Message-Id: <1645522563-17183-3-git-send-email-hammerh0314@gmail.com>
Date:   Tue, 22 Feb 2022 17:36:03 +0800
From:   Hammer Hsieh <hammerh0314@...il.com>
To:     gregkh@...uxfoundation.org, robh+dt@...nel.org,
        linux-serial@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, jirislaby@...nel.org,
        p.zabel@...gutronix.de
Cc:     wells.lu@...plus.com, hammer.hsieh@...plus.com,
        Hammer Hsieh <hammerh0314@...il.com>
Subject: [PATCH v9 2/2] serial:sunplus-uart:Add Sunplus SoC UART Driver

Add Sunplus SoC UART Driver.
SP7021 UART block contains 5 UARTs.
There are UART0~4 that supported in SP7021, the features list as below.
Support Full-duplex communication.
Support data packet length configurable.
Support stop bit number configurable.
Support force break condition.
Support baud rate configurable.
Support error detection and report.
Support RXD Noise Rejection Vote configurable.

UART0 pinout only support TX/RX two pins.
UART1 to UART4 pinout support TX/RX/CTS/RTS four pins.
Normally UART0 used for kernel console, also can be used for normal uart.
Command line set "console=ttySUP0,115200", SUP means Sunplus Uart Port.
UART driver probe will create path named "/dev/ttySUPx".

https://sunplus.atlassian.net/wiki/spaces/doc/pages/1873412290/13.+Universal+Asynchronous+Receiver+Transmitter+UART

Signed-off-by: Hammer Hsieh <hammerh0314@...il.com>
---
Changes in v9:
 - Addressed kernel test robot warning issue (clang version 15.0.0 arm64)
   [cannot apply to tty/tty-testing robh/for-next linus/master v5.17-rc4 next-20220215]
   Modify uninitialized variables.

 - Addressed kernel test robot error issue (gcc 11.2.0 sh4)
   [cannot apply to tty/tty-testing robh/for-next linus/master v5.17-rc4 next-20220215]
   Modify for redefinition of '__inittest' and 'init_module'.

 MAINTAINERS                       |   1 +
 drivers/tty/serial/Kconfig        |  25 ++
 drivers/tty/serial/Makefile       |   1 +
 drivers/tty/serial/sunplus-uart.c | 770 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/serial_core.h  |   3 +
 5 files changed, 800 insertions(+)
 create mode 100644 drivers/tty/serial/sunplus-uart.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 3c1362e..2dc2fe6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17949,6 +17949,7 @@ SUNPLUS UART DRIVER
 M:	Hammer Hsieh <hammerh0314@...il.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/serial/sunplus,sp7021-uart.yaml
+F:	drivers/tty/serial/sunplus-uart.c
 
 SUPERH
 M:	Yoshinori Sato <ysato@...rs.sourceforge.jp>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 131a6a5..0865da3 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1561,6 +1561,31 @@ config SERIAL_LITEUART_CONSOLE
 	  and warnings and which allows logins in single user mode).
 	  Otherwise, say 'N'.
 
+config SERIAL_SUNPLUS
+	tristate "Sunplus UART support"
+	depends on OF || COMPILE_TEST
+	select SERIAL_CORE
+	help
+	  Select this option if you would like to use Sunplus serial port on
+	  Sunplus SoC SP7021.
+	  If you enable this option, Sunplus serial ports in the system will
+	  be registered as ttySUPx.
+	  This driver can also be built as a module. If so, the module will be
+	  called sunplus-uart.
+
+config SERIAL_SUNPLUS_CONSOLE
+	bool "Console on Sunplus UART"
+	depends on SERIAL_SUNPLUS
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	help
+	  Select this option if you would like to use a Sunplus UART as the
+	  system console.
+	  Even if you say Y here, the currently visible virtual console
+	  (/dev/tty0) will still be used as the system console by default, but
+	  you can alter that using a kernel command line option such as
+	  "console=ttySUPx".
+
 endmenu
 
