Add UART driver for RDA Micro RDA8810PL SoC.

Signed-off-by: Andreas Färber <afaer...@suse.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasi...@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 .../admin-guide/kernel-parameters.txt         |   6 +
 drivers/tty/serial/Kconfig                    |  19 +
 drivers/tty/serial/Makefile                   |   1 +
 drivers/tty/serial/rda-uart.c                 | 831 ++++++++++++++++++
 include/uapi/linux/serial_core.h              |   3 +
 5 files changed, 860 insertions(+)
 create mode 100644 drivers/tty/serial/rda-uart.c

diff --git a/Documentation/admin-guide/kernel-parameters.txt 
b/Documentation/admin-guide/kernel-parameters.txt
index 81d1d5a74728..07078880f7fd 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1020,6 +1020,12 @@
                        specified address. The serial port must already be
                        setup and configured. Options are not yet supported.
 
+               rda,<addr>
+                       Start an early, polled-mode console on a serial port
+                       of an RDA Micro SoC, such as RDA8810PL, at the
+                       specified address. The serial port must already be
+                       setup and configured. Options are not yet supported.
+
                smh     Use ARM semihosting calls for early console.
 
                s3c2410,<addr>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 32886c304641..67b9bf3b500e 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1529,6 +1529,25 @@ config SERIAL_OWL_CONSOLE
          Say 'Y' here if you wish to use Actions Semiconductor S500/S900 UART
          as the system console.
 
+config SERIAL_RDA
+       bool "RDA Micro serial port support"
+       depends on ARCH_RDA || COMPILE_TEST
+       select SERIAL_CORE
+       help
+         This driver is for RDA8810PL SoC's UART.
+         Say 'Y' here if you wish to use the on-board serial port.
+         Otherwise, say 'N'.
+
+config SERIAL_RDA_CONSOLE
+       bool "Console on RDA Micro serial port"
+       depends on SERIAL_RDA=y
+       select SERIAL_CORE_CONSOLE
+       select SERIAL_EARLYCON
+       default y
+       help
+         Say 'Y' here if you wish to use the RDA8810PL UART as the system
+         console. Only earlycon is implemented currently.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index daac675612df..8c303736b7e8 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_MVEBU_UART)       += mvebu-uart.o
 obj-$(CONFIG_SERIAL_PIC32)     += pic32_uart.o
 obj-$(CONFIG_SERIAL_MPS2_UART) += mps2-uart.o
 obj-$(CONFIG_SERIAL_OWL)       += owl-uart.o
+obj-$(CONFIG_SERIAL_RDA)       += rda-uart.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)        += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/rda-uart.c b/drivers/tty/serial/rda-uart.c
new file mode 100644
index 000000000000..284623eefaeb
--- /dev/null
+++ b/drivers/tty/serial/rda-uart.c
@@ -0,0 +1,831 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RDA8810PL serial device driver
+ *
+ * Copyright RDA Microelectronics Company Limited
+ * Copyright (c) 2017 Andreas Färber
+ * Copyright (c) 2018 Manivannan Sadhasivam
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#define RDA_UART_PORT_NUM 3
+#define RDA_UART_DEV_NAME "ttyRDA"
+
+#define RDA_UART_CTRL          0x00
+#define RDA_UART_STATUS                0x04
+#define RDA_UART_RXTX_BUFFER   0x08
+#define RDA_UART_IRQ_MASK      0x0c
+#define RDA_UART_IRQ_CAUSE     0x10
+#define RDA_UART_IRQ_TRIGGERS  0x14
+#define RDA_UART_CMD_SET       0x18
+#define RDA_UART_CMD_CLR       0x1c
+
+/* UART_CTRL Bits */
+#define RDA_UART_ENABLE                        BIT(0)
+#define RDA_UART_DBITS_8               BIT(1)
+#define RDA_UART_TX_SBITS_2            BIT(2)
+#define RDA_UART_PARITY_EN             BIT(3)
+#define RDA_UART_PARITY(x)             (((x) & 0x3) << 4)
+#define RDA_UART_PARITY_ODD            RDA_UART_PARITY(0)
+#define RDA_UART_PARITY_EVEN           RDA_UART_PARITY(1)
+#define RDA_UART_PARITY_SPACE          RDA_UART_PARITY(2)
+#define RDA_UART_PARITY_MARK           RDA_UART_PARITY(3)
