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

Santosh Shilimkar had written, on 12/20/2010 06:14 AM, the following:

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-----Original Message-----
From: Nishanth Menon [mailto:nm@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:
[..]

quoted

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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

quoted

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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?

Ref:
[1] http://infocenter.arm.com/help/topic/com.arm.doc.ddi0344k/Babigfeh.html
[2]
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0344k/Bgbciiaf.html

-- 
Regards,
Nishanth Menon