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Subject[PATCH 04/10] tty: xuartps: Add polled mode support for xuartps
Date
From: Vlad Lungu <vlad.lungu@windriver.com>

This allows KDB/KGDB to run.

Signed-off-by: Vlad Lungu <vlad.lungu@windriver.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
This is squashed from these original patches:
tty: xuartps: Add polled mode support for xuartps

This allows KDB/KGDB to run.
There is a bug somewhere that blocks KDB when paging;
set the LINES environment variable to a big value and
scroll in your terminal.

Signed-off-by: Vlad Lungu <vlad.lungu@windriver.com>

and

tty: xuartps: Fix poll read

This fixes the KDB paging issue.

Signed-off-by: Vlad Lungu <vlad.lungu@windriver.com>

Additionally I fixed a few style issues.
---
drivers/tty/serial/xilinx_uartps.c | 52 ++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 5d5557af4d22..62259f37ddda 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -775,6 +775,54 @@ static void xuartps_enable_ms(struct uart_port *port)
/* N/A */
}

+#ifdef CONFIG_CONSOLE_POLL
+static int xuartps_poll_get_char(struct uart_port *port)
+{
+ u32 imr;
+ int c;
+
+ /* Disable all interrupts */
+ imr = xuartps_readl(XUARTPS_IMR_OFFSET);
+ xuartps_writel(imr, XUARTPS_IDR_OFFSET);
+
+ /* Check if FIFO is empty */
+ if (xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_RXEMPTY)
+ c = NO_POLL_CHAR;
+ else /* Read a character */
+ c = (unsigned char) xuartps_readl(XUARTPS_FIFO_OFFSET);
+
+ /* Enable interrupts */
+ xuartps_writel(imr, XUARTPS_IER_OFFSET);
+
+ return c;
+}
+
+static void xuartps_poll_put_char(struct uart_port *port, unsigned char c)
+{
+ u32 imr;
+
+ /* Disable all interrupts */
+ imr = xuartps_readl(XUARTPS_IMR_OFFSET);
+ xuartps_writel(imr, XUARTPS_IDR_OFFSET);
+
+ /* Wait until FIFO is empty */
+ while (!(xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_TXEMPTY))
+ cpu_relax();
+
+ /* Write a character */
+ xuartps_writel(c, XUARTPS_FIFO_OFFSET);
+
+ /* Wait until FIFO is empty */
+ while (!(xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_TXEMPTY))
+ cpu_relax();
+
+ /* Enable interrupts */
+ xuartps_writel(imr, XUARTPS_IER_OFFSET);
+
+ return;
+}
+#endif
+
/** The UART operations structure
*/
static struct uart_ops xuartps_ops = {
@@ -807,6 +855,10 @@ static struct uart_ops xuartps_ops = {
.config_port = xuartps_config_port, /* Configure when driver
* adds a xuartps port
*/
+#ifdef CONFIG_CONSOLE_POLL
+ .poll_get_char = xuartps_poll_get_char,
+ .poll_put_char = xuartps_poll_put_char,
+#endif
};

static struct uart_port xuartps_port[2];
--
1.8.4.1


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