* L2 cache stability workaround for 4460 ES1.0
@ 2012-04-02 6:55 Roger Quadros
2012-04-02 7:38 ` Shilimkar, Santosh
0 siblings, 1 reply; 6+ messages in thread
From: Roger Quadros @ 2012-04-02 6:55 UTC (permalink / raw)
To: Shilimkar, Santosh; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
[-- Attachment #1: Type: text/plain, Size: 490 bytes --]
Hi Santosh,
I came across the attached patch from you. I also came across this post
stating that it was decided not to send this patch upstream.
http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
The problem is that we have to keep porting this patch each time we
update the kernel.
Do you know if the root cause has been found? If not can we have this
patch upstream till the root cause is found?
It seems the patch at least makes the kernel usable on ES1.0.
regards,
-roger
[-- Attachment #2: 0001-OMAP4460-L2X0-work-around-for-stability.patch --]
[-- Type: text/x-patch, Size: 2956 bytes --]
>From 68ab20c60335eef5aceb9c5f978b8d6ef4b11d9b Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Date: Tue, 27 Mar 2012 11:20:09 -0400
Subject: [PATCH 1/3] OMAP4460: L2X0: work-around for stability.
OMAP4460 ES1.0 seems to suffer from stability with L2 cache enabled.
The root-cause analysis is ongoing but in meantime this chabe is
to enable a software WA with L2 cache enabled build. The WA consist
of locking certain cache ways based on their positions on the
physical memory layout.
Downside of this WA is that effective L2 cache size will be 512 KB
instead of 1 MB.
clalancette: Changed so that the workaround is only activated
for ES1.0, and not ES1.1.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Chris Lalancette <clalancette@gmail.com>
---
arch/arm/include/asm/hardware/cache-l2x0.h | 5 +++++
arch/arm/mach-omap2/omap4-common.c | 18 ++++++++++++++++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/arch/arm/include/asm/hardware/cache-l2x0.h b/arch/arm/include/asm/hardware/cache-l2x0.h
index 7df239b..8e3f8f2 100644
--- a/arch/arm/include/asm/hardware/cache-l2x0.h
+++ b/arch/arm/include/asm/hardware/cache-l2x0.h
@@ -56,6 +56,11 @@
#define L2X0_LOCKDOWN_STRIDE 0x08
#define L2X0_ADDR_FILTER_START 0xC00
#define L2X0_ADDR_FILTER_END 0xC04
+#define L2X0_LOCKDOWN_WAY_D0 0x900
+#define L2X0_LOCKDOWN_WAY_D1 0x908
+#define L2X0_LOCKDOWN_WAY_I0 0x904
+#define L2X0_LOCKDOWN_WAY_I1 0x90C
+
#define L2X0_TEST_OPERATION 0xF00
#define L2X0_LINE_DATA 0xF10
#define L2X0_LINE_TAG 0xF30
diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
index 70de277..4e190c8 100644
--- a/arch/arm/mach-omap2/omap4-common.c
+++ b/arch/arm/mach-omap2/omap4-common.c
@@ -129,6 +129,7 @@ static void omap4_l2x0_set_debug(unsigned long val)
static int __init omap_l2_cache_init(void)
{
u32 aux_ctrl = 0;
+ u32 lockdown = 0;
/*
* To avoid code running on other OMAPs in
@@ -164,6 +165,23 @@ static int __init omap_l2_cache_init(void)
if (omap_rev() != OMAP4430_REV_ES1_0)
omap_smc1(0x109, aux_ctrl);
+ /*
+ * WA for OMAP4460 ES1.0 L2 cache corruption issue.
+ * Lock-down specific L2 cache ways which makes effective
+ * L2 size as 512 KB instead of 1 MB
+ *
+ * The L2 cache in the ES1.1 doesn't have this issue, so only enable
+ * the workaround for ES1.0.
+ */
+ if (omap_rev() == OMAP4460_REV_ES1_0) {
+ printk(KERN_INFO "OMAP4460 ES1.0 detected, enabling L2 cache stability workaround\n");
+ lockdown = 0xa5a5;
+ writel_relaxed(lockdown, l2cache_base + L2X0_LOCKDOWN_WAY_D0);
+ writel_relaxed(lockdown, l2cache_base + L2X0_LOCKDOWN_WAY_D1);
+ writel_relaxed(lockdown, l2cache_base + L2X0_LOCKDOWN_WAY_I0);
+ writel_relaxed(lockdown, l2cache_base + L2X0_LOCKDOWN_WAY_I1);
+ }
+
/* Enable PL310 L2 Cache controller */
omap_smc1(0x102, 0x1);
--
1.7.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: L2 cache stability workaround for 4460 ES1.0
2012-04-02 6:55 L2 cache stability workaround for 4460 ES1.0 Roger Quadros
@ 2012-04-02 7:38 ` Shilimkar, Santosh
2012-04-02 7:55 ` Roger Quadros
0 siblings, 1 reply; 6+ messages in thread
From: Shilimkar, Santosh @ 2012-04-02 7:38 UTC (permalink / raw)
To: Roger Quadros; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
On Mon, Apr 2, 2012 at 12:25 PM, Roger Quadros <rogerq@ti.com> wrote:
> Hi Santosh,
>
> I came across the attached patch from you. I also came across this post
> stating that it was decided not to send this patch upstream.
