termios_encode_baud_rate(termios, baud, baud);
}

static const char *sprd_type(struct uart_port *port)
{
	return "SPX";
}

static void sprd_release_port(struct uart_port *port)
{
	/* nothing to do */
}

static int sprd_request_port(struct uart_port *port)
{
	return 0;
}

static void sprd_config_port(struct uart_port *port, int flags)
{
	if (flags & UART_CONFIG_TYPE)
		port->type = PORT_SPRD;
}

static int sprd_verify_port(struct uart_port *port,
				   struct serial_struct *ser)
{
	if (ser->type != PORT_SPRD)
		return -EINVAL;
	if (port->irq != ser->irq)
		return -EINVAL;
	return 0;
}

static struct uart_ops serial_sprd_ops = {
	.tx_empty = sprd_tx_empty,
	.get_mctrl = sprd_get_mctrl,
	.set_mctrl = sprd_set_mctrl,
	.stop_tx = sprd_stop_tx,
	.start_tx = sprd_start_tx,
	.stop_rx = sprd_stop_rx,
	.break_ctl = sprd_break_ctl,
	.startup = sprd_startup,
	.shutdown = sprd_shutdown,
	.set_termios = sprd_set_termios,
	.type = sprd_type,
	.release_port = sprd_release_port,
	.request_port = sprd_request_port,
	.config_port = sprd_config_port,
	.verify_port = sprd_verify_port,
};

#ifdef CONFIG_SERIAL_SPRD_CONSOLE
static inline void wait_for_xmitr(struct uart_port *port)
{
	unsigned int status, tmout = 10000;

	/* wait up to 10ms for the character(s) to be sent */
	do {
		status = serial_in(port, SPRD_STS1);
		if (--tmout == 0)
			break;
		udelay(1);
	} while (status & 0xff00);
}

static void sprd_console_putchar(struct uart_port *port, int ch)
{
	wait_for_xmitr(port);
	serial_out(port, SPRD_TXD, ch);
}

static void sprd_console_write(struct console *co, const char *s,
				      unsigned int count)
{
	struct uart_port *port = &sprd_port[co->index]->port;
	int locked = 1;
	unsigned long flags;

	if (port->sysrq)
		locked = 0;
	else if (oops_in_progress)
		locked = spin_trylock_irqsave(&port->lock, flags);
	else
		spin_lock_irqsave(&port->lock, flags);

	uart_console_write(port, s, count, sprd_console_putchar);

	/* wait for transmitter to become empty */
	wait_for_xmitr(port);

	if (locked)
		spin_unlock_irqrestore(&port->lock, flags);
}

static int __init sprd_console_setup(struct console *co, char *options)
{
	struct uart_port *port;
	int baud = 115200;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	if (co->index >= UART_NR_MAX || co->index < 0)
		co->index = 0;

	port = &sprd_port[co->index]->port;
	if (port == NULL) {
		pr_info("serial port %d not yet initialized\n", co->index);
		return -ENODEV;
	}
	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);

	return uart_set_options(port, co, baud, parity, bits, flow);
}

static struct uart_driver sprd_uart_driver;
static struct console sprd_console = {
	.name = SPRD_TTY_NAME,
	.write = sprd_console_write,
	.device = uart_console_device,
	.setup = sprd_console_setup,
	.flags = CON_PRINTBUFFER,
	.index = -1,
	.data = &sprd_uart_driver,
};

#define SPRD_CONSOLE	(&sprd_console)

/* Support for earlycon */
static void sprd_putc(struct uart_port *port, int c)
{
	unsigned int timeout = SPRD_TIMEOUT;

	while (timeout-- &&
		   !(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
		cpu_relax();

	writeb(c, port->membase + SPRD_TXD);
}

static void sprd_early_write(struct console *con, const char *s,
				    unsigned n)
{
	struct earlycon_device *dev = con->data;

	uart_console_write(&dev->port, s, n, sprd_putc);
}

static int __init sprd_early_console_setup(
				struct earlycon_device *device,
				const char *opt)
{
	if (!device->port.membase)
		return -ENODEV;

	device->con->write = sprd_early_write;
	return 0;
}

EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
		    sprd_early_console_setup);