 config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 7da0856..61cc8de 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_SERIAL_RDA)	+= rda-uart.o
 obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
 obj-$(CONFIG_SERIAL_SIFIVE)	+= sifive.o
 obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
+obj-$(CONFIG_SERIAL_SUNPLUS)	+= sunplus-uart.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/sunplus-uart.c b/drivers/tty/serial/sunplus-uart.c
new file mode 100644
index 0000000..450c8e7
--- /dev/null
+++ b/drivers/tty/serial/sunplus-uart.c
@@ -0,0 +1,770 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sunplus SoC UART driver
+ *
+ * Author: Hammer Hsieh <hammerh0314@...il.com>
+ *
+ * Note1: This driver is 8250-like uart, but are not register compatible.
+ *
+ * Note2: On some buses, for preventing data incoherence, must do a read
+ * for ensure write made it to hardware. In this driver, function startup
+ * and shutdown did not do a read but only do a write directly. For what?
+ * In Sunplus bus communication between memory bus and peripheral bus with
+ * posted write, it will send a specific command after last write command
+ * to make sure write done. Then memory bus identify the specific command
+ * and send done signal back to master device. After master device received
+ * done signal, then proceed next write command. It is no need to do a read
+ * before write.
+ */
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/sysrq.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <asm/irq.h>
+
+/* Register offsets */
+#define SUP_UART_DATA			0x00
+#define SUP_UART_LSR			0x04
+#define SUP_UART_MSR			0x08
+#define SUP_UART_LCR			0x0C
+#define SUP_UART_MCR			0x10
+#define SUP_UART_DIV_L			0x14
+#define SUP_UART_DIV_H			0x18
+#define SUP_UART_ISC			0x1C
+#define SUP_UART_TX_RESIDUE		0x20
+#define SUP_UART_RX_RESIDUE		0x24
+
+/* Line Status Register bits */
+#define SUP_UART_LSR_BC			BIT(5) /* break condition status */
+#define SUP_UART_LSR_FE			BIT(4) /* frame error status */
+#define SUP_UART_LSR_OE			BIT(3) /* overrun error status */
+#define SUP_UART_LSR_PE			BIT(2) /* parity error status */
+#define SUP_UART_LSR_RX			BIT(1) /* 1: receive fifo not empty */
+#define SUP_UART_LSR_TX			BIT(0) /* 1: transmit fifo is not full */
+#define SUP_UART_LSR_TX_NOT_FULL	1
+#define SUP_UART_LSR_BRK_ERROR_BITS	GENMASK(5, 2)
+
+/* Line Control Register bits */
+#define SUP_UART_LCR_SBC		BIT(5) /* select break condition */
+
+/* Modem Control Register bits */
+#define SUP_UART_MCR_RI			BIT(3) /* ring indicator */
+#define SUP_UART_MCR_DCD		BIT(2) /* data carrier detect */
+
+/* Interrupt Status/Control Register bits */
+#define SUP_UART_ISC_RXM		BIT(5) /* RX interrupt enable */
+#define SUP_UART_ISC_TXM		BIT(4) /* TX interrupt enable */
+#define SUP_UART_ISC_RX			BIT(1) /* RX interrupt status */
+#define SUP_UART_ISC_TX			BIT(0) /* TX interrupt status */
+
+#define SUP_DUMMY_READ			BIT(16) /* drop bytes received on a !CREAD port */
+#define SUP_UART_NR			5
+
+struct sunplus_uart_port {
+	struct uart_port port;
+	struct clk *clk;
+	struct reset_control *rstc;
+};
+
+static void sp_uart_put_char(struct uart_port *port, unsigned int ch)
+{
+	writel(ch, port->membase + SUP_UART_DATA);
+}
+
+static u32 sunplus_tx_buf_not_full(struct uart_port *port)
+{
+	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
+
+	return (lsr & SUP_UART_LSR_TX) ? SUP_UART_LSR_TX_NOT_FULL : 0;
+}
+
+static unsigned int sunplus_tx_empty(struct uart_port *port)
+{
+	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
+
+	return (lsr & UART_LSR_TEMT) ? TIOCSER_TEMT : 0;
+}
+
+static void sunplus_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	unsigned int mcr = readl(port->membase + SUP_UART_MCR);
+
+	if (mctrl & TIOCM_DTR)
+		mcr |= UART_MCR_DTR;
+	else
+		mcr &= ~UART_MCR_DTR;
+
+	if (mctrl & TIOCM_RTS)
