[ARM] 3760/1: This patch adds timeouts while working with SSP registers. Such timeouts were en
Patch from Paul Sokolovsky
This patch adds timeouts while working with SSP registers. Such
timeouts were envisioned by docstrings in ssp.c, but were not
implemented. There were actual lockups while accessing
touchscreen for iPaqs h1910, h4000 due to lack of the timeouts.
This is updated version of previously submitted patch: 3738/1.
Signed-off-by: Paul Sokolovsky <pmiscml@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/ssp.c b/arch/arm/mach-pxa/ssp.c
index 93096bef..1fddfea 100644
--- a/arch/arm/mach-pxa/ssp.c
+++ b/arch/arm/mach-pxa/ssp.c
@@ -40,6 +40,8 @@
#define PXA_SSP_PORTS 3
+#define TIMEOUT 100000
+
struct ssp_info_ {
int irq;
u32 clock;
@@ -92,13 +94,18 @@
* The caller is expected to perform the necessary locking.
*
* Returns:
- * %-ETIMEDOUT timeout occurred (for future)
+ * %-ETIMEDOUT timeout occurred
* 0 success
*/
int ssp_write_word(struct ssp_dev *dev, u32 data)
{
- while (!(SSSR_P(dev->port) & SSSR_TNF))
+ int timeout = TIMEOUT;
+
+ while (!(SSSR_P(dev->port) & SSSR_TNF)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
cpu_relax();
+ }
SSDR_P(dev->port) = data;
@@ -117,15 +124,21 @@
* The caller is expected to perform the necessary locking.
*
* Returns:
- * %-ETIMEDOUT timeout occurred (for future)
+ * %-ETIMEDOUT timeout occurred
* 32-bit data success
*/
-int ssp_read_word(struct ssp_dev *dev)
+int ssp_read_word(struct ssp_dev *dev, u32 *data)
{
- while (!(SSSR_P(dev->port) & SSSR_RNE))
- cpu_relax();
+ int timeout = TIMEOUT;
- return SSDR_P(dev->port);
+ while (!(SSSR_P(dev->port) & SSSR_RNE)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ cpu_relax();
+ }
+
+ *data = SSDR_P(dev->port);
+ return 0;
}
/**
@@ -136,13 +149,21 @@
*
* The caller is expected to perform the necessary locking.
*/
-void ssp_flush(struct ssp_dev *dev)
+int ssp_flush(struct ssp_dev *dev)
{
+ int timeout = TIMEOUT * 2;
+
do {
while (SSSR_P(dev->port) & SSSR_RNE) {
+ if (!--timeout)
+ return -ETIMEDOUT;
(void) SSDR_P(dev->port);
}
+ if (!--timeout)
+ return -ETIMEDOUT;
} while (SSSR_P(dev->port) & SSSR_BSY);
+
+ return 0;
}
/**