#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
#define SPRD_CONSOLE		NULL
#endif

static struct uart_driver sprd_uart_driver = {
	.owner = THIS_MODULE,
	.driver_name = "sprd_serial",
	.dev_name = SPRD_TTY_NAME,
	.major = 0,
	.minor = 0,
	.nr = UART_NR_MAX,
	.cons = SPRD_CONSOLE,
};

static int sprd_probe_dt_alias(int index, struct device *dev)
{
	struct device_node *np;
	int ret = index;

	if (!IS_ENABLED(CONFIG_OF))
		return ret;

	np = dev->of_node;
	if (!np)
		return ret;

	ret = of_alias_get_id(np, "serial");
	if (IS_ERR_VALUE(ret))
		ret = index;
	else if (ret >= ARRAY_SIZE(sprd_port) || sprd_port[ret] != NULL) {
		dev_warn(dev, "requested serial port %d not available.\n", ret);
		ret = index;
	}

	return ret;
}

static int sprd_remove(struct platform_device *dev)
{
	struct sprd_uart_port *sup = platform_get_drvdata(dev);

	if (sup) {
		uart_remove_one_port(&sprd_uart_driver, &sup->port);
		sprd_port[sup->port.line] = NULL;
		sprd_ports_num--;
	}

	if (!sprd_ports_num)
		uart_unregister_driver(&sprd_uart_driver);

	return 0;
}

static int sprd_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct uart_port *up;
	struct clk *clk;
	int irq;
	int index;
	int ret;

	for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
		if (sprd_port[index] == NULL)
			break;

	if (index == ARRAY_SIZE(sprd_port))
		return -EBUSY;

	index = sprd_probe_dt_alias(index, &pdev->dev);

	sprd_port[index] = devm_kzalloc(&pdev->dev,
		sizeof(*sprd_port[index]), GFP_KERNEL);
	if (!sprd_port[index])
		return -ENOMEM;

	up = &sprd_port[index]->port;
	up->dev = &pdev->dev;
	up->line = index;
	up->type = PORT_SPRD;
	up->iotype = SERIAL_IO_PORT;
	up->uartclk = SPRD_DEF_RATE;
	up->fifosize = SPRD_FIFO_SIZE;
	up->ops = &serial_sprd_ops;
	up->flags = UPF_BOOT_AUTOCONF;

	clk = devm_clk_get(&pdev->dev, NULL);
	if (!IS_ERR(clk))
		up->uartclk = clk_get_rate(clk);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "not provide mem resource\n");
		return -ENODEV;
	}
	up->mapbase = res->start;
	up->membase = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(up->membase))
		return PTR_ERR(up->membase);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "not provide irq resource\n");
		return -ENODEV;
	}
	up->irq = irq;

	if (!sprd_ports_num) {
		ret = uart_register_driver(&sprd_uart_driver);
		if (ret < 0) {
			pr_err("Failed to register SPRD-UART driver\n");
			return ret;
		}
	}
	sprd_ports_num++;

	ret = uart_add_one_port(&sprd_uart_driver, up);
	if (ret) {
		sprd_port[index] = NULL;
		sprd_remove(pdev);
	}

	platform_set_drvdata(pdev, up);

	return ret;
}

static int sprd_suspend(struct device *dev)
{
	struct sprd_uart_port *sup = dev_get_drvdata(dev);

	uart_suspend_port(&sprd_uart_driver, &sup->port);

	return 0;
}

static int sprd_resume(struct device *dev)
{
	struct sprd_uart_port *sup = dev_get_drvdata(dev);

	uart_resume_port(&sprd_uart_driver, &sup->port);

	return 0;
}

static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);

static const struct of_device_id serial_ids[] = {
	{.compatible = "sprd,sc9836-uart",},
	{}
};

static struct platform_driver sprd_platform_driver = {
	.probe		= sprd_probe,
	.remove		= sprd_remove,
	.driver		= {
		.name	= "sprd_serial",
		.of_match_table = of_match_ptr(serial_ids),
		.pm	= &sprd_pm_ops,
	},
};

