[PATCH / RFC] MCI: imx-esdhc: implement workaround for errata ENGcm12360

[Sascha Hauer]

Hi Markus,

On Thu, Sep 05, 2013 at 03:31:20PM +0200, Markus Niebel wrote:
> From: Markus Niebel <Markus.Niebel at tqs.de>
> 
> Signed-off-by: Markus Niebel <Markus.Niebel at tqs.de>
> 
> At least i.MX53 has errata ENGcm12360:
> 
> Occurs when a pending command which issues busy