sparc,sunzilog: Add console polling support for sunzilog serial driver

Allow kgdboc to work on sparc hardware with the Zilog serial chips.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/serial/sunzilog.c b/drivers/serial/sunzilog.c
index 2c7a66af4f52..978b3cee02d7 100644
--- a/drivers/serial/sunzilog.c
+++ b/drivers/serial/sunzilog.c
@@ -102,6 +102,8 @@ struct uart_sunzilog_port {
 #endif
 };
 
+static void sunzilog_putchar(struct uart_port *port, int ch);
+
 #define ZILOG_CHANNEL_FROM_PORT(PORT)   ((struct zilog_channel __iomem *)((PORT)->membase))
 #define UART_ZILOG(PORT)                ((struct uart_sunzilog_port *)(PORT))
 
@@ -996,6 +998,50 @@ static int sunzilog_verify_port(struct uart_port *port, struct serial_struct *se
         return -EINVAL;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int sunzilog_get_poll_char(struct uart_port *port)
+{
+        unsigned char ch, r1;
+        struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
+        struct zilog_channel __iomem *channel
+                = ZILOG_CHANNEL_FROM_PORT(&up->port);
+
+
+        r1 = read_zsreg(channel, R1);
+        if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
+                writeb(ERR_RES, &channel->control);
+                ZSDELAY();
+                ZS_WSYNC(channel);
+        }
+
+        ch = readb(&channel->control);
+        ZSDELAY();
+
+        /* This funny hack depends upon BRK_ABRT not interfering
+         * with the other bits we care about in R1.
+         */
+        if (ch & BRK_ABRT)
+                r1 |= BRK_ABRT;
+
+        if (!(ch & Rx_CH_AV))
+                return NO_POLL_CHAR;
+
+        ch = readb(&channel->data);
+        ZSDELAY();
+
+        ch &= up->parity_mask;
+        return ch;
+}
+
+static void sunzilog_put_poll_char(struct uart_port *port,
+                        unsigned char ch)
+{
+        struct uart_sunzilog_port *up = (struct uart_sunzilog_port *)port;
+
+        sunzilog_putchar(&up->port, ch);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
 static struct uart_ops sunzilog_pops = {
         .tx_empty       =       sunzilog_tx_empty,
         .set_mctrl      =       sunzilog_set_mctrl,
@@ -1013,6 +1059,10 @@ static struct uart_ops sunzilog_pops = {
         .request_port   =       sunzilog_request_port,
         .config_port    =       sunzilog_config_port,
         .verify_port    =       sunzilog_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+        .poll_get_char  =       sunzilog_get_poll_char,
+        .poll_put_char  =       sunzilog_put_poll_char,
+#endif
 };
 
 static int uart_chip_count;