ipu common: reset ipuv3 correctly

This patch checks self-clear sw_ipu_rst bit in
SCR register of SRC controller to be cleared
after setting it to high to reset IPUv3. This
makes sure that IPUv3 finishes sofware reset.
A timeout mechanism is added to stop polling
on the bit status in case the bit could not be
cleared by the hardware automatically within
10 millisecond.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>

diff --git a/drivers/video/ipu_common.c b/drivers/video/ipu_common.c
index 0f2d113..ad4af52 100644 (file)
--- a/drivers/video/ipu_common.c
+++ b/drivers/video/ipu_common.c
@@ -94,6 +94,7 @@ struct ipu_ch_param {
        temp1; \
 })
 
+#define IPU_SW_RST_TOUT_USEC   (10000)
 
 void clk_enable(struct clk *clk)
 {
@@ -398,11 +399,20 @@ void ipu_reset(void)
 {
        u32 *reg;
        u32 value;
+       int timeout = IPU_SW_RST_TOUT_USEC;
 
        reg = (u32 *)SRC_BASE_ADDR;
        value = __raw_readl(reg);
        value = value | SW_IPU_RST;
        __raw_writel(value, reg);
+
+       while (__raw_readl(reg) & SW_IPU_RST) {
+               udelay(1);
+               if (!(timeout--)) {
+                       printf("ipu software reset timeout\n");
+                       break;
+               }
+       };
 }
 
 /*