module_platform_driver(sprd_platform_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");
Commit	Line	Data
b7396a38 CZ	1	/*
	2	* Copyright (C) 2012-2015 Spreadtrum Communications Inc.
	3	*
	4	* This software is licensed under the terms of the GNU General Public
	5	* License version 2, as published by the Free Software Foundation, and
	6	* may be copied, distributed, and modified under those terms.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*/
	13
	14	#if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
	15	#define SUPPORT_SYSRQ
	16	#endif
	17
	18	#include <linux/clk.h>
	19	#include <linux/console.h>
	20	#include <linux/delay.h>
	21	#include <linux/io.h>
	22	#include <linux/ioport.h>
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
	25	#include <linux/of.h>
	26	#include <linux/platform_device.h>
	27	#include <linux/serial_core.h>
	28	#include <linux/serial.h>
	29	#include <linux/slab.h>
	30	#include <linux/tty.h>
	31	#include <linux/tty_flip.h>
	32
	33	/* device name */
	34	#define UART_NR_MAX 8
	35	#define SPRD_TTY_NAME "ttyS"
	36	#define SPRD_FIFO_SIZE 128
	37	#define SPRD_DEF_RATE 26000000
	38	#define SPRD_BAUD_IO_LIMIT 3000000
	39	#define SPRD_TIMEOUT 256
	40
	41	/* the offset of serial registers and BITs for them */
	42	/* data registers */
	43	#define SPRD_TXD 0x0000
	44	#define SPRD_RXD 0x0004
	45
	46	/* line status register and its BITs */
	47	#define SPRD_LSR 0x0008
	48	#define SPRD_LSR_OE BIT(4)
	49	#define SPRD_LSR_FE BIT(3)
	50	#define SPRD_LSR_PE BIT(2)
	51	#define SPRD_LSR_BI BIT(7)
	52	#define SPRD_LSR_TX_OVER BIT(15)
	53
	54	/* data number in TX and RX fifo */
	55	#define SPRD_STS1 0x000C
	56
	57	/* interrupt enable register and its BITs */
	58	#define SPRD_IEN 0x0010
	59	#define SPRD_IEN_RX_FULL BIT(0)
	60	#define SPRD_IEN_TX_EMPTY BIT(1)
	61	#define SPRD_IEN_BREAK_DETECT BIT(7)
	62	#define SPRD_IEN_TIMEOUT BIT(13)
	63
	64	/* interrupt clear register */
65	#define SPRD_ICLR 0x0014
66
67	/* line control register */
68	#define SPRD_LCR 0x0018
69	#define SPRD_LCR_STOP_1BIT 0x10
70	#define SPRD_LCR_STOP_2BIT 0x30
71	#define SPRD_LCR_DATA_LEN (BIT(2) \| BIT(3))
72	#define SPRD_LCR_DATA_LEN5 0x0
73	#define SPRD_LCR_DATA_LEN6 0x4
74	#define SPRD_LCR_DATA_LEN7 0x8
75	#define SPRD_LCR_DATA_LEN8 0xc
76	#define SPRD_LCR_PARITY (BIT(0) \| BIT(1))
77	#define SPRD_LCR_PARITY_EN 0x2
78	#define SPRD_LCR_EVEN_PAR 0x0
79	#define SPRD_LCR_ODD_PAR 0x1
80
81	/* control register 1 */
82	#define SPRD_CTL1 0x001C
83	#define RX_HW_FLOW_CTL_THLD BIT(6)
84	#define RX_HW_FLOW_CTL_EN BIT(7)
85	#define TX_HW_FLOW_CTL_EN BIT(8)
86	#define RX_TOUT_THLD_DEF 0x3E00
87	#define RX_HFC_THLD_DEF 0x40
88
89	/* fifo threshold register */
90	#define SPRD_CTL2 0x0020
91	#define THLD_TX_EMPTY 0x40
92	#define THLD_RX_FULL 0x40
93
94	/* config baud rate register */
95	#define SPRD_CLKD0 0x0024
96	#define SPRD_CLKD1 0x0028
97
98	/* interrupt mask status register */
99	#define SPRD_IMSR 0x002C
100	#define SPRD_IMSR_RX_FIFO_FULL BIT(0)
101	#define SPRD_IMSR_TX_FIFO_EMPTY BIT(1)
102	#define SPRD_IMSR_BREAK_DETECT BIT(7)
103	#define SPRD_IMSR_TIMEOUT BIT(13)
104
105	struct reg_backup {
106	u32 ien;
107	u32 ctrl0;
108	u32 ctrl1;
109	u32 ctrl2;
110	u32 clkd0;
111	u32 clkd1;
112	u32 dspwait;
113	};
114
115	struct sprd_uart_port {
116	struct uart_port port;
117	struct reg_backup reg_bak;
118	char name[16];
119	};
120
121	static struct sprd_uart_port *sprd_port[UART_NR_MAX];
122	static int sprd_ports_num;
123