+#define RDA_UART_DIV_MODE              BIT(20)
+#define RDA_UART_IRDA_EN               BIT(21)
+#define RDA_UART_DMA_EN                        BIT(22)
+#define RDA_UART_FLOW_CNT_EN           BIT(23)
+#define RDA_UART_LOOP_BACK_EN          BIT(24)
+#define RDA_UART_RX_LOCK_ERR           BIT(25)
+#define RDA_UART_RX_BREAK_LEN(x)       (((x) & 0xf) << 28)
+
+/* UART_STATUS Bits */
+#define RDA_UART_RX_FIFO(x)            (((x) & 0x7f) << 0)
+#define RDA_UART_RX_FIFO_MASK          (0x7f << 0)
+#define RDA_UART_TX_FIFO(x)            (((x) & 0x1f) << 8)
+#define RDA_UART_TX_FIFO_MASK          (0x1f << 8)
+#define RDA_UART_TX_ACTIVE             BIT(14)
+#define RDA_UART_RX_ACTIVE             BIT(15)
+#define RDA_UART_RX_OVERFLOW_ERR       BIT(16)
+#define RDA_UART_TX_OVERFLOW_ERR       BIT(17)
+#define RDA_UART_RX_PARITY_ERR         BIT(18)
+#define RDA_UART_RX_FRAMING_ERR                BIT(19)
+#define RDA_UART_RX_BREAK_INT          BIT(20)
+#define RDA_UART_DCTS                  BIT(24)
+#define RDA_UART_CTS                   BIT(25)
+#define RDA_UART_DTR                   BIT(28)
+#define RDA_UART_CLK_ENABLED           BIT(31)
+
+/* UART_RXTX_BUFFER Bits */
+#define RDA_UART_RX_DATA(x)            (((x) & 0xff) << 0)
+#define RDA_UART_TX_DATA(x)            (((x) & 0xff) << 0)
+
+/* UART_IRQ_MASK Bits */
+#define RDA_UART_TX_MODEM_STATUS       BIT(0)
+#define RDA_UART_RX_DATA_AVAILABLE     BIT(1)
+#define RDA_UART_TX_DATA_NEEDED                BIT(2)
+#define RDA_UART_RX_TIMEOUT            BIT(3)
+#define RDA_UART_RX_LINE_ERR           BIT(4)
+#define RDA_UART_TX_DMA_DONE           BIT(5)
+#define RDA_UART_RX_DMA_DONE           BIT(6)
+#define RDA_UART_RX_DMA_TIMEOUT                BIT(7)
+#define RDA_UART_DTR_RISE              BIT(8)
+#define RDA_UART_DTR_FALL              BIT(9)
+
+/* UART_IRQ_CAUSE Bits */
+#define RDA_UART_TX_MODEM_STATUS_U     BIT(16)
+#define RDA_UART_RX_DATA_AVAILABLE_U   BIT(17)
+#define RDA_UART_TX_DATA_NEEDED_U      BIT(18)
+#define RDA_UART_RX_TIMEOUT_U          BIT(19)
+#define RDA_UART_RX_LINE_ERR_U         BIT(20)
+#define RDA_UART_TX_DMA_DONE_U         BIT(21)
+#define RDA_UART_RX_DMA_DONE_U         BIT(22)
+#define RDA_UART_RX_DMA_TIMEOUT_U      BIT(23)
+#define RDA_UART_DTR_RISE_U            BIT(24)
+#define RDA_UART_DTR_FALL_U            BIT(25)
+
+/* UART_TRIGGERS Bits */
+#define RDA_UART_RX_TRIGGER(x)         (((x) & 0x1f) << 0)
+#define RDA_UART_TX_TRIGGER(x)         (((x) & 0xf) << 8)
+#define RDA_UART_AFC_LEVEL(x)          (((x) & 0x1f) << 16)
+
+/* UART_CMD_SET Bits */
+#define RDA_UART_RI                    BIT(0)
+#define RDA_UART_DCD                   BIT(1)
+#define RDA_UART_DSR                   BIT(2)
+#define RDA_UART_TX_BREAK_CONTROL      BIT(3)
+#define RDA_UART_TX_FINISH_N_WAIT      BIT(4)
+#define RDA_UART_RTS                   BIT(5)
+#define RDA_UART_RX_FIFO_RESET         BIT(6)
+#define RDA_UART_TX_FIFO_RESET         BIT(7)
+
+#define RDA_UART_TX_FIFO_SIZE  16
+
+static struct uart_driver rda_uart_driver;
+
+struct rda_uart_port {
+       struct uart_port port;
+       struct clk *clk;
+};
+
+#define to_rda_uart_port(port) container_of(port, struct rda_uart_port, port)
+
+static struct rda_uart_port *rda_uart_ports[RDA_UART_PORT_NUM];
+
+static inline void rda_uart_write(struct uart_port *port, u32 val,
+                                 unsigned int off)
+{
+       writel(val, port->membase + off);
+}
+
+static inline u32 rda_uart_read(struct uart_port *port, unsigned int off)
+{
+       return readl(port->membase + off);
+}
+
+static unsigned int rda_uart_tx_empty(struct uart_port *port)
+{
+       unsigned long flags;
+       unsigned int ret;
+       u32 val;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       val = rda_uart_read(port, RDA_UART_STATUS);
+       ret = (val & RDA_UART_TX_FIFO_MASK) ? TIOCSER_TEMT : 0;
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return ret;
+}
+
+static unsigned int rda_uart_get_mctrl(struct uart_port *port)
+{
+       unsigned int mctrl = 0;
+       u32 cmd_set, status;
+
+       cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
