Implement serial console driver to complement earlycon.

Based on LeMaker linux-actions tree.

Signed-off-by: Andreas Färber <afaer...@suse.de>
---
 v4 -> v5:
 * Don't clear HUPCL, IGNBRK or BRKINT (Alan)
 * Don't set CLOCAL (Alan)
 * Added tty_termios_encode_baud_rate() call (Alan)
 * Extended get_mctrl with RTS/CTS
 * Adopted GENMASK() macro (Andy)
 * Dropped cast from void * (Andy)
 * Adopted devm_clk_get() (Andy)
 * Checked for uartclk == 0 (Andy)
 * Changed port ID from 117 to unused 36 (Andy)
 * Adopted spin_lock_irqsave() in owl_uart_irq() (Andy)
 * Adopted platform_get_irq() (Andy)
 * Implemented TIOCM_LOOP in set_mctrl
 * Switched platform driver to s500/s900 compatibles from owl
 * Set TX fifosize based on compatible (16 -> 32 for S900)
 
 v3 -> v4: Unchanged
 
 v2 -> v3:
 * Adopted BIT() macro
 * Implemented baudrate setting
 
 v2: new
 
 drivers/tty/serial/Kconfig       |   4 +-
 drivers/tty/serial/owl-uart.c    | 635 ++++++++++++++++++++++++++++++++++++++-
 include/uapi/linux/serial_core.h |   1 +
 3 files changed, 636 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 1f096e2bb398..b788fee54249 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1689,7 +1689,7 @@ config SERIAL_MVEBU_CONSOLE
          Otherwise, say 'N'.
 
 config SERIAL_OWL
-       bool "Actions Semi Owl serial port support"
+       tristate "Actions Semi Owl serial port support"
        depends on ARCH_ACTIONS || COMPILE_TEST
        select SERIAL_CORE
        help
@@ -1705,7 +1705,7 @@ config SERIAL_OWL_CONSOLE
        default y
        help
          Say 'Y' here if you wish to use Actions Semiconductor S500/S900 UART
-         as the system console. Only earlycon is implemented currently.
+         as the system console.
 
 endmenu
 
diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
index 1b8008797a1b..683b05478ade 100644
--- a/drivers/tty/serial/owl-uart.c
+++ b/drivers/tty/serial/owl-uart.c
@@ -20,6 +20,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/clk.h>
 #include <linux/console.h>
 #include <linux/delay.h>
 #include <linux/io.h>
@@ -28,22 +29,66 @@
 #include <linux/platform_device.h>
 #include <linux/serial.h>
 #include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#define OWL_UART_PORT_NUM 7
+#define OWL_UART_DEV_NAME "ttyOWL"
 
 #define OWL_UART_CTL   0x000
+#define OWL_UART_RXDAT 0x004
 #define OWL_UART_TXDAT 0x008
 #define OWL_UART_STAT  0x00c
 
+#define OWL_UART_CTL_DWLS_MASK         GENMASK(1, 0)
+#define OWL_UART_CTL_DWLS_5BITS                (0x0 << 0)
+#define OWL_UART_CTL_DWLS_6BITS                (0x1 << 0)
+#define OWL_UART_CTL_DWLS_7BITS                (0x2 << 0)
+#define OWL_UART_CTL_DWLS_8BITS                (0x3 << 0)
+#define OWL_UART_CTL_STPS_2BITS                BIT(2)
+#define OWL_UART_CTL_PRS_MASK          GENMASK(6, 4)
+#define OWL_UART_CTL_PRS_NONE          (0x0 << 4)
+#define OWL_UART_CTL_PRS_ODD           (0x4 << 4)
+#define OWL_UART_CTL_PRS_MARK          (0x5 << 4)
+#define OWL_UART_CTL_PRS_EVEN          (0x6 << 4)
+#define OWL_UART_CTL_PRS_SPACE         (0x7 << 4)
+#define OWL_UART_CTL_AFE               BIT(12)
 #define OWL_UART_CTL_TRFS_TX           BIT(14)
 #define OWL_UART_CTL_EN                        BIT(15)
+#define OWL_UART_CTL_RXDE              BIT(16)
+#define OWL_UART_CTL_TXDE              BIT(17)
 #define OWL_UART_CTL_RXIE              BIT(18)
 #define OWL_UART_CTL_TXIE              BIT(19)
+#define OWL_UART_CTL_LBEN              BIT(20)
 