124	static inline unsigned int serial_in(struct uart_port *port, int offset)
125	{
126	return readl_relaxed(port->membase + offset);
127	}
128
129	static inline void serial_out(struct uart_port *port, int offset, int value)
130	{
131	writel_relaxed(value, port->membase + offset);
132	}
133
134	static unsigned int sprd_tx_empty(struct uart_port *port)
135	{
136	if (serial_in(port, SPRD_STS1) & 0xff00)
137	return 0;
138	else
139	return TIOCSER_TEMT;
140	}
141
142	static unsigned int sprd_get_mctrl(struct uart_port *port)
143	{
144	return TIOCM_DSR \| TIOCM_CTS;
145	}
146
147	static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
148	{
149	/* nothing to do */
150	}
151
152	static void sprd_stop_tx(struct uart_port *port)
153	{
154	unsigned int ien, iclr;
155
156	iclr = serial_in(port, SPRD_ICLR);
157	ien = serial_in(port, SPRD_IEN);
158
159	iclr \|= SPRD_IEN_TX_EMPTY;
160	ien &= ~SPRD_IEN_TX_EMPTY;
161
162	serial_out(port, SPRD_ICLR, iclr);
163	serial_out(port, SPRD_IEN, ien);
164	}
165
166	static void sprd_start_tx(struct uart_port *port)
167	{
168	unsigned int ien;
169
170	ien = serial_in(port, SPRD_IEN);
171	if (!(ien & SPRD_IEN_TX_EMPTY)) {
172	ien \|= SPRD_IEN_TX_EMPTY;
173	serial_out(port, SPRD_IEN, ien);
174	}
175	}
176
177	static void sprd_stop_rx(struct uart_port *port)
178	{
179	unsigned int ien, iclr;
180
181	iclr = serial_in(port, SPRD_ICLR);
182	ien = serial_in(port, SPRD_IEN);
183
184	ien &= ~(SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT);
185	iclr \|= SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT;
186
187	serial_out(port, SPRD_IEN, ien);
188	serial_out(port, SPRD_ICLR, iclr);
189	}
190
191	/* The Sprd serial does not support this function. */
192	static void sprd_break_ctl(struct uart_port *port, int break_state)
193	{
194	/* nothing to do */
195	}
196
197	static int handle_lsr_errors(struct uart_port *port,
198	unsigned int *flag,
199	unsigned int *lsr)
200	{
201	int ret = 0;
202
203	/* statistics */
204	if (*lsr & SPRD_LSR_BI) {
205	*lsr &= ~(SPRD_LSR_FE \| SPRD_LSR_PE);
206	port->icount.brk++;
207	ret = uart_handle_break(port);
208	if (ret)
209	return ret;
210	} else if (*lsr & SPRD_LSR_PE)
211	port->icount.parity++;
212	else if (*lsr & SPRD_LSR_FE)
213	port->icount.frame++;
214	if (*lsr & SPRD_LSR_OE)
215	port->icount.overrun++;
216
217	/* mask off conditions which should be ignored */
218	*lsr &= port->read_status_mask;
219	if (*lsr & SPRD_LSR_BI)
220	*flag = TTY_BREAK;
221	else if (*lsr & SPRD_LSR_PE)
222	*flag = TTY_PARITY;
223	else if (*lsr & SPRD_LSR_FE)
224	*flag = TTY_FRAME;
225
226	return ret;
227	}
228
229	static inline void sprd_rx(struct uart_port *port)
230	{
231	struct tty_port *tty = &port->state->port;
232	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
233
234	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
235	lsr = serial_in(port, SPRD_LSR);
236	ch = serial_in(port, SPRD_RXD);
237	flag = TTY_NORMAL;
238	port->icount.rx++;
239
240	if (lsr & (SPRD_LSR_BI \| SPRD_LSR_PE \|
241	SPRD_LSR_FE \| SPRD_LSR_OE))
242	if (handle_lsr_errors(port, &lsr, &flag))
243	continue;
244	if (uart_handle_sysrq_char(port, ch))
245	continue;
246
247	uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
248	}
249
250	tty_flip_buffer_push(tty);
251	}
252
253	static inline void sprd_tx(struct uart_port *port)
254	{
255	struct circ_buf *xmit = &port->state->xmit;
256	int count;
257
258	if (port->x_char) {
259	serial_out(port, SPRD_TXD, port->x_char);
260	port->icount.tx++;
