tty: serial: msm: Add earlycon support

Add support for DT based and command line based early console on platforms
with the msm serial hardware.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index adc1cd7c3bc7a2a1c4c2d362ce9286b30f3030a4..67e93f139b574590e3fd9330cd6047ab2b066269 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -942,6 +942,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        must already be setup and configured. Options are not
                        yet supported.
 
+               msm_serial,<addr>
+                       Start an early, polled-mode console on an msm serial
+                       port at the specified address. The serial port
+                       must already be setup and configured. Options are not
+                       yet supported.
+
+               msm_serial_dm,<addr>
+                       Start an early, polled-mode console on an msm serial
+                       dm port 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.
 
        earlyprintk=    [X86,SH,BLACKFIN,ARM,M68k]

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 02a896f4dbcddccb4df50c9242d2b968a34e1063..649b784081c7a815b82fff2dbd51b33619e9d742 100644 (file)
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1070,6 +1070,7 @@ config SERIAL_MSM_CONSOLE
        bool "MSM serial console support"
        depends on SERIAL_MSM=y
        select SERIAL_CORE_CONSOLE
+       select SERIAL_EARLYCON
 
 config SERIAL_MSM_HS
        tristate "MSM UART High Speed: Serial Driver"

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index 4f9640d0b1bbc4d077b1625c32a51732e3ba7681..4b6c78331a649cc37501bcfa562b5a03634f425b 100644 (file)
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -845,22 +845,15 @@ static inline struct uart_port *get_port_from_line(unsigned int line)
 }
 
 #ifdef CONFIG_SERIAL_MSM_CONSOLE
-static void msm_console_write(struct console *co, const char *s,
-                             unsigned int count)
+static void __msm_console_write(struct uart_port *port, const char *s,
+                               unsigned int count, bool is_uartdm)
 {
        int i;
-       struct uart_port *port;
-       struct msm_port *msm_port;
        int num_newlines = 0;
        bool replaced = false;
        void __iomem *tf;
 
-       BUG_ON(co->index < 0 || co->index >= UART_NR);
-
-       port = get_port_from_line(co->index);
-       msm_port = UART_TO_MSM(port);
-
-       if (msm_port->is_uartdm)
+       if (is_uartdm)
                tf = port->membase + UARTDM_TF;
        else
                tf = port->membase + UART_TF;
@@ -872,7 +865,7 @@ static void msm_console_write(struct console *co, const char *s,
        count += num_newlines;
 
        spin_lock(&port->lock);
-       if (msm_port->is_uartdm)
+       if (is_uartdm)
                reset_dm_count(port, count);
 
        i = 0;
@@ -881,7 +874,7 @@ static void msm_console_write(struct console *co, const char *s,
                unsigned int num_chars;
                char buf[4] = { 0 };
 
-               if (msm_port->is_uartdm)
+               if (is_uartdm)
                        num_chars = min(count - i, (unsigned int)sizeof(buf));
                else
                        num_chars = 1;
@@ -910,6 +903,20 @@ static void msm_console_write(struct console *co, const char *s,
        spin_unlock(&port->lock);
 }
 
+static void msm_console_write(struct console *co, const char *s,
+                             unsigned int count)
+{
+       struct uart_port *port;
+       struct msm_port *msm_port;
+
+       BUG_ON(co->index < 0 || co->index >= UART_NR);
+
+       port = get_port_from_line(co->index);
+       msm_port = UART_TO_MSM(port);
+
+       __msm_console_write(port, s, count, msm_port->is_uartdm);
+}
+
 static int __init msm_console_setup(struct console *co, char *options)
 {
        struct uart_port *port;
@@ -952,6 +959,49 @@ static int __init msm_console_setup(struct console *co, char *options)
        return uart_set_options(port, co, baud, parity, bits, flow);
 }
 
+static void
+msm_serial_early_write(struct console *con, const char *s, unsigned n)
+{
+       struct earlycon_device *dev = con->data;
+
+       __msm_console_write(&dev->port, s, n, false);
+}
+
+static int __init
+msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
+{
+       if (!device->port.membase)
+               return -ENODEV;
+
+       device->con->write = msm_serial_early_write;
+       return 0;
+}
+EARLYCON_DECLARE(msm_serial, msm_serial_early_console_setup);
+OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
+                   msm_serial_early_console_setup);
+
+static void
+msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
+{
+       struct earlycon_device *dev = con->data;
+
+       __msm_console_write(&dev->port, s, n, true);
+}
+
+static int __init
+msm_serial_early_console_setup_dm(struct earlycon_device *device,
+                                 const char *opt)
+{
+       if (!device->port.membase)
+               return -ENODEV;
+
+       device->con->write = msm_serial_early_write_dm;
+       return 0;
+}
+EARLYCON_DECLARE(msm_serial_dm, msm_serial_early_console_setup_dm);
+OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
+                   msm_serial_early_console_setup_dm);
+
 static struct uart_driver msm_uart_driver;
 
 static struct console msm_console = {