Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 950 insertions, 0 deletions

diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
new file mode 100644
index 000000000..eca41ac54
--- /dev/null
+++ b/drivers/tty/serial/uartlite.c
@@ -0,0 +1,950 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * uartlite.c: Serial driver for Xilinx uartlite serial controller
+ *
+ * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
+ * Copyright (C) 2007 Secret Lab Technologies Ltd.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/bitfield.h>
+#include <linux/console.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
+
+#define ULITE_NAME		"ttyUL"
+#define ULITE_MAJOR		204
+#define ULITE_MINOR		187
+#define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
+
+/* ---------------------------------------------------------------------
+ * Register definitions
+ *
+ * For register details see datasheet:
+ * https://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
+ */
+
+#define ULITE_RX		0x00
+#define ULITE_TX		0x04
+#define ULITE_STATUS		0x08
+#define ULITE_CONTROL		0x0c
+
+#define ULITE_REGION		16
+
+#define ULITE_STATUS_RXVALID	0x01
+#define ULITE_STATUS_RXFULL	0x02
+#define ULITE_STATUS_TXEMPTY	0x04
+#define ULITE_STATUS_TXFULL	0x08
+#define ULITE_STATUS_IE		0x10
+#define ULITE_STATUS_OVERRUN	0x20
+#define ULITE_STATUS_FRAME	0x40
+#define ULITE_STATUS_PARITY	0x80
+
+#define ULITE_CONTROL_RST_TX	0x01
+#define ULITE_CONTROL_RST_RX	0x02
+#define ULITE_CONTROL_IE	0x10
+#define UART_AUTOSUSPEND_TIMEOUT	3000	/* ms */
+
+/* Static pointer to console port */
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+static struct uart_port *console_port;
+#endif
+
+/**
+ * struct uartlite_data: Driver private data
+ * reg_ops: Functions to read/write registers
+ * clk: Our parent clock, if present
+ * baud: The baud rate configured when this device was synthesized
+ * cflags: The cflags for parity and data bits
+ */
+struct uartlite_data {
+	const struct uartlite_reg_ops *reg_ops;
+	struct clk *clk;
+	unsigned int baud;
+	tcflag_t cflags;
+};
+
+struct uartlite_reg_ops {
+	u32 (*in)(void __iomem *addr);
+	void (*out)(u32 val, void __iomem *addr);
+};
+
+static u32 uartlite_inbe32(void __iomem *addr)
+{
+	return ioread32be(addr);
+}
+
+static void uartlite_outbe32(u32 val, void __iomem *addr)
+{
+	iowrite32be(val, addr);
+}
+
+static const struct uartlite_reg_ops uartlite_be = {
+	.in = uartlite_inbe32,
+	.out = uartlite_outbe32,
+};
+
+static u32 uartlite_inle32(void __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static void uartlite_outle32(u32 val, void __iomem *addr)
+{
+	iowrite32(val, addr);
+}
+
+static const struct uartlite_reg_ops uartlite_le = {
+	.in = uartlite_inle32,
+	.out = uartlite_outle32,
+};
+
+static inline u32 uart_in32(u32 offset, struct uart_port *port)
+{
+	struct uartlite_data *pdata = port->private_data;
+
+	return pdata->reg_ops->in(port->membase + offset);
+}
+
+static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
+{
+	struct uartlite_data *pdata = port->private_data;
+
+	pdata->reg_ops->out(val, port->membase + offset);
+}
+
+static struct uart_port ulite_ports[ULITE_NR_UARTS];
+
+static struct uart_driver ulite_uart_driver;
+
+/* ---------------------------------------------------------------------
+ * Core UART driver operations
+ */
+
+static int ulite_receive(struct uart_port *port, int stat)
+{
+	struct tty_port *tport = &port->state->port;
+	unsigned char ch = 0;
+	char flag = TTY_NORMAL;
+
+	if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
+		     | ULITE_STATUS_FRAME)) == 0)
+		return 0;
+
+	/* stats */
+	if (stat & ULITE_STATUS_RXVALID) {
+		port->icount.rx++;
+		ch = uart_in32(ULITE_RX, port);
+
+		if (stat & ULITE_STATUS_PARITY)
+			port->icount.parity++;
+	}
+
+	if (stat & ULITE_STATUS_OVERRUN)
