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-rw-r--r--drivers/tty/serial/xilinx_uartps.c50
1 files changed, 49 insertions, 1 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 8c0745951605..5d5557af4d22 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -11,13 +11,17 @@
*
*/
+#if defined(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
#include <linux/platform_device.h>
#include <linux/serial.h>
+#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
-#include <linux/console.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/io.h>
@@ -128,6 +132,9 @@
#define XUARTPS_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
#define XUARTPS_IXR_MASK 0x00001FFF /* Valid bit mask */
+/* Goes in read_status_mask for break detection as the HW doesn't do it*/
+#define XUARTPS_IXR_BRK 0x80000000
+
/** Channel Status Register
*
* The channel status register (CSR) is provided to enable the control logic
@@ -171,6 +178,23 @@ static irqreturn_t xuartps_isr(int irq, void *dev_id)
*/
isrstatus = xuartps_readl(XUARTPS_ISR_OFFSET);
+ /*
+ * There is no hardware break detection, so we interpret framing
+ * error with all-zeros data as a break sequence. Most of the time,
+ * there's another non-zero byte at the end of the sequence.
+ */
+
+ if (isrstatus & XUARTPS_IXR_FRAMING) {
+ while (!(xuartps_readl(XUARTPS_SR_OFFSET) &
+ XUARTPS_SR_RXEMPTY)) {
+ if (!xuartps_readl(XUARTPS_FIFO_OFFSET)) {
+ port->read_status_mask |= XUARTPS_IXR_BRK;
+ isrstatus &= ~XUARTPS_IXR_FRAMING;
+ }
+ }
+ xuartps_writel(XUARTPS_IXR_FRAMING, XUARTPS_ISR_OFFSET);
+ }
+
/* drop byte with parity error if IGNPAR specified */
if (isrstatus & port->ignore_status_mask & XUARTPS_IXR_PARITY)
isrstatus &= ~(XUARTPS_IXR_RXTRIG | XUARTPS_IXR_TOUT);
@@ -184,6 +208,30 @@ static irqreturn_t xuartps_isr(int irq, void *dev_id)
while ((xuartps_readl(XUARTPS_SR_OFFSET) &
XUARTPS_SR_RXEMPTY) != XUARTPS_SR_RXEMPTY) {
data = xuartps_readl(XUARTPS_FIFO_OFFSET);
+
+ /* Non-NULL byte after BREAK is garbage (99%) */
+ if (data && (port->read_status_mask &
+ XUARTPS_IXR_BRK)) {
+ port->read_status_mask &= ~XUARTPS_IXR_BRK;
+ port->icount.brk++;
+ if (uart_handle_break(port))
+ continue;
+ }
+
+ /*
+ * uart_handle_sysrq_char() doesn't work if
+ * spinlocked, for some reason
+ */
+ if (port->sysrq) {
+ spin_unlock(&port->lock);
+ if (uart_handle_sysrq_char(port,
+ (unsigned char)data)) {
+ spin_lock(&port->lock);
+ continue;
+ }
+ spin_lock(&port->lock);
+ }
+
port->icount.rx++;
if (isrstatus & XUARTPS_IXR_PARITY) {