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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2012-2015 Spreadtrum Communications Inc.
 */

#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		256000

/* 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
#define SPRD_ICLR_TIMEOUT	BIT(13)

/* 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;
	}

	if (ims & SPRD_IMSR_TIMEOUT)
		serial_out(port, SPRD_ICLR, SPRD_ICLR_TIMEOUT);

	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;
	if (port->iotype != ser->io_type)
		return -EINVAL;
	return 0;
}

static const 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 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;
}
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 (ret < 0)
		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 = UPIO_MEM;
	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_OR_NULL(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: %d\n", irq);
		return irq;
	}
	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;
}

#ifdef CONFIG_PM_SLEEP
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;
}
#endif

static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);

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

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
e3b3d0f5	1	// SPDX-License-Identifier: GPL-2.0
b7396a38 CZ	2	/*
b7396a38 CZ	3	* Copyright (C) 2012-2015 Spreadtrum Communications Inc.
b7396a38 CZ	4	*/
	5
	6	#if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
	7	#define SUPPORT_SYSRQ
	8	#endif
	9
	10	#include <linux/clk.h>
	11	#include <linux/console.h>
	12	#include <linux/delay.h>
	13	#include <linux/io.h>
	14	#include <linux/ioport.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/of.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/serial_core.h>
	20	#include <linux/serial.h>
	21	#include <linux/slab.h>
	22	#include <linux/tty.h>
	23	#include <linux/tty_flip.h>
	24
	25	/* device name */
	26	#define UART_NR_MAX 8
	27	#define SPRD_TTY_NAME "ttyS"
	28	#define SPRD_FIFO_SIZE 128
	29	#define SPRD_DEF_RATE 26000000
	30	#define SPRD_BAUD_IO_LIMIT 3000000
e1dc9b08	31	#define SPRD_TIMEOUT 256000
b7396a38 CZ	32
	33	/* the offset of serial registers and BITs for them */
	34	/* data registers */
	35	#define SPRD_TXD 0x0000
	36	#define SPRD_RXD 0x0004
	37
	38	/* line status register and its BITs */
	39	#define SPRD_LSR 0x0008
	40	#define SPRD_LSR_OE BIT(4)
	41	#define SPRD_LSR_FE BIT(3)
	42	#define SPRD_LSR_PE BIT(2)
	43	#define SPRD_LSR_BI BIT(7)
	44	#define SPRD_LSR_TX_OVER BIT(15)
	45
	46	/* data number in TX and RX fifo */
	47	#define SPRD_STS1 0x000C
	48
	49	/* interrupt enable register and its BITs */
	50	#define SPRD_IEN 0x0010
	51	#define SPRD_IEN_RX_FULL BIT(0)
	52	#define SPRD_IEN_TX_EMPTY BIT(1)
	53	#define SPRD_IEN_BREAK_DETECT BIT(7)
	54	#define SPRD_IEN_TIMEOUT BIT(13)
	55
	56	/* interrupt clear register */
	57	#define SPRD_ICLR 0x0014
43507825	58	#define SPRD_ICLR_TIMEOUT BIT(13)
b7396a38 CZ	59
	60	/* line control register */
	61	#define SPRD_LCR 0x0018
	62	#define SPRD_LCR_STOP_1BIT 0x10
	63	#define SPRD_LCR_STOP_2BIT 0x30
	64	#define SPRD_LCR_DATA_LEN (BIT(2) \| BIT(3))
	65	#define SPRD_LCR_DATA_LEN5 0x0
	66	#define SPRD_LCR_DATA_LEN6 0x4
