On 11/25/2014 07:16 AM, Chunyan Zhang wrote:
Add a full sc9836-uart driver for SC9836 SoC which is based on the
spreadtrum sharkl64 platform.
This driver also support earlycon.

Signed-off-by: Chunyan Zhang<chunyan.zh...@spreadtrum.com>
Signed-off-by: Orson Zhai<orson.z...@spreadtrum.com>
Originally-by: Lanqing Liu<lanqing....@spreadtrum.com>
---
  Documentation/devices.txt        |    3 +
  drivers/tty/serial/Kconfig       |   23 ++
  drivers/tty/serial/Makefile      |    1 +
  drivers/tty/serial/sprd_serial.c |  752 ++++++++++++++++++++++++++++++++++++++
  include/uapi/linux/serial_core.h |    3 +
  5 files changed, 782 insertions(+)
  create mode 100644 drivers/tty/serial/sprd_serial.c

diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index 87b4c5e..1da0432 100644
--- a/Documentation/devices.txt
+++ b/Documentation/devices.txt
@@ -2816,6 +2816,9 @@ Your cooperation is appreciated.
                 210 = /dev/ttyMAX1             MAX3100 serial port 1
                 211 = /dev/ttyMAX2             MAX3100 serial port 2
                 212 = /dev/ttyMAX3             MAX3100 serial port 3
+                213 = /dev/ttySPX0             SPRD serial port 0
+                   ...
+                216 = /dev/ttySPX3             SPRD serial port 3

  205 char      Low-density serial ports (alternate device)
                  0 = /dev/culu0                Callout device for ttyLU0
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 649b784..2c2cf60 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1573,6 +1573,29 @@ config SERIAL_MEN_Z135
          This driver can also be build as a module. If so, the module will be 
called
          men_z135_uart.ko

+config SERIAL_SPRD
+       tristate "Support for SPRD serial"
+       depends on ARCH_SPRD
+       select SERIAL_CORE
+       help
+          This enables the driver for the Spreadtrum's serial.
+
+config SERIAL_SPRD_NR
+        int "Maximum number of sprd serial ports"
+        depends on SERIAL_SPRD
+        default "4"
+
+config SERIAL_SPRD_CONSOLE
+        bool "SPRD UART console support"
+        depends on SERIAL_SPRD=y
+        select SERIAL_CORE_CONSOLE
+       select SERIAL_EARLYCON
+        help
+         Support for early debug console using Spreadtrum's serial. This 
enables
+         the console before standard serial driver is probed. This is enabled
+         with "earlycon" on the kernel command line. The console is
+         enabled when early_param is processed.
+
  endmenu

  config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 9a548ac..4801aca 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_ARC)      += arc_uart.o
  obj-$(CONFIG_SERIAL_RP2)      += rp2.o
  obj-$(CONFIG_SERIAL_FSL_LPUART)       += fsl_lpuart.o
  obj-$(CONFIG_SERIAL_MEN_Z135) += men_z135_uart.o
+obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o

  # GPIOLIB helpers for modem control lines
  obj-$(CONFIG_SERIAL_MCTRL_GPIO)       += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
new file mode 100644
index 0000000..58214c8
--- /dev/null
+++ b/drivers/tty/serial/sprd_serial.c
@@ -0,0 +1,752 @@
+/*
+ * Copyright (C) 2012 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include<linux/module.h>
+#include<linux/tty.h>
+#include<linux/ioport.h>
+#include<linux/console.h>
+#include<linux/platform_device.h>
+#include<linux/tty_flip.h>
+#include<linux/serial_core.h>
+#include<linux/serial.h>
+#include<linux/delay.h>
+#include<linux/io.h>
+#include<asm/irq.h>
+#include<linux/slab.h>
+#include<linux/of.h>
+#include<linux/kernel.h>
+#include<linux/slab.h>
+#include<linux/clk.h>
How about sorting this includes? asm/irq.h go first followed linux/ in alphabatical order?