+       status = rda_uart_read(port, RDA_UART_STATUS);
+       if (cmd_set & RDA_UART_RTS)
+               mctrl |= TIOCM_RTS;
+       if (!(status & RDA_UART_CTS))
+               mctrl |= TIOCM_CTS;
+
+       return mctrl;
+}
+
+static void rda_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       u32 val;
+
+       if (mctrl & TIOCM_RTS) {
+               val = rda_uart_read(port, RDA_UART_CMD_SET);
+               rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_SET);
+       } else {
+               /* Clear RTS to stop to receive. */
+               val = rda_uart_read(port, RDA_UART_CMD_CLR);
+               rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_CLR);
+       }
+
+       val = rda_uart_read(port, RDA_UART_CTRL);
+
+       if (mctrl & TIOCM_LOOP)
+               val |= RDA_UART_LOOP_BACK_EN;
+       else
+               val &= ~RDA_UART_LOOP_BACK_EN;
+
+       rda_uart_write(port, val, RDA_UART_CTRL);
+}
+
+static void rda_uart_stop_tx(struct uart_port *port)
+{
+       u32 val;
+
+       val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       val &= ~RDA_UART_TX_DATA_NEEDED;
+       rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+       val = rda_uart_read(port, RDA_UART_CMD_SET);
+       val |= RDA_UART_TX_FIFO_RESET;
+       rda_uart_write(port, val, RDA_UART_CMD_SET);
+}
+
+static void rda_uart_stop_rx(struct uart_port *port)
+{
+       u32 val;
+
+       val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       val &= ~(RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
+       rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+       /* Read Rx buffer before reset to avoid Rx timeout interrupt */
+       val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
+
+       val = rda_uart_read(port, RDA_UART_CMD_SET);
+       val |= RDA_UART_RX_FIFO_RESET;
+       rda_uart_write(port, val, RDA_UART_CMD_SET);
+}
+
+static void rda_uart_start_tx(struct uart_port *port)
+{
+       u32 val;
+
+       if (uart_tx_stopped(port)) {
+               rda_uart_stop_tx(port);
+               return;
+       }
+
+       val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       val |= RDA_UART_TX_DATA_NEEDED;
+       rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+}
+
+static void rda_uart_change_baudrate(struct rda_uart_port *rda_port,
+                                    unsigned long baud)
+{
+       clk_set_rate(rda_port->clk, baud * 8);
+}
+
+static void rda_uart_set_termios(struct uart_port *port,
+                                struct ktermios *termios,
+                                struct ktermios *old)
+{
+       struct rda_uart_port *rda_port = to_rda_uart_port(port);
+       unsigned long flags;
+       unsigned int ctrl, cmd_set, cmd_clr, triggers;
+       unsigned int baud;
+       u32 irq_mask;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       baud = uart_get_baud_rate(port, termios, old, 9600, port->uartclk / 4);
+       rda_uart_change_baudrate(rda_port, baud);
+
+       ctrl = rda_uart_read(port, RDA_UART_CTRL);
+       cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
+       cmd_clr = rda_uart_read(port, RDA_UART_CMD_CLR);
+
+       switch (termios->c_cflag & CSIZE) {
+       case CS5:
+       case CS6:
+               dev_warn(port->dev, "bit size not supported, using 7 bits\n");
+               /* Fall through */
+       case CS7:
+               ctrl &= ~RDA_UART_DBITS_8;
+               break;
+       default:
+               ctrl |= RDA_UART_DBITS_8;
+               break;
+       }
+
+       /* stop bits */
+       if (termios->c_cflag & CSTOPB)
+               ctrl |= RDA_UART_TX_SBITS_2;
+       else
+               ctrl &= ~RDA_UART_TX_SBITS_2;
+
+       /* parity check */
+       if (termios->c_cflag & PARENB) {
+               ctrl |= RDA_UART_PARITY_EN;
+
+               /* Mark or Space parity */
+               if (termios->c_cflag & CMSPAR) {
+                       if (termios->c_cflag & PARODD)
+                               ctrl |= RDA_UART_PARITY_MARK;
+                       else
+                               ctrl |= RDA_UART_PARITY_SPACE;
