kgdb: kgdboc console poll hooks for mpsc uart

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

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 147 insertions, 1 deletions

diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c
index c9f53e71f252..61d3ade5286c 100644
--- a/drivers/serial/mpsc.c
+++ b/drivers/serial/mpsc.c
@@ -921,6 +921,10 @@ static int mpsc_make_ready(struct mpsc_port_info *pi)
         return 0;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int serial_polled;
+#endif
+
 /*
  ******************************************************************************
  *
@@ -956,7 +960,12 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi)
         while (!((cmdstat = be32_to_cpu(rxre->cmdstat))
                                 & SDMA_DESC_CMDSTAT_O)) {
                 bytes_in = be16_to_cpu(rxre->bytecnt);
-
+#ifdef CONFIG_CONSOLE_POLL
+                if (unlikely(serial_polled)) {
+                        serial_polled = 0;
+                        return 0;
+                }
+#endif
                 /* Following use of tty struct directly is deprecated */
                 if (unlikely(tty_buffer_request_room(tty, bytes_in)
                                         < bytes_in)) {
@@ -1017,6 +1026,12 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi)
                 if (uart_handle_sysrq_char(&pi->port, *bp)) {
                         bp++;
                         bytes_in--;
+#ifdef CONFIG_CONSOLE_POLL
+                        if (unlikely(serial_polled)) {
+                                serial_polled = 0;
+                                return 0;
+                        }
+#endif
                         goto next_frame;
                 }
 
@@ -1519,6 +1534,133 @@ static int mpsc_verify_port(struct uart_port *port, struct serial_struct *ser)
 
         return rc;
 }
+#ifdef CONFIG_CONSOLE_POLL
+/* Serial polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static char poll_buf[2048];
+static int poll_ptr;
+static int poll_cnt;
+static void mpsc_put_poll_char(struct uart_port *port,
+                                                           unsigned char c);
+
+static int mpsc_get_poll_char(struct uart_port *port)
+{
+        struct mpsc_port_info *pi = (struct mpsc_port_info *)port;
+        struct mpsc_rx_desc *rxre;
+        u32     cmdstat, bytes_in, i;
+        u8      *bp;
+
+        if (!serial_polled)
+                serial_polled = 1;
+
+        pr_debug("mpsc_rx_intr[%d]: Handling Rx intr\n", pi->port.line);
+
+        if (poll_cnt) {
+                poll_cnt--;
+                return poll_buf[poll_ptr++];
+        }
+        poll_ptr = 0;
+        poll_cnt = 0;
+
+        while (poll_cnt == 0) {
+                rxre = (struct mpsc_rx_desc *)(pi->rxr +
+                       (pi->rxr_posn*MPSC_RXRE_SIZE));
+                dma_cache_sync(pi->port.dev, (void *)rxre,
+                               MPSC_RXRE_SIZE, DMA_FROM_DEVICE);
+#if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
+                if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
+                        invalidate_dcache_range((ulong)rxre,
+                        (ulong)rxre + MPSC_RXRE_SIZE);
+#endif
+                /*
+                 * Loop through Rx descriptors handling ones that have
+                 * been completed.
+                 */
+                while (poll_cnt == 0 &&
+                       !((cmdstat = be32_to_cpu(rxre->cmdstat)) &
+                         SDMA_DESC_CMDSTAT_O)){
+                        bytes_in = be16_to_cpu(rxre->bytecnt);
+                        bp = pi->rxb + (pi->rxr_posn * MPSC_RXBE_SIZE);
+                        dma_cache_sync(pi->port.dev, (void *) bp,
+                                       MPSC_RXBE_SIZE, DMA_FROM_DEVICE);
+#if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
+                        if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
+                                invalidate_dcache_range((ulong)bp,
+                                        (ulong)bp + MPSC_RXBE_SIZE);
+#endif
+                        if ((unlikely(cmdstat & (SDMA_DESC_CMDSTAT_BR |
+                         SDMA_DESC_CMDSTAT_FR | SDMA_DESC_CMDSTAT_OR))) &&
+                                !(cmdstat & pi->port.ignore_status_mask)) {
+                                poll_buf[poll_cnt] = *bp;
+                                poll_cnt++;
+                        } else {
+                                for (i = 0; i < bytes_in; i++) {
+                                        poll_buf[poll_cnt] = *bp++;
+                                        poll_cnt++;
+                                }
+                                pi->port.icount.rx += bytes_in;
+                        }
+                        rxre->bytecnt = cpu_to_be16(0);
+                        wmb();
+                        rxre->cmdstat = cpu_to_be32(SDMA_DESC_CMDSTAT_O |
+                                                    SDMA_DESC_CMDSTAT_EI |
+                                                    SDMA_DESC_CMDSTAT_F |
+                                                    SDMA_DESC_CMDSTAT_L);
+                        wmb();
+                        dma_cache_sync(pi->port.dev, (void *)rxre,
+                                       MPSC_RXRE_SIZE, DMA_BIDIRECTIONAL);
+#if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
+                        if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
+                                flush_dcache_range((ulong)rxre,
+                                           (ulong)rxre + MPSC_RXRE_SIZE);
+#endif
+
+                        /* Advance to next descriptor */
+                        pi->rxr_posn = (pi->rxr_posn + 1) &
+                                (MPSC_RXR_ENTRIES - 1);
+                        rxre = (struct mpsc_rx_desc *)(pi->rxr +
+                                       (pi->rxr_posn * MPSC_RXRE_SIZE));
+                        dma_cache_sync(pi->port.dev, (void *)rxre,
+                                       MPSC_RXRE_SIZE, DMA_FROM_DEVICE);
+#if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
+                        if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
+                                invalidate_dcache_range((ulong)rxre,
+                                                (ulong)rxre + MPSC_RXRE_SIZE);
+#endif
+                }
+
+                /* Restart rx engine, if its stopped */
+                if ((readl(pi->sdma_base + SDMA_SDCM) & SDMA_SDCM_ERD) == 0)
+                        mpsc_start_rx(pi);
+        }
+        if (poll_cnt) {
+                poll_cnt--;
+                return poll_buf[poll_ptr++];
+        }
+
+        return 0;
+}
+
+
+static void mpsc_put_poll_char(struct uart_port *port,
+                         unsigned char c)
+{
+        struct mpsc_port_info *pi = (struct mpsc_port_info *)port;
+        u32 data;
+
+        data = readl(pi->mpsc_base + MPSC_MPCR);
+        writeb(c, pi->mpsc_base + MPSC_CHR_1);
+        mb();
+        data = readl(pi->mpsc_base + MPSC_CHR_2);
+        data |= MPSC_CHR_2_TTCS;
+        writel(data, pi->mpsc_base + MPSC_CHR_2);
+        mb();
+
+        while (readl(pi->mpsc_base + MPSC_CHR_2) & MPSC_CHR_2_TTCS);
+}
+#endif
 
 static struct uart_ops mpsc_pops = {
         .tx_empty       = mpsc_tx_empty,
@@ -1537,6 +1679,10 @@ static struct uart_ops mpsc_pops = {
         .request_port   = mpsc_request_port,
         .config_port    = mpsc_config_port,
         .verify_port    = mpsc_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+        .poll_get_char = mpsc_get_poll_char,
+        .poll_put_char = mpsc_put_poll_char,
+#endif
 };
 
 /*