kgdb: kgdboc console poll hooks for cpm uart

Add in console polling hooks for the cpm uart for use with kgdb and
kgdboc.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
CC: galak@kernel.crashing.org

1 files changed, 94 insertions, 1 deletions

diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index 93e407ee08b..1ff80de177d 100644
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -201,6 +201,10 @@ static void cpm_uart_int_tx(struct uart_port *port)
         cpm_uart_tx_pump(port);
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int serial_polled;
+#endif
+
 /*
  * Receive characters
  */
@@ -222,6 +226,12 @@ static void cpm_uart_int_rx(struct uart_port *port)
          */
         bdp = pinfo->rx_cur;
         for (;;) {
+#ifdef CONFIG_CONSOLE_POLL
+                if (unlikely(serial_polled)) {
+                        serial_polled = 0;
+                        return;
+                }
+#endif
                 /* get status */
                 status = in_be16(&bdp->cbd_sc);
                 /* If this one is empty, return happy */
@@ -253,7 +263,12 @@ static void cpm_uart_int_rx(struct uart_port *port)
                                 goto handle_error;
                         if (uart_handle_sysrq_char(port, ch))
                                 continue;
-
+#ifdef CONFIG_CONSOLE_POLL
+                        if (unlikely(serial_polled)) {
+                                serial_polled = 0;
+                                return;
+                        }
+#endif
                       error_return:
                         tty_insert_flip_char(tty, ch, flg);
 
@@ -865,6 +880,80 @@ static void cpm_uart_config_port(struct uart_port *port, int flags)
                 cpm_uart_request_port(port);
         }
 }
+
+#ifdef CONFIG_CONSOLE_POLL
+/* Serial polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+#define GDB_BUF_SIZE    512     /* power of 2, please */
+
+static char poll_buf[GDB_BUF_SIZE];
+static char *pollp;
+static int poll_chars;
+
+static int poll_wait_key(char *obuf, struct uart_cpm_port *pinfo)
+{
+        u_char          c, *cp;
+        volatile cbd_t  *bdp;
+        int             i;
+
+        /* Get the address of the host memory buffer.
+         */
+        bdp = pinfo->rx_cur;
+        while (bdp->cbd_sc & BD_SC_EMPTY)
+                ;
+
+        /* If the buffer address is in the CPM DPRAM, don't
+         * convert it.
+         */
+        cp = cpm2cpu_addr(bdp->cbd_bufaddr, pinfo);
+
+        if (obuf) {
+                i = c = bdp->cbd_datlen;
+                while (i-- > 0)
+                        *obuf++ = *cp++;
+        } else
+                c = *cp;
+        bdp->cbd_sc &= ~(BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV | BD_SC_ID);
+        bdp->cbd_sc |= BD_SC_EMPTY;
+
+        if (bdp->cbd_sc & BD_SC_WRAP)
+                bdp = pinfo->rx_bd_base;
+        else
+                bdp++;
+        pinfo->rx_cur = (cbd_t *)bdp;
+
+        return (int)c;
+}
+
+static int cpm_get_poll_char(struct uart_port *port)
+{
+        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
+
+        if (!serial_polled) {
+                serial_polled = 1;
+                poll_chars = 0;
+        }
+        if (poll_chars <= 0) {
+                poll_chars = poll_wait_key(poll_buf, pinfo);
+                pollp = poll_buf;
+        }
+        poll_chars--;
+        return *pollp++;
+}
+
+static void cpm_put_poll_char(struct uart_port *port,
+                         unsigned char c)
+{
+        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
+        static char ch[2];
+
+        ch[0] = (char)c;
+        cpm_uart_early_write(pinfo->port.line, ch, 1);
+}
+#endif /* CONFIG_CONSOLE_POLL */
+
 static struct uart_ops cpm_uart_pops = {
         .tx_empty       = cpm_uart_tx_empty,
         .set_mctrl      = cpm_uart_set_mctrl,
@@ -882,6 +971,10 @@ static struct uart_ops cpm_uart_pops = {
         .request_port   = cpm_uart_request_port,
         .config_port    = cpm_uart_config_port,
         .verify_port    = cpm_uart_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+        .poll_get_char = cpm_get_poll_char,
+        .poll_put_char = cpm_put_poll_char,
+#endif
 };
 
 struct uart_cpm_port cpm_uart_ports[UART_NR];