OMAP: TILER: Use fixed retries when programming PAT

Added mutex locking around DMM PAT programming.  Also fixed the
number of retries when waiting for register accesses to finish.  The
loops will now poll up to 1ms.

Change-Id: I27149d1d44451b97153e6d160130d243dde596a0
Signed-off-by: Andy Gross <andy.gross@ti.com>

1 files changed, 53 insertions, 24 deletions

diff --git a/drivers/media/video/tiler/dmm.c b/drivers/media/video/tiler/dmm.c
index a5482e2..ce0f07a 100644
--- a/drivers/media/video/tiler/dmm.c
+++ b/drivers/media/video/tiler/dmm.c
@@ -23,6 +23,7 @@
 #include <linux/io.h>              /* ioremap() */
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 
 #include <mach/dmm.h>
 
@@ -39,6 +40,8 @@
 #define DEBUG(x, y)
 #endif
 
+static struct mutex dmm_mtx;
+
 static struct omap_dmm_platform_data *device_data;
 
 static int dmm_probe(struct platform_device *pdev)
@@ -68,19 +71,22 @@ static struct platform_driver dmm_driver_ldm = {
 
 s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 {
+	s32 ret = -EFAULT;
 	void __iomem *r;
-	u32 v;
+	u32 v, i;
 
 	/* Only manual refill supported */
 	if (mode != MANUAL)
-		return -EFAULT;
+		return ret;
+
+	mutex_lock(&dmm_mtx);
 
 	/* Check that the DMM_PAT_STATUS register has not reported an error */
 	r = dmm->base + DMM_PAT_STATUS__0;
 	v = __raw_readl(r);
-	if ((v & 0xFC00) != 0) {
-		while (1)
-			printk(KERN_ERR "dmm_pat_refill() error.\n");
+	if (WARN(v & 0xFC00, KERN_ERR "Abort dmm refill, bad status\n")) {
+		ret = -EIO;
+		goto refill_error;
 	}
 
 	/* Set "next" register to NULL */
@@ -113,10 +119,14 @@ s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 	wmb();
 
 	r = dmm->base + DMM_PAT_IRQSTATUS_RAW;
-	do {
-		v = __raw_readl(r);
-		DEBUG("DMM_PAT_IRQSTATUS_RAW", v);
-	} while (v != 0x0);
+	i = 1000;
+	while(__raw_readl(r) != 0) {
+		if (--i == 0) {
+			printk(KERN_ERR "Cannot clear status register\n");
+			goto refill_error;
+		}
+		udelay(1);
+	}
 
 	/* Fill data register */
 	r = dmm->base + DMM_PAT_DATA__0;
@@ -129,10 +139,14 @@ s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 	wmb();
 
 	/* Read back PAT_DATA__0 to see if write was successful */
-	do {
-		v = __raw_readl(r);
-		DEBUG("DMM_PAT_DATA__0", v);
-	} while (v != pd->data);
+	i = 1000;
+	while(__raw_readl(r) != pd->data) {
+		if (--i == 0) {
+			printk(KERN_ERR "Write failed to PAT_DATA__0\n");
+			goto refill_error;
+		}
+		udelay(1);
+	}
 
 	r = dmm->base + DMM_PAT_CTRL__0;
 	v = __raw_readl(r);
@@ -146,10 +160,14 @@ s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 
 	/* Check if PAT_IRQSTATUS_RAW is set after the PAT has been refilled */
 	r = dmm->base + DMM_PAT_IRQSTATUS_RAW;
-	do {
-		v = __raw_readl(r);
-		DEBUG("DMM_PAT_IRQSTATUS_RAW", v);
-	} while ((v & 0x3) != 0x3);
+	i = 1000;
+	while((__raw_readl(r) & 0x3) != 0x3) {
+		if (--i == 0) {
+			printk(KERN_ERR "Status check failed after PAT refill\n");
+			goto refill_error;
+		}
+		udelay(1);
+	}
 
 	/* Again, clear the DMM_PAT_IRQSTATUS register */
 	r = dmm->base + DMM_PAT_IRQSTATUS;
@@ -157,10 +175,14 @@ s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 	wmb();
 
 	r = dmm->base + DMM_PAT_IRQSTATUS_RAW;
-	do {
-		v = __raw_readl(r);
-		DEBUG("DMM_PAT_IRQSTATUS_RAW", v);
-	} while (v != 0x0);
+	i = 1000;
+	while (__raw_readl(r) != 0x0) {
+		if (--i == 0) {
+			printk(KERN_ERR "Failed to clear DMM PAT IRQSTATUS\n");
+			goto refill_error;
+		}
+		udelay(1);
+	}
 
 	/* Again, set "next" register to NULL to clear any PAT STATUS errors */
 	r = dmm->base + DMM_PAT_DESCR__0;
@@ -175,11 +197,16 @@ s32 dmm_pat_refill(struct dmm *dmm, struct pat *pd, enum pat_mode mode)
 	r = dmm->base + DMM_PAT_STATUS__0;
 	v = __raw_readl(r);
 	if ((v & 0xFC00) != 0) {
-		while (1)
-			printk(KERN_ERR "dmm_pat_refill() error.\n");
+		printk(KERN_ERR "Abort dmm refill.  Operation failed\n");
+		goto refill_error;
 	}
 
-	return 0;
+	ret = 0;
+
+refill_error:
+	mutex_unlock(&dmm_mtx);
+
+	return ret;
 }
 EXPORT_SYMBOL(dmm_pat_refill);
 
@@ -233,11 +260,13 @@ EXPORT_SYMBOL(dmm_pat_release);
 
 static s32 __init dmm_init(void)
 {
+	mutex_init(&dmm_mtx);
 	return platform_driver_register(&dmm_driver_ldm);
 }
 
 static void __exit dmm_exit(void)
 {
+	mutex_destroy(&dmm_mtx);
 	platform_driver_unregister(&dmm_driver_ldm);
 }