+		port->icount.overrun++;
+
+	if (stat & ULITE_STATUS_FRAME)
+		port->icount.frame++;
+
+
+	/* drop byte with parity error if IGNPAR specificed */
+	if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
+		stat &= ~ULITE_STATUS_RXVALID;
+
+	stat &= port->read_status_mask;
+
+	if (stat & ULITE_STATUS_PARITY)
+		flag = TTY_PARITY;
+
+
+	stat &= ~port->ignore_status_mask;
+
+	if (stat & ULITE_STATUS_RXVALID)
+		tty_insert_flip_char(tport, ch, flag);
+
+	if (stat & ULITE_STATUS_FRAME)
+		tty_insert_flip_char(tport, 0, TTY_FRAME);
+
+	if (stat & ULITE_STATUS_OVERRUN)
+		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
+
+	return 1;
+}
+
+static int ulite_transmit(struct uart_port *port, int stat)
+{
+	struct circ_buf *xmit  = &port->state->xmit;
+
+	if (stat & ULITE_STATUS_TXFULL)
+		return 0;
+
+	if (port->x_char) {
+		uart_out32(port->x_char, ULITE_TX, port);
+		port->x_char = 0;
+		port->icount.tx++;
+		return 1;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+		return 0;
+
+	uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
+	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
+	port->icount.tx++;
+
+	/* wake up */
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	return 1;
+}
+
+static irqreturn_t ulite_isr(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	int stat, busy, n = 0;
+	unsigned long flags;
+
+	do {
+		spin_lock_irqsave(&port->lock, flags);
+		stat = uart_in32(ULITE_STATUS, port);
+		busy  = ulite_receive(port, stat);
+		busy |= ulite_transmit(port, stat);
+		spin_unlock_irqrestore(&port->lock, flags);
+		n++;
+	} while (busy);
+
+	/* work done? */
+	if (n > 1) {
+		tty_flip_buffer_push(&port->state->port);
+		return IRQ_HANDLED;
+	} else {
+		return IRQ_NONE;
+	}
+}
+
+static unsigned int ulite_tx_empty(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int ret;
+
+	spin_lock_irqsave(&port->lock, flags);
+	ret = uart_in32(ULITE_STATUS, port);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int ulite_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+}
+
+static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* N/A */
+}
+
+static void ulite_stop_tx(struct uart_port *port)
+{
+	/* N/A */
+}
+
+static void ulite_start_tx(struct uart_port *port)
+{
+	ulite_transmit(port, uart_in32(ULITE_STATUS, port));
+}
+
+static void ulite_stop_rx(struct uart_port *port)
+{
+	/* don't forward any more data (like !CREAD) */
+	port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
+		| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+}
+
+static void ulite_break_ctl(struct uart_port *port, int ctl)
+{
+	/* N/A */
+}
+
+static int ulite_startup(struct uart_port *port)
+{
+	struct uartlite_data *pdata = port->private_data;
+	int ret;
+
+	ret = clk_enable(pdata->clk);
+	if (ret) {
+		dev_err(port->dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
+			  "uartlite", port);
+	if (ret)
+		return ret;
+
+	uart_out32(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
+		ULITE_CONTROL, port);
+	uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
+
+	return 0;
+}
+
+static void ulite_shutdown(struct uart_port *port)
+{
+	struct uartlite_data *pdata = port->private_data;
+
+	uart_out32(0, ULITE_CONTROL, port);
+	uart_in32(ULITE_CONTROL, port); /* dummy */
+	free_irq(port->irq, port);
+	clk_disable(pdata->clk);
+}
+
+static void ulite_set_termios(struct uart_port *port,
+			      struct ktermios *termios,
+			      const struct ktermios *old)
+{
+	unsigned long flags;
+	struct uartlite_data *pdata = port->private_data;
+
+	/* Set termios to what the hardware supports */
+	termios->c_iflag &= ~BRKINT;
+	termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CSIZE);
+	termios->c_cflag |= pdata->cflags & (PARENB | PARODD | CSIZE);
+	tty_termios_encode_baud_rate(termios, pdata->baud, pdata->baud);
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
