diff mbox series

[v2,2/2] serial:sunplus-uart:Add Sunplus SoC UART Driver

Message ID 1636530670-6995-3-git-send-email-hammer.hsieh@sunplus.com
State New
Headers show
Series [v3,1/2] dt-bindings:serial:Add bindings doc for Sunplus SoC UART Driver | expand

Commit Message

Hammer Hsieh Nov. 10, 2021, 7:51 a.m. UTC
Add Sunplus SoC UART Driver

Signed-off-by: Hammer Hsieh <hammer.hsieh@sunplus.com>
---
Changes in v2:
 - Addressed all comments from Mr. Greg Kroah-Hartman.

 MAINTAINERS                       |    2 +
 drivers/tty/serial/Kconfig        |   23 +
 drivers/tty/serial/Makefile       |    1 +
 drivers/tty/serial/sunplus-uart.c | 1591 +++++++++++++++++++++++++++++++++++++
 include/soc/sunplus/sp_uart.h     |  147 ++++
 5 files changed, 1764 insertions(+)
 create mode 100644 drivers/tty/serial/sunplus-uart.c
 create mode 100644 include/soc/sunplus/sp_uart.h
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index f2ee40c..14790a4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17949,6 +17949,8 @@  SUNPLUS UART DRIVER
 M:	Hammer Hsieh <hammer.hsieh@sunplus.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/serial/sunplus,sp7021-uart.yaml
+F:	drivers/tty/serial/sunplus-uart.c
+F:	include/soc/sunplus/sp-uart.h
 
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 131a6a5..319f5db 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1561,6 +1561,29 @@  config SERIAL_LITEUART_CONSOLE
 	  and warnings and which allows logins in single user mode).
 	  Otherwise, say 'N'.
 
+config SERIAL_SUNPLUS
+	bool "Sunplus UART support"
+	depends on OF
+	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 ttySx.
+
+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=ttySx".
+
 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..bfc19e2
--- /dev/null
+++ b/drivers/tty/serial/sunplus-uart.c
@@ -0,0 +1,1591 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sunplus SoC UART driver
+ *
+ * Author: Hammer Hsieh <hammer.hsieh@sunplus.com>
+ * Tony Huang <tony.huang@sunplus.com>
+ * Wells Lu <wells.lu@sunplus.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/of_platform.h>
+#include <asm/irq.h>
+#include <linux/sysrq.h>
+#include <linux/serial_core.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/delay.h>
+#include <linux/hrtimer.h>
+#include <soc/sunplus/sp_uart.h>
+#include <dt-bindings/clock/sp-sp7021.h>
+
+/*
+ * UART_NR : Nunmer of UART channel, serial0, ...
+ * UART_DMARX_NR : Nunmer of UART RX DMA, serial10, ...
+ * UART_DMATX_NR : Nunmer of UART TX DMA, serial20, ...
+ *
+ */
+#define UART_NR			5
+#define UART_DMARX_NR	2
+#define UART_DMATX_NR	2
+
+/*
+ * IS_UARTDMARX_ID(X) : if true , do rxdma init in probe
+ * IS_UARTDMATX_ID(X) : if true , do txdma init in probe
+ *
+ */
+#define ID_BASE_DMARX	10
+#define ID_BASE_DMATX	20
+
+#define IS_UARTDMARX_ID(X) \
+	(((X) >= (ID_BASE_DMARX)) && ((X) < (ID_BASE_DMARX + UART_DMARX_NR)))
+#define IS_UARTDMATX_ID(X) \
+	(((X) >= (ID_BASE_DMATX)) && ((X) < (ID_BASE_DMATX + UART_DMATX_NR)))
+
+struct sunplus_uart_port {
+	char name[16];
+	struct uart_port uport;
+	struct sunplus_dma_info *uartdma_rx;
+	struct sunplus_dma_info *uartdma_tx;
+	struct clk *clk;
+	struct reset_control *rstc;
+	unsigned int pllsys_rate;
+	struct gpio_desc *rts_gpio;
+	struct hrtimer rts_check_tx_empty;
+	struct hrtimer rts_delay_before_send;
+	struct hrtimer rts_delay_after_send;
+};
+struct sunplus_uart_port sunplus_uart_ports[UART_NR];
+static struct uart_driver sunplus_uart_driver;
+
+struct sunplus_dma_info {
+	void __iomem *membase;
+	void __iomem *gdma_membase;
+	unsigned long addr_phy;
+	int irq;
+	int which_uart;
+	struct sunplus_uart_port *binding_port;
+	void *buf_va;
+	dma_addr_t dma_handle;
+};
+static struct sunplus_dma_info
+	sunplus_uartdma[UART_DMARX_NR + UART_DMATX_NR];
+
+static inline struct sunplus_uart_port *to_sunplus_uart(struct uart_port *uport)
+{
+	return container_of(uport, struct sunplus_uart_port, uport);
+}
+
+static inline void sp_uart_put_char(struct uart_port *port, unsigned int ch)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *tx_dma = sp_port->uartdma_tx;
+	u32 addr_sw, addr_start;
+	u32 offset_sw;
+	u8 *byte_ptr;
+
+	if (!tx_dma) {
+		writel(ch, port->membase + SP_UART_DATA);
+	} else {
+		addr_sw = readl(tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+		addr_start = readl(tx_dma->membase + SP_UART_TXDMA_START_ADDR);
+		offset_sw = addr_sw - addr_start;
+		byte_ptr = (u8 *)(tx_dma->buf_va + offset_sw);
+		*byte_ptr = (u8)(ch);
+		if (offset_sw == (PAGE_SIZE - 1))
+			writel((u32)(tx_dma->dma_handle),
+				tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+		else
+			writel((addr_sw + 1),
+				tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+	}
+}
+
+static inline u32 sp_uart_line_status_tx_buf_not_full(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *tx_dma = sp_port->uartdma_tx;
+	u32 addr_sw, addr_hw;
+
+	if (tx_dma) {
+		if (readl(tx_dma->membase + SP_UART_TXDMA_STATUS) & TXDMA_BUF_FULL)
+			return 0;
+
+		addr_sw = readl(tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+		addr_hw = readl(tx_dma->membase + SP_UART_TXDMA_RD_ADR);
+		if (addr_sw >= addr_hw)
+			return (PAGE_SIZE - (addr_sw - addr_hw));
+		else
+			return (addr_hw - addr_sw);
+
+	} else {
+		if (readl(port->membase + SP_UART_LSR) & SP_UART_LSR_TX)
+			return 1;
+		else
+			return 0;
+	}
+}
+
+/*
+ * Note:
+ * When (uart0_as_console == 0), please make sure:
+ *     There is no "console=ttyS0,115200", "earlyprintk", ... in kernel command line.