+
+/* device name */
+#define UART_NR_MAX            CONFIG_SERIAL_SPRD_NR
+#define SPRD_TTY_NAME          "ttySPX"
+#define SPRD_TTY_MAJOR         204
+#define SPRD_TTY_MINOR_START   213
+#define SPRD_FIFO_SIZE         128
+#define SPRD_DEF_RATE          26000000
+
+/* the offset of serial registers and BITs for them */
+/* data registers */
+#define SPRD_TXD               0x0000
+#define SPRD_RXD               0x0004
+
+/* line status register and its BITs  */
+#define SPRD_LSR               0x0008
+#define SPRD_LSR_OE            BIT(4)
+#define SPRD_LSR_FE            BIT(3)
+#define SPRD_LSR_PE            BIT(2)
+#define SPRD_LSR_BI            BIT(7)
+#define SPRD_LSR_TX_OVER       BIT(15)
+
+/* data number in TX and RX fifo */
+#define SPRD_STS1              0x000C
+
+/* interrupt enable register and its BITs */
+#define SPRD_IEN               0x0010
+#define SPRD_IEN_RX_FULL       BIT(0)
+#define SPRD_IEN_TX_EMPTY      BIT(1)
+#define SPRD_IEN_BREAK_DETECT  BIT(7)
+#define SPRD_IEN_TIMEOUT       BIT(13)
+
+/* interrupt clear register */
+#define SPRD_ICLR              0x0014
+
+/* line control register */
+#define SPRD_LCR               0x0018
+#define SPRD_LCR_STOP_1BIT     0x10
+#define SPRD_LCR_STOP_2BIT     0x30
+#define SPRD_LCR_DATA_LEN      (BIT(2) | BIT(3))
+#define SPRD_LCR_DATA_LEN5     0x0
+#define SPRD_LCR_DATA_LEN6     0x4
+#define SPRD_LCR_DATA_LEN7     0x8
+#define SPRD_LCR_DATA_LEN8     0xc
+#define SPRD_LCR_PARITY                (BIT(0) | BIT(1))
+#define SPRD_LCR_PARITY_EN     0x2
+#define SPRD_LCR_EVEN_PAR      0x0
+#define SPRD_LCR_ODD_PAR       0x1
+
+/* control register 1 */
+#define SPRD_CTL1              0x001C
+#define RX_HW_FLOW_CTL_THLD    BIT(6)
+#define RX_HW_FLOW_CTL_EN      BIT(7)
+#define TX_HW_FLOW_CTL_EN      BIT(8)
+
+/* fifo threshold register */
+#define SPRD_CTL2              0x0020
+#define THLD_TX_EMPTY          0x40
+#define THLD_RX_FULL           0x40
+
+/* config baud rate register */
+#define SPRD_CLKD0             0x0024
+#define SPRD_CLKD1             0x0028
+
+/* interrupt mask status register */
+#define SPRD_IMSR              0x002C
+#define SPRD_IMSR_RX_FIFO_FULL BIT(0)
+#define SPRD_IMSR_TX_FIFO_EMPTY        BIT(1)
+#define SPRD_IMSR_BREAK_DETECT BIT(7)
+#define SPRD_IMSR_TIMEOUT      BIT(13)
+
+struct reg_backup {
+       uint32_t ien;
+       uint32_t ctrl0;
+       uint32_t ctrl1;
+       uint32_t ctrl2;
+       uint32_t clkd0;
+       uint32_t clkd1;
+       uint32_t dspwait;
+};
+struct sprd_uart_port {
+       struct uart_port port;
+       struct reg_backup reg_bak;
+       char name[16];
+};
+static struct sprd_uart_port *sprd_port[UART_NR_MAX] = { NULL };
+
+static inline unsigned int serial_in(struct uart_port *port, int offset)
+{
+       return readl_relaxed(port->membase + offset);
+}
+
+static inline void serial_out(struct uart_port *port, int offset, int value)
+{
+       writel_relaxed(value, port->membase + offset);
+}
+
+static unsigned int sprd_tx_empty(struct uart_port *port)
+{
+       if (serial_in(port, SPRD_STS1)&  0xff00)
+               return 0;
+       else
+               return TIOCSER_TEMT;
+}
+
+static unsigned int sprd_get_mctrl(struct uart_port *port)
+{
+       return TIOCM_DSR | TIOCM_CTS;
+}
+
+static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       /* nothing to do */
+}
+
+static void sprd_stop_tx(struct uart_port *port)
+{
+       unsigned int ien, iclr;
+
+       iclr = serial_in(port, SPRD_ICLR);
+       ien = serial_in(port, SPRD_IEN);
+
+       iclr |= SPRD_IEN_TX_EMPTY;
+       ien&= ~SPRD_IEN_TX_EMPTY;
+
+       serial_out(port, SPRD_ICLR, iclr);
+       serial_out(port, SPRD_IEN, ien);
+}
+
+static void sprd_start_tx(struct uart_port *port)
+{
+       unsigned int ien;
+
+       ien = serial_in(port, SPRD_IEN);
+       if (!(ien&  SPRD_IEN_TX_EMPTY)) {
+               ien |= SPRD_IEN_TX_EMPTY;
+               serial_out(port, SPRD_IEN, ien);
+       }
+}
+
+static void sprd_stop_rx(struct uart_port *port)
+{
+       unsigned int ien, iclr;
+