261	port->x_char = 0;
262	return;
263	}
264
265	if (uart_circ_empty(xmit) \|\| uart_tx_stopped(port)) {
266	sprd_stop_tx(port);
267	return;
268	}
269
270	count = THLD_TX_EMPTY;
271	do {
272	serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
273	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
274	port->icount.tx++;
275	if (uart_circ_empty(xmit))
276	break;
277	} while (--count > 0);
278
279	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
280	uart_write_wakeup(port);
281
282	if (uart_circ_empty(xmit))
283	sprd_stop_tx(port);
284	}
285
286	/* this handles the interrupt from one port */
287	static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
288	{
289	struct uart_port *port = dev_id;
290	unsigned int ims;
291
292	spin_lock(&port->lock);
293
294	ims = serial_in(port, SPRD_IMSR);
295
c4e6dcfa AL	296	if (!ims) {
c4e6dcfa AL	297	spin_unlock(&port->lock);
b7396a38	298	return IRQ_NONE;
c4e6dcfa	299	}
b7396a38 CZ	300
	301	serial_out(port, SPRD_ICLR, ~0);
	302
	303	if (ims & (SPRD_IMSR_RX_FIFO_FULL \|
	304	SPRD_IMSR_BREAK_DETECT \| SPRD_IMSR_TIMEOUT))
	305	sprd_rx(port);
	306
	307	if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
	308	sprd_tx(port);
	309
	310	spin_unlock(&port->lock);
	311
	312	return IRQ_HANDLED;
	313	}
	314
	315	static int sprd_startup(struct uart_port *port)
	316	{
	317	int ret = 0;
	318	unsigned int ien, fc;
	319	unsigned int timeout;
	320	struct sprd_uart_port *sp;
	321	unsigned long flags;
	322
	323	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) \| THLD_RX_FULL));
	324
	325	/* clear rx fifo */
	326	timeout = SPRD_TIMEOUT;
	327	while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
	328	serial_in(port, SPRD_RXD);
	329
	330	/* clear tx fifo */
	331	timeout = SPRD_TIMEOUT;
	332	while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
	333	cpu_relax();
	334
	335	/* clear interrupt */
	336	serial_out(port, SPRD_IEN, 0);
	337	serial_out(port, SPRD_ICLR, ~0);
	338
	339	/* allocate irq */
	340	sp = container_of(port, struct sprd_uart_port, port);
	341	snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
	342	ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
	343	IRQF_SHARED, sp->name, port);
	344	if (ret) {
	345	dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
	346	port->irq, ret);
	347	return ret;
	348	}
	349	fc = serial_in(port, SPRD_CTL1);
	350	fc \|= RX_TOUT_THLD_DEF \| RX_HFC_THLD_DEF;
	351	serial_out(port, SPRD_CTL1, fc);
	352
	353	/* enable interrupt */
	354	spin_lock_irqsave(&port->lock, flags);
	355	ien = serial_in(port, SPRD_IEN);
	356	ien \|= SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT \| SPRD_IEN_TIMEOUT;
	357	serial_out(port, SPRD_IEN, ien);
	358	spin_unlock_irqrestore(&port->lock, flags);
	359
	360	return 0;
	361	}
	362
	363	static void sprd_shutdown(struct uart_port *port)
364	{
365	serial_out(port, SPRD_IEN, 0);
366	serial_out(port, SPRD_ICLR, ~0);
367	devm_free_irq(port->dev, port->irq, port);
368	}
369
370	static void sprd_set_termios(struct uart_port *port,
371	struct ktermios *termios,
372	struct ktermios *old)
373	{
374	unsigned int baud, quot;
375	unsigned int lcr = 0, fc;
376	unsigned long flags;
377
378	/* ask the core to calculate the divisor for us */
379	baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);
380
381	quot = (unsigned int)((port->uartclk + baud / 2) / baud);
382
383	/* set data length */
384	switch (termios->c_cflag & CSIZE) {
385	case CS5:
386	lcr \|= SPRD_LCR_DATA_LEN5;