+               } else if (termios->c_cflag & PARODD) {
+                       ctrl |= RDA_UART_PARITY_ODD;
+               } else {
+                       ctrl |= RDA_UART_PARITY_EVEN;
+               }
+       } else {
+               ctrl &= ~RDA_UART_PARITY_EN;
+       }
+
+       /* Hardware handshake (RTS/CTS) */
+       if (termios->c_cflag & CRTSCTS) {
+               ctrl   |= RDA_UART_FLOW_CNT_EN;
+               cmd_set |= RDA_UART_RTS;
+       } else {
+               ctrl   &= ~RDA_UART_FLOW_CNT_EN;
+               cmd_clr |= RDA_UART_RTS;
+       }
+
+       ctrl |= RDA_UART_ENABLE;
+       ctrl &= ~RDA_UART_DMA_EN;
+
+       triggers  = (RDA_UART_AFC_LEVEL(20) | RDA_UART_RX_TRIGGER(16));
+       irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+       rda_uart_write(port, triggers, RDA_UART_IRQ_TRIGGERS);
+       rda_uart_write(port, ctrl, RDA_UART_CTRL);
+       rda_uart_write(port, cmd_set, RDA_UART_CMD_SET);
+       rda_uart_write(port, cmd_clr, RDA_UART_CMD_CLR);
+
+       rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
+
+       /* Don't rewrite B0 */
+       if (tty_termios_baud_rate(termios))
+               tty_termios_encode_baud_rate(termios, baud, baud);
+
+       /* update the per-port timeout */
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void rda_uart_send_chars(struct uart_port *port)
+{
+       struct circ_buf *xmit = &port->state->xmit;
+       unsigned int ch;
+       u32 val;
+
+       if (uart_tx_stopped(port))
+               return;
+
+       if (port->x_char) {
+               while (!(rda_uart_read(port, RDA_UART_STATUS) &
+                        RDA_UART_TX_FIFO_MASK))
+                       cpu_relax();
+
+               rda_uart_write(port, port->x_char, RDA_UART_RXTX_BUFFER);
+               port->icount.tx++;
+               port->x_char = 0;
+       }
+
+       while (rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK) {
+               if (uart_circ_empty(xmit))
+                       break;
+
+               ch = xmit->buf[xmit->tail];
+               rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
+               xmit->tail = (xmit->tail + 1) & (SERIAL_XMIT_SIZE - 1);
+               port->icount.tx++;
+       }
+
+       if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+               uart_write_wakeup(port);
+
+       if (!uart_circ_empty(xmit)) {
+               /* Re-enable Tx FIFO interrupt */
+               val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+               val |= RDA_UART_TX_DATA_NEEDED;
+               rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+       }
+}
+
+static void rda_uart_receive_chars(struct uart_port *port)
+{
+       u32 status, val;
+
+       status = rda_uart_read(port, RDA_UART_STATUS);
+       while ((status & RDA_UART_RX_FIFO_MASK)) {
+               char flag = TTY_NORMAL;
+
+               if (status & RDA_UART_RX_PARITY_ERR) {
+                       port->icount.parity++;
+                       flag = TTY_PARITY;
+               }
+
+               if (status & RDA_UART_RX_FRAMING_ERR) {
+                       port->icount.frame++;
+                       flag = TTY_FRAME;
+               }
+
+               if (status & RDA_UART_RX_OVERFLOW_ERR) {
+                       port->icount.overrun++;
+                       flag = TTY_OVERRUN;
+               }
+
+               val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
+               val &= 0xff;
+
+               port->icount.rx++;
+               tty_insert_flip_char(&port->state->port, val, flag);
+
+               status = rda_uart_read(port, RDA_UART_STATUS);
+       }
+
+       spin_unlock(&port->lock);
+       tty_flip_buffer_push(&port->state->port);
+       spin_lock(&port->lock);
+}
+
+static irqreturn_t rda_interrupt(int irq, void *dev_id)
+{
+       struct uart_port *port = dev_id;
+       unsigned long flags;
+       u32 val, irq_mask;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       /* Clear IRQ cause */
+       val = rda_uart_read(port, RDA_UART_IRQ_CAUSE);