	67	#define SPRD_LCR_DATA_LEN7 0x8
	68	#define SPRD_LCR_DATA_LEN8 0xc
	69	#define SPRD_LCR_PARITY (BIT(0) \| BIT(1))
	70	#define SPRD_LCR_PARITY_EN 0x2
	71	#define SPRD_LCR_EVEN_PAR 0x0
	72	#define SPRD_LCR_ODD_PAR 0x1
	73
	74	/* control register 1 */
	75	#define SPRD_CTL1 0x001C
	76	#define RX_HW_FLOW_CTL_THLD BIT(6)
	77	#define RX_HW_FLOW_CTL_EN BIT(7)
	78	#define TX_HW_FLOW_CTL_EN BIT(8)
	79	#define RX_TOUT_THLD_DEF 0x3E00
	80	#define RX_HFC_THLD_DEF 0x40
	81
	82	/* fifo threshold register */
	83	#define SPRD_CTL2 0x0020
	84	#define THLD_TX_EMPTY 0x40
	85	#define THLD_RX_FULL 0x40
	86
	87	/* config baud rate register */
	88	#define SPRD_CLKD0 0x0024
	89	#define SPRD_CLKD1 0x0028
	90
	91	/* interrupt mask status register */
	92	#define SPRD_IMSR 0x002C
	93	#define SPRD_IMSR_RX_FIFO_FULL BIT(0)
	94	#define SPRD_IMSR_TX_FIFO_EMPTY BIT(1)
	95	#define SPRD_IMSR_BREAK_DETECT BIT(7)
	96	#define SPRD_IMSR_TIMEOUT BIT(13)
	97
	98	struct reg_backup {
	99	u32 ien;
	100	u32 ctrl0;
	101	u32 ctrl1;
	102	u32 ctrl2;
	103	u32 clkd0;
	104	u32 clkd1;
	105	u32 dspwait;
	106	};
	107
	108	struct sprd_uart_port {
	109	struct uart_port port;
	110	struct reg_backup reg_bak;
	111	char name[16];
	112	};
	113
	114	static struct sprd_uart_port *sprd_port[UART_NR_MAX];
	115	static int sprd_ports_num;
	116
	117	static inline unsigned int serial_in(struct uart_port *port, int offset)
	118	{
	119	return readl_relaxed(port->membase + offset);
	120	}
	121
	122	static inline void serial_out(struct uart_port *port, int offset, int value)
123	{
124	writel_relaxed(value, port->membase + offset);
125	}
126
127	static unsigned int sprd_tx_empty(struct uart_port *port)
128	{
129	if (serial_in(port, SPRD_STS1) & 0xff00)
130	return 0;
131	else
132	return TIOCSER_TEMT;
133	}
134
135	static unsigned int sprd_get_mctrl(struct uart_port *port)
136	{
137	return TIOCM_DSR \| TIOCM_CTS;
138	}
139
140	static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
141	{
142	/* nothing to do */
143	}
144
145	static void sprd_stop_tx(struct uart_port *port)
146	{
147	unsigned int ien, iclr;
148
149	iclr = serial_in(port, SPRD_ICLR);
150	ien = serial_in(port, SPRD_IEN);
151
152	iclr \|= SPRD_IEN_TX_EMPTY;
153	ien &= ~SPRD_IEN_TX_EMPTY;
154
155	serial_out(port, SPRD_ICLR, iclr);
156	serial_out(port, SPRD_IEN, ien);
157	}
158
159	static void sprd_start_tx(struct uart_port *port)
160	{
161	unsigned int ien;
162
163	ien = serial_in(port, SPRD_IEN);
164	if (!(ien & SPRD_IEN_TX_EMPTY)) {
165	ien \|= SPRD_IEN_TX_EMPTY;
166	serial_out(port, SPRD_IEN, ien);
167	}
168	}
169
170	static void sprd_stop_rx(struct uart_port *port)
171	{
172	unsigned int ien, iclr;
173
174	iclr = serial_in(port, SPRD_ICLR);
175	ien = serial_in(port, SPRD_IEN);
176
177	ien &= ~(SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT);
178	iclr \|= SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT;
179
180	serial_out(port, SPRD_IEN, ien);
181	serial_out(port, SPRD_ICLR, iclr);
182	}
183
184	/* The Sprd serial does not support this function. */
185	static void sprd_break_ctl(struct uart_port *port, int break_state)
186	{
187	/* nothing to do */
188	}
189
190	static int handle_lsr_errors(struct uart_port *port,
191	unsigned int *flag,
192	unsigned int *lsr)
193	{
194	int ret = 0;