387	break;
388	case CS6:
389	lcr \|= SPRD_LCR_DATA_LEN6;
390	break;
391	case CS7:
392	lcr \|= SPRD_LCR_DATA_LEN7;
393	break;
394	case CS8:
395	default:
396	lcr \|= SPRD_LCR_DATA_LEN8;
397	break;
398	}
399
400	/* calculate stop bits */
401	lcr &= ~(SPRD_LCR_STOP_1BIT \| SPRD_LCR_STOP_2BIT);
402	if (termios->c_cflag & CSTOPB)
403	lcr \|= SPRD_LCR_STOP_2BIT;
404	else
405	lcr \|= SPRD_LCR_STOP_1BIT;
406
407	/* calculate parity */
408	lcr &= ~SPRD_LCR_PARITY;
409	termios->c_cflag &= ~CMSPAR; /* no support mark/space */
410	if (termios->c_cflag & PARENB) {
411	lcr \|= SPRD_LCR_PARITY_EN;
412	if (termios->c_cflag & PARODD)
413	lcr \|= SPRD_LCR_ODD_PAR;
414	else
415	lcr \|= SPRD_LCR_EVEN_PAR;
416	}
417
418	spin_lock_irqsave(&port->lock, flags);
419
420	/* update the per-port timeout */
421	uart_update_timeout(port, termios->c_cflag, baud);
422
423	port->read_status_mask = SPRD_LSR_OE;
424	if (termios->c_iflag & INPCK)
425	port->read_status_mask \|= SPRD_LSR_FE \| SPRD_LSR_PE;
426	if (termios->c_iflag & (IGNBRK \| BRKINT \| PARMRK))
427	port->read_status_mask \|= SPRD_LSR_BI;
428
429	/* characters to ignore */
430	port->ignore_status_mask = 0;
431	if (termios->c_iflag & IGNPAR)
432	port->ignore_status_mask \|= SPRD_LSR_PE \| SPRD_LSR_FE;
433	if (termios->c_iflag & IGNBRK) {
434	port->ignore_status_mask \|= SPRD_LSR_BI;
435	/*
436	* If we're ignoring parity and break indicators,
437	* ignore overruns too (for real raw support).
438	*/
439	if (termios->c_iflag & IGNPAR)
440	port->ignore_status_mask \|= SPRD_LSR_OE;
441	}
442
443	/* flow control */
444	fc = serial_in(port, SPRD_CTL1);
445	fc &= ~(RX_HW_FLOW_CTL_THLD \| RX_HW_FLOW_CTL_EN \| TX_HW_FLOW_CTL_EN);
446	if (termios->c_cflag & CRTSCTS) {
447	fc \|= RX_HW_FLOW_CTL_THLD;
448	fc \|= RX_HW_FLOW_CTL_EN;
449	fc \|= TX_HW_FLOW_CTL_EN;
450	}
451
452	/* clock divider bit0~bit15 */
453	serial_out(port, SPRD_CLKD0, quot & 0xffff);
454
455	/* clock divider bit16~bit20 */
456	serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
457	serial_out(port, SPRD_LCR, lcr);
458	fc \|= RX_TOUT_THLD_DEF \| RX_HFC_THLD_DEF;
459	serial_out(port, SPRD_CTL1, fc);
460
461	spin_unlock_irqrestore(&port->lock, flags);
462
463	/* Don't rewrite B0 */
464	if (tty_termios_baud_rate(termios))
465	tty_termios_encode_baud_rate(termios, baud, baud);
466	}
467
468	static const char sprd_type(struct uart_port port)
469	{
470	return "SPX";
471	}
472
473	static void sprd_release_port(struct uart_port *port)
474	{
475	/* nothing to do */
476	}
477
478	static int sprd_request_port(struct uart_port *port)
479	{
480	return 0;
481	}
482
483	static void sprd_config_port(struct uart_port *port, int flags)
484	{
485	if (flags & UART_CONFIG_TYPE)
486	port->type = PORT_SPRD;
487	}
488
489	static int sprd_verify_port(struct uart_port *port,
490	struct serial_struct *ser)
491	{
492	if (ser->type != PORT_SPRD)
493	return -EINVAL;
494	if (port->irq != ser->irq)
495	return -EINVAL;
496	return 0;
497	}
498
499	static struct uart_ops serial_sprd_ops = {
500	.tx_empty = sprd_tx_empty,
501	.get_mctrl = sprd_get_mctrl,
502	.set_mctrl = sprd_set_mctrl,
503	.stop_tx = sprd_stop_tx,
504	.start_tx = sprd_start_tx,
505	.stop_rx = sprd_stop_rx,
506	.break_ctl = sprd_break_ctl,
507	.startup = sprd_startup,
508	.shutdown = sprd_shutdown,
509	.set_termios = sprd_set_termios,
510	.type = sprd_type,
511	.release_port = sprd_release_port,
512	.request_port = sprd_request_port,
513	.config_port = sprd_config_port,