+		| ULITE_STATUS_TXFULL;
+
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |=
+			ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
+
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= ULITE_STATUS_PARITY
+			| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+
+	/* ignore all characters if CREAD is not set */
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |=
+			ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
+			| ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
+
+	/* update timeout */
+	uart_update_timeout(port, termios->c_cflag, pdata->baud);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *ulite_type(struct uart_port *port)
+{
+	return port->type == PORT_UARTLITE ? "uartlite" : NULL;
+}
+
+static void ulite_release_port(struct uart_port *port)
+{
+	release_mem_region(port->mapbase, ULITE_REGION);
+	iounmap(port->membase);
+	port->membase = NULL;
+}
+
+static int ulite_request_port(struct uart_port *port)
+{
+	struct uartlite_data *pdata = port->private_data;
+	int ret;
+
+	pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
+		 port, (unsigned long long) port->mapbase);
+
+	if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
+		dev_err(port->dev, "Memory region busy\n");
+		return -EBUSY;
+	}
+
+	port->membase = ioremap(port->mapbase, ULITE_REGION);
+	if (!port->membase) {
+		dev_err(port->dev, "Unable to map registers\n");
+		release_mem_region(port->mapbase, ULITE_REGION);
+		return -EBUSY;
+	}
+
+	pdata->reg_ops = &uartlite_be;
+	ret = uart_in32(ULITE_CONTROL, port);
+	uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port);
+	ret = uart_in32(ULITE_STATUS, port);
+	/* Endianess detection */
+	if ((ret & ULITE_STATUS_TXEMPTY) != ULITE_STATUS_TXEMPTY)
+		pdata->reg_ops = &uartlite_le;
+
+	return 0;
+}
+
+static void ulite_config_port(struct uart_port *port, int flags)
+{
+	if (!ulite_request_port(port))
+		port->type = PORT_UARTLITE;
+}
+
+static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	/* we don't want the core code to modify any port params */
+	return -EINVAL;
+}
+
+static void ulite_pm(struct uart_port *port, unsigned int state,
+		     unsigned int oldstate)
+{
+	int ret;
+
+	if (!state) {
+		ret = pm_runtime_get_sync(port->dev);
+		if (ret < 0)
+			dev_err(port->dev, "Failed to enable clocks\n");
+	} else {
+		pm_runtime_mark_last_busy(port->dev);
+		pm_runtime_put_autosuspend(port->dev);
+	}
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int ulite_get_poll_char(struct uart_port *port)
+{
+	if (!(uart_in32(ULITE_STATUS, port) & ULITE_STATUS_RXVALID))
+		return NO_POLL_CHAR;
+
+	return uart_in32(ULITE_RX, port);
+}
+
+static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
+{
+	while (uart_in32(ULITE_STATUS, port) & ULITE_STATUS_TXFULL)
+		cpu_relax();
+
+	/* write char to device */
+	uart_out32(ch, ULITE_TX, port);
+}
+#endif
+
+static const struct uart_ops ulite_ops = {
+	.tx_empty	= ulite_tx_empty,
+	.set_mctrl	= ulite_set_mctrl,
+	.get_mctrl	= ulite_get_mctrl,
+	.stop_tx	= ulite_stop_tx,
+	.start_tx	= ulite_start_tx,
+	.stop_rx	= ulite_stop_rx,
+	.break_ctl	= ulite_break_ctl,
+	.startup	= ulite_startup,
+	.shutdown	= ulite_shutdown,
+	.set_termios	= ulite_set_termios,
+	.type		= ulite_type,
+	.release_port	= ulite_release_port,
+	.request_port	= ulite_request_port,
+	.config_port	= ulite_config_port,
+	.verify_port	= ulite_verify_port,
+	.pm		= ulite_pm,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	= ulite_get_poll_char,
+	.poll_put_char	= ulite_put_poll_char,
+#endif
+};
+
+/* ---------------------------------------------------------------------
+ * Console driver operations
+ */
+
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+static void ulite_console_wait_tx(struct uart_port *port)
+{
+	u8 val;
+
+	/*
+	 * Spin waiting for TX fifo to have space available.
