serial: pch_uart: add console poll support

Implement console poll for pch_uart, this could enable KGDBoC when
on pch-uart console.

Signed-off-by: Liang Li <liang.li@windriver.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 79 insertions, 24 deletions

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 7a6c989924b3..21a7e179edf3 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1493,29 +1493,6 @@ static int pch_uart_verify_port(struct uart_port *port,
         return 0;
 }
 
-static struct uart_ops pch_uart_ops = {
-        .tx_empty = pch_uart_tx_empty,
-        .set_mctrl = pch_uart_set_mctrl,
-        .get_mctrl = pch_uart_get_mctrl,
-        .stop_tx = pch_uart_stop_tx,
-        .start_tx = pch_uart_start_tx,
-        .stop_rx = pch_uart_stop_rx,
-        .enable_ms = pch_uart_enable_ms,
-        .break_ctl = pch_uart_break_ctl,
-        .startup = pch_uart_startup,
-        .shutdown = pch_uart_shutdown,
-        .set_termios = pch_uart_set_termios,
-/*      .pm             = pch_uart_pm,          Not supported yet */
-/*      .set_wake       = pch_uart_set_wake,    Not supported yet */
-        .type = pch_uart_type,
-        .release_port = pch_uart_release_port,
-        .request_port = pch_uart_request_port,
-        .config_port = pch_uart_config_port,
-        .verify_port = pch_uart_verify_port
-};
-
-#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
-
 /*
  *      Wait for transmitter & holding register to empty
  */
@@ -1547,6 +1524,84 @@ static void wait_for_xmitr(struct eg20t_port *up, int bits)
         }
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for communicate via uart while
+ * in an interrupt or debug context.
+ */
+static int pch_uart_get_poll_char(struct uart_port *port)
+{
+        struct eg20t_port *priv =
+                container_of(port, struct eg20t_port, port);
+        u8 lsr = ioread8(priv->membase + UART_LSR);
+
+        if (!(lsr & UART_LSR_DR))
+                return NO_POLL_CHAR;
+
+        return ioread8(priv->membase + PCH_UART_RBR);
+}
+
+
+static void pch_uart_put_poll_char(struct uart_port *port,
+                         unsigned char c)
+{
+        unsigned int ier;
+        struct eg20t_port *priv =
+                container_of(port, struct eg20t_port, port);
+
+        /*
+         * First save the IER then disable the interrupts
+         */
+        ier = ioread8(priv->membase + UART_IER);
+        pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
+
+        wait_for_xmitr(priv, UART_LSR_THRE);
+        /*
+         * Send the character out.
+         * If a LF, also do CR...
+         */
+        iowrite8(c, priv->membase + PCH_UART_THR);
+        if (c == 10) {
+                wait_for_xmitr(priv, UART_LSR_THRE);
+                iowrite8(13, priv->membase + PCH_UART_THR);
+        }
+
+        /*
+         * Finally, wait for transmitter to become empty
+         * and restore the IER
+         */
+        wait_for_xmitr(priv, BOTH_EMPTY);
+        iowrite8(ier, priv->membase + UART_IER);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
+static struct uart_ops pch_uart_ops = {
+        .tx_empty = pch_uart_tx_empty,
+        .set_mctrl = pch_uart_set_mctrl,
+        .get_mctrl = pch_uart_get_mctrl,
+        .stop_tx = pch_uart_stop_tx,
+        .start_tx = pch_uart_start_tx,
+        .stop_rx = pch_uart_stop_rx,
+        .enable_ms = pch_uart_enable_ms,
+        .break_ctl = pch_uart_break_ctl,
+        .startup = pch_uart_startup,
+        .shutdown = pch_uart_shutdown,
+        .set_termios = pch_uart_set_termios,
+/*      .pm             = pch_uart_pm,          Not supported yet */
+/*      .set_wake       = pch_uart_set_wake,    Not supported yet */
+        .type = pch_uart_type,
+        .release_port = pch_uart_release_port,
+        .request_port = pch_uart_request_port,
+        .config_port = pch_uart_config_port,
+        .verify_port = pch_uart_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+        .poll_get_char = pch_uart_get_poll_char,
+        .poll_put_char = pch_uart_put_poll_char,
+#endif
+};
+
+#ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
+
 static void pch_console_putchar(struct uart_port *port, int ch)
 {
         struct eg20t_port *priv =
@@ -1655,7 +1710,7 @@ static struct console pch_console = {
 #define PCH_CONSOLE     (&pch_console)
 #else
 #define PCH_CONSOLE     NULL
-#endif
+#endif  /* CONFIG_SERIAL_PCH_UART_CONSOLE */
 
 static struct uart_driver pch_uart_driver = {
         .owner = THIS_MODULE,