+		mcr |= UART_MCR_RTS;
+	else
+		mcr &= ~UART_MCR_RTS;
+
+	if (mctrl & TIOCM_CAR)
+		mcr |= SUP_UART_MCR_DCD;
+	else
+		mcr &= ~SUP_UART_MCR_DCD;
+
+	if (mctrl & TIOCM_RI)
+		mcr |= SUP_UART_MCR_RI;
+	else
+		mcr &= ~SUP_UART_MCR_RI;
+
+	if (mctrl & TIOCM_LOOP)
+		mcr |= UART_MCR_LOOP;
+	else
+		mcr &= ~UART_MCR_LOOP;
+
+	writel(mcr, port->membase + SUP_UART_MCR);
+}
+
+static unsigned int sunplus_get_mctrl(struct uart_port *port)
+{
+	unsigned int mcr, ret = 0;
+
+	mcr = readl(port->membase + SUP_UART_MCR);
+
+	if (mcr & UART_MCR_DTR)
+		ret |= TIOCM_DTR;
+
+	if (mcr & UART_MCR_RTS)
+		ret |= TIOCM_RTS;
+
+	if (mcr & SUP_UART_MCR_DCD)
+		ret |= TIOCM_CAR;
+
+	if (mcr & SUP_UART_MCR_RI)
+		ret |= TIOCM_RI;
+
+	if (mcr & UART_MCR_LOOP)
+		ret |= TIOCM_LOOP;
+
+	return ret;
+}
+
+static void sunplus_stop_tx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SUP_UART_ISC);
+	isc &= ~SUP_UART_ISC_TXM;
+	writel(isc, port->membase + SUP_UART_ISC);
+}
+
+static void sunplus_start_tx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SUP_UART_ISC);
+	isc |= SUP_UART_ISC_TXM;
+	writel(isc, port->membase + SUP_UART_ISC);
+}
+
+static void sunplus_stop_rx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SUP_UART_ISC);
+	isc &= ~SUP_UART_ISC_RXM;
+	writel(isc, port->membase + SUP_UART_ISC);
+}
+
+static void sunplus_break_ctl(struct uart_port *port, int ctl)
+{
+	unsigned long flags;
+	unsigned int lcr;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	lcr = readl(port->membase + SUP_UART_LCR);
+
+	if (ctl)
+		lcr |= SUP_UART_LCR_SBC; /* start break */
+	else
+		lcr &= ~SUP_UART_LCR_SBC; /* stop break */
+
+	writel(lcr, port->membase + SUP_UART_LCR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void transmit_chars(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+
+	if (port->x_char) {
+		sp_uart_put_char(port, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		sunplus_stop_tx(port);
+		return;
+	}
+
+	do {
+		sp_uart_put_char(port, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE;
+		port->icount.tx++;
+
+		if (uart_circ_empty(xmit))
+			break;
+	} while (sunplus_tx_buf_not_full(port));
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		sunplus_stop_tx(port);
+}
+
+static void receive_chars(struct uart_port *port)
+{
+	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
+	unsigned int ch, flag;
+
+	do {
+		ch = readl(port->membase + SUP_UART_DATA);
+		flag = TTY_NORMAL;
+		port->icount.rx++;
+
+		if (unlikely(lsr & SUP_UART_LSR_BRK_ERROR_BITS)) {
+			if (lsr & SUP_UART_LSR_BC) {
+				lsr &= ~(SUP_UART_LSR_FE | SUP_UART_LSR_PE);
+				port->icount.brk++;
+				flag = TTY_BREAK;
+				if (uart_handle_break(port))
+					goto ignore_char;
+			} else if (lsr & SUP_UART_LSR_PE) {
+				port->icount.parity++;
+				flag = TTY_PARITY;
+			} else if (lsr & SUP_UART_LSR_FE) {
+				port->icount.frame++;
+				flag = TTY_FRAME;
+			}
+
+			if (lsr & SUP_UART_LSR_OE)
+				port->icount.overrun++;
+		}
+
+		if (port->ignore_status_mask & SUP_DUMMY_READ)
+			goto ignore_char;
+
+		if (uart_handle_sysrq_char(port, ch))
+			goto ignore_char;
+
+		uart_insert_char(port, lsr, SUP_UART_LSR_OE, ch, flag);
+
+ignore_char:
+		lsr = readl(port->membase + SUP_UART_LSR);
+	} while (lsr & SUP_UART_LSR_RX);
+
+	tty_flip_buffer_push(&port->state->port);
+}
+
+static irqreturn_t sunplus_uart_irq(int irq, void *args)
+{
+	struct uart_port *port = args;
+	unsigned int isc;
+
+	spin_lock(&port->lock);
+
+	isc = readl(port->membase + SUP_UART_ISC);
+
+	if (isc & SUP_UART_ISC_RX)
+		receive_chars(port);
+
+	if (isc & SUP_UART_ISC_TX)
+		transmit_chars(port);
+
+	spin_unlock(&port->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int sunplus_startup(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int isc = 0;
+	int ret;
+
+	ret = request_irq(port->irq, sunplus_uart_irq, 0, "sunplus_uart", port);