+	 * When using the Microblaze Debug Module this can take up to 1s
+	 */
+	if (read_poll_timeout_atomic(uart_in32, val, !(val & ULITE_STATUS_TXFULL),
+				     0, 1000000, false, ULITE_STATUS, port))
+		dev_warn(port->dev,
+			 "timeout waiting for TX buffer empty\n");
+}
+
+static void ulite_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	ulite_console_wait_tx(port);
+	uart_out32(ch, ULITE_TX, port);
+}
+
+static void ulite_console_write(struct console *co, const char *s,
+				unsigned int count)
+{
+	struct uart_port *port = console_port;
+	unsigned long flags;
+	unsigned int ier;
+	int locked = 1;
+
+	if (oops_in_progress) {
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	} else
+		spin_lock_irqsave(&port->lock, flags);
+
+	/* save and disable interrupt */
+	ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE;
+	uart_out32(0, ULITE_CONTROL, port);
+
+	uart_console_write(port, s, count, ulite_console_putchar);
+
+	ulite_console_wait_tx(port);
+
+	/* restore interrupt state */
+	if (ier)
+		uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
+
+	if (locked)
+		spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static int ulite_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port = NULL;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index >= 0 && co->index < ULITE_NR_UARTS)
+		port = ulite_ports + co->index;
+
+	/* Has the device been initialized yet? */
+	if (!port || !port->mapbase) {
+		pr_debug("console on ttyUL%i not present\n", co->index);
+		return -ENODEV;
+	}
+
+	console_port = port;
+
+	/* not initialized yet? */
+	if (!port->membase) {
+		if (ulite_request_port(port))
+			return -ENODEV;
+	}
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct console ulite_console = {
+	.name	= ULITE_NAME,
+	.write	= ulite_console_write,
+	.device	= uart_console_device,
+	.setup	= ulite_console_setup,
+	.flags	= CON_PRINTBUFFER,
+	.index	= -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
+	.data	= &ulite_uart_driver,
+};
+
+static void early_uartlite_putc(struct uart_port *port, unsigned char c)
+{
+	/*
+	 * Limit how many times we'll spin waiting for TX FIFO status.
+	 * This will prevent lockups if the base address is incorrectly
+	 * set, or any other issue on the UARTLITE.
+	 * This limit is pretty arbitrary, unless we are at about 10 baud
+	 * we'll never timeout on a working UART.
+	 */
+	unsigned retries = 1000000;
+
+	while (--retries &&
+	       (readl(port->membase + ULITE_STATUS) & ULITE_STATUS_TXFULL))
+		;
+
+	/* Only attempt the iowrite if we didn't timeout */
+	if (retries)
+		writel(c & 0xff, port->membase + ULITE_TX);
+}
+
+static void early_uartlite_write(struct console *console,
+				 const char *s, unsigned n)
+{
+	struct earlycon_device *device = console->data;
+	uart_console_write(&device->port, s, n, early_uartlite_putc);
+}
+
+static int __init early_uartlite_setup(struct earlycon_device *device,
+				       const char *options)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = early_uartlite_write;
+	return 0;
+}
+EARLYCON_DECLARE(uartlite, early_uartlite_setup);
+OF_EARLYCON_DECLARE(uartlite_b, "xlnx,opb-uartlite-1.00.b", early_uartlite_setup);
+OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup);
+
+#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
+
+static struct uart_driver ulite_uart_driver = {
+	.owner		= THIS_MODULE,
+	.driver_name	= "uartlite",
+	.dev_name	= ULITE_NAME,
+	.major		= ULITE_MAJOR,
+	.minor		= ULITE_MINOR,
+	.nr		= ULITE_NR_UARTS,
+#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
+	.cons		= &ulite_console,
+#endif
+};
+
+/* ---------------------------------------------------------------------
+ * Port assignment functions (mapping devices to uart_port structures)