+       iclr = serial_in(port, SPRD_ICLR);
+       ien = serial_in(port, SPRD_IEN);
+
+       ien&= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
+       iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;
+
+       serial_out(port, SPRD_IEN, ien);
+       serial_out(port, SPRD_ICLR, iclr);
+}
+
+/* The Sprd serial does not support this function.  */
+static void sprd_break_ctl(struct uart_port *port, int break_state)
+{
+       /* nothing to do */
+}
+
+static inline int handle_lsr_errors(struct uart_port *port,
+       unsigned int *flag, unsigned int *lsr)
+{
+       int ret = 0;
+
+       /* stastics */
+       if (*lsr&  SPRD_LSR_BI) {
+               *lsr&= ~(SPRD_LSR_FE | SPRD_LSR_PE);
+               port->icount.brk++;
+               ret = uart_handle_break(port);
+               if (ret)
+                       return ret;
+       } else if (*lsr&  SPRD_LSR_PE)
+               port->icount.parity++;
+       else if (*lsr&  SPRD_LSR_FE)
+               port->icount.frame++;
+       if (*lsr&  SPRD_LSR_OE)
+               port->icount.overrun++;
+
+       /* mask off conditions which should be ignored */
+       *lsr&= port->read_status_mask;
+       if (*lsr&  SPRD_LSR_BI)
+               *flag = TTY_BREAK;
+       else if (*lsr&  SPRD_LSR_PE)
+               *flag = TTY_PARITY;
+       else if (*lsr&  SPRD_LSR_FE)
+               *flag = TTY_FRAME;
+
+       return ret;
+}
+
+static inline void sprd_rx(int irq, void *dev_id)
+{
+       struct uart_port *port = (struct uart_port *)dev_id;
+       struct tty_port *tty =&port->state->port;
+       unsigned int ch, flag, lsr, max_count = 2048;
+
+       while ((serial_in(port, SPRD_STS1)&  0x00ff)&&  max_count--) {
+               lsr = serial_in(port, SPRD_LSR);
+               ch = serial_in(port, SPRD_RXD);
+               flag = TTY_NORMAL;
+               port->icount.rx++;
+
+               if (unlikely(lsr&  (SPRD_LSR_BI | SPRD_LSR_PE
+                               | SPRD_LSR_FE | SPRD_LSR_OE)))
+                       if (handle_lsr_errors(port,&lsr,&flag))
+                               continue;
+               if (uart_handle_sysrq_char(port, ch))
+                       continue;
+
+               uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
+       }
+
+       tty_flip_buffer_push(tty);
+}
+
+static inline void sprd_tx(int irq, void *dev_id)
+{
+       struct uart_port *port = dev_id;
+       struct circ_buf *xmit =&port->state->xmit;
+       int count;
+
+       if (port->x_char) {
+               serial_out(port, SPRD_TXD, port->x_char);
+               port->icount.tx++;
+               port->x_char = 0;
+               return;
+       }
+       if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+               sprd_stop_tx(port);
+               return;
+       }
+       count = THLD_TX_EMPTY;
+       do {
+               serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
+               xmit->tail = (xmit->tail + 1)&  (UART_XMIT_SIZE - 1);
+               port->icount.tx++;
+               if (uart_circ_empty(xmit))
+                       break;
+       } while (--count>  0);
+
+       if (uart_circ_chars_pending(xmit)<  WAKEUP_CHARS)
+               uart_write_wakeup(port);
+
+       if (uart_circ_empty(xmit))
+               sprd_stop_tx(port);
+}
+
+/*
+ *this handles the interrupt from one port
+ */
+static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
+{
+       struct uart_port *port = (struct uart_port *)dev_id;
+       u32 ims;
+
+       ims = serial_in(port, SPRD_IMSR);
+
+       serial_out(port, SPRD_ICLR, ~0);
+
+       if (ims&  (SPRD_IMSR_RX_FIFO_FULL |
+               SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT)) {
+               sprd_rx(irq, port);
+       }
+       if (ims&  SPRD_IMSR_TX_FIFO_EMPTY)
+               sprd_tx(irq, port);
+
+       return IRQ_HANDLED;
You are always returning IRQ_HANDLED and this is registered as a SHARED irq. Is there a chance this handler is called and the irq event doesn't
belong to this device?