+       rda_uart_write(port, val, RDA_UART_IRQ_CAUSE);
+
+       if (val & (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT))
+               rda_uart_receive_chars(port);
+
+       if (val & (RDA_UART_TX_DATA_NEEDED)) {
+               irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+               irq_mask &= ~RDA_UART_TX_DATA_NEEDED;
+               rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
+
+               rda_uart_send_chars(port);
+       }
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return IRQ_HANDLED;
+}
+
+static int rda_uart_startup(struct uart_port *port)
+{
+       unsigned long flags;
+       int ret;
+       u32 val;
+
+       spin_lock_irqsave(&port->lock, flags);
+       rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       ret = request_irq(port->irq, rda_interrupt, IRQF_NO_SUSPEND,
+                         "rda-uart", port);
+       if (ret)
+               return ret;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       val = rda_uart_read(port, RDA_UART_CTRL);
+       val |= RDA_UART_ENABLE;
+       rda_uart_write(port, val, RDA_UART_CTRL);
+
+       /* enable rx interrupt */
+       val = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       val |= (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
+       rda_uart_write(port, val, RDA_UART_IRQ_MASK);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return 0;
+}
+
+static void rda_uart_shutdown(struct uart_port *port)
+{
+       unsigned long flags;
+       u32 val;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       rda_uart_stop_tx(port);
+       rda_uart_stop_rx(port);
+
+       val = rda_uart_read(port, RDA_UART_CTRL);
+       val &= ~RDA_UART_ENABLE;
+       rda_uart_write(port, val, RDA_UART_CTRL);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *rda_uart_type(struct uart_port *port)
+{
+       return (port->type == PORT_RDA) ? "rda-uart" : NULL;
+}
+
+static int rda_uart_request_port(struct uart_port *port)
+{
+       struct platform_device *pdev = to_platform_device(port->dev);
+       struct resource *res;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENXIO;
+
+       if (!devm_request_mem_region(port->dev, port->mapbase,
+                                    resource_size(res), dev_name(port->dev)))
+               return -EBUSY;
+
+       if (port->flags & UPF_IOREMAP) {
+               port->membase = devm_ioremap_nocache(port->dev, port->mapbase,
+                                                    resource_size(res));
+               if (!port->membase)
+                       return -EBUSY;
+       }
+
+       return 0;
+}
+
+static void rda_uart_config_port(struct uart_port *port, int flags)
+{
+       unsigned long irq_flags;
+
+       if (flags & UART_CONFIG_TYPE) {
+               port->type = PORT_RDA;
+               rda_uart_request_port(port);
+       }
+
+       spin_lock_irqsave(&port->lock, irq_flags);
+
+       /* Clear mask, so no surprise interrupts. */
+       rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+       /* Clear status register */
+       rda_uart_write(port, 0, RDA_UART_STATUS);
+
+       spin_unlock_irqrestore(&port->lock, irq_flags);
+}
+
+static void rda_uart_release_port(struct uart_port *port)
+{
+       struct platform_device *pdev = to_platform_device(port->dev);
+       struct resource *res;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return;
+
+       if (port->flags & UPF_IOREMAP) {
+               devm_release_mem_region(port->dev, port->mapbase,
+                                       resource_size(res));
+               devm_iounmap(port->dev, port->membase);
+               port->membase = NULL;
+       }
+}
+
+static int rda_uart_verify_port(struct uart_port *port,
+                               struct serial_struct *ser)
+{
+       if (port->type != PORT_RDA)
+               return -EINVAL;
+
+       if (port->irq != ser->irq)
+               return -EINVAL;
+
+       return 0;
+}
+
+static const struct uart_ops rda_uart_ops = {
+       .tx_empty       = rda_uart_tx_empty,
+       .get_mctrl      = rda_uart_get_mctrl,