 #define OWL_UART_STAT_RIP              BIT(0)
 #define OWL_UART_STAT_TIP              BIT(1)
+#define OWL_UART_STAT_RXER             BIT(2)
+#define OWL_UART_STAT_TFER             BIT(3)
+#define OWL_UART_STAT_RXST             BIT(4)
+#define OWL_UART_STAT_RFEM             BIT(5)
 #define OWL_UART_STAT_TFFU             BIT(6)
-#define OWL_UART_STAT_TRFL_MASK                (0x1f << 11)
+#define OWL_UART_STAT_CTSS             BIT(7)
+#define OWL_UART_STAT_RTSS             BIT(8)
+#define OWL_UART_STAT_TFES             BIT(10)
+#define OWL_UART_STAT_TRFL_MASK                GENMASK(16, 11)
 #define OWL_UART_STAT_UTBB             BIT(17)
 
+static struct uart_driver owl_uart_driver;
+
+struct owl_uart_info {
+       unsigned int tx_fifosize;
+};
+
+struct owl_uart_port {
+       struct uart_port port;
+       struct clk *clk;
+};
+
+#define to_owl_uart_port(prt) container_of(prt, struct owl_uart_port, prt)
+
+static struct owl_uart_port *owl_uart_ports[OWL_UART_PORT_NUM];
+
 static inline void owl_uart_write(struct uart_port *port, u32 val, unsigned 
int off)
 {
        writel(val, port->membase + off);
@@ -54,6 +99,397 @@ static inline u32 owl_uart_read(struct uart_port *port, 
unsigned int off)
        return readl(port->membase + off);
 }
 