195
196	/* statistics */
197	if (*lsr & SPRD_LSR_BI) {
198	*lsr &= ~(SPRD_LSR_FE \| SPRD_LSR_PE);
199	port->icount.brk++;
200	ret = uart_handle_break(port);
201	if (ret)
202	return ret;
203	} else if (*lsr & SPRD_LSR_PE)
204	port->icount.parity++;
205	else if (*lsr & SPRD_LSR_FE)
206	port->icount.frame++;
207	if (*lsr & SPRD_LSR_OE)
208	port->icount.overrun++;
209
210	/* mask off conditions which should be ignored */
211	*lsr &= port->read_status_mask;
212	if (*lsr & SPRD_LSR_BI)
213	*flag = TTY_BREAK;
214	else if (*lsr & SPRD_LSR_PE)
215	*flag = TTY_PARITY;
216	else if (*lsr & SPRD_LSR_FE)
217	*flag = TTY_FRAME;
218
219	return ret;
220	}
221
222	static inline void sprd_rx(struct uart_port *port)
223	{
224	struct tty_port *tty = &port->state->port;
225	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
226
227	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
228	lsr = serial_in(port, SPRD_LSR);
229	ch = serial_in(port, SPRD_RXD);
230	flag = TTY_NORMAL;
231	port->icount.rx++;
232
233	if (lsr & (SPRD_LSR_BI \| SPRD_LSR_PE \|
234	SPRD_LSR_FE \| SPRD_LSR_OE))
235	if (handle_lsr_errors(port, &lsr, &flag))
236	continue;
237	if (uart_handle_sysrq_char(port, ch))
238	continue;
239
240	uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
241	}
242
243	tty_flip_buffer_push(tty);
244	}
245
246	static inline void sprd_tx(struct uart_port *port)
247	{
248	struct circ_buf *xmit = &port->state->xmit;
249	int count;
250
251	if (port->x_char) {
252	serial_out(port, SPRD_TXD, port->x_char);
253	port->icount.tx++;
254	port->x_char = 0;
255	return;
256	}
257
258	if (uart_circ_empty(xmit) \|\| uart_tx_stopped(port)) {
259	sprd_stop_tx(port);
260	return;
261	}
262
263	count = THLD_TX_EMPTY;
264	do {
265	serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
266	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
267	port->icount.tx++;
268	if (uart_circ_empty(xmit))
269	break;
270	} while (--count > 0);
271
272	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
273	uart_write_wakeup(port);
274
275	if (uart_circ_empty(xmit))
276	sprd_stop_tx(port);
277	}
278
279	/* this handles the interrupt from one port */
280	static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
281	{
282	struct uart_port *port = dev_id;
283	unsigned int ims;
284
285	spin_lock(&port->lock);
286
287	ims = serial_in(port, SPRD_IMSR);
288
c4e6dcfa AL	289	if (!ims) {
c4e6dcfa AL	290	spin_unlock(&port->lock);
b7396a38	291	return IRQ_NONE;
c4e6dcfa	292	}
b7396a38	293
43507825 LL	294	if (ims & SPRD_IMSR_TIMEOUT)
43507825 LL	295	serial_out(port, SPRD_ICLR, SPRD_ICLR_TIMEOUT);
b7396a38 CZ	296
	297	if (ims & (SPRD_IMSR_RX_FIFO_FULL \|
	298	SPRD_IMSR_BREAK_DETECT \| SPRD_IMSR_TIMEOUT))
	299	sprd_rx(port);
	300
	301	if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
	302	sprd_tx(port);
	303
	304	spin_unlock(&port->lock);
	305
	306	return IRQ_HANDLED;
	307	}
	308
	309	static int sprd_startup(struct uart_port *port)
	310	{
	311	int ret = 0;
	312	unsigned int ien, fc;
	313	unsigned int timeout;
	314	struct sprd_uart_port *sp;
	315	unsigned long flags;
	316
	317	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) \| THLD_RX_FULL));
	318
	319	/* clear rx fifo */
	320	timeout = SPRD_TIMEOUT;
	321	while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
