[PATCHv3 4/9] ARM: OMAP2+: AM33XX: Reserve memory to comply with EMIF spec

Kevin Hilman khilman at linaro.org
Thu Aug 8 14:16:44 EDT 2013


Dave Gerlach <d-gerlach at ti.com> writes:

> From: Vaibhav Bedia <vaibhav.bedia at ti.com>
>
> SDRAM controller on AM33XX requires that a modification of certain
> bit-fields in PWR_MGMT_CTRL register (ref. section 7.3.5.13 in
> AM335x-Rev H) is followed by a dummy read access to SDRAM. This
> scenario arises when entering a low power state like DeepSleep.
> To ensure that the read is not from a cached region we reserve
> some memory during bootup using the arm_memblock_steal() API.

Hmm, sounds to me an awful lot like the existing omap_bus_sync() ?

However, you remove that feature when you remove omap_reserve() here
becasue omap_reserve() ss not called from your new reserve function.
Are you *really* sure you don't need the functions called there?  This
is a pretty big change that's not mentioned anywhere in the changelog.

Kevin



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