+static void owl_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       u32 ctl;
+
+       ctl = owl_uart_read(port, OWL_UART_CTL);
+
+       if (mctrl & TIOCM_LOOP)
+               ctl |= OWL_UART_CTL_LBEN;
+       else
+               ctl &= ~OWL_UART_CTL_LBEN;
+
+       owl_uart_write(port, ctl, OWL_UART_CTL);
+}
+
+static unsigned int owl_uart_get_mctrl(struct uart_port *port)
+{
+       unsigned int mctrl = TIOCM_CAR | TIOCM_DSR;
+       u32 stat, ctl;
+
+       ctl = owl_uart_read(port, OWL_UART_CTL);
+       stat = owl_uart_read(port, OWL_UART_STAT);
+       if (stat & OWL_UART_STAT_RTSS)
+               mctrl |= TIOCM_RTS;
+       if ((stat & OWL_UART_STAT_CTSS) || !(ctl & OWL_UART_CTL_AFE))
+               mctrl |= TIOCM_CTS;
+       return mctrl;
+}
+
+static unsigned int owl_uart_tx_empty(struct uart_port *port)
+{
+       unsigned long flags;
+       u32 val;
+       unsigned int ret;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       val = owl_uart_read(port, OWL_UART_STAT);
+       ret = (val & OWL_UART_STAT_TFES) ? TIOCSER_TEMT : 0;
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return ret;
+}
+
+static void owl_uart_stop_rx(struct uart_port *port)
+{
+       u32 val;
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val &= ~(OWL_UART_CTL_RXIE | OWL_UART_CTL_RXDE);
+       owl_uart_write(port, val, OWL_UART_CTL);
+
+       val = owl_uart_read(port, OWL_UART_STAT);
+       val |= OWL_UART_STAT_RIP;
+       owl_uart_write(port, val, OWL_UART_STAT);
+}
+
+static void owl_uart_stop_tx(struct uart_port *port)
+{
+       u32 val;
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_TXDE);
+       owl_uart_write(port, val, OWL_UART_CTL);
+
+       val = owl_uart_read(port, OWL_UART_STAT);
+       val |= OWL_UART_STAT_TIP;
+       owl_uart_write(port, val, OWL_UART_STAT);
+}
+
+static void owl_uart_start_tx(struct uart_port *port)
+{
+       u32 val;
+
+       if (uart_tx_stopped(port)) {
+               owl_uart_stop_tx(port);
+               return;
+       }
+
+       val = owl_uart_read(port, OWL_UART_STAT);
+       val |= OWL_UART_STAT_TIP;
+       owl_uart_write(port, val, OWL_UART_STAT);
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val |= OWL_UART_CTL_TXIE;
+       owl_uart_write(port, val, OWL_UART_CTL);
+}
+
+static void owl_uart_send_chars(struct uart_port *port)
+{
+       struct circ_buf *xmit = &port->state->xmit;
+       unsigned int ch;
+
+       if (uart_tx_stopped(port))
+               return;
+
+       if (port->x_char) {
+               while (!(owl_uart_read(port, OWL_UART_STAT) & 
OWL_UART_STAT_TFFU))
+                       cpu_relax();
+               owl_uart_write(port, port->x_char, OWL_UART_TXDAT);
+               port->icount.tx++;
+               port->x_char = 0;
+       }
+
+       while (!(owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TFFU)) {
+               if (uart_circ_empty(xmit))
+                       break;
+
+               ch = xmit->buf[xmit->tail];
+               owl_uart_write(port, ch, OWL_UART_TXDAT);
+               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))
+               owl_uart_stop_tx(port);
+}
+
+static void owl_uart_receive_chars(struct uart_port *port)
+{
+       u32 stat, val;
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val &= ~OWL_UART_CTL_TRFS_TX;
+       owl_uart_write(port, val, OWL_UART_CTL);
+
+       stat = owl_uart_read(port, OWL_UART_STAT);
+       while (!(stat & OWL_UART_STAT_RFEM)) {
+               char flag = TTY_NORMAL;
+
+               if (stat & OWL_UART_STAT_RXER)
+                       port->icount.overrun++;
+
+               if (stat & OWL_UART_STAT_RXST) {
+                       /* We are not able to distinguish the error type. */
+                       port->icount.brk++;
+                       port->icount.frame++;
+
+                       stat &= port->read_status_mask;
+                       if (stat & OWL_UART_STAT_RXST)
+                               flag = TTY_PARITY;
+               } else
+                       port->icount.rx++;
+
+               val = owl_uart_read(port, OWL_UART_RXDAT);
+               val &= 0xff;
+
+               if ((stat & port->ignore_status_mask) == 0)
+                       tty_insert_flip_char(&port->state->port, val, flag);
+
+               stat = owl_uart_read(port, OWL_UART_STAT);
+       }
+
+       spin_unlock(&port->lock);
+       tty_flip_buffer_push(&port->state->port);
+       spin_lock(&port->lock);
+}
+
+static irqreturn_t owl_uart_irq(int irq, void *dev_id)
+{
+       struct uart_port *port = dev_id;
+       unsigned long flags;
+       u32 stat;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       stat = owl_uart_read(port, OWL_UART_STAT);
+
+       if (stat & OWL_UART_STAT_RIP)
+               owl_uart_receive_chars(port);
+
+       if (stat & OWL_UART_STAT_TIP)
+               owl_uart_send_chars(port);
+
+       stat = owl_uart_read(port, OWL_UART_STAT);
+       stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP;
+       owl_uart_write(port, stat, OWL_UART_STAT);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return IRQ_HANDLED;