+ *     In /etc/inittab, there is no something like "ttyS0::respawn:/bin/sh"
+ */
+unsigned int uart0_as_console = ~0;
+unsigned int uart_enable_status = ~0;
+
+static struct sunplus_dma_info *sunplus_uartdma_rx_binding(int id)
+{
+	int i;
+
+	for (i = 0; i < UART_DMARX_NR; i++) {
+		if ((sunplus_uartdma[i].which_uart == id) && (sunplus_uartdma[i].membase)) {
+			sunplus_uartdma[i].binding_port = &sunplus_uart_ports[id];
+			return &sunplus_uartdma[i];
+		}
+	}
+	return NULL;
+}
+
+static struct sunplus_dma_info *sunplus_uartdma_tx_binding(int id)
+{
+	int i;
+
+	for (i = UART_DMARX_NR; i < (UART_DMARX_NR + UART_DMATX_NR); i++) {
+		if ((sunplus_uartdma[i].which_uart == id) && (sunplus_uartdma[i].membase)) {
+			sunplus_uartdma[i].binding_port = &sunplus_uart_ports[id];
+			return &sunplus_uartdma[i];
+		}
+	}
+	return NULL;
+}
+
+static inline void wait_for_xmitr(struct uart_port *port)
+{
+	while (1) {
+		if (sp_uart_line_status_tx_buf_not_full(port))
+			break;
+	}
+}
+
+static unsigned int sunplus_tx_empty(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *tx_dma = sp_port->uartdma_tx;
+
+	if (tx_dma) {
+		if (readl(tx_dma->membase + SP_UART_TXDMA_STATUS) & TXDMA_BUF_EMPTY)
+			return TIOCSER_TEMT;
+		else
+			return 0;
+	} else {
+		return ((readl(port->membase + SP_UART_LSR) & SP_UART_LSR_TXE)
+			? TIOCSER_TEMT : 0);
+	}
+}
+
+static void sunplus_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	unsigned int mcr = readl(port->membase + SP_UART_MCR);
+	ktime_t ktime;
+
+	if (mctrl & TIOCM_DTR)
+		mcr |= SP_UART_MCR_DTS;
+	else
+		mcr &= ~SP_UART_MCR_DTS;
+
+	if (mctrl & TIOCM_RTS) {
+		if ((sp_port->uport.rs485.flags & SER_RS485_ENABLED)
+			&& (sp_port->uport.rs485.flags & SER_RS485_RTS_ON_SEND))
+			mcr &= ~SP_UART_MCR_RTS;  /* RTS invert */
+		else
+			mcr |= SP_UART_MCR_RTS;
+	} else {
+		/* data transfer ended */
+		if (sp_port->uport.rs485.flags & SER_RS485_ENABLED)
+			return;
+
+		mcr &= ~SP_UART_MCR_RTS;
+	}
+
+	if (mctrl & TIOCM_CAR)
+		mcr |= SP_UART_MCR_DCD;
+	else
+		mcr &= ~SP_UART_MCR_DCD;
+
+	if (mctrl & TIOCM_RI)
+		mcr |= SP_UART_MCR_RI;
+	else
+		mcr &= ~SP_UART_MCR_RI;
+
+	if (mctrl & TIOCM_LOOP)
+		mcr |= SP_UART_MCR_LB;
+	else
+		mcr &= ~SP_UART_MCR_LB;
+
+	writel(mcr, port->membase + SP_UART_MCR);
+
+	if (sp_port->uport.rs485.flags & SER_RS485_ENABLED) {
+		mcr = readl(port->membase + SP_UART_MCR);
+		if (mctrl & TIOCM_RTS) {
+			if (((mcr & SP_UART_MCR_RTS)
+				&& (sp_port->uport.rs485.flags & SER_RS485_RTS_AFTER_SEND))
+				|| (sp_port->uport.rs485.flags & SER_RS485_RTS_ON_SEND)) {
+				if (!IS_ERR(sp_port->rts_gpio))
+					gpiod_set_value(sp_port->rts_gpio, 1);
+				dev_dbg(port->dev, "%s set rts_gpio=1\n", port->name);
+				if (sp_port->uport.rs485.delay_rts_before_send == 0) {
+					ktime = ktime_set(0, 500000); /* 500us */
+					hrtimer_start(&sp_port->rts_check_tx_empty,
+						ktime, HRTIMER_MODE_REL);
+				}
+			}
+		}
+	}
+}
+
+static unsigned int sunplus_get_mctrl(struct uart_port *port)
+{
+	unsigned int ret, mcr;
+
+	mcr = readl(port->membase + SP_UART_MCR);
+
+	if (mcr & SP_UART_MCR_DTS)
+		ret |= TIOCM_DTR;
+
+	if (mcr & SP_UART_MCR_RTS)
+		ret |= TIOCM_RTS;
+
+	if (mcr & SP_UART_MCR_DCD)
+		ret |= TIOCM_CAR;
+
+	if (mcr & SP_UART_MCR_RI)
+		ret |= TIOCM_RI;
+
+	if (mcr & SP_UART_MCR_LB)
+		ret |= TIOCM_LOOP;
+
+	if (mcr & SP_UART_MCR_AC)
+		ret |= TIOCM_CTS;
+
+	return ret;
+}
+
+static void sunplus_stop_tx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SP_UART_ISC);
+	isc &= ~SP_UART_ISC_TXM;
+	writel(isc, port->membase + SP_UART_ISC);
+}
+
+static inline void __start_tx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SP_UART_ISC);
+	isc |= SP_UART_ISC_TXM;
+	writel(isc, port->membase + SP_UART_ISC);
+}
+
+static void sunplus_start_tx(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	ktime_t ktime;
+	int val;
+
+	if (sp_port->uport.rs485.flags & SER_RS485_ENABLED) {
+		val = (sp_port->uport.rs485.flags & SER_RS485_RTS_ON_SEND ? 1 : 0);
+		if (!IS_ERR(sp_port->rts_gpio))
+			gpiod_set_value(sp_port->rts_gpio, val);
+
+		dev_dbg(port->dev, "%s set rts_gpio=%d\n", sp_port->uport.name, val);
+		if (sp_port->uport.rs485.delay_rts_before_send > 0) {
+			long nsec = sp_port->uport.rs485.delay_rts_before_send * 1000000;
+
+			ktime = ktime_set(0, nsec);
+			hrtimer_start(&sp_port->rts_delay_before_send, ktime, HRTIMER_MODE_REL);
+			return;
+		}
+	}
+	__start_tx(port);
+}
+
+static void sunplus_stop_rx(struct uart_port *port)
+{
+	unsigned int isc;
+
+	isc = readl(port->membase + SP_UART_ISC);
+	isc &= ~SP_UART_ISC_RXM;
+	writel(isc, port->membase + SP_UART_ISC);
+}
+
+static void sunplus_enable_ms(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+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 + SP_UART_LCR);
+
+	if (ctl != 0)
+		lcr |= SP_UART_LCR_BC;	/* start break */
+	else
+		lcr &= ~SP_UART_LCR_BC;	/* stop break */
+
+	writel(lcr, port->membase + SP_UART_LCR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void transmit_chars(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *tx_dma = sp_port->uartdma_tx;
+	u32 tx_buf_available;
+	u32 addr_sw, addr_start;
+	u32 offset_sw;
+	u8 *byte_ptr;
+	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;
+	}
+
+	if (tx_dma) {
+		addr_sw = readl(tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+		addr_start = readl(tx_dma->membase + SP_UART_TXDMA_START_ADDR);
+		offset_sw = addr_sw - addr_start;
+		byte_ptr = (u8 *)(tx_dma->buf_va + offset_sw);
+		tx_buf_available = sp_uart_line_status_tx_buf_not_full(port);
+		while (tx_buf_available) {
+			*byte_ptr = xmit->buf[xmit->tail];
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+			port->icount.tx++;
+
+			byte_ptr++;
+			addr_sw++;
+			offset_sw++;
+			tx_buf_available--;
+			if (offset_sw == PAGE_SIZE) {
+				offset_sw = 0;
+				addr_sw = (u32)(tx_dma->dma_handle);
+				byte_ptr = (u8 *)(tx_dma->buf_va);
+			}
+
+			if (uart_circ_empty(xmit))
+				break;
+		}
+		writel(addr_sw, tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+	} else {
+		do {
+			sp_uart_put_char(port, xmit->buf[xmit->tail]);
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+			port->icount.tx++;
+
+			if (uart_circ_empty(xmit))
+				break;
+		} while (sp_uart_line_status_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);
+}
+
+/* called by ISR */
+static void receive_chars(struct uart_port *port)
+{
+	struct tty_struct *tty = port->state->port.tty;
+	unsigned int lsr = readl(port->membase + SP_UART_LSR);
+	unsigned int ch, flag;
+
+	do {
+		ch = readl(port->membase + SP_UART_DATA);
+
+		flag = TTY_NORMAL;
+		port->icount.rx++;
+
+		if (unlikely(lsr & SP_UART_LSR_BRK_ERROR_BITS)) {
+			if (port->cons == NULL)
+				dev_err(port->dev, "UART%d, SP_UART_LSR_BRK_ERROR_BITS, lsr = 0x%08X\n",
+					port->line, lsr);
+
+			if (lsr & SP_UART_LSR_BC) {
+				lsr &= ~(SP_UART_LSR_FE | SP_UART_LSR_PE);
+				port->icount.brk++;
+				if (uart_handle_break(port))
+					goto ignore_char;
+			} else if (lsr & SP_UART_LSR_PE) {
+				if (port->cons == NULL)
+					dev_err(port->dev, "UART%d, SP_UART_LSR_PE\n", port->line);
+				port->icount.parity++;
+			} else if (lsr & SP_UART_LSR_FE) {
+				if (port->cons == NULL)
+					dev_err(port->dev, "UART%d, SP_UART_LSR_FE\n", port->line);
+				port->icount.frame++;
+			}
+			if (lsr & SP_UART_LSR_OE) {
+				if (port->cons == NULL)
+					dev_err(port->dev, "UART%d, SP_UART_LSR_OE\n", port->line);
+				port->icount.overrun++;
+			}
+
+			/*
+			 * Mask off conditions which should be ignored.