514	.verify_port = sprd_verify_port,
515	};
516
517	#ifdef CONFIG_SERIAL_SPRD_CONSOLE
518	static inline void wait_for_xmitr(struct uart_port *port)
519	{
520	unsigned int status, tmout = 10000;
521
522	/* wait up to 10ms for the character(s) to be sent */
523	do {
524	status = serial_in(port, SPRD_STS1);
525	if (--tmout == 0)
526	break;
527	udelay(1);
528	} while (status & 0xff00);
529	}
530
531	static void sprd_console_putchar(struct uart_port *port, int ch)
532	{
533	wait_for_xmitr(port);
534	serial_out(port, SPRD_TXD, ch);
535	}
536
537	static void sprd_console_write(struct console co, const char s,
538	unsigned int count)
539	{
540	struct uart_port *port = &sprd_port[co->index]->port;
541	int locked = 1;
542	unsigned long flags;
543
544	if (port->sysrq)
545	locked = 0;
546	else if (oops_in_progress)
547	locked = spin_trylock_irqsave(&port->lock, flags);
548	else
549	spin_lock_irqsave(&port->lock, flags);
550
551	uart_console_write(port, s, count, sprd_console_putchar);
552
553	/* wait for transmitter to become empty */
554	wait_for_xmitr(port);
555
556	if (locked)
557	spin_unlock_irqrestore(&port->lock, flags);
558	}
559
560	static int __init sprd_console_setup(struct console co, char options)
561	{
562	struct uart_port *port;
563	int baud = 115200;
564	int bits = 8;
565	int parity = 'n';
566	int flow = 'n';
567
568	if (co->index >= UART_NR_MAX \|\| co->index < 0)
569	co->index = 0;
570
571	port = &sprd_port[co->index]->port;
572	if (port == NULL) {
573	pr_info("serial port %d not yet initialized\n", co->index);
574	return -ENODEV;
575	}
576	if (options)
577	uart_parse_options(options, &baud, &parity, &bits, &flow);
578
579	return uart_set_options(port, co, baud, parity, bits, flow);
580	}
581
582	static struct uart_driver sprd_uart_driver;
583	static struct console sprd_console = {
584	.name = SPRD_TTY_NAME,
585	.write = sprd_console_write,
586	.device = uart_console_device,
587	.setup = sprd_console_setup,
588	.flags = CON_PRINTBUFFER,
589	.index = -1,
590	.data = &sprd_uart_driver,
591	};
592
593	#define SPRD_CONSOLE (&sprd_console)
594
595	/* Support for earlycon */
596	static void sprd_putc(struct uart_port *port, int c)
597	{
598	unsigned int timeout = SPRD_TIMEOUT;
599
600	while (timeout-- &&
601	!(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
602	cpu_relax();
603
604	writeb(c, port->membase + SPRD_TXD);
605	}
606
607	static void sprd_early_write(struct console con, const char s,
608	unsigned n)
609	{
610	struct earlycon_device *dev = con->data;
611
612	uart_console_write(&dev->port, s, n, sprd_putc);
613	}
614
615	static int __init sprd_early_console_setup(
616	struct earlycon_device *device,
617	const char *opt)
618	{
619	if (!device->port.membase)
620	return -ENODEV;
621
622	device->con->write = sprd_early_write;
623	return 0;
624	}
625
626	EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
627	OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
628	sprd_early_console_setup);
629
630	#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
631	#define SPRD_CONSOLE NULL
632	#endif
633
634	static struct uart_driver sprd_uart_driver = {
635	.owner = THIS_MODULE,
636	.driver_name = "sprd_serial",
637	.dev_name = SPRD_TTY_NAME,
638	.major = 0,
639	.minor = 0,
640	.nr = UART_NR_MAX,
641	.cons = SPRD_CONSOLE,
642	};
643
644	static int sprd_probe_dt_alias(int index, struct device *dev)
645	{
646	struct device_node *np;
647	int ret = index;
648
649	if (!IS_ENABLED(CONFIG_OF))
650	return ret;
651
