cx18: Fix write retries for registers that always change - part 2.

From: Andy Walls <awalls@radix.net>

cx18: Fix write retries for registers that always change - part 2.
Some registers, especially interrupt related ones, will never read
back the value just written.  Modified interrupt register readback
checks to make sure the intended effect was achieved.

Priority: high

Signed-off-by: Andy Walls <awalls@radix.net>

1 files changed, 15 insertions, 2 deletions

diff --git a/linux/drivers/media/video/cx18/cx18-io.c b/linux/drivers/media/video/cx18/cx18-io.c
index 31be5e868..220fae8d4 100644
--- a/linux/drivers/media/video/cx18/cx18-io.c
+++ b/linux/drivers/media/video/cx18/cx18-io.c
@@ -88,6 +88,19 @@ void cx18_writel_retry(struct cx18 *cx, u32 val, void __iomem *addr)
 	cx18_log_write_retries(cx, i, addr);
 }
 
+void _cx18_writel_expect(struct cx18 *cx, u32 val, void __iomem *addr,
+			 u32 eval, u32 mask)
+{
+	int i;
+	eval &= mask;
+	for (i = 0; i < CX18_MAX_MMIO_RETRIES; i++) {
+		cx18_writel_noretry(cx, val, addr);
+		if (eval == (cx18_readl_noretry(cx, addr) & mask))
+			break;
+	}
+	cx18_log_write_retries(cx, i, addr);
+}
+
 void cx18_writew_retry(struct cx18 *cx, u16 val, void __iomem *addr)
 {
 	int i;
@@ -218,7 +231,7 @@ void cx18_memset_io(struct cx18 *cx, void __iomem *addr, int val, size_t count)
 void cx18_sw1_irq_enable(struct cx18 *cx, u32 val)
 {
 	u32 r;
-	cx18_write_reg_noretry(cx, val, SW1_INT_STATUS);
+	cx18_write_reg_expect(cx, val, SW1_INT_STATUS, ~val, val);
 	r = cx18_read_reg(cx, SW1_INT_ENABLE_PCI);
 	cx18_write_reg(cx, r | val, SW1_INT_ENABLE_PCI);
 }
@@ -233,7 +246,7 @@ void cx18_sw1_irq_disable(struct cx18 *cx, u32 val)
 void cx18_sw2_irq_enable(struct cx18 *cx, u32 val)
 {
 	u32 r;
-	cx18_write_reg_noretry(cx, val, SW2_INT_STATUS);
+	cx18_write_reg_expect(cx, val, SW2_INT_STATUS, ~val, val);
 	r = cx18_read_reg(cx, SW2_INT_ENABLE_PCI);
 	cx18_write_reg(cx, r | val, SW2_INT_ENABLE_PCI);
 }