>
> http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
>
> The problem is that we have to keep porting this patch each time we
> update the kernel.
>
> Do you know if the root cause has been found? If not can we have this
> patch upstream till the root cause is found?
>
Yes and fixed in OMAP4460 ES1.2.
> It seems the patch at least makes the kernel usable on ES1.0.
>
I know but that still is not enough. It's like 80 % WA of the issue
seen on ES1.0. We are not suppose to have many boards with
ES1.0
Regards
Santosh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: L2 cache stability workaround for 4460 ES1.0
2012-04-02 7:38 ` Shilimkar, Santosh
@ 2012-04-02 7:55 ` Roger Quadros
2012-04-02 7:58 ` Shilimkar, Santosh
0 siblings, 1 reply; 6+ messages in thread
From: Roger Quadros @ 2012-04-02 7:55 UTC (permalink / raw)
To: Shilimkar, Santosh; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
On 04/02/2012 10:38 AM, Shilimkar, Santosh wrote:
> On Mon, Apr 2, 2012 at 12:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>> Hi Santosh,
>>
>> I came across the attached patch from you. I also came across this post
>> stating that it was decided not to send this patch upstream.
>>
>> http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
>>
>> The problem is that we have to keep porting this patch each time we
>> update the kernel.
>>
>> Do you know if the root cause has been found? If not can we have this
>> patch upstream till the root cause is found?
>>
> Yes and fixed in OMAP4460 ES1.2.
Did you mean ES1.1?
Could you please point me to the errata ID? The only cache related
errata I can see is Errata ID: i690
>
>> It seems the patch at least makes the kernel usable on ES1.0.
>>
> I know but that still is not enough. It's like 80 % WA of the issue
> seen on ES1.0. We are not suppose to have many boards with
> ES1.0
>
Even better if there are not many boards. It seems most of the boards
will be with TI. I think we should have the fix in even if it is not
100% fix.
What do you say?
regards,
-roger
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: L2 cache stability workaround for 4460 ES1.0
2012-04-02 7:55 ` Roger Quadros
@ 2012-04-02 7:58 ` Shilimkar, Santosh
2012-04-02 8:02 ` Roger Quadros
0 siblings, 1 reply; 6+ messages in thread
From: Shilimkar, Santosh @ 2012-04-02 7:58 UTC (permalink / raw)
To: Roger Quadros; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
On Mon, Apr 2, 2012 at 1:25 PM, Roger Quadros <rogerq@ti.com> wrote:
> On 04/02/2012 10:38 AM, Shilimkar, Santosh wrote:
>> On Mon, Apr 2, 2012 at 12:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>>> Hi Santosh,
>>>
>>> I came across the attached patch from you. I also came across this post
>>> stating that it was decided not to send this patch upstream.
>>>
>>> http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
>>>
>>> The problem is that we have to keep porting this patch each time we
>>> update the kernel.
>>>
>>> Do you know if the root cause has been found? If not can we have this
>>> patch upstream till the root cause is found?
>>>
>> Yes and fixed in OMAP4460 ES1.2.
>
> Did you mean ES1.1?
>
yep. Sorry for the typo.
> Could you please point me to the errata ID? The only cache related
> errata I can see is Errata ID: i690
>
>>
>>> It seems the patch at least makes the kernel usable on ES1.0.
>>>
>> I know but that still is not enough. It's like 80 % WA of the issue
>> seen on ES1.0. We are not suppose to have many boards with
>> ES1.0
>>
> Even better if there are not many boards. It seems most of the boards
> will be with TI. I think we should have the fix in even if it is not
> 100% fix.
>
> What do you say?
>
My request is to get rid of ES1.0 board because the WA just
not completely correct. Don't feel patching kernel for silicon
which is not suppose to be used nether has complete WA
to support it.
Regards
Santosh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: L2 cache stability workaround for 4460 ES1.0
2012-04-02 7:58 ` Shilimkar, Santosh
@ 2012-04-02 8:02 ` Roger Quadros
2012-04-02 9:13 ` Shilimkar, Santosh
0 siblings, 1 reply; 6+ messages in thread
From: Roger Quadros @ 2012-04-02 8:02 UTC (permalink / raw)
To: Shilimkar, Santosh; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
On 04/02/2012 10:58 AM, Shilimkar, Santosh wrote:
> On Mon, Apr 2, 2012 at 1:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>> On 04/02/2012 10:38 AM, Shilimkar, Santosh wrote:
>>> On Mon, Apr 2, 2012 at 12:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>>>> Hi Santosh,
>>>>
>>>> I came across the attached patch from you. I also came across this post
>>>> stating that it was decided not to send this patch upstream.