	322	serial_in(port, SPRD_RXD);
	323
	324	/* clear tx fifo */
	325	timeout = SPRD_TIMEOUT;
	326	while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
	327	cpu_relax();
	328
	329	/* clear interrupt */
	330	serial_out(port, SPRD_IEN, 0);
	331	serial_out(port, SPRD_ICLR, ~0);
	332
	333	/* allocate irq */
	334	sp = container_of(port, struct sprd_uart_port, port);
	335	snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
	336	ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
	337	IRQF_SHARED, sp->name, port);
	338	if (ret) {
	339	dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
	340	port->irq, ret);
	341	return ret;
	342	}
	343	fc = serial_in(port, SPRD_CTL1);
	344	fc \|= RX_TOUT_THLD_DEF \| RX_HFC_THLD_DEF;
	345	serial_out(port, SPRD_CTL1, fc);
	346
	347	/* enable interrupt */
	348	spin_lock_irqsave(&port->lock, flags);
	349	ien = serial_in(port, SPRD_IEN);
	350	ien \|= SPRD_IEN_RX_FULL \| SPRD_IEN_BREAK_DETECT \| SPRD_IEN_TIMEOUT;
	351	serial_out(port, SPRD_IEN, ien);
	352	spin_unlock_irqrestore(&port->lock, flags);
	353
	354	return 0;
	355	}
	356
	357	static void sprd_shutdown(struct uart_port *port)
	358	{
	359	serial_out(port, SPRD_IEN, 0);
360	serial_out(port, SPRD_ICLR, ~0);
361	devm_free_irq(port->dev, port->irq, port);
362	}
363
364	static void sprd_set_termios(struct uart_port *port,
365	struct ktermios *termios,
366	struct ktermios *old)
367	{
368	unsigned int baud, quot;
369	unsigned int lcr = 0, fc;
370	unsigned long flags;
371
372	/* ask the core to calculate the divisor for us */
373	baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);
374
375	quot = (unsigned int)((port->uartclk + baud / 2) / baud);
376
377	/* set data length */
378	switch (termios->c_cflag & CSIZE) {
379	case CS5:
380	lcr \|= SPRD_LCR_DATA_LEN5;
381	break;
382	case CS6:
383	lcr \|= SPRD_LCR_DATA_LEN6;
384	break;
385	case CS7:
386	lcr \|= SPRD_LCR_DATA_LEN7;
387	break;
388	case CS8:
389	default:
390	lcr \|= SPRD_LCR_DATA_LEN8;
391	break;
392	}
393
394	/* calculate stop bits */
395	lcr &= ~(SPRD_LCR_STOP_1BIT \| SPRD_LCR_STOP_2BIT);
396	if (termios->c_cflag & CSTOPB)
397	lcr \|= SPRD_LCR_STOP_2BIT;
398	else
399	lcr \|= SPRD_LCR_STOP_1BIT;
400
401	/* calculate parity */
402	lcr &= ~SPRD_LCR_PARITY;
403	termios->c_cflag &= ~CMSPAR; /* no support mark/space */
404	if (termios->c_cflag & PARENB) {
405	lcr \|= SPRD_LCR_PARITY_EN;
406	if (termios->c_cflag & PARODD)
407	lcr \|= SPRD_LCR_ODD_PAR;
408	else
409	lcr \|= SPRD_LCR_EVEN_PAR;
410	}
411
412	spin_lock_irqsave(&port->lock, flags);
413
414	/* update the per-port timeout */
415	uart_update_timeout(port, termios->c_cflag, baud);
416
417	port->read_status_mask = SPRD_LSR_OE;
418	if (termios->c_iflag & INPCK)
419	port->read_status_mask \|= SPRD_LSR_FE \| SPRD_LSR_PE;
420	if (termios->c_iflag & (IGNBRK \| BRKINT \| PARMRK))
421	port->read_status_mask \|= SPRD_LSR_BI;
422
423	/* characters to ignore */
424	port->ignore_status_mask = 0;
425	if (termios->c_iflag & IGNPAR)
426	port->ignore_status_mask \|= SPRD_LSR_PE \| SPRD_LSR_FE;
427	if (termios->c_iflag & IGNBRK) {
428	port->ignore_status_mask \|= SPRD_LSR_BI;
429	/*
430	* If we're ignoring parity and break indicators,
431	* ignore overruns too (for real raw support).
