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>

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
 };
 
 /*