>>>>
>>>> http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
>>>>
>>>> The problem is that we have to keep porting this patch each time we
>>>> update the kernel.
>>>>
>>>> Do you know if the root cause has been found? If not can we have this
>>>> patch upstream till the root cause is found?
>>>>
>>> Yes and fixed in OMAP4460 ES1.2.
>>
>> Did you mean ES1.1?
>>
> yep. Sorry for the typo.
>
>> Could you please point me to the errata ID? The only cache related
>> errata I can see is Errata ID: i690
>>
>>>
>>>> It seems the patch at least makes the kernel usable on ES1.0.
>>>>
>>> I know but that still is not enough. It's like 80 % WA of the issue
>>> seen on ES1.0. We are not suppose to have many boards with
>>> ES1.0
>>>
>> Even better if there are not many boards. It seems most of the boards
>> will be with TI. I think we should have the fix in even if it is not
>> 100% fix.
>>
>> What do you say?
>>
> My request is to get rid of ES1.0 board because the WA just
> not completely correct. Don't feel patching kernel for silicon
> which is not suppose to be used nether has complete WA
> to support it.
>
OK Santosh. seems like cache is broken bad on ES1.0.
Is it possible to disable the cache for ES1.0 and print a warning
message about it?
regards,
-roger
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: L2 cache stability workaround for 4460 ES1.0
2012-04-02 8:02 ` Roger Quadros
@ 2012-04-02 9:13 ` Shilimkar, Santosh
0 siblings, 0 replies; 6+ messages in thread
From: Shilimkar, Santosh @ 2012-04-02 9:13 UTC (permalink / raw)
To: Roger Quadros; +Cc: Dechesne, Nicolas, linux-omap@vger.kernel.org
On Mon, Apr 2, 2012 at 1:32 PM, Roger Quadros <rogerq@ti.com> wrote:
> On 04/02/2012 10:58 AM, Shilimkar, Santosh wrote:
>> On Mon, Apr 2, 2012 at 1:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>>> On 04/02/2012 10:38 AM, Shilimkar, Santosh wrote:
>>>> On Mon, Apr 2, 2012 at 12:25 PM, Roger Quadros <rogerq@ti.com> wrote:
>>>>> Hi Santosh,
>>>>>
>>>>> I came across the attached patch from you. I also came across this post
>>>>> stating that it was decided not to send this patch upstream.
>>>>>
>>>>> http://www.digipedia.pl/usenet/thread/18885/8437/#post8496
>>>>>
>>>>> The problem is that we have to keep porting this patch each time we
>>>>> update the kernel.
>>>>>
>>>>> Do you know if the root cause has been found? If not can we have this
>>>>> patch upstream till the root cause is found?
>>>>>
>>>> Yes and fixed in OMAP4460 ES1.2.
>>>
>>> Did you mean ES1.1?
>>>
>> yep. Sorry for the typo.
>>
>>> Could you please point me to the errata ID? The only cache related
>>> errata I can see is Errata ID: i690
>>>
>>>>
>>>>> It seems the patch at least makes the kernel usable on ES1.0.
>>>>>
>>>> I know but that still is not enough. It's like 80 % WA of the issue
>>>> seen on ES1.0. We are not suppose to have many boards with
>>>> ES1.0
>>>>
>>> Even better if there are not many boards. It seems most of the boards
>>> will be with TI. I think we should have the fix in even if it is not
>>> 100% fix.
>>>
>>> What do you say?
>>>
>> My request is to get rid of ES1.0 board because the WA just
>> not completely correct. Don't feel patching kernel for silicon
>> which is not suppose to be used nether has complete WA
>> to support it.
>>
> OK Santosh. seems like cache is broken bad on ES1.0.
>
> Is it possible to disable the cache for ES1.0 and print a warning
> message about it?
>
Let's not add that support. See there are very few boards in
TI where ES1.0 is used so I suggest those users keep using
whatever works for them. Disable or the partial WA.
Regards
Santosh
^ permalink raw reply [flat|nested] 6+ messages in thread
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2012-04-02 6:55 L2 cache stability workaround for 4460 ES1.0 Roger Quadros
2012-04-02 7:38 ` Shilimkar, Santosh
2012-04-02 7:55 ` Roger Quadros
2012-04-02 7:58 ` Shilimkar, Santosh
2012-04-02 8:02 ` Roger Quadros
2012-04-02 9:13 ` Shilimkar, Santosh
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