432	*/
433	if (termios->c_iflag & IGNPAR)
434	port->ignore_status_mask \|= SPRD_LSR_OE;
435	}
436
437	/* flow control */
438	fc = serial_in(port, SPRD_CTL1);
439	fc &= ~(RX_HW_FLOW_CTL_THLD \| RX_HW_FLOW_CTL_EN \| TX_HW_FLOW_CTL_EN);
440	if (termios->c_cflag & CRTSCTS) {
441	fc \|= RX_HW_FLOW_CTL_THLD;
442	fc \|= RX_HW_FLOW_CTL_EN;
443	fc \|= TX_HW_FLOW_CTL_EN;
444	}
445
446	/* clock divider bit0~bit15 */
447	serial_out(port, SPRD_CLKD0, quot & 0xffff);
448
449	/* clock divider bit16~bit20 */
450	serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
451	serial_out(port, SPRD_LCR, lcr);
452	fc \|= RX_TOUT_THLD_DEF \| RX_HFC_THLD_DEF;
453	serial_out(port, SPRD_CTL1, fc);
454
455	spin_unlock_irqrestore(&port->lock, flags);
456
457	/* Don't rewrite B0 */
458	if (tty_termios_baud_rate(termios))
459	tty_termios_encode_baud_rate(termios, baud, baud);
460	}
461
462	static const char sprd_type(struct uart_port port)
463	{
464	return "SPX";
465	}
466
467	static void sprd_release_port(struct uart_port *port)
468	{
469	/* nothing to do */
470	}
471
472	static int sprd_request_port(struct uart_port *port)
473	{
474	return 0;
475	}
476
477	static void sprd_config_port(struct uart_port *port, int flags)
478	{
479	if (flags & UART_CONFIG_TYPE)
480	port->type = PORT_SPRD;
481	}
482
483	static int sprd_verify_port(struct uart_port *port,
484	struct serial_struct *ser)
485	{
486	if (ser->type != PORT_SPRD)
487	return -EINVAL;
488	if (port->irq != ser->irq)
489	return -EINVAL;
7950dc58 PH	490	if (port->iotype != ser->io_type)
7950dc58 PH	491	return -EINVAL;
b7396a38 CZ	492	return 0;
	493	}
	494
2331e068	495	static const struct uart_ops serial_sprd_ops = {
b7396a38 CZ	496	.tx_empty = sprd_tx_empty,
	497	.get_mctrl = sprd_get_mctrl,
	498	.set_mctrl = sprd_set_mctrl,
	499	.stop_tx = sprd_stop_tx,
	500	.start_tx = sprd_start_tx,
	501	.stop_rx = sprd_stop_rx,
	502	.break_ctl = sprd_break_ctl,
	503	.startup = sprd_startup,
	504	.shutdown = sprd_shutdown,
	505	.set_termios = sprd_set_termios,
	506	.type = sprd_type,
	507	.release_port = sprd_release_port,
	508	.request_port = sprd_request_port,
	509	.config_port = sprd_config_port,
	510	.verify_port = sprd_verify_port,
	511	};
	512
	513	#ifdef CONFIG_SERIAL_SPRD_CONSOLE
63744a69	514	static void wait_for_xmitr(struct uart_port *port)
b7396a38 CZ	515	{
	516	unsigned int status, tmout = 10000;
	517
	518	/* wait up to 10ms for the character(s) to be sent */
	519	do {
	520	status = serial_in(port, SPRD_STS1);
	521	if (--tmout == 0)
	522	break;
	523	udelay(1);
	524	} while (status & 0xff00);
	525	}
	526
	527	static void sprd_console_putchar(struct uart_port *port, int ch)
	528	{
	529	wait_for_xmitr(port);
	530	serial_out(port, SPRD_TXD, ch);
	531	}
	532
	533	static void sprd_console_write(struct console co, const char s,
	534	unsigned int count)
	535	{
	536	struct uart_port *port = &sprd_port[co->index]->port;
	537	int locked = 1;
	538	unsigned long flags;
	539
	540	if (port->sysrq)
	541	locked = 0;
	542	else if (oops_in_progress)
	543	locked = spin_trylock_irqsave(&port->lock, flags);
	544	else
	545	spin_lock_irqsave(&port->lock, flags);
	546
	547	uart_console_write(port, s, count, sprd_console_putchar);