Murali
+}
+
+static int sprd_startup(struct uart_port *port)
+{
+       int ret = 0;
+       unsigned int ien, ctrl1;
+       struct sprd_uart_port *sp;
+
+       serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY<<  8) | THLD_RX_FULL));
+
+       /* clear rx fifo */
+       while (serial_in(port, SPRD_STS1)&  0x00ff)
+               serial_in(port, SPRD_RXD);
+
+       /* clear tx fifo */
+       while (serial_in(port, SPRD_STS1)&  0xff00)
+               ;
+
+       /* clear interrupt */
+       serial_out(port, SPRD_IEN, 0x0);
+       serial_out(port, SPRD_ICLR, ~0);
+
+       /* allocate irq */
+       sp = container_of(port, struct sprd_uart_port, port);
+       snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
+       ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
+                       IRQF_SHARED, sp->name, port);
+       if (ret) {
+               dev_err(port->dev, "fail to request serial irq %d\n",
+                       port->irq);
+               return ret;
+       }
+       ctrl1 = serial_in(port, SPRD_CTL1);
+       ctrl1 |= 0x3e00 | THLD_RX_FULL;
+       serial_out(port, SPRD_CTL1, ctrl1);
+
+       /* enable interrupt */
+       spin_lock(&port->lock);
+       ien = serial_in(port, SPRD_IEN);
+       ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
+       serial_out(port, SPRD_IEN, ien);
+       spin_unlock(&port->lock);
+
+       return 0;
+}
+
+static void sprd_shutdown(struct uart_port *port)
+{
+       serial_out(port, SPRD_IEN, 0x0);
+       serial_out(port, SPRD_ICLR, ~0);
+       devm_free_irq(port->dev, port->irq, port);
+}
+
+static void sprd_set_termios(struct uart_port *port,
+                                   struct ktermios *termios,
+                                   struct ktermios *old)
+{
+       unsigned int baud, quot;
+       unsigned int lcr, fc;
+
+       /* ask the core to calculate the divisor for us */
+       baud = uart_get_baud_rate(port, termios, old, 1200, 3000000);
+
+       quot = (unsigned int)((port->uartclk + baud / 2) / baud);
+
+       /* set data length */
+       lcr = serial_in(port, SPRD_LCR);
+       lcr&= ~SPRD_LCR_DATA_LEN;
+       switch (termios->c_cflag&  CSIZE) {
+       case CS5:
+               lcr |= SPRD_LCR_DATA_LEN5;
+               break;
+       case CS6:
+               lcr |= SPRD_LCR_DATA_LEN6;
+               break;
+       case CS7:
+               lcr |= SPRD_LCR_DATA_LEN7;
+               break;
+       case CS8:
+       default:
+               lcr |= SPRD_LCR_DATA_LEN8;
+               break;
+       }
+
+       /* calculate stop bits */
+       lcr&= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
+       if (termios->c_cflag&  CSTOPB)
+               lcr |= SPRD_LCR_STOP_2BIT;
+       else
+               lcr |= SPRD_LCR_STOP_1BIT;
+
+       /* calculate parity */
+       lcr&= ~SPRD_LCR_PARITY;
+       if (termios->c_cflag&  PARENB) {
+               lcr |= SPRD_LCR_PARITY_EN;
+               if (termios->c_cflag&  PARODD)
+                       lcr |= SPRD_LCR_ODD_PAR;
+               else
+                       lcr |= SPRD_LCR_EVEN_PAR;
+       }
+
+       /* change the port state. */
+       /* update the per-port timeout */
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       port->read_status_mask = SPRD_LSR_OE;
+       if (termios->c_iflag&  INPCK)
+               port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
+       if (termios->c_iflag&  (BRKINT | PARMRK))
+               port->read_status_mask |= SPRD_LSR_BI;
+
+       /* characters to ignore */
+       port->ignore_status_mask = 0;
+       if (termios->c_iflag&  IGNPAR)
+               port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
+       if (termios->c_iflag&  IGNBRK) {
+               port->ignore_status_mask |= SPRD_LSR_BI;
+               /*
+                * If we're ignoring parity and break indicators,
+                * ignore overruns too (for real raw support).