+	if (ret)
+		return ret;
+
+	spin_lock_irqsave(&port->lock, flags);
+	/* isc define Bit[7:4] int setting, Bit[3:0] int status
+	 * isc register will clean Bit[3:0] int status after read
+	 * only do a write to Bit[7:4] int setting
+	 */
+	isc |= SUP_UART_ISC_RXM;
+	writel(isc, port->membase + SUP_UART_ISC);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return 0;
+}
+
+static void sunplus_shutdown(struct uart_port *port)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	/* isc define Bit[7:4] int setting, Bit[3:0] int status
+	 * isc register will clean Bit[3:0] int status after read
+	 * only do a write to Bit[7:4] int setting
+	 */
+	writel(0, port->membase + SUP_UART_ISC); /* disable all interrupt */
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	free_irq(port->irq, port);
+}
+
+static void sunplus_set_termios(struct uart_port *port,
+				struct ktermios *termios,
+				struct ktermios *oldtermios)
+{
+	u32 ext, div, div_l, div_h, baud, lcr;
+	u32 clk = port->uartclk;
+	unsigned long flags;
+
+	baud = uart_get_baud_rate(port, termios, oldtermios, 0, port->uartclk / 16);
+
+	/* baud rate = uartclk / ((16 * divisor + 1) + divisor_ext) */
+	clk += baud >> 1;
+	div = clk / baud;
+	ext = div & 0x0F;
+	div = (div >> 4) - 1;
+	div_l = (div & 0xFF) | (ext << 12);
+	div_h = div >> 8;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr = UART_LCR_WLEN5;
+		break;
+	case CS6:
+		lcr = UART_LCR_WLEN6;
+		break;
+	case CS7:
+		lcr = UART_LCR_WLEN7;
+		break;
+	default:
+		lcr = UART_LCR_WLEN8;
+		break;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		lcr |= UART_LCR_STOP;
+
+	if (termios->c_cflag & PARENB) {
+		lcr |= UART_LCR_PARITY;
+
+		if (!(termios->c_cflag & PARODD))
+			lcr |= UART_LCR_EPAR;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = 0;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= SUP_UART_LSR_PE | SUP_UART_LSR_FE;
+
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SUP_UART_LSR_BC;
+
+	/* Characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= SUP_UART_LSR_FE | SUP_UART_LSR_PE;
+
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= SUP_UART_LSR_BC;
+
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= SUP_UART_LSR_OE;
+	}
+
+	/* Ignore all characters if CREAD is not set */
+	if ((termios->c_cflag & CREAD) == 0) {
+		port->ignore_status_mask |= SUP_DUMMY_READ;
+		/* flush rx data FIFO */
+		writel(0, port->membase + SUP_UART_RX_RESIDUE);
+	}
+
+	/* Settings for baud rate divisor and lcr */
+	writel(div_h, port->membase + SUP_UART_DIV_H);
+	writel(div_l, port->membase + SUP_UART_DIV_L);
+	writel(lcr, port->membase + SUP_UART_LCR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void sunplus_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+	int new = termios->c_line;
+
+	if (new == N_PPS)
+		port->flags |= UPF_HARDPPS_CD;
+	else
+		port->flags &= ~UPF_HARDPPS_CD;
+}
+
+static const char *sunplus_type(struct uart_port *port)
+{
+	return port->type == PORT_SUNPLUS ? "sunplus_uart" : NULL;
+}
+
+static void sunplus_config_port(struct uart_port *port, int type)
+{
+	if (type & UART_CONFIG_TYPE)
+		port->type = PORT_SUNPLUS;
+}
+
+static int sunplus_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	if (ser->type != PORT_UNKNOWN && ser->type != PORT_SUNPLUS)
+		return -EINVAL;
+
+	return 0;
+}
+
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+static void wait_for_xmitr(struct uart_port *port)
+{
+	unsigned int val;
+	int ret;
+
+	/* Wait while FIFO is full or timeout */
+	ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val,
+					(val & SUP_UART_LSR_TX), 1, 10000);
+
+	if (ret == -ETIMEDOUT) {
+		dev_err(port->dev, "Timeout waiting while UART TX FULL\n");
+		return;
+	}
+}
+#endif
+
+#ifdef CONFIG_CONSOLE_POLL
+static void sunplus_poll_put_char(struct uart_port *port, unsigned char data)
+{
+	wait_for_xmitr(port);