+			 */
+
+			/* lsr &= port->read_status_mask; */
+
+			if (lsr & SP_UART_LSR_BC)
+				flag = TTY_BREAK;
+			else if (lsr & SP_UART_LSR_PE)
+				flag = TTY_PARITY;
+			else if (lsr & SP_UART_LSR_FE)
+				flag = TTY_FRAME;
+		}
+
+		if (port->ignore_status_mask & SP_UART_CREAD_DISABLED)
+			goto ignore_char;
+
+		if (uart_handle_sysrq_char(port, ch))
+			goto ignore_char;
+
+		uart_insert_char(port, lsr, SP_UART_LSR_OE, ch, flag);
+
+ignore_char:
+		lsr = readl(port->membase + SP_UART_LSR);
+	} while (lsr & SP_UART_LSR_RX);
+
+	if (tty) {
+		spin_unlock(&port->lock);
+		tty_flip_buffer_push(tty->port);
+		spin_lock(&port->lock);
+	}
+}
+
+static irqreturn_t sunplus_uart_irq(int irq, void *args)
+{
+	struct uart_port *port = (struct uart_port *)args;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	if (readl(port->membase + SP_UART_ISC) & SP_UART_ISC_RX)
+		receive_chars(port);
+
+	if (readl(port->membase + SP_UART_ISC) & SP_UART_ISC_TX)
+		transmit_chars(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+/* called by ISR */
+static void receive_chars_rxdma(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *rx_dma = sp_port->uartdma_rx;
+	struct tty_struct *tty = port->state->port.tty;
+	u32 offset_sw, offset_hw, rx_size, dma_start;
+	u8 *sw_ptr, *buf_end_ptr, *u8_ptr;
+	u32 icount_rx;
+	u32 tmp_u32, value;
+	u8 tmp_buf[32];
+	int i;
+
+	dma_start = readl(rx_dma->membase + SP_UART_RXDMA_START_ADDR);
+	offset_sw = readl(rx_dma->membase + SP_UART_RXDMA_RD_ADR) - dma_start;
+	offset_hw = readl(rx_dma->membase + SP_UART_RXDMA_WR_ADR) - dma_start;
+
+	if (offset_hw >= offset_sw)
+		rx_size = offset_hw - offset_sw;
+	else
+		rx_size = offset_hw + PAGE_SIZE - offset_sw;
+
+	sw_ptr = (u8 *)(rx_dma->buf_va + offset_sw);
+	buf_end_ptr = (u8 *)(rx_dma->buf_va + PAGE_SIZE);
+
+	/*
+	 * Retrieve all data in ISR.
+	 * The max. received size is (buffer_size - threshold_size)
+	 * = (rxdma_length_thr[31:16] - rxdma_length_thr[15:0])
+	 * In order to limit the execution time in this ISR:
+	 * => Increase rxdma_length_thr[15:0] to shorten each ISR execution time.
+	 * => Don't need to set a small threshold_size,
+	 *    and split a long ISR into several shorter ISRs.
+	 */
+	icount_rx = 0;
+	while (rx_size > icount_rx) {
+		/* 32-byte aligned */
+		if (!(((unsigned long)(sw_ptr)) & (32 - 1))
+		    && ((rx_size - icount_rx) >= 32)) {
+			/*
+			 * Copy 32 bytes data from non cache area to cache area.
+			 * => It should use less DRAM controller's read command.
+			 */
+			memcpy(tmp_buf, sw_ptr, 32);
+			u8_ptr = (u8 *)(tmp_buf);
+			for (i = 0; i < 32; i++) {
+				port->icount.rx++;
+				uart_insert_char(port, 0, SP_UART_LSR_OE,
+					(unsigned int)(*u8_ptr), TTY_NORMAL);
+				u8_ptr++;
+			}
+			sw_ptr += 32;
+			icount_rx += 32;
+		} else {
+			port->icount.rx++;
+			uart_insert_char(port, 0, SP_UART_LSR_OE,
+				(unsigned int)(*sw_ptr), TTY_NORMAL);
+			sw_ptr++;
+			icount_rx++;
+		}
+		if (sw_ptr >= buf_end_ptr)
+			sw_ptr = (u8 *)(rx_dma->buf_va);
+	}
+
+	tmp_u32 = readl(rx_dma->membase + SP_UART_RXDMA_RD_ADR) + rx_size;
+
+	if (tmp_u32 <= readl(rx_dma->membase + SP_UART_RXDMA_END_ADDR))
+		writel(tmp_u32, rx_dma->membase + SP_UART_RXDMA_RD_ADR);
+	else
+		writel((tmp_u32 - PAGE_SIZE), rx_dma->membase + SP_UART_RXDMA_RD_ADR);
+
+	spin_unlock(&port->lock);
+	tty_flip_buffer_push(tty->port);
+	spin_lock(&port->lock);
+
+	value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+	value |= DMA_INT;
+	writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+
+	value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+	value |= DMA_GO;
+	writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+
+}
+
+static irqreturn_t sunplus_uart_rxdma_irq(int irq, void *args)
+{
+	struct uart_port *port = (struct uart_port *)args;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	receive_chars_rxdma(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static int sunplus_startup(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *rx_dma, *tx_dma;
+	u32 timeout, interrupt_en;
+	unsigned int ch, value;
+	int ret;
+
+	if (sp_port->uport.rs485.flags & SER_RS485_ENABLED)
+		hrtimer_cancel(&sp_port->rts_delay_after_send);
+
+#ifdef CONFIG_PM_RUNTIME_UART
+	if (port->line > 0) {
+		ret = pm_runtime_get_sync(port->dev);
+		if (ret < 0)
+			goto out;
+	}
+#endif
+
+	ret = request_irq(port->irq, sunplus_uart_irq, 0, sp_port->name, port);
+	if (ret)
+		return ret;
+
+	rx_dma = sp_port->uartdma_rx;
+
+	if (rx_dma) {
+		if (rx_dma->buf_va == NULL) {
+			/* Drop data in Rx FIFO (PIO mode) */
+			while (readl(port->membase + SP_UART_LSR) & SP_UART_LSR_RX)
+				ch = readl(port->membase + SP_UART_DATA);
+
+			rx_dma->buf_va =
+				dma_alloc_coherent(port->dev, PAGE_SIZE,
+				&(rx_dma->dma_handle), GFP_KERNEL);
+			if (rx_dma->buf_va == NULL) {
+				dev_err(port->dev, "Can't allocation buffer for %s\n",
+					sp_port->name);
+				ret = -ENOMEM;
+				goto error_01;
+			}
+
+			writel((u32)(rx_dma->dma_handle),
+				rx_dma->membase + SP_UART_RXDMA_START_ADDR);
+			writel((u32)(rx_dma->dma_handle),
+				rx_dma->membase + SP_UART_RXDMA_RD_ADR);
+
+			/* Switch clock source when setting baud rate */
+			timeout = (sp_port->pllsys_rate / 2) / 1000;	/* 1 msec */
+			writel(timeout, rx_dma->membase + SP_UART_RXDMA_TIMEOUT_SET);
+
+			/*
+			 * When there are only rxdma_length_thr[15:0] bytes