+                */
+               if (termios->c_iflag&  IGNPAR)
+                       port->ignore_status_mask |= SPRD_LSR_OE;
+       }
+
+       /* flow control */
+       fc = serial_in(port, SPRD_CTL1);
+       fc&= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
+       if (termios->c_cflag&  CRTSCTS) {
+               fc |= RX_HW_FLOW_CTL_THLD;
+               fc |= RX_HW_FLOW_CTL_EN;
+               fc |= TX_HW_FLOW_CTL_EN;
+       }
+
+       /* clock divider bit0~bit15 */
+       serial_out(port, SPRD_CLKD0, quot&  0xffff);
+
+       /* clock divider bit16~bit20 */
+       serial_out(port, SPRD_CLKD1, (quot&  0x1f0000)>>  16);
+       serial_out(port, SPRD_LCR, lcr);
+       fc |= 0x3e00 | THLD_RX_FULL;
+       serial_out(port, SPRD_CTL1, fc);
+}
+
+static const char *sprd_type(struct uart_port *port)
+{
+       return "SPX";
+}
+
+static void sprd_release_port(struct uart_port *port)
+{
+       /* nothing to do */
+}
+
+static int sprd_request_port(struct uart_port *port)
+{
+       return 0;
+}
+
+static void sprd_config_port(struct uart_port *port, int flags)
+{
+       if (flags&  UART_CONFIG_TYPE)
+               port->type = PORT_SPRD;
+}
+
+static int sprd_verify_port(struct uart_port *port,
+                                  struct serial_struct *ser)
+{
+       if (unlikely(ser->type != PORT_SPRD))
+               return -EINVAL;
+       if (unlikely(port->irq != ser->irq))
+               return -EINVAL;
+       return 0;
+}
+
+static struct uart_ops serial_sprd_ops = {
+       .tx_empty = sprd_tx_empty,
+       .get_mctrl = sprd_get_mctrl,
+       .set_mctrl = sprd_set_mctrl,
+       .stop_tx = sprd_stop_tx,
+       .start_tx = sprd_start_tx,
+       .stop_rx = sprd_stop_rx,
+       .break_ctl = sprd_break_ctl,
+       .startup = sprd_startup,
+       .shutdown = sprd_shutdown,
+       .set_termios = sprd_set_termios,
+       .type = sprd_type,
+       .release_port = sprd_release_port,
+       .request_port = sprd_request_port,
+       .config_port = sprd_config_port,
+       .verify_port = sprd_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_SPRD_CONSOLE
+static inline void wait_for_xmitr(struct uart_port *port)
+{
+       unsigned int status, tmout = 10000;
+
+       /* wait up to 10ms for the character(s) to be sent */
+       do {
+               status = serial_in(port, SPRD_STS1);
+               if (--tmout == 0)
+                       break;
+               udelay(1);
+       } while (status&  0xff00);
+}
+
+static void sprd_console_putchar(struct uart_port *port, int ch)
+{
+       wait_for_xmitr(port);
+       serial_out(port, SPRD_TXD, ch);
+}
+
+static void sprd_console_write(struct console *co, const char *s,
+                                     unsigned int count)
+{
+       struct uart_port *port = (struct uart_port *)sprd_port[co->index];
+       int ien;
+       int locked = 1;
+
+       if (oops_in_progress)
+               locked = spin_trylock(&port->lock);
+       else
+               spin_lock(&port->lock);
+       /* save the IEN then disable the interrupts */
+       ien = serial_in(port, SPRD_IEN);
+       serial_out(port, SPRD_IEN, 0x0);
+
+       uart_console_write(port, s, count, sprd_console_putchar);
+
+       /* wait for transmitter to become empty and restore the IEN */
+       wait_for_xmitr(port);
+       serial_out(port, SPRD_IEN, ien);
+       if (locked)
