[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-sa1100/ssp.c b/arch/arm/mach-sa1100/ssp.c
index 1604dad..5eba5fb 100644
--- a/arch/arm/mach-sa1100/ssp.c
+++ b/arch/arm/mach-sa1100/ssp.c
@@ -23,6 +23,8 @@
#include <asm/hardware.h>
#include <asm/hardware/ssp.h>
+#define TIMEOUT 100000
+
static irqreturn_t ssp_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
unsigned int status = Ser4SSSR;
@@ -47,18 +49,27 @@
* The caller is expected to perform the necessary locking.
*
* Returns:
- * %-ETIMEDOUT timeout occurred (for future)
+ * %-ETIMEDOUT timeout occurred
* 0 success
*/
int ssp_write_word(u16 data)
{
- while (!(Ser4SSSR & SSSR_TNF))
+ int timeout = TIMEOUT;
+
+ while (!(Ser4SSSR & SSSR_TNF)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
cpu_relax();
+ }
Ser4SSDR = data;
- while (!(Ser4SSSR & SSSR_BSY))
+ timeout = TIMEOUT;
+ while (!(Ser4SSSR & SSSR_BSY)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
cpu_relax();
+ }
return 0;
}
@@ -75,15 +86,22 @@
* The caller is expected to perform the necessary locking.
*
* Returns:
- * %-ETIMEDOUT timeout occurred (for future)
+ * %-ETIMEDOUT timeout occurred
* 16-bit data success
*/
-int ssp_read_word(void)
+int ssp_read_word(u16 *data)
{
- while (!(Ser4SSSR & SSSR_RNE))
- cpu_relax();
+ int timeout = TIMEOUT;
- return Ser4SSDR;
+ while (!(Ser4SSSR & SSSR_RNE)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ cpu_relax();
+ }
+
+ *data = (u16)Ser4SSDR;
+
+ return 0;
}
/**
@@ -93,14 +111,26 @@
* is empty.
*
* The caller is expected to perform the necessary locking.
+ *
+ * Returns:
+ * %-ETIMEDOUT timeout occurred
+ * 0 success
*/
-void ssp_flush(void)
+int ssp_flush(void)
{
+ int timeout = TIMEOUT * 2;
+
do {
while (Ser4SSSR & SSSR_RNE) {
+ if (!--timeout)
+ return -ETIMEDOUT;
(void) Ser4SSDR;
}
+ if (!--timeout)
+ return -ETIMEDOUT;
} while (Ser4SSSR & SSSR_BSY);
+
+ return 0;
}
/**