[PATCH v4 5/7] OMAP3630: PM: Disable L2 cache while invalidating L2 cache

Nishanth Menon nm at ti.com
Mon Dec 20 08:08:14 EST 2010

Santosh Shilimkar had written, on 12/20/2010 06:14 AM, the following:
>> -----Original Message-----
>> From: Nishanth Menon [mailto:nm at ti.com]
>> Sent: Monday, December 20, 2010 5:15 PM
>> To: Santosh Shilimkar
>> Cc: linux-omap; linux-arm; Jean Pihet; Kevin; Tony
>> Subject: Re: [PATCH v4 5/7] OMAP3630: PM: Disable L2 cache while
>> invalidating L2 cache
>> Santosh Shilimkar wrote, on 12/20/2010 01:13 AM:
>> [..]
>>>> This is be done according to ARM documentation. Currently this is
>>>> identified
>>>> as being needed on OMAP3630 as the disable/enable is done from
> "public
>>>> side"
>>>> while, on OMAP3430, this is done in the "secure side".
>>> Can you point me to ARM doc which says " for L2 invalidation, the
>>> controller
>>> needs to be disabled" ?
>> please see section 8.3 of the Cortex-A8 TRM
> Yes. Have seen it and it doesn't say at least what your patch
> description is saying.
See [1]
To disable the L2 cache, but leave the L1 data cache enabled, use the 
following sequence:
    1. Disable the C bit.
for details on C bit: see [2]
    2. Clean and invalidate the L1 and L2 caches.
Does this help or do you have a suggestion on how the commit message 
could be improved?

[1] http://infocenter.arm.com/help/topic/com.arm.doc.ddi0344k/Babigfeh.html

Nishanth Menon

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