+               spin_unlock(&port->lock);
+}
+
+static int __init sprd_console_setup(struct console *co, char *options)
+{
+       struct uart_port *port;
+       int baud = 115200;
+       int bits = 8;
+       int parity = 'n';
+       int flow = 'n';
+
+       if (unlikely(co->index>= UART_NR_MAX || co->index<  0))
+               co->index = 0;
+
+       port = (struct uart_port *)sprd_port[co->index];
+       if (port == NULL) {
+               pr_info("srial port %d not yet initialized\n", co->index);
+               return -ENODEV;
+       }
+       if (options)
+               uart_parse_options(options,&baud,&parity,&bits,&flow);
+
+       return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver sprd_uart_driver;
+static struct console sprd_console = {
+       .name = SPRD_TTY_NAME,
+       .write = sprd_console_write,
+       .device = uart_console_device,
+       .setup = sprd_console_setup,
+       .flags = CON_PRINTBUFFER,
+       .index = -1,
+       .data =&sprd_uart_driver,
+};
+
+#define SPRD_CONSOLE   (&sprd_console)
+
+/* Support for earlycon */
+static void sprd_putc(struct uart_port *port, int c)
+{
+       while (!(readl(port->membase + SPRD_LSR)&  SPRD_LSR_TX_OVER))
+               ;
+       writeb(c, port->membase + SPRD_TXD);
+}
+
+static void sprd_early_write(struct console *con, const char *s,
+                                   unsigned n)
+{
+       struct earlycon_device *dev = con->data;
+
+       uart_console_write(&dev->port, s, n, sprd_putc);
+}
+
+static int __init sprd_early_console_setup(
+                               struct earlycon_device *device,
+                               const char *opt)
+{
+       if (!device->port.membase)
+               return -ENODEV;
+
+       device->con->write = sprd_early_write;
+       return 0;
+}
+
+EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
+OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
+                   sprd_early_console_setup);
+
+#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
+#define SPRD_CONSOLE           NULL
+#endif
+
+static struct uart_driver sprd_uart_driver = {
+       .owner = THIS_MODULE,
+       .driver_name = "sprd_serial",
+       .dev_name = SPRD_TTY_NAME,
+       .major = SPRD_TTY_MAJOR,
+       .minor = SPRD_TTY_MINOR_START,
+       .nr = UART_NR_MAX,
+       .cons = SPRD_CONSOLE,
+};
+
+static int sprd_probe(struct platform_device *pdev)
+{
+       struct resource *mem;
+       struct device_node *np = pdev->dev.of_node;
+       struct uart_port *up;
+       struct clk *clk;
+       int irq;
+
+
+       if (np)
+               pdev->id = of_alias_get_id(np, "serial");
+
+       if (unlikely(pdev->id<  0 || pdev->id>= UART_NR_MAX)) {
+               dev_err(&pdev->dev, "does not support id %d\n", pdev->id);
+               return -ENXIO;
+       }
+
+       sprd_port[pdev->id] = devm_kzalloc(&pdev->dev,
+               sizeof(*sprd_port[pdev->id]), GFP_KERNEL);
+       if (!sprd_port[pdev->id])
+               return -ENOMEM;
+
+       up = (struct uart_port *)sprd_port[pdev->id];
+       up->dev =&pdev->dev;
+       up->line = pdev->id;
+       up->type = PORT_SPRD;
+       up->iotype = SERIAL_IO_PORT;
+       up->uartclk = SPRD_DEF_RATE;
+       up->fifosize = SPRD_FIFO_SIZE;
+       up->ops =&serial_sprd_ops;
+       up->flags = ASYNC_BOOT_AUTOCONF;
+
+       clk = devm_clk_get(&pdev->dev, NULL);