+ */
+
+/** ulite_assign: register a uartlite device with the driver
+ *
+ * @dev: pointer to device structure
+ * @id: requested id number.  Pass -1 for automatic port assignment
+ * @base: base address of uartlite registers
+ * @irq: irq number for uartlite
+ * @pdata: private data for uartlite
+ *
+ * Returns: 0 on success, <0 otherwise
+ */
+static int ulite_assign(struct device *dev, int id, phys_addr_t base, int irq,
+			struct uartlite_data *pdata)
+{
+	struct uart_port *port;
+	int rc;
+
+	/* if id = -1; then scan for a free id and use that */
+	if (id < 0) {
+		for (id = 0; id < ULITE_NR_UARTS; id++)
+			if (ulite_ports[id].mapbase == 0)
+				break;
+	}
+	if (id < 0 || id >= ULITE_NR_UARTS) {
+		dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
+		return -EINVAL;
+	}
+
+	if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
+		dev_err(dev, "cannot assign to %s%i; it is already in use\n",
+			ULITE_NAME, id);
+		return -EBUSY;
+	}
+
+	port = &ulite_ports[id];
+
+	spin_lock_init(&port->lock);
+	port->fifosize = 16;
+	port->regshift = 2;
+	port->iotype = UPIO_MEM;
+	port->iobase = 1; /* mark port in use */
+	port->mapbase = base;
+	port->membase = NULL;
+	port->ops = &ulite_ops;
+	port->irq = irq;
+	port->flags = UPF_BOOT_AUTOCONF;
+	port->dev = dev;
+	port->type = PORT_UNKNOWN;
+	port->line = id;
+	port->private_data = pdata;
+
+	dev_set_drvdata(dev, port);
+
+	/* Register the port */
+	rc = uart_add_one_port(&ulite_uart_driver, port);
+	if (rc) {
+		dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
+		port->mapbase = 0;
+		dev_set_drvdata(dev, NULL);
+		return rc;
+	}
+
+	return 0;
+}
+
+/** ulite_release: register a uartlite device with the driver
+ *
+ * @dev: pointer to device structure
+ */
+static int ulite_release(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	int rc = 0;
+
+	if (port) {
+		rc = uart_remove_one_port(&ulite_uart_driver, port);
+		dev_set_drvdata(dev, NULL);
+		port->mapbase = 0;
+	}
+
+	return rc;
+}
+
+/**
+ * ulite_suspend - Stop the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 always.
+ */
+static int __maybe_unused ulite_suspend(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+
+	if (port)
+		uart_suspend_port(&ulite_uart_driver, port);
+
+	return 0;
+}
+
+/**
+ * ulite_resume - Resume the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 on success, errno otherwise.
+ */
+static int __maybe_unused ulite_resume(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+
+	if (port)
+		uart_resume_port(&ulite_uart_driver, port);
+
+	return 0;
+}
+
+static int __maybe_unused ulite_runtime_suspend(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct uartlite_data *pdata = port->private_data;
+
+	clk_disable(pdata->clk);
+	return 0;
+};
+
+static int __maybe_unused ulite_runtime_resume(struct device *dev)
+{
+	struct uart_port *port = dev_get_drvdata(dev);
+	struct uartlite_data *pdata = port->private_data;
+	int ret;
+
+	ret = clk_enable(pdata->clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable clock.\n");
+		return ret;
+	}
+	return 0;
+}
+
+/* ---------------------------------------------------------------------
+ * Platform bus binding
+ */
+
+static const struct dev_pm_ops ulite_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(ulite_suspend, ulite_resume)
+	SET_RUNTIME_PM_OPS(ulite_runtime_suspend,
+			   ulite_runtime_resume, NULL)
+};
+
+#if defined(CONFIG_OF)
+/* Match table for of_platform binding */
+static const struct of_device_id ulite_of_match[] = {
+	{ .compatible = "xlnx,opb-uartlite-1.00.b", },
+	{ .compatible = "xlnx,xps-uartlite-1.00.a", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ulite_of_match);
+#endif /* CONFIG_OF */
+