+			 * of free buffer => Trigger interrupt
+			 */
+			writel((PAGE_SIZE << 16) | (PAGE_SIZE - (PAGE_SIZE >> 3)),
+			    rx_dma->membase + SP_UART_RXDMA_LENGTH_THR);
+
+			value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+			value &= ~DMA_SEL_UARTX_MASK;
+			value |= (DMA_INIT | (rx_dma->which_uart << DMA_SEL_UARTX_SHIFT));
+			writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+
+			value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+			value &= ~DMA_INIT;
+			writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+
+			value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+			value |= (DMA_SW_RST_B | DMA_AUTO_ENABLE | DMA_TIMEOUT_INT_EN | DMA_ENABLE);
+			writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+
+			value = readl(rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+			value |= DMA_GO;
+			writel(value, rx_dma->membase + SP_UART_RXDMA_ENABLE_SEL);
+		}
+
+		ret = request_irq(rx_dma->irq, sunplus_uart_rxdma_irq, 0, "UARTDMA_RX", port);
+		if (ret) {
+			dma_free_coherent(port->dev, PAGE_SIZE,
+				rx_dma->buf_va, rx_dma->dma_handle);
+			goto error_00;
+		}
+	}
+
+	tx_dma = sp_port->uartdma_tx;
+	if (tx_dma) {
+		if (tx_dma->buf_va == NULL) {
+			tx_dma->buf_va =
+				dma_alloc_coherent(port->dev, PAGE_SIZE,
+				&(tx_dma->dma_handle), GFP_KERNEL);
+			if (tx_dma->buf_va == NULL) {
+				dev_err(port->dev, "Can't allocation buffer for %s\n",
+					sp_port->name);
+				ret = -ENOMEM;
+				goto error_01;
+			}
+
+			/*
+			 * set 1ms , set wr_adr , set start_addr/end_addr ,
+			 * set bind to uart# , set int enable ,
+			 * set txdma enable (Use ring buffer for UART's Tx)
+			 */
+			writel((sp_port->pllsys_rate / 1000),
+				tx_dma->membase + SP_UART_TXDMA_TMR_UNIT);
+			writel((u32)(tx_dma->dma_handle), tx_dma->membase + SP_UART_TXDMA_WR_ADR);
+			writel((u32)(tx_dma->dma_handle),
+				tx_dma->membase + SP_UART_TXDMA_START_ADDR);
+			writel(((u32)(tx_dma->dma_handle) + PAGE_SIZE - 1),
+				tx_dma->membase + SP_UART_TXDMA_END_ADDR);
+			writel(tx_dma->which_uart, tx_dma->membase + SP_UART_TXDMA_SEL);
+			writel(0x41, tx_dma->gdma_membase + SP_UART_TXGDMA_INT_EN);
+			writel(0x00000005, tx_dma->membase + SP_UART_TXDMA_ENABLE);
+		}
+	}
+
+	/*
+	 * don't need to use spin_lock_irqsave() because interrupts
+	 * are globally disabled
+	 */
+	spin_lock_irq(&port->lock);
+
+	/* SP_UART_ISC_TXM is enabled in .start_tx() */
+	interrupt_en = 0;
+	if (rx_dma == NULL)
+		interrupt_en |= SP_UART_ISC_RXM;
+
+	writel(interrupt_en, port->membase + SP_UART_ISC);
+
+	spin_unlock_irq(&port->lock);
+
+#ifdef CONFIG_PM_RUNTIME_UART
+	if (port->line > 0)
+		pm_runtime_put(port->dev);
+
+	return 0;
+
+out:
+	if (port->line > 0) {
+		pm_runtime_mark_last_busy(port->dev);
+		pm_runtime_put_autosuspend(port->dev);
+	}
+#endif
+	return 0;
+
+error_01:
+	if (rx_dma) {
+		dma_free_coherent(port->dev, PAGE_SIZE,
+			rx_dma->buf_va, rx_dma->dma_handle);
+		free_irq(rx_dma->irq, port);
+	}
+error_00:
+	free_irq(port->irq, port);
+	return ret;
+}
+
+static void sunplus_shutdown(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	struct sunplus_dma_info *rx_dma;
+	unsigned int mcr, value;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	writel(0, port->membase + SP_UART_ISC);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	free_irq(port->irq, port);
+
+	rx_dma = sp_port->uartdma_rx;
+	if (rx_dma) {
+		/* Drop whatever is still in buffer */
+		value = readl(rx_dma->membase + SP_UART_RXDMA_WR_ADR);
+		writel(value, rx_dma->membase + SP_UART_RXDMA_RD_ADR);
+
+		free_irq(rx_dma->irq, port);
+	}
+
+	/* Disable flow control of Tx, so that queued data can be sent out
+	 * There is no way for s/w to let h/w abort in the middle of
+	 * transaction.
+	 * Don't reset module except it's in idle state. Otherwise, it might
+	 * cause bus to hang.
+	 */
+	mcr = readl(port->membase + SP_UART_MCR);
+	mcr &= ~SP_UART_MCR_AC;
+	writel(mcr, port->membase + SP_UART_MCR);
+
+}
+
+static void sunplus_set_termios(struct uart_port *port,
+	struct ktermios *termios, struct ktermios *oldtermios)
+{
+	u32 clk, ext, div, div_l, div_h, baud;
+	u32 lcr, mcr;
+	unsigned long flags;
+
+	clk = port->uartclk;
+
+	baud = uart_get_baud_rate(port, termios, oldtermios, 0, port->uartclk / 16);
+
+	/*
+	 * Send all data in Tx FIFO before changing clock source,
+	 * it should be UART0 only
+	 */
+	while (!(readl(port->membase + SP_UART_LSR) & SP_UART_LSR_TXE))
+		;
+
+	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 = SP_UART_LCR_WL5;
+		break;
+	case CS6:
+		lcr = SP_UART_LCR_WL6;
+		break;
+	case CS7:
+		lcr = SP_UART_LCR_WL7;
+		break;
+	default:	/* CS8 */
+		lcr = SP_UART_LCR_WL8;
+		break;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		lcr |= SP_UART_LCR_ST;
+
+	if (termios->c_cflag & PARENB) {
+		lcr |= SP_UART_LCR_PE;
+
+		if (!(termios->c_cflag & PARODD))
+			lcr |= SP_UART_LCR_PR;
+	}
+
+	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 |= SP_UART_LSR_PE | SP_UART_LSR_FE;
+
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SP_UART_LSR_BC;
+
+	/*
+	 * Characters to ignore
+	 */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= SP_UART_LSR_FE | SP_UART_LSR_PE;
+
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= SP_UART_LSR_BC;
+
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= SP_UART_LSR_OE;
+	}
+
+	/*
+	 * Ignore all characters if CREAD is not set.