+       .set_mctrl      = rda_uart_set_mctrl,
+       .start_tx       = rda_uart_start_tx,
+       .stop_tx        = rda_uart_stop_tx,
+       .stop_rx        = rda_uart_stop_rx,
+       .startup        = rda_uart_startup,
+       .shutdown       = rda_uart_shutdown,
+       .set_termios    = rda_uart_set_termios,
+       .type           = rda_uart_type,
+       .request_port   = rda_uart_request_port,
+       .release_port   = rda_uart_release_port,
+       .config_port    = rda_uart_config_port,
+       .verify_port    = rda_uart_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_RDA_CONSOLE
+
+static void rda_console_putchar(struct uart_port *port, int ch)
+{
+       if (!port->membase)
+               return;
+
+       while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
+               cpu_relax();
+
+       rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
+}
+
+static void rda_uart_port_write(struct uart_port *port, const char *s,
+                               u_int count)
+{
+       u32 old_irq_mask;
+       unsigned long flags;
+       int locked;
+
+       local_irq_save(flags);
+
+       if (port->sysrq) {
+               locked = 0;
+       } else if (oops_in_progress) {
+               locked = spin_trylock(&port->lock);
+       } else {
+               spin_lock(&port->lock);
+               locked = 1;
+       }
+
+       old_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
+       rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
+
+       uart_console_write(port, s, count, rda_console_putchar);
+
+       /* wait until all contents have been sent out */
+       while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
+               cpu_relax();
+
+       rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK);
+
+       if (locked)
+               spin_unlock(&port->lock);
+
+       local_irq_restore(flags);
+}
+
+static void rda_uart_console_write(struct console *co, const char *s,
+                                  u_int count)
+{
+       struct rda_uart_port *rda_port;
+
+       rda_port = rda_uart_ports[co->index];
+       if (!rda_port)
+               return;
+
+       rda_uart_port_write(&rda_port->port, s, count);
+}
+
+static int rda_uart_console_setup(struct console *co, char *options)
+{
+       struct rda_uart_port *rda_port;
+       int baud = 921600;
+       int bits = 8;
+       int parity = 'n';
+       int flow = 'n';
+
+       if (co->index < 0 || co->index >= RDA_UART_PORT_NUM)
+               return -EINVAL;
+
+       rda_port = rda_uart_ports[co->index];
+       if (!rda_port || !rda_port->port.membase)
+               return -ENODEV;
+
+       if (options)
+               uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+       return uart_set_options(&rda_port->port, co, baud, parity, bits, flow);
+}
+
+static struct console rda_uart_console = {
+       .name = RDA_UART_DEV_NAME,
+       .write = rda_uart_console_write,
+       .device = uart_console_device,
+       .setup = rda_uart_console_setup,
+       .flags = CON_PRINTBUFFER,
+       .index = -1,
+       .data = &rda_uart_driver,
+};
+
+static int __init rda_uart_console_init(void)
+{
+       register_console(&rda_uart_console);
+
+       return 0;
+}
+console_initcall(rda_uart_console_init);
+
+static void rda_uart_early_console_write(struct console *co,
+                                        const char *s,
+                                        u_int count)
+{
+       struct earlycon_device *dev = co->data;
+
+       rda_uart_port_write(&dev->port, s, count);
+}
+
+static int __init
+rda_uart_early_console_setup(struct earlycon_device *device, const char *opt)
+{
+       if (!device->port.membase)
+               return -ENODEV;
+
+       device->con->write = rda_uart_early_console_write;
+
+       return 0;
+}
+
+OF_EARLYCON_DECLARE(rda, "rda,8810pl-uart",
+                   rda_uart_early_console_setup);
+
+#define RDA_UART_CONSOLE (&rda_uart_console)
+#else
+#define RDA_UART_CONSOLE NULL
+#endif /* CONFIG_SERIAL_RDA_CONSOLE */
+
+static struct uart_driver rda_uart_driver = {
+       .owner = THIS_MODULE,