+}
+
+static void owl_uart_shutdown(struct uart_port *port)
+{
+       u32 val;
+       unsigned long flags;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_RXIE
+               | OWL_UART_CTL_TXDE | OWL_UART_CTL_RXDE | OWL_UART_CTL_EN);
+       owl_uart_write(port, val, OWL_UART_CTL);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       free_irq(port->irq, port);
+}
+
+static int owl_uart_startup(struct uart_port *port)
+{
+       u32 val;
+       unsigned long flags;
+       int ret;
+
+       ret = request_irq(port->irq, owl_uart_irq, IRQF_TRIGGER_HIGH,
+                       "owl-uart", port);
+       if (ret)
+               return ret;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       val = owl_uart_read(port, OWL_UART_STAT);
+       val |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP
+               | OWL_UART_STAT_RXER | OWL_UART_STAT_TFER | OWL_UART_STAT_RXST;
+       owl_uart_write(port, val, OWL_UART_STAT);
+
+       val = owl_uart_read(port, OWL_UART_CTL);
+       val |= OWL_UART_CTL_RXIE | OWL_UART_CTL_TXIE;
+       val |= OWL_UART_CTL_EN;
+       owl_uart_write(port, val, OWL_UART_CTL);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       return 0;
+}
+
+static void owl_uart_change_baudrate(struct owl_uart_port *owl_port,
+                                    unsigned long baud)
+{
+       clk_set_rate(owl_port->clk, baud * 8);
+}
+
+static void owl_uart_set_termios(struct uart_port *port,
+                                struct ktermios *termios,
+                                struct ktermios *old)
+{
+       struct owl_uart_port *owl_port = to_owl_uart_port(port);
+       unsigned int baud;
+       u32 ctl;
+       unsigned long flags;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       ctl = owl_uart_read(port, OWL_UART_CTL);
+
+       ctl &= ~OWL_UART_CTL_DWLS_MASK;
+       switch (termios->c_cflag & CSIZE) {
+       case CS5:
+               ctl |= OWL_UART_CTL_DWLS_5BITS;
+               break;
+       case CS6:
+               ctl |= OWL_UART_CTL_DWLS_6BITS;
+               break;
+       case CS7:
+               ctl |= OWL_UART_CTL_DWLS_7BITS;
+               break;
+       case CS8:
+       default:
+               ctl |= OWL_UART_CTL_DWLS_8BITS;
+               break;
+       }
+
+       if (termios->c_cflag & CSTOPB)
+               ctl |= OWL_UART_CTL_STPS_2BITS;
+       else
+               ctl &= ~OWL_UART_CTL_STPS_2BITS;
+
+       ctl &= ~OWL_UART_CTL_PRS_MASK;
+       if (termios->c_cflag & PARENB) {
+               if (termios->c_cflag & CMSPAR) {
+                       if (termios->c_cflag & PARODD)
+                               ctl |= OWL_UART_CTL_PRS_MARK;
+                       else
+                               ctl |= OWL_UART_CTL_PRS_SPACE;
+               } else if (termios->c_cflag & PARODD)
+                       ctl |= OWL_UART_CTL_PRS_ODD;
+               else
+                       ctl |= OWL_UART_CTL_PRS_EVEN;
+       } else
+               ctl |= OWL_UART_CTL_PRS_NONE;
+
+       if (termios->c_cflag & CRTSCTS)
+               ctl |= OWL_UART_CTL_AFE;
+       else
+               ctl &= ~OWL_UART_CTL_AFE;
+
+       owl_uart_write(port, ctl, OWL_UART_CTL);
+
+       baud = uart_get_baud_rate(port, termios, old, 9600, 3200000);
+       owl_uart_change_baudrate(owl_port, baud);
+
+       /* Don't rewrite B0 */
+       if (tty_termios_baud_rate(termios))
+               tty_termios_encode_baud_rate(termios, baud, baud);
+
+       port->read_status_mask |= OWL_UART_STAT_RXER;
+       if (termios->c_iflag & INPCK)
+               port->read_status_mask |= OWL_UART_STAT_RXST;
+
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void owl_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 owl_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 const char *owl_uart_type(struct uart_port *port)
+{
+       return (port->type == PORT_OWL) ? "owl-uart" : NULL;
+}
+
+static int owl_uart_verify_port(struct uart_port *port,
+                               struct serial_struct *ser)
+{
+       if (port->type != PORT_OWL)
+               return -EINVAL;
+
+       if (port->irq != ser->irq)
+               return -EINVAL;
+
+       return 0;
+}
+
+static void owl_uart_config_port(struct uart_port *port, int flags)
+{
+       if (flags & UART_CONFIG_TYPE) {
+               port->type = PORT_OWL;
+               owl_uart_request_port(port);
+       }
+}
+
+static struct uart_ops owl_uart_ops = {
+       .set_mctrl = owl_uart_set_mctrl,
+       .get_mctrl = owl_uart_get_mctrl,
+       .tx_empty = owl_uart_tx_empty,
+       .start_tx = owl_uart_start_tx,
+       .stop_rx = owl_uart_stop_rx,
+       .stop_tx = owl_uart_stop_tx,
+       .startup = owl_uart_startup,
+       .shutdown = owl_uart_shutdown,
+       .set_termios = owl_uart_set_termios,
+       .type = owl_uart_type,
+       .config_port = owl_uart_config_port,
+       .request_port = owl_uart_request_port,
+       .release_port = owl_uart_release_port,
+       .verify_port = owl_uart_verify_port,
+};
+
 #ifdef CONFIG_SERIAL_OWL_CONSOLE
 