+	 */
+	if ((termios->c_cflag & CREAD) == 0) {
+		port->ignore_status_mask |= SP_UART_CREAD_DISABLED;
+		/* flush rx data FIFO */
+		writel(0, port->membase + SP_UART_RX_RESIDUE);
+	}
+
+	mcr = readl(port->membase + SP_UART_MCR);
+
+	if (termios->c_cflag & CRTSCTS)
+		mcr |= (SP_UART_MCR_AC | SP_UART_MCR_AR);
+	else
+		mcr &= ~(SP_UART_MCR_AC | SP_UART_MCR_AR);
+
+	writel(mcr, port->membase + SP_UART_MCR);
+
+	/* do not set these in emulation */
+	writel(div_h, port->membase + SP_UART_DIV_H);
+	writel(div_l, port->membase + SP_UART_DIV_L);
+	writel(lcr, port->membase + SP_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;
+		sunplus_enable_ms(port);
+	} else {
+		port->flags &= ~UPF_HARDPPS_CD;
+	}
+}
+
+static const char *sunplus_type(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+
+	return sp_port->name;
+}
+
+static void sunplus_release_port(struct uart_port *port)
+{
+}
+
+static int sunplus_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+static void sunplus_config_port(struct uart_port *port, int type)
+{
+	if (type & UART_CONFIG_TYPE) {
+		port->type = PORT_SUNPLUS;
+		sunplus_request_port(port);
+	}
+}
+
+static int sunplus_verify_port(struct uart_port *port, struct serial_struct *serial)
+{
+	return -EINVAL;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int sunplus_poll_init(struct uart_port *port)
+{
+	return 0;
+}
+
+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;
+
+	do {
+		lsr = readl(port->membase + SP_UART_LSR);
+	} while (!(lsr & SP_UART_LSR_RX));
+
+	return readl(port->membase + SP_UART_DATA);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
+static enum hrtimer_restart sp_rts_check_tx_empty(struct hrtimer *t)
+{
+	struct sunplus_uart_port *sp_port;
+	unsigned int mcr, lsr;
+	unsigned char val;
+	ktime_t ktime;
+	unsigned long nsec;
+
+	sp_port = container_of(t, struct sunplus_uart_port, rts_check_tx_empty);
+	mcr = readl(sp_port->uport.membase + SP_UART_MCR);
+	lsr = readl(sp_port->uport.membase + SP_UART_LSR);
+	// TX is NOT empty
+	if (!(lsr & SP_UART_LSR_TXE))
+		return HRTIMER_RESTART;
+	// TX is empty
+	nsec = sp_port->uport.rs485.delay_rts_after_send * 1000000;
+	// schedule RTS set
+	if (nsec > 0) {
+		ktime = ktime_set(0, nsec);
+		hrtimer_start(&sp_port->rts_delay_after_send, ktime, HRTIMER_MODE_REL);
+		return HRTIMER_NORESTART;
+	}
+	// immediately set RTS
+	val = (sp_port->uport.rs485.flags & SER_RS485_RTS_AFTER_SEND ? 1 : 0);
+	if (sp_port->uport.rs485.flags & SER_RS485_RTS_ON_SEND)
+		mcr |= SP_UART_MCR_RTS;
+	else
+		mcr &= ~SP_UART_MCR_RTS;
+	if (sp_port->uport.rs485.flags & SER_RS485_ENABLED && !IS_ERR(sp_port->rts_gpio)) {
+		gpiod_set_value(sp_port->rts_gpio, val);
+		dev_dbg(sp_port->uport.dev, "%s set rts_gpio=%d\n",
+			sp_port->uport.name, val);
+	} else
+		writel(mcr, sp_port->uport.membase + SP_UART_MCR);
+
+	return HRTIMER_NORESTART;
+}
+
+static enum hrtimer_restart sp_rts_delay_before_send(struct hrtimer *t)
+{
+	struct sunplus_uart_port *sp_port;
+	ktime_t ktime;
+
+	sp_port = container_of(t, struct sunplus_uart_port, rts_delay_before_send);
+	ktime = ktime_set(0, 500000); //500us
+	hrtimer_start(&sp_port->rts_check_tx_empty, ktime, HRTIMER_MODE_REL);
+	__start_tx(&sp_port->uport);
+	return HRTIMER_NORESTART;
+}
+
+static enum hrtimer_restart sp_rts_delay_after_send(struct hrtimer *t)
+{
+	struct sunplus_uart_port *sp_port;
+	unsigned char val;
+	unsigned int mcr;
+
+	sp_port = container_of(t, struct sunplus_uart_port, rts_delay_after_send);
+	mcr = readl(sp_port->uport.membase + SP_UART_MCR);
+
+	val = (sp_port->uport.rs485.flags & SER_RS485_RTS_AFTER_SEND ? 1 : 0);
+	if (sp_port->uport.rs485.flags & SER_RS485_RTS_ON_SEND)
+		mcr |= SP_UART_MCR_RTS;
+	else
+		mcr &= ~SP_UART_MCR_RTS;
+	if (sp_port->uport.rs485.flags & SER_RS485_ENABLED && !IS_ERR(sp_port->rts_gpio)) {
+		gpiod_set_value(sp_port->rts_gpio, val);
+		dev_dbg(sp_port->uport.dev, "%s set rts_gpio=%d\n",
+			sp_port->uport.name, val);
+	} else
+		writel(mcr, sp_port->uport.membase + SP_UART_MCR);
+
+	return HRTIMER_NORESTART;
+}
+
+static int sunplus_uart_rs485_on(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+
+	if (IS_ERR(sp_port->rts_gpio)) {
+		dev_err(port->dev, "%s No valid rts_gpio, disabling 485\n",
+			port->name);
+		port->rs485.flags &= ~SER_RS485_ENABLED;
+		return (-EINVAL);
+	}
+
+	if (!sp_port->rts_check_tx_empty.function) {
+		hrtimer_init(&(sp_port->rts_check_tx_empty), CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		sp_port->rts_check_tx_empty.function = sp_rts_check_tx_empty;
+	}
+	if (!sp_port->rts_delay_before_send.function) {
+		hrtimer_init(&(sp_port->rts_delay_before_send), CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		sp_port->rts_delay_before_send.function = sp_rts_delay_before_send;
+	}
+	if (!sp_port->rts_delay_after_send.function) {
+		hrtimer_init(&(sp_port->rts_delay_after_send), CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		sp_port->rts_delay_after_send.function = sp_rts_delay_after_send;
+	}
+	return (0);
+}
+
+static int sunplus_uart_rs485_off(struct uart_port *port)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+
+	port->rs485.flags &= ~SER_RS485_ENABLED;
+	if (sp_port->rts_check_tx_empty.function) {
+		hrtimer_cancel(&sp_port->rts_check_tx_empty);
+		sp_port->rts_check_tx_empty.function = NULL;
+	}
+	if (sp_port->rts_delay_before_send.function) {
+		hrtimer_cancel(&sp_port->rts_delay_before_send);
+		sp_port->rts_delay_before_send.function = NULL;
+	}