+       .driver_name = "rda-uart",
+       .dev_name = RDA_UART_DEV_NAME,
+       .nr = RDA_UART_PORT_NUM,
+       .cons = RDA_UART_CONSOLE,
+};
+
+static const struct of_device_id rda_uart_dt_matches[] = {
+       { .compatible = "rda,8810pl-uart" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, rda_uart_dt_matches);
+
+static int rda_uart_probe(struct platform_device *pdev)
+{
+       struct resource *res_mem;
+       struct rda_uart_port *rda_port;
+       int ret, irq;
+
+       if (pdev->dev.of_node)
+               pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+
+       if (pdev->id < 0 || pdev->id >= RDA_UART_PORT_NUM) {
+               dev_err(&pdev->dev, "id %d out of range\n", pdev->id);
+               return -EINVAL;
+       }
+
+       res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res_mem) {
+               dev_err(&pdev->dev, "could not get mem\n");
+               return -ENODEV;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(&pdev->dev, "could not get irq\n");
+               return irq;
+       }
+
+       if (rda_uart_ports[pdev->id]) {
+               dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
+               return -EBUSY;
+       }
+
+       rda_port = devm_kzalloc(&pdev->dev, sizeof(*rda_port), GFP_KERNEL);
+       if (!rda_port)
+               return -ENOMEM;
+
+       rda_port->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(rda_port->clk)) {
+               dev_err(&pdev->dev, "could not get clk\n");
+               return PTR_ERR(rda_port->clk);
+       }
+
+       rda_port->port.dev = &pdev->dev;
+       rda_port->port.regshift = 0;
+       rda_port->port.line = pdev->id;
+       rda_port->port.type = PORT_RDA;
+       rda_port->port.iotype = UPIO_MEM;
+       rda_port->port.mapbase = res_mem->start;
+       rda_port->port.irq = irq;
+       rda_port->port.uartclk = clk_get_rate(rda_port->clk);
+       if (rda_port->port.uartclk == 0) {
+               dev_err(&pdev->dev, "clock rate is zero\n");
+               return -EINVAL;
+       }
+       rda_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP |
+                              UPF_LOW_LATENCY;
+       rda_port->port.x_char = 0;
+       rda_port->port.fifosize = RDA_UART_TX_FIFO_SIZE;
+       rda_port->port.ops = &rda_uart_ops;
+
+       rda_uart_ports[pdev->id] = rda_port;
+       platform_set_drvdata(pdev, rda_port);
+
+       ret = uart_add_one_port(&rda_uart_driver, &rda_port->port);
+       if (ret)
+               rda_uart_ports[pdev->id] = NULL;
+
+       return ret;
+}
+
+static int rda_uart_remove(struct platform_device *pdev)
+{
+       struct rda_uart_port *rda_port = platform_get_drvdata(pdev);
+
+       uart_remove_one_port(&rda_uart_driver, &rda_port->port);
+       rda_uart_ports[pdev->id] = NULL;
+
+       return 0;
+}
+
+static struct platform_driver rda_uart_platform_driver = {
+       .probe = rda_uart_probe,
+       .remove = rda_uart_remove,
+       .driver = {
+               .name = "rda-uart",
+               .of_match_table = rda_uart_dt_matches,
+       },
+};
+
+static int __init rda_uart_init(void)
+{
+       int ret;
+
+       ret = uart_register_driver(&rda_uart_driver);
+       if (ret)
+               return ret;
+
+       ret = platform_driver_register(&rda_uart_platform_driver);
+       if (ret)
+               uart_unregister_driver(&rda_uart_driver);
+
+       return ret;
+}
+
+static void __init rda_uart_exit(void)
+{
+       platform_driver_unregister(&rda_uart_platform_driver);
+       uart_unregister_driver(&rda_uart_driver);
+}
+
+module_init(rda_uart_init);
+module_exit(rda_uart_exit);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasi...@linaro.org>");
+MODULE_DESCRIPTION("RDA8810PL serial device driver");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index dce5f9dae121..df4a7534e239 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -281,4 +281,7 @@
 /* MediaTek BTIF */
 #define PORT_MTK_BTIF  117
 
+/* RDA UART */
+#define PORT_RDA       118
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
2.17.1

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