	548
	549	/* wait for transmitter to become empty */
	550	wait_for_xmitr(port);
	551
	552	if (locked)
	553	spin_unlock_irqrestore(&port->lock, flags);
	554	}
	555
	556	static int __init sprd_console_setup(struct console co, char options)
	557	{
	558	struct uart_port *port;
	559	int baud = 115200;
	560	int bits = 8;
	561	int parity = 'n';
	562	int flow = 'n';
	563
	564	if (co->index >= UART_NR_MAX \|\| co->index < 0)
	565	co->index = 0;
	566
	567	port = &sprd_port[co->index]->port;
	568	if (port == NULL) {
	569	pr_info("serial port %d not yet initialized\n", co->index);
	570	return -ENODEV;
	571	}
	572	if (options)
	573	uart_parse_options(options, &baud, &parity, &bits, &flow);
	574
	575	return uart_set_options(port, co, baud, parity, bits, flow);
	576	}
	577
	578	static struct uart_driver sprd_uart_driver;
579	static struct console sprd_console = {
580	.name = SPRD_TTY_NAME,
581	.write = sprd_console_write,
582	.device = uart_console_device,
583	.setup = sprd_console_setup,
584	.flags = CON_PRINTBUFFER,
585	.index = -1,
586	.data = &sprd_uart_driver,
587	};
588
589	#define SPRD_CONSOLE (&sprd_console)
590
591	/* Support for earlycon */
592	static void sprd_putc(struct uart_port *port, int c)
593	{
594	unsigned int timeout = SPRD_TIMEOUT;
595
596	while (timeout-- &&
597	!(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
598	cpu_relax();
599
600	writeb(c, port->membase + SPRD_TXD);
601	}
602
603	static void sprd_early_write(struct console con, const char s,
604	unsigned n)
605	{
606	struct earlycon_device *dev = con->data;
607
608	uart_console_write(&dev->port, s, n, sprd_putc);
609	}
610
611	static int __init sprd_early_console_setup(
612	struct earlycon_device *device,
613	const char *opt)
614	{
615	if (!device->port.membase)
616	return -ENODEV;
617
618	device->con->write = sprd_early_write;
619	return 0;
620	}
b7396a38 CZ	621	OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
	622	sprd_early_console_setup);
	623
	624	#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
	625	#define SPRD_CONSOLE NULL
	626	#endif
	627
	628	static struct uart_driver sprd_uart_driver = {
	629	.owner = THIS_MODULE,
	630	.driver_name = "sprd_serial",
	631	.dev_name = SPRD_TTY_NAME,
	632	.major = 0,
	633	.minor = 0,
	634	.nr = UART_NR_MAX,
	635	.cons = SPRD_CONSOLE,
	636	};
	637
	638	static int sprd_probe_dt_alias(int index, struct device *dev)
	639	{
	640	struct device_node *np;
	641	int ret = index;
	642
	643	if (!IS_ENABLED(CONFIG_OF))
	644	return ret;
	645
	646	np = dev->of_node;
	647	if (!np)
	648	return ret;
	649
	650	ret = of_alias_get_id(np, "serial");
287980e4	651	if (ret < 0)
b7396a38 CZ	652	ret = index;
	653	else if (ret >= ARRAY_SIZE(sprd_port) \|\| sprd_port[ret] != NULL) {
	654	dev_warn(dev, "requested serial port %d not available.\n", ret);
	655	ret = index;
	656	}
	657
	658	return ret;
	659	}
	660
	661	static int sprd_remove(struct platform_device *dev)
	662	{
	663	struct sprd_uart_port *sup = platform_get_drvdata(dev);
	664
	665	if (sup) {
	666	uart_remove_one_port(&sprd_uart_driver, &sup->port);
	667	sprd_port[sup->port.line] = NULL;
	668	sprd_ports_num--;
	669	}
	670
	671	if (!sprd_ports_num)