+	if (sp_port->rts_delay_after_send.function) {
+		hrtimer_cancel(&sp_port->rts_delay_after_send);
+		sp_port->rts_delay_after_send.function = NULL;
+	}
+	return (0);
+}
+
+static int sunplus_uart_config_rs485(struct uart_port *port,
+	struct serial_rs485 *rs485)
+{
+	struct sunplus_uart_port *sp_port = to_sunplus_uart(port);
+	int val;
+
+	if (IS_ERR(sp_port->rts_gpio)) {
+		dev_err(port->dev, "%s No valid rts_gpio - skipping rs485\n",
+			port->name);
+		port->rs485.flags &= ~SER_RS485_ENABLED;
+		return (-EINVAL);
+	}
+
+#ifdef CONFIG_PM_RUNTIME_UART
+	pm_runtime_get_sync(sp_port->dev);
+#endif
+
+	rs485->delay_rts_before_send =
+		min(rs485->delay_rts_before_send, 10000U);
+	rs485->delay_rts_after_send  =
+		min(rs485->delay_rts_after_send, 10000U);
+
+	if (rs485->flags & SER_RS485_ENABLED) {
+		sunplus_uart_rs485_on(port);
+		val = (rs485->flags & SER_RS485_RTS_AFTER_SEND ? 1 : 0);
+		gpiod_set_value(sp_port->rts_gpio, val);
+	} else
+		sunplus_uart_rs485_off(port);
+
+	port->rs485 = *rs485;
+
+#ifdef CONFIG_PM_RUNTIME_UART
+	pm_runtime_mark_last_busy(sp_port->dev);
+	pm_runtime_put_autosuspend(sp_port->dev);
+#endif
+	return (0);
+}
+
+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,
+	.enable_ms		= sunplus_enable_ms,
+	.break_ctl		= sunplus_break_ctl,
+	.startup		= sunplus_startup,
+	.shutdown		= sunplus_shutdown,
+	.set_termios	= sunplus_set_termios,
+	.set_ldisc		= sunplus_set_ldisc,
+	.type			= sunplus_type,
+	.release_port	= sunplus_release_port,
+	.request_port	= sunplus_request_port,
+	.config_port	= sunplus_config_port,
+	.verify_port	= sunplus_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_init		= sunplus_poll_init,
+	.poll_put_char	= sunplus_poll_put_char,
+	.poll_get_char	= sunplus_poll_get_char,
+#endif /* CONFIG_CONSOLE_POLL */
+};
+
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+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_uart_ports[co->index].uport.sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock(&sunplus_uart_ports[co->index].uport.lock);
+	else
+		spin_lock(&sunplus_uart_ports[co->index].uport.lock);
+
+	uart_console_write(&sunplus_uart_ports[co->index].uport,
+		s, count, sunplus_uart_console_putchar);
+
+	if (locked)
+		spin_unlock(&sunplus_uart_ports[co->index].uport.lock);
+
+	local_irq_restore(flags);
+}
+
+static int __init sunplus_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) || (co->index < 0))
+		return -EINVAL;
+
+	port = &sunplus_uart_ports[co->index].uport;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct console sunplus_console = {
+	.name		= "ttyS",
+	.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	= "ttyS",
+	.major		= TTY_MAJOR,
+	.minor		= 64,
+	.nr			= UART_NR,
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+	.cons		= &sunplus_console
+#endif
+};
+
+static int sunplus_uart_probe(struct platform_device *pdev)
+{
+	struct resource *res_mem;
+	struct uart_port *port;
+	struct clk *clk, *pllsys;
+	unsigned int pllsys_rate;
+	int ret, irq;
+	int idx_offset, idx;
+	int idx_which_uart;
+	char peri_name[16];
+
+	if (pdev->dev.of_node) {
+		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+		if (pdev->id < 0)
+			pdev->id = of_alias_get_id(pdev->dev.of_node, "uart");
+	}
+
+	idx_offset = -1;
+
+	if (IS_UARTDMARX_ID(pdev->id))
+		idx_offset = 0;
+	else if (IS_UARTDMATX_ID(pdev->id))
+		idx_offset = UART_DMARX_NR;
+
+	/* init txdma or rxdma */
+	if (idx_offset >= 0) {
+		clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+
+		ret = clk_prepare_enable(clk);
+		if (ret)
+			return ret;
+
+		if (idx_offset == 0)
+			idx = idx_offset + pdev->id - ID_BASE_DMARX;
+		else
+			idx = idx_offset + pdev->id - ID_BASE_DMATX;
+
+		res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res_mem)
+			return -ENODEV;
+
+		sprintf(peri_name, "PERI%d", (idx & 0x01));
+
+		clk = devm_clk_get(&pdev->dev, peri_name);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+
+		ret = clk_prepare_enable(clk);
+		if (ret)
+			return ret;
+
+		sunplus_uartdma[idx].addr_phy =
+			(unsigned long)(res_mem->start);
+		sunplus_uartdma[idx].membase =
+			devm_ioremap_resource(&pdev->dev, res_mem);
+
+		if (IS_ERR(sunplus_uartdma[idx].membase))
+			return PTR_ERR(sunplus_uartdma[idx].membase);
+
+		if (IS_UARTDMARX_ID(pdev->id)) {
+			irq = platform_get_irq(pdev, 0);
+			if (irq < 0)
+				return -ENODEV;
+
+			sunplus_uartdma[idx].irq = irq;
+		} else {
+			res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+			if (!res_mem)
+				return -ENODEV;
+
+			sunplus_uartdma[idx].gdma_membase =
+				devm_ioremap_resource(&pdev->dev, res_mem);
+
+			if (IS_ERR(sunplus_uartdma[idx].gdma_membase))
+				return -EINVAL;
+		}
+
+		if (of_property_read_u32(pdev->dev.of_node, "which-uart", &idx_which_uart) != 0) {
+			dev_err(&pdev->dev, "\"which-uart\" is not assigned.");
+			return -EINVAL;
+		}
+
+		if (idx_which_uart >= UART_NR) {
+			dev_err(&pdev->dev, "\"which-uart\" is not valid.");
+			return -EINVAL;
+		}
+
+		sunplus_uartdma[idx].which_uart = idx_which_uart;
+
+		return 0;
+	} else if (pdev->id < 0 || pdev->id >= UART_NR)
+		return -EINVAL;
+
+	/* init uart */
+	port = &sunplus_uart_ports[pdev->id].uport;
+	if (port->membase)
+		return -EBUSY;
+
+	memset(port, 0, sizeof(*port));
+
+	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res_mem)
+		return -ENODEV;
+
+	port->dev = &pdev->dev;
+	port->mapbase = res_mem->start;
+
+	port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
+	if (IS_ERR(port->membase))