 static void owl_console_putchar(struct uart_port *port, int ch)
@@ -110,6 +546,57 @@ static void owl_uart_port_write(struct uart_port *port, 
const char *s,
        local_irq_restore(flags);
 }
 
+static void owl_uart_console_write(struct console *co, const char *s,
+                                  u_int count)
+{
+       struct owl_uart_port *owl_port;
+
+       owl_port = owl_uart_ports[co->index];
+       if (!owl_port)
+               return;
+
+       owl_uart_port_write(&owl_port->port, s, count);
+}
+
+static int owl_uart_console_setup(struct console *co, char *options)
+{
+       struct owl_uart_port *owl_port;
+       int baud = 115200;
+       int bits = 8;
+       int parity = 'n';
+       int flow = 'n';
+
+       if (co->index < 0 || co->index >= OWL_UART_PORT_NUM)
+               return -EINVAL;
+
+       owl_port = owl_uart_ports[co->index];
+       if (!owl_port || !owl_port->port.membase)
+               return -ENODEV;
+
+       if (options)
+               uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+       return uart_set_options(&owl_port->port, co, baud, parity, bits, flow);
+}
+
+static struct console owl_uart_console = {
+       .name = OWL_UART_DEV_NAME,
+       .write = owl_uart_console_write,
+       .device = uart_console_device,
+       .setup = owl_uart_console_setup,
+       .flags = CON_PRINTBUFFER,
+       .index = -1,
+       .data = &owl_uart_driver,
+};
+
+static int __init owl_uart_console_init(void)
+{
+       register_console(&owl_uart_console);
+
+       return 0;
+}
+console_initcall(owl_uart_console_init);
+
 static void owl_uart_early_console_write(struct console *co,
                                         const char *s,
                                         u_int count)
@@ -132,4 +619,148 @@ owl_uart_early_console_setup(struct earlycon_device 
*device, const char *opt)
 OF_EARLYCON_DECLARE(owl, "actions,owl-uart",
                    owl_uart_early_console_setup);
 