	672	uart_unregister_driver(&sprd_uart_driver);
	673
	674	return 0;
	675	}
	676
	677	static int sprd_probe(struct platform_device *pdev)
	678	{
	679	struct resource *res;
	680	struct uart_port *up;
	681	struct clk *clk;
	682	int irq;
	683	int index;
	684	int ret;
	685
	686	for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
	687	if (sprd_port[index] == NULL)
	688	break;
	689
	690	if (index == ARRAY_SIZE(sprd_port))
	691	return -EBUSY;
	692
	693	index = sprd_probe_dt_alias(index, &pdev->dev);
	694
	695	sprd_port[index] = devm_kzalloc(&pdev->dev,
	696	sizeof(*sprd_port[index]), GFP_KERNEL);
	697	if (!sprd_port[index])
	698	return -ENOMEM;
	699
	700	up = &sprd_port[index]->port;
	701	up->dev = &pdev->dev;
	702	up->line = index;
	703	up->type = PORT_SPRD;
7950dc58	704	up->iotype = UPIO_MEM;
b7396a38 CZ	705	up->uartclk = SPRD_DEF_RATE;
	706	up->fifosize = SPRD_FIFO_SIZE;
	707	up->ops = &serial_sprd_ops;
	708	up->flags = UPF_BOOT_AUTOCONF;
	709
	710	clk = devm_clk_get(&pdev->dev, NULL);
ff0daa1c	711	if (!IS_ERR_OR_NULL(clk))
b7396a38 CZ	712	up->uartclk = clk_get_rate(clk);
	713
	714	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	715	if (!res) {
	716	dev_err(&pdev->dev, "not provide mem resource\n");
	717	return -ENODEV;
	718	}
	719	up->mapbase = res->start;
	720	up->membase = devm_ioremap_resource(&pdev->dev, res);
	721	if (IS_ERR(up->membase))
	722	return PTR_ERR(up->membase);
	723
	724	irq = platform_get_irq(pdev, 0);
	725	if (irq < 0) {
ec085c5a GS	726	dev_err(&pdev->dev, "not provide irq resource: %d\n", irq);
ec085c5a GS	727	return irq;
b7396a38 CZ	728	}
	729	up->irq = irq;
	730
	731	if (!sprd_ports_num) {
	732	ret = uart_register_driver(&sprd_uart_driver);
	733	if (ret < 0) {
	734	pr_err("Failed to register SPRD-UART driver\n");
	735	return ret;
	736	}
	737	}
	738	sprd_ports_num++;
	739
	740	ret = uart_add_one_port(&sprd_uart_driver, up);
	741	if (ret) {
	742	sprd_port[index] = NULL;
	743	sprd_remove(pdev);
	744	}
	745
	746	platform_set_drvdata(pdev, up);
	747
	748	return ret;
	749	}
	750
b51e3f5a	751	#ifdef CONFIG_PM_SLEEP
b7396a38 CZ	752	static int sprd_suspend(struct device *dev)
	753	{
	754	struct sprd_uart_port *sup = dev_get_drvdata(dev);
	755
	756	uart_suspend_port(&sprd_uart_driver, &sup->port);
	757
	758	return 0;
	759	}
	760
	761	static int sprd_resume(struct device *dev)
	762	{
	763	struct sprd_uart_port *sup = dev_get_drvdata(dev);
	764
	765	uart_resume_port(&sprd_uart_driver, &sup->port);
	766
	767	return 0;
	768	}
b51e3f5a	769	#endif
b7396a38 CZ	770
	771	static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);
	772
	773	static const struct of_device_id serial_ids[] = {
	774	{.compatible = "sprd,sc9836-uart",},
	775	{}
	776	};
7edb23ce	777	MODULE_DEVICE_TABLE(of, serial_ids);
b7396a38 CZ	778
	779	static struct platform_driver sprd_platform_driver = {
	780	.probe = sprd_probe,
	781	.remove = sprd_remove,
	782	.driver = {
	783	.name = "sprd_serial",
	784	.of_match_table = of_match_ptr(serial_ids),
	785	.pm = &sprd_pm_ops,
	786	},
	787	};
	788
	789	module_platform_driver(sprd_platform_driver);
	790
	791	MODULE_LICENSE("GPL v2");
	792	MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");