+		return PTR_ERR(port->membase);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -ENODEV;
+
+	uart_get_rs485_mode(port);
+	sunplus_uart_ports[pdev->id].rts_gpio =
+		devm_gpiod_get(&pdev->dev, "rts", GPIOD_OUT_LOW);
+	port->rs485_config = sunplus_uart_config_rs485;
+	sunplus_uart_ports[pdev->id].rts_check_tx_empty.function = NULL;
+	sunplus_uart_ports[pdev->id].rts_delay_before_send.function = NULL;
+	sunplus_uart_ports[pdev->id].rts_delay_after_send.function = NULL;
+	if (port->rs485.flags & SER_RS485_ENABLED)
+		sunplus_uart_rs485_on(port);
+
+	sunplus_uart_ports[pdev->id].clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(sunplus_uart_ports[pdev->id].clk))
+		return PTR_ERR(sunplus_uart_ports[pdev->id].clk);
+
+	ret = clk_prepare_enable(sunplus_uart_ports[pdev->id].clk);
+	if (ret)
+		return ret;
+
+	sunplus_uart_ports[pdev->id].rstc =
+		devm_reset_control_get(&pdev->dev, NULL);
+
+	if (IS_ERR(sunplus_uart_ports[pdev->id].rstc))
+		return PTR_ERR(sunplus_uart_ports[pdev->id].rstc);
+
+	ret = reset_control_deassert(sunplus_uart_ports[pdev->id].rstc);
+	if (ret)
+		return ret;
+
+	clk = sunplus_uart_ports[pdev->id].clk;
+	if (IS_ERR(clk))
+		port->uartclk = XTAL;
+	else
+		port->uartclk = clk_get_rate(clk);
+
+	pllsys = clk_get_sys("pllsys", NULL);
+	pllsys_rate = clk_get_rate(pllsys);
+
+	sunplus_uart_ports[pdev->id].pllsys_rate = pllsys_rate;
+
+	port->iotype = UPIO_MEM;
+	port->irq = irq;
+	port->ops = &sunplus_uart_ops;
+	port->flags = UPF_BOOT_AUTOCONF;
+	port->fifosize = 128;
+	port->line = pdev->id;
+
+#ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
+	if (pdev->id == 0)
+		port->cons = &sunplus_console;
+#endif
+
+	port->private_data = container_of(&sunplus_uart_ports[pdev->id].uport,
+		struct sunplus_uart_port, uport);
+
+	sprintf(sunplus_uart_ports[pdev->id].name, "sp_uart%d", pdev->id);
+
+	sunplus_uart_ports[pdev->id].uartdma_rx =
+		sunplus_uartdma_rx_binding(pdev->id);
+
+	if (sunplus_uart_ports[pdev->id].uartdma_rx)
+		dev_info(port->dev, "%s's Rx is in DMA mode.\n",
+			sunplus_uart_ports[pdev->id].name);
+	else
+		dev_info(port->dev, "%s's Rx is in PIO mode.\n",
+			sunplus_uart_ports[pdev->id].name);
+
+	sunplus_uart_ports[pdev->id].uartdma_tx =
+		sunplus_uartdma_tx_binding(pdev->id);
+
+	if (sunplus_uart_ports[pdev->id].uartdma_tx)
+		dev_info(port->dev, "%s's Tx is in DMA mode.\n",
+			sunplus_uart_ports[pdev->id].name);
+	else
+		dev_info(port->dev, "%s's Tx is in PIO mode.\n",
+			sunplus_uart_ports[pdev->id].name);
+
+	ret = uart_add_one_port(&sunplus_uart_driver, port);
+	if (ret) {
+		port->membase = NULL;
+		return ret;
+	}
+	platform_set_drvdata(pdev, port);
+
+#ifdef CONFIG_PM_RUNTIME_UART
+	if (pdev->id != 0) {
+		pm_runtime_set_autosuspend_delay(&pdev->dev, 5000);
+		pm_runtime_use_autosuspend(&pdev->dev);
+		pm_runtime_set_active(&pdev->dev);
+		pm_runtime_enable(&pdev->dev);
+	}
+#endif
+	return 0;
+}
+
+static int sunplus_uart_remove(struct platform_device *pdev)
+{
+#ifdef CONFIG_PM_RUNTIME_UART
+	if (pdev->id != 0) {
+		pm_runtime_disable(&pdev->dev);
+		pm_runtime_set_suspended(&pdev->dev);
+	}
+#endif
+	uart_remove_one_port(&sunplus_uart_driver,
+		&sunplus_uart_ports[pdev->id].uport);
+
+	if (pdev->id < UART_NR) {
+		clk_disable_unprepare(sunplus_uart_ports[pdev->id].clk);
+		reset_control_assert(sunplus_uart_ports[pdev->id].rstc);
+	}
+
+	return 0;
+}
+
+static int sunplus_uart_suspend(struct platform_device *pdev,
+	pm_message_t state)
+{
+	/* Don't suspend uart0 for cmd line usage */
+	if ((pdev->id < UART_NR) && (pdev->id > 0))
+		reset_control_assert(sunplus_uart_ports[pdev->id].rstc);
+
+	return 0;
+}
+
+static int sunplus_uart_resume(struct platform_device *pdev)
+{
+	if (pdev->id < UART_NR) {
+		clk_prepare_enable(sunplus_uart_ports[pdev->id].clk);
+		reset_control_deassert(sunplus_uart_ports[pdev->id].rstc);
+	}
+	return 0;
+}
+
+static const struct of_device_id sp_uart_of_match[] = {
+	{ .compatible = "sunplus,sp7021-uart" },
+	{ .compatible = "sunplus,sp7021-uart-rxdma" },
+	{ .compatible = "sunplus,sp7021-uart-txdma" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sp_uart_of_match);
+
+#ifdef CONFIG_PM_RUNTIME_UART
+static int sunplus_uart_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	/* Don't suspend uart0 for cmd line usage */
+	if ((pdev->id < UART_NR) && (pdev->id > 0))
+		reset_control_assert(sunplus_uart_ports[pdev->id].rstc);
+
+	return 0;
+}
+
+static int sunplus_uart_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	if (pdev->id < UART_NR) {
+		clk_prepare_enable(sunplus_uart_ports[pdev->id].clk);
+		reset_control_deassert(sunplus_uart_ports[pdev->id].rstc);
+	}
+
+	return 0;
+}
+static const struct dev_pm_ops sp7021_uart_pm_ops = {
+	.runtime_suspend = sunplus_uart_runtime_suspend,
+	.runtime_resume  = sunplus_uart_runtime_resume,
+};
+#define sunplus_uart_pm_ops  (&sp7021_uart_pm_ops)
+#endif
+
+static struct platform_driver sunplus_uart_platform_driver = {
+	.probe		= sunplus_uart_probe,
+	.remove		= sunplus_uart_remove,
+	.suspend	= sunplus_uart_suspend,
+	.resume		= sunplus_uart_resume,
+	.driver = {
+		.name	= "sunplus-uart",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(sp_uart_of_match),
+#ifdef CONFIG_PM_RUNTIME_UART
+		.pm     = sunplus_uart_pm_ops,
+#endif
+	}
+};
+
+static int __init sunplus_uart_init(void)
+{
+	int ret;
+
+	memset(sunplus_uart_ports, 0, sizeof(sunplus_uart_ports));
+	memset(sunplus_uartdma, 0, sizeof(sunplus_uartdma));
+
+	if (!uart0_as_console || !(uart_enable_status & 0x01))