+static int ulite_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct uartlite_data *pdata;
+	int irq, ret;
+	int id = pdev->id;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(struct uartlite_data),
+			     GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	if (IS_ENABLED(CONFIG_OF)) {
+		const char *prop;
+		struct device_node *np = pdev->dev.of_node;
+		u32 val = 0;
+
+		prop = "port-number";
+		ret = of_property_read_u32(np, prop, &id);
+		if (ret && ret != -EINVAL)
+of_err:
+			return dev_err_probe(&pdev->dev, ret,
+					     "could not read %s\n", prop);
+
+		prop = "current-speed";
+		ret = of_property_read_u32(np, prop, &pdata->baud);
+		if (ret)
+			goto of_err;
+
+		prop = "xlnx,use-parity";
+		ret = of_property_read_u32(np, prop, &val);
+		if (ret && ret != -EINVAL)
+			goto of_err;
+
+		if (val) {
+			prop = "xlnx,odd-parity";
+			ret = of_property_read_u32(np, prop, &val);
+			if (ret)
+				goto of_err;
+
+			if (val)
+				pdata->cflags |= PARODD;
+			pdata->cflags |= PARENB;
+		}
+
+		val = 8;
+		prop = "xlnx,data-bits";
+		ret = of_property_read_u32(np, prop, &val);
+		if (ret && ret != -EINVAL)
+			goto of_err;
+
+		switch (val) {
+		case 5:
+			pdata->cflags |= CS5;
+			break;
+		case 6:
+			pdata->cflags |= CS6;
+			break;
+		case 7:
+			pdata->cflags |= CS7;
+			break;
+		case 8:
+			pdata->cflags |= CS8;
+			break;
+		default:
+			return dev_err_probe(&pdev->dev, -EINVAL,
+					     "bad data bits %d\n", val);
+		}
+	} else {
+		pdata->baud = 9600;
+		pdata->cflags = CS8;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	pdata->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
+	if (IS_ERR(pdata->clk)) {
+		if (PTR_ERR(pdata->clk) != -ENOENT)
+			return PTR_ERR(pdata->clk);
+
+		/*
+		 * Clock framework support is optional, continue on
+		 * anyways if we don't find a matching clock.
+		 */
+		pdata->clk = NULL;
+	}
+
+	ret = clk_prepare_enable(pdata->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to prepare clock\n");
+		return ret;
+	}
+
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	if (!ulite_uart_driver.state) {
+		dev_dbg(&pdev->dev, "uartlite: calling uart_register_driver()\n");
+		ret = uart_register_driver(&ulite_uart_driver);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Failed to register driver\n");
+			clk_disable_unprepare(pdata->clk);
+			return ret;
+		}
+	}
+
+	ret = ulite_assign(&pdev->dev, id, res->start, irq, pdata);
+
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	return ret;
+}
+
+static int ulite_remove(struct platform_device *pdev)
+{
+	struct uart_port *port = dev_get_drvdata(&pdev->dev);
+	struct uartlite_data *pdata = port->private_data;
+	int rc;
+
+	clk_disable_unprepare(pdata->clk);
+	rc = ulite_release(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	return rc;
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:uartlite");
+
+static struct platform_driver ulite_platform_driver = {
+	.probe = ulite_probe,
+	.remove = ulite_remove,
+	.driver = {
+		.name  = "uartlite",
+		.of_match_table = of_match_ptr(ulite_of_match),
+		.pm = &ulite_pm_ops,
+	},
+};
+
+/* ---------------------------------------------------------------------
+ * Module setup/teardown
+ */
+
+static int __init ulite_init(void)
+{
+
+	pr_debug("uartlite: calling platform_driver_register()\n");
+	return platform_driver_register(&ulite_platform_driver);
+}
+
+static void __exit ulite_exit(void)
+{
+	platform_driver_unregister(&ulite_platform_driver);
+	if (ulite_uart_driver.state)
+		uart_unregister_driver(&ulite_uart_driver);
+}
+
+module_init(ulite_init);
+module_exit(ulite_exit);
+
+MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
+MODULE_DESCRIPTION("Xilinx uartlite serial driver");
+MODULE_LICENSE("GPL");