652	np = dev->of_node;
653	if (!np)
654	return ret;
655
656	ret = of_alias_get_id(np, "serial");
657	if (IS_ERR_VALUE(ret))
658	ret = index;
659	else if (ret >= ARRAY_SIZE(sprd_port) \|\| sprd_port[ret] != NULL) {
660	dev_warn(dev, "requested serial port %d not available.\n", ret);
661	ret = index;
662	}
663
664	return ret;
665	}
666
667	static int sprd_remove(struct platform_device *dev)
668	{
669	struct sprd_uart_port *sup = platform_get_drvdata(dev);
670
671	if (sup) {
672	uart_remove_one_port(&sprd_uart_driver, &sup->port);
673	sprd_port[sup->port.line] = NULL;
674	sprd_ports_num--;
675	}
676
677	if (!sprd_ports_num)
678	uart_unregister_driver(&sprd_uart_driver);
679
680	return 0;
681	}
682
683	static int sprd_probe(struct platform_device *pdev)
684	{
685	struct resource *res;
686	struct uart_port *up;
687	struct clk *clk;
688	int irq;
689	int index;
690	int ret;
691
692	for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
693	if (sprd_port[index] == NULL)
694	break;
695
696	if (index == ARRAY_SIZE(sprd_port))
697	return -EBUSY;
698
699	index = sprd_probe_dt_alias(index, &pdev->dev);
700
701	sprd_port[index] = devm_kzalloc(&pdev->dev,
702	sizeof(*sprd_port[index]), GFP_KERNEL);
703	if (!sprd_port[index])
704	return -ENOMEM;
705
706	up = &sprd_port[index]->port;
707	up->dev = &pdev->dev;
708	up->line = index;
709	up->type = PORT_SPRD;
710	up->iotype = SERIAL_IO_PORT;
711	up->uartclk = SPRD_DEF_RATE;
712	up->fifosize = SPRD_FIFO_SIZE;
713	up->ops = &serial_sprd_ops;
714	up->flags = UPF_BOOT_AUTOCONF;
715
716	clk = devm_clk_get(&pdev->dev, NULL);
717	if (!IS_ERR(clk))
718	up->uartclk = clk_get_rate(clk);
719
720	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
721	if (!res) {
722	dev_err(&pdev->dev, "not provide mem resource\n");
723	return -ENODEV;
724	}
725	up->mapbase = res->start;
726	up->membase = devm_ioremap_resource(&pdev->dev, res);
727	if (IS_ERR(up->membase))
728	return PTR_ERR(up->membase);
729
730	irq = platform_get_irq(pdev, 0);
731	if (irq < 0) {
732	dev_err(&pdev->dev, "not provide irq resource\n");
733	return -ENODEV;
734	}
735	up->irq = irq;
736
737	if (!sprd_ports_num) {
738	ret = uart_register_driver(&sprd_uart_driver);
739	if (ret < 0) {
740	pr_err("Failed to register SPRD-UART driver\n");
741	return ret;
742	}
743	}
744	sprd_ports_num++;
745
746	ret = uart_add_one_port(&sprd_uart_driver, up);
747	if (ret) {
748	sprd_port[index] = NULL;
749	sprd_remove(pdev);
750	}
751
752	platform_set_drvdata(pdev, up);
753
754	return ret;
755	}
756
757	static int sprd_suspend(struct device *dev)
758	{
759	struct sprd_uart_port *sup = dev_get_drvdata(dev);
760
761	uart_suspend_port(&sprd_uart_driver, &sup->port);
762
763	return 0;
764	}
765
766	static int sprd_resume(struct device *dev)
767	{
768	struct sprd_uart_port *sup = dev_get_drvdata(dev);
769
770	uart_resume_port(&sprd_uart_driver, &sup->port);
771
772	return 0;
773	}
774
775	static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);
776
777	static const struct of_device_id serial_ids[] = {
778	{.compatible = "sprd,sc9836-uart",},
779	{}
780	};
781
782	static struct platform_driver sprd_platform_driver = {
783	.probe = sprd_probe,
784	.remove = sprd_remove,
785	.driver = {
786	.name = "sprd_serial",
787	.of_match_table = of_match_ptr(serial_ids),
788	.pm = &sprd_pm_ops,
789	},
790	};
791
792	module_platform_driver(sprd_platform_driver);
793
794	MODULE_LICENSE("GPL v2");
795	MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");