-#endif /* CONFIG_SERIAL_OWL_CONSOLE */
+#define OWL_UART_CONSOLE (&owl_uart_console)
+#else
+#define OWL_UART_CONSOLE NULL
+#endif
+
+static struct uart_driver owl_uart_driver = {
+       .owner = THIS_MODULE,
+       .driver_name = "owl-uart",
+       .dev_name = OWL_UART_DEV_NAME,
+       .nr = OWL_UART_PORT_NUM,
+       .cons = OWL_UART_CONSOLE,
+};
+
+static const struct owl_uart_info owl_s500_info = {
+       .tx_fifosize = 16,
+};
+
+static const struct owl_uart_info owl_s900_info = {
+       .tx_fifosize = 32,
+};
+
+static const struct of_device_id owl_uart_dt_matches[] = {
+       { .compatible = "actions,s500-uart", .data = &owl_s500_info },
+       { .compatible = "actions,s900-uart", .data = &owl_s900_info },
+       { }
+};
+MODULE_DEVICE_TABLE(of, owl_uart_dt_matches);
+
+static int owl_uart_probe(struct platform_device *pdev)
+{
+       const struct of_device_id *match;
+       const struct owl_uart_info *info = NULL;
+       struct resource *res_mem;
+       struct owl_uart_port *owl_port;
+       int ret, irq;
+
+       if (pdev->dev.of_node) {
+               pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+               match = of_match_node(owl_uart_dt_matches, pdev->dev.of_node);
+               if (match)
+                       info = match->data;
+       }
+
+       if (pdev->id < 0 || pdev->id >= OWL_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 (owl_uart_ports[pdev->id]) {
+               dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
+               return -EBUSY;
+       }
+
+       owl_port = devm_kzalloc(&pdev->dev, sizeof(*owl_port), GFP_KERNEL);
+       if (!owl_port)
+               return -ENOMEM;
+
+       owl_port->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(owl_port->clk)) {
+               dev_err(&pdev->dev, "could not get clk\n");
+               return PTR_ERR(owl_port->clk);
+       }
+
+       owl_port->port.dev = &pdev->dev;
+       owl_port->port.line = pdev->id;
+       owl_port->port.type = PORT_OWL;
+       owl_port->port.iotype = UPIO_MEM;
+       owl_port->port.mapbase = res_mem->start;
+       owl_port->port.irq = irq;
+       owl_port->port.uartclk = clk_get_rate(owl_port->clk);
+       if (owl_port->port.uartclk == 0) {
+               dev_err(&pdev->dev, "clock rate is zero\n");
+               return -EINVAL;
+       }
+       owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | 
UPF_LOW_LATENCY;
+       owl_port->port.x_char = 0;
+       owl_port->port.fifosize = (info) ? info->tx_fifosize : 16;
+       owl_port->port.ops = &owl_uart_ops;
+
+       owl_uart_ports[pdev->id] = owl_port;
+       platform_set_drvdata(pdev, owl_port);
+
+       ret = uart_add_one_port(&owl_uart_driver, &owl_port->port);
+       if (ret)
+               owl_uart_ports[pdev->id] = NULL;
+
+       return ret;
+}
+
+static int owl_uart_remove(struct platform_device *pdev)
+{
+       struct owl_uart_port *owl_port = platform_get_drvdata(pdev);
+
+       uart_remove_one_port(&owl_uart_driver, &owl_port->port);
+       owl_uart_ports[pdev->id] = NULL;
+
+       return 0;
+}
+
+static struct platform_driver owl_uart_platform_driver = {
+       .probe = owl_uart_probe,
+       .remove = owl_uart_remove,
+       .driver = {
+               .name = "owl-uart",
+               .of_match_table = owl_uart_dt_matches,
+       },
+};
+
+static int __init owl_uart_init(void)
+{
+       int ret;
+
+       ret = uart_register_driver(&owl_uart_driver);
+       if (ret)
+               return ret;
+
+       ret = platform_driver_register(&owl_uart_platform_driver);
+       if (ret)
+               uart_unregister_driver(&owl_uart_driver);
+
+       return ret;
+}
+
+static void __init owl_uart_exit(void)
+{
+       platform_driver_unregister(&owl_uart_platform_driver);
+       uart_unregister_driver(&owl_uart_driver);
+}
+
+module_init(owl_uart_init);
+module_exit(owl_uart_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index c34a2a3eeff5..38bea3217ead 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -70,6 +70,7 @@
 #define PORT_CLPS711X  33
 #define PORT_SA1100    34
 #define PORT_UART00    35
+#define PORT_OWL       36
 #define PORT_21285     37
 
 /* Sparc type numbers.  */
-- 
2.12.3

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