+		sunplus_uart_driver.cons = NULL;
+
+	/* /proc/tty/driver/(sunplus_uart_driver->driver_name) */
+	ret = uart_register_driver(&sunplus_uart_driver);
+	if (ret < 0)
+		return ret;
+
+	ret = platform_driver_register(&sunplus_uart_platform_driver);
+	if (ret != 0) {
+		uart_unregister_driver(&sunplus_uart_driver);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(sunplus_uart_init);
+
+module_param(uart0_as_console, uint, 0444);
+
+#ifdef CONFIG_SERIAL_EARLYCON
+static void sunplus_uart_putc(struct uart_port *port, int c)
+{
+	unsigned int status;
+
+	for (;;) {
+		status = readl(port->membase + SP_UART_LSR);
+		if ((status & SP_UART_LSR_TXE) == SP_UART_LSR_TXE)
+			break;
+		cpu_relax();
+	}
+	writel(c, port->membase + SP_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);
+}
+
+int __init sunplus_uart_early_setup(struct earlycon_device *device,
+					 const char *opt)
+{
+	if (!(device->port.membase || device->port.iobase))
+		return -ENODEV;
+
+	device->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 <hammer.hsieh@sunplus.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/soc/sunplus/sp_uart.h b/include/soc/sunplus/sp_uart.h
new file mode 100644
index 0000000..44bc1fb
--- /dev/null
+++ b/include/soc/sunplus/sp_uart.h
@@ -0,0 +1,147 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Sunplus SoC UART driver header file
+ */
+
+#ifndef __SP_UART_H__
+#define __SP_UART_H__
+
+#ifdef CONFIG_DEBUG_SP_UART
+#include <mach/io_map.h>
+
+#define LL_UART_PADDR		PA_IOB_ADDR(18 * 32 * 4)
+#define LL_UART_VADDR		VA_IOB_ADDR(18 * 32 * 4)
+#define LOGI_ADDR_UART0_REG	VA_IOB_ADDR(18 * 32 * 4)
+#endif
+
+/*
+ * UART REG
+ *
+ */
+#define SP_UART_DATA			0x00
+#define SP_UART_LSR				0x04
+#define SP_UART_MSR				0x08
+#define SP_UART_LCR				0x0C
+#define SP_UART_MCR				0x10
+#define SP_UART_DIV_L			0x14
+#define SP_UART_DIV_H			0x18
+#define SP_UART_ISC				0x1C
+#define SP_UART_TX_RESIDUE		0x20
+#define SP_UART_RX_RESIDUE		0x24
+
+/* lsr
+ * 1: trasmit fifo is empty
+ */
+#define SP_UART_LSR_TXE		(1 << 6)
+
+/* interrupt
+ * SP_UART_LSR_BC : break condition
+ * SP_UART_LSR_FE : frame error
+ * SP_UART_LSR_OE : overrun error
+ * SP_UART_LSR_PE : parity error
+ * SP_UART_LSR_RX : 1: receive fifo not empty
+ * SP_UART_LSR_TX : 1: transmit fifo is not full
+ */
+#define SP_UART_CREAD_DISABLED		(1 << 16)
+#define SP_UART_LSR_BC		(1 << 5)
+#define SP_UART_LSR_FE		(1 << 4)
+#define SP_UART_LSR_OE		(1 << 3)
+#define SP_UART_LSR_PE		(1 << 2)
+#define SP_UART_LSR_RX		(1 << 1)
+#define SP_UART_LSR_TX		(1 << 0)
+
+#define SP_UART_LSR_BRK_ERROR_BITS	\
+	(SP_UART_LSR_PE | SP_UART_LSR_OE | SP_UART_LSR_FE | SP_UART_LSR_BC)
+
+/* lcr */
+#define SP_UART_LCR_WL5		(0 << 0)
+#define SP_UART_LCR_WL6		(1 << 0)
+#define SP_UART_LCR_WL7		(2 << 0)
+#define SP_UART_LCR_WL8		(3 << 0)
+#define SP_UART_LCR_ST		(1 << 2)
+#define SP_UART_LCR_PE		(1 << 3)
+#define SP_UART_LCR_PR		(1 << 4)
+#define SP_UART_LCR_BC		(1 << 5)
+
+/* isc
+ * SP_UART_ISC_MSM : Modem status ctrl
+ * SP_UART_ISC_LSM : Line status interrupt
+ * SP_UART_ISC_RXM : RX interrupt, when got some input data
+ * SP_UART_ISC_TXM : TX interrupt, when trans start
+ */
+#define SP_UART_ISC_MSM		(1 << 7)
+#define SP_UART_ISC_LSM		(1 << 6)
+#define SP_UART_ISC_RXM		(1 << 5)
+#define SP_UART_ISC_TXM		(1 << 4)
+#define HAS_UART_ISC_FLAGMASK	0x0F
+#define SP_UART_ISC_MS		(1 << 3)
+#define SP_UART_ISC_LS		(1 << 2)
+#define SP_UART_ISC_RX		(1 << 1)
+#define SP_UART_ISC_TX		(1 << 0)
+
+/* modem control register */
+#define SP_UART_MCR_AT		(1 << 7)
+#define SP_UART_MCR_AC		(1 << 6)
+#define SP_UART_MCR_AR		(1 << 5)
+#define SP_UART_MCR_LB		(1 << 4)
+#define SP_UART_MCR_RI		(1 << 3)
+#define SP_UART_MCR_DCD		(1 << 2)
+#define SP_UART_MCR_RTS		(1 << 1)
+#define SP_UART_MCR_DTS		(1 << 0)
+
+/*
+ * RX DMA REG
+ *
+ */
+#define SP_UART_RXDMA_ENABLE_SEL		0x00
+#define DMA_INT				(1 << 31)
+#define DMA_MSI_ID_SHIFT	12
+#define DMA_MSI_ID_MASK		(0x7F << DMA_MSI_ID_SHIFT)
+#define DMA_SEL_UARTX_SHIFT	8
+#define DMA_SEL_UARTX_MASK	(0x07 << DMA_SEL_UARTX_SHIFT)
+#define DMA_SW_RST_B		(1 << 7)
+#define DMA_INIT			(1 << 6)
+#define DMA_GO				(1 << 5)
+#define DMA_AUTO_ENABLE		(1 << 4)
+#define DMA_TIMEOUT_INT_EN	(1 << 3)
+#define DMA_P_SAFE_DISABLE	(1 << 2)
+#define DMA_PBUS_DATA_SWAP	(1 << 1)
+#define DMA_ENABLE			(1 << 0)
+#define SP_UART_RXDMA_START_ADDR		0x04
+#define SP_UART_RXDMA_TIMEOUT_SET		0x08
+#define SP_UART_RXDMA_WR_ADR			0x10
+#define SP_UART_RXDMA_RD_ADR			0x14
+#define SP_UART_RXDMA_LENGTH_THR		0x18
+#define SP_UART_RXDMA_END_ADDR			0x1C
+#define SP_UART_RXDMA_DATABYTES			0x20
+#define SP_UART_RXDMA_DEBUG_INFO		0x24
+/*
+ * TX DMA REG
+ *
+ */
+#define SP_UART_TXDMA_ENABLE			0x00
+#define SP_UART_TXDMA_SEL				0x04
+#define SP_UART_TXDMA_START_ADDR		0x08
+#define SP_UART_TXDMA_END_ADDR			0x0C
+#define SP_UART_TXDMA_WR_ADR			0x10
+#define SP_UART_TXDMA_RD_ADR			0x14
+#define SP_UART_TXDMA_STATUS			0x18
+#define TXDMA_BUF_FULL	0x01
+#define TXDMA_BUF_EMPTY	0x02
+#define SP_UART_TXDMA_TMR_UNIT			0x1C
+#define SP_UART_TXDMA_TMR_CNT			0x20
+#define SP_UART_TXDMA_RST_DONE			0x24
+/*
+ * TX GDMA REG
+ *
+ */
+#define SP_UART_TXGDMA_HW_VER			0x00
+#define SP_UART_TXGDMA_CONFIG			0x04
+#define SP_UART_TXGDMA_LENGTH			0x08
+#define SP_UART_TXGDMA_ADDR				0x0C
+#define SP_UART_TXGDMA_PORT_MUX			0x10
+#define SP_UART_TXGDMA_INT_FLAG			0x14
+#define SP_UART_TXGDMA_INT_EN			0x18
+#define SP_UART_TXGDMA_SOFT_RESET_STATUS	0x1C
+
+#endif /* __SP_UART_H__ */