+       if (!IS_ERR(clk))
+               up->uartclk = clk_get_rate(clk);
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (unlikely(!mem)) {
+               dev_err(&pdev->dev, "not provide mem resource\n");
+               return -ENODEV;
+       }
+       up->mapbase = mem->start;
+       up->membase = ioremap(mem->start, resource_size(mem));
+
+       irq = platform_get_irq(pdev, 0);
+       if (unlikely(irq<  0)) {
+               dev_err(&pdev->dev, "not provide irq resource\n");
+               return -ENODEV;
+       }
+       up->irq = irq;
+
+       platform_set_drvdata(pdev, up);
+
+       return uart_add_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_remove(struct platform_device *dev)
+{
+       struct uart_port *up = platform_get_drvdata(dev);
+
+       return uart_remove_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_suspend(struct platform_device *dev, pm_message_t state)
+{
+       int id = dev->id;
+       struct uart_port *port = (struct uart_port *)sprd_port[id];
+       struct reg_backup *reg_bak =&(sprd_port[id]->reg_bak);
+
+       reg_bak->ien = serial_in(port, SPRD_IEN);
+       reg_bak->ctrl0 = serial_in(port, SPRD_LCR);
+       reg_bak->ctrl1 = serial_in(port, SPRD_CTL1);
+       reg_bak->ctrl2 = serial_in(port, SPRD_CTL2);
+       reg_bak->clkd0 = serial_in(port, SPRD_CLKD0);
+       reg_bak->clkd1 = serial_in(port, SPRD_CLKD1);
+
+       return 0;
+}
+
+static int sprd_resume(struct platform_device *dev)
+{
+       int id = dev->id;
+       struct uart_port *port = (struct uart_port *)sprd_port[id];
+       struct reg_backup *reg_bak =&(sprd_port[id]->reg_bak);
+
+       serial_out(port, SPRD_LCR, reg_bak->ctrl0);
+       serial_out(port, SPRD_CTL1, reg_bak->ctrl1);
+       serial_out(port, SPRD_CTL2, reg_bak->ctrl2);
+       serial_out(port, SPRD_CLKD0, reg_bak->clkd0);
+       serial_out(port, SPRD_CLKD1, reg_bak->clkd1);
+       serial_out(port, SPRD_IEN, reg_bak->ien);
+
+       return 0;
+}
+
+static const struct of_device_id serial_ids[] = {
+       {.compatible = "sprd,sc9836-uart",},
+       {}
+};
+
+static struct platform_driver sprd_platform_driver = {
+       .probe = sprd_probe,
+       .remove = sprd_remove,
+       .suspend = sprd_suspend,
+       .resume = sprd_resume,
+       .driver = {
+                  .name = "sprd_serial",
+                  .owner = THIS_MODULE,
+                  .of_match_table = of_match_ptr(serial_ids),
+                  },
+};
+
+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);
+       if (unlikely(ret != 0))
+               return ret;
+
+       ret = platform_driver_register(&sprd_platform_driver);
+       if (unlikely(ret != 0))
+               uart_unregister_driver(&sprd_uart_driver);
+
+       return ret;
+}
+
+static void __exit sprd_serial_exit(void)
+{
+       platform_driver_unregister(&sprd_platform_driver);
+       uart_unregister_driver(&sprd_uart_driver);
+}
+
+module_init(sprd_serial_init);
+module_exit(sprd_serial_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 16ad852..d9a8c88 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -247,4 +247,7 @@
  /* MESON */
  #define PORT_MESON    109

+/* SPRD SERIAL  */
+#define PORT_SPRD   110
+
  #endif /* _UAPILINUX_SERIAL_CORE_H */


--
Murali Karicheri
Linux Kernel, Texas Instruments

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