[Patch v2 2/2] ARM: OMAP2: am33xx-hwmod: Fix "register offset NULL check" bug

[Paul Walmsley]

+ Koen

Hi

On Thu, 31 Jan 2013, Hebbar Gururaja wrote:

> am33xx_cm_wait_module_ready() checks if register offset is NULL.
> 
> int am33xx_cm_wait_module_ready(u16 inst, s16 cdoffs, u16 clkctrl_offs)
> {
> 	int i = 0;
> 
> 	if (!clkctrl_offs)
> 		return 0;
> 
> In case of AM33xx, CLKCTRL register offset for different clock domains
> are not uniformly placed. An example of this would be the RTC clock
> domain with CLKCTRL offset at 0x00.
> In such cases the module ready check is skipped which leads to a data
> abort during boot-up when RTC registers is accessed.
> 
> Remove this check here to avoid checking module readiness for modules
> with clkctrl register offset at 0x00.
> 
> Signed-off-by: Hebbar Gururaja <gururaja.hebbar at ti.com>

Some text has been added to the patch description to describe Koen's test 
results, and the updated patch has been queued for v3.8-rc fixes.  Updated 
patch follows.

- Paul

From: Hebbar Gururaja <gururaja.hebbar at ti.com>
Date: Thu, 31 Jan 2013 19:55:27 +0530
Subject: [PATCH] ARM: OMAP2: am33xx-hwmod: Fix "register offset NULL check"
 bug

am33xx_cm_wait_module_ready() checks if register offset is NULL.

int am33xx_cm_wait_module_ready(u16 inst, s16 cdoffs, u16 clkctrl_offs)
{
	int i = 0;

	if (!clkctrl_offs)
		return 0;

In case of AM33xx, CLKCTRL register offset for different clock domains
are not uniformly placed. An example of this would be the RTC clock
domain with CLKCTRL offset at 0x00.
In such cases the module ready check is skipped which leads to a data
abort during boot-up when RTC registers is accessed.

Remove this check here to avoid checking module readiness for modules
with clkctrl register offset at 0x00.

Koen Kooi notes that this patch fixes a crash on boot with
CONFIG_RTC_DRV_OMAP=y with v3.8-rc5.

Signed-off-by: Hebbar Gururaja <gururaja.hebbar at ti.com>
Cc: Koen Kooi <koen at dominion.thruhere.net>
[paul at pwsan.com: noted Koen's test in the patch description]
Signed-off-by: Paul Walmsley <paul at pwsan.com>
---
 arch/arm/mach-omap2/cm33xx.c |    3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/arm/mach-omap2/cm33xx.c b/arch/arm/mach-omap2/cm33xx.c
index 058ce3c..325a515 100644
--- a/arch/arm/mach-omap2/cm33xx.c
+++ b/arch/arm/mach-omap2/cm33xx.c
@@ -241,9 +241,6 @@ int am33xx_cm_wait_module_ready(u16 inst, s16 cdoffs, u16 clkctrl_offs)
 {
 	int i = 0;
 
-	if (!clkctrl_offs)
-		return 0;
-
 	omap_test_timeout(_is_module_ready(inst, cdoffs, clkctrl_offs),
 			  MAX_MODULE_READY_TIME, i);
 
-- 
1.7.10.4