+	sp_uart_put_char(port, data);
+}
+
+static int sunplus_poll_get_char(struct uart_port *port)
+{
+	unsigned int lsr = readl(port->membase + SUP_UART_LSR);
+
+	if (!(lsr & SUP_UART_LSR_RX))
+		return NO_POLL_CHAR;
+
+	return readl(port->membase + SUP_UART_DATA);
+}
+#endif
+
+static const struct uart_ops sunplus_uart_ops = {
+	.tx_empty	= sunplus_tx_empty,
+	.set_mctrl	= sunplus_set_mctrl,
+	.get_mctrl	= sunplus_get_mctrl,
+	.stop_tx	= sunplus_stop_tx,
+	.start_tx	= sunplus_start_tx,
+	.stop_rx	= sunplus_stop_rx,
+	.break_ctl	= sunplus_break_ctl,
+	.startup	= sunplus_startup,
+	.shutdown	= sunplus_shutdown,
+	.set_termios	= sunplus_set_termios,
+	.set_ldisc	= sunplus_set_ldisc,
+	.type		= sunplus_type,
+	.config_port	= sunplus_config_port,
+	.verify_port	= sunplus_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_put_char	= sunplus_poll_put_char,
+	.poll_get_char	= sunplus_poll_get_char,
+#endif
+};
+
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+struct sunplus_uart_port *sunplus_console_ports[SUP_UART_NR];
+
+static void sunplus_uart_console_putchar(struct uart_port *port, int ch)
+{
+	wait_for_xmitr(port);
+	sp_uart_put_char(port, ch);
+}
+
+static void sunplus_console_write(struct console *co,
+				  const char *s,
+				  unsigned int count)
+{
+	unsigned long flags;
+	int locked = 1;
+
+	local_irq_save(flags);
+
+	if (sunplus_console_ports[co->index]->port.sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock(&sunplus_console_ports[co->index]->port.lock);
+	else
+		spin_lock(&sunplus_console_ports[co->index]->port.lock);
+
+	uart_console_write(&sunplus_console_ports[co->index]->port, s, count,
+			   sunplus_uart_console_putchar);
+
+	if (locked)
+		spin_unlock(&sunplus_console_ports[co->index]->port.lock);
+
+	local_irq_restore(flags);
+}
+
+static int __init sunplus_console_setup(struct console *co, char *options)
+{
+	struct sunplus_uart_port *sup;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index < 0 || co->index >= SUP_UART_NR)
+		return -EINVAL;
+
+	sup = sunplus_console_ports[co->index];
+	if (!sup)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(&sup->port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver sunplus_uart_driver;
+static struct console sunplus_uart_console = {
+	.name		= "ttySUP",
+	.write		= sunplus_console_write,
+	.device		= uart_console_device,
+	.setup		= sunplus_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &sunplus_uart_driver
+};
+#endif
+
+static struct uart_driver sunplus_uart_driver = {
+	.owner		= THIS_MODULE,
+	.driver_name	= "sunplus_uart",
+	.dev_name	= "ttySUP",
+	.major		= TTY_MAJOR,
+	.minor		= 64,
+	.nr		= SUP_UART_NR,
+	.cons		= &sunplus_uart_console,
+};
+
+static void sunplus_uart_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static void sunplus_uart_reset_control_assert(void *data)
+{
+	reset_control_assert(data);
+}
+
+static int sunplus_uart_probe(struct platform_device *pdev)
+{
+	struct sunplus_uart_port *sup;
+	struct uart_port *port;
+	struct resource *res;
+	int ret, irq;
+
+	pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+
+	if (pdev->id < 0 || pdev->id >= SUP_UART_NR)
+		return -EINVAL;
+
+	sup = devm_kzalloc(&pdev->dev, sizeof(*sup), GFP_KERNEL);
+	if (!sup)
+		return -ENOMEM;
+
+	sup->clk = devm_clk_get_optional(&pdev->dev, NULL);
+	if (IS_ERR(sup->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(sup->clk), "clk not found\n");
+
+	ret = clk_prepare_enable(sup->clk);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_disable_unprepare, sup->clk);
+	if (ret)
+		return ret;
+
+	sup->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(sup->rstc))
+		return dev_err_probe(&pdev->dev, PTR_ERR(sup->rstc), "rstc not found\n");
+
+	port = &sup->port;
+
+	port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(port->membase))
+		return dev_err_probe(&pdev->dev, PTR_ERR(port->membase), "membase not found\n");
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	port->mapbase = res->start;
+	port->uartclk = clk_get_rate(sup->clk);
+	port->line = pdev->id;
+	port->irq = irq;
+	port->dev = &pdev->dev;
+	port->iotype = UPIO_MEM;
+	port->ops = &sunplus_uart_ops;
+	port->flags = UPF_BOOT_AUTOCONF;
+	port->fifosize = 128;
+
+	ret = reset_control_deassert(sup->rstc);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&pdev->dev, sunplus_uart_reset_control_assert, sup->rstc);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+	sunplus_console_ports[sup->port.line] = sup;
+#endif
+
+	platform_set_drvdata(pdev, &sup->port);
+
+	ret = uart_add_one_port(&sunplus_uart_driver, &sup->port);
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+	if (ret)
+		sunplus_console_ports[sup->port.line] = NULL;
+#endif
+
+	return ret;
+}
+
+static int sunplus_uart_remove(struct platform_device *pdev)
+{
+	struct sunplus_uart_port *sup = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&sunplus_uart_driver, &sup->port);
+
+	return 0;
+}
+
+static int __maybe_unused sunplus_uart_suspend(struct device *dev)
+{
+	struct sunplus_uart_port *sup = dev_get_drvdata(dev);
+
+	if (!uart_console(&sup->port))
+		uart_suspend_port(&sunplus_uart_driver, &sup->port);
+
+	return 0;
+}
+
+static int __maybe_unused sunplus_uart_resume(struct device *dev)
+{
+	struct sunplus_uart_port *sup = dev_get_drvdata(dev);
+
+	if (!uart_console(&sup->port))
+		uart_resume_port(&sunplus_uart_driver, &sup->port);
+
+	return 0;
+}
+
+static const struct dev_pm_ops sunplus_uart_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sunplus_uart_suspend, sunplus_uart_resume)
+};
+
+static const struct of_device_id sp_uart_of_match[] = {
+	{ .compatible = "sunplus,sp7021-uart" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sp_uart_of_match);
+
+static struct platform_driver sunplus_uart_platform_driver = {
+	.probe		= sunplus_uart_probe,
+	.remove		= sunplus_uart_remove,
+	.driver = {
+		.name	= "sunplus_uart",
+		.of_match_table = sp_uart_of_match,
+		.pm     = &sunplus_uart_pm_ops,
+	}
+};
+
+static int __init sunplus_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&sunplus_uart_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&sunplus_uart_platform_driver);
+	if (ret)
+		uart_unregister_driver(&sunplus_uart_driver);
+
+	return ret;
+}
+module_init(sunplus_uart_init);
+
+static void __exit sunplus_uart_exit(void)
+{
+	platform_driver_unregister(&sunplus_uart_platform_driver);
+	uart_unregister_driver(&sunplus_uart_driver);
+}
+module_exit(sunplus_uart_exit);
+
+#ifdef CONFIG_SERIAL_EARLYCON
+static void sunplus_uart_putc(struct uart_port *port, int c)
+{
+	unsigned int val;
+	int ret;
+
+	ret = readl_poll_timeout_atomic(port->membase + SUP_UART_LSR, val,
+					(val & UART_LSR_TEMT), 1, 10000);
+	if (ret)
+		return;
+
+	writel(c, port->membase + SUP_UART_DATA);
+}
+
+static void sunplus_uart_early_write(struct console *con, const char *s, unsigned int n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, sunplus_uart_putc);
+}
+
+static int __init
+sunplus_uart_early_setup(struct earlycon_device *dev, const char *opt)
+{
+	if (!(dev->port.membase || dev->port.iobase))
+		return -ENODEV;
+
+	dev->con->write = sunplus_uart_early_write;
+
+	return 0;
+}
+OF_EARLYCON_DECLARE(sunplus_uart, "sunplus,sp7021-uart", sunplus_uart_early_setup);
+#endif
+
+MODULE_DESCRIPTION("Sunplus UART driver");
+MODULE_AUTHOR("Hammer Hsieh <hammerh0314@...il.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index c4042dc..2dfe443 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -274,4 +274,7 @@
 /* Freescale LINFlexD UART */
 #define PORT_LINFLEXUART	122
 
+/* Sunplus UART */
+#define PORT_SUNPLUS	123
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
2.7.4

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