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authorAnirudha Sarangi <anirudha.sarangi@xilinx.com>2016-09-21 15:01:18 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-22 11:49:55 +0200
commita3081893cab48df3facff8144d9506610213241a (patch)
tree2a3defd7d48e9eafac8f89cb87d42a8fd6d77e93 /drivers/tty
parent87f1f809c9b90903e6a9ee0a8356a2303fd4270d (diff)
downloadlinux-a3081893cab48df3facff8144d9506610213241a.tar.bz2
serial: xuartps: Do not enable parity error interrupt
The patch makes changes not to enable parity error interrupt. With the current implementation, each parity error results in two distinct interrupts (almost always). The first one is normal parity error interrupt with no data in the fifo and the second one is a proper Rx interrupt with the received data in the fifo. By disabling parity error interrupt we still ensure handling of parity errors as for the Rx fifo interrupt the parity error still shows up in the interrupt status register. Considering the fact that the by default INPCK and IGNPAR are not set, this is the optimal implementation for parity error handling. Signed-off-by: Anirudha Sarangi <anirudh@xilinx.com> Signed-off-by: Michal Simek <michal.simek@xilinx.com> [stelford@cadence.com: cherry picked from https://github.com/Xilinx/linux-xlnx commit bf9f610b445e2c9ed33c41e1e0e30b43be4e1f97 with manual conflict resolution] Signed-off-by: Scott Telford <stelford@cadence.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/xilinx_uartps.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index e0c6a8619b9f..98f7b590ec55 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -130,8 +130,21 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
#define CDNS_UART_IXR_MASK 0x00001FFF /* Valid bit mask */
-#define CDNS_UART_RX_IRQS (CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | \
- CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG | \
+ /*
+ * Do not enable parity error interrupt for the following
+ * reason: When parity error interrupt is enabled, each Rx
+ * parity error always results in 2 events. The first one
+ * being parity error interrupt and the second one with a
+ * proper Rx interrupt with the incoming data. Disabling
+ * parity error interrupt ensures better handling of parity
+ * error events. With this change, for a parity error case, we
+ * get a Rx interrupt with parity error set in ISR register
+ * and we still handle parity errors in the desired way.
+ */
+
+#define CDNS_UART_RX_IRQS (CDNS_UART_IXR_FRAMING | \
+ CDNS_UART_IXR_OVERRUN | \
+ CDNS_UART_IXR_RXTRIG | \
CDNS_UART_IXR_TOUT)
/* Goes in read_status_mask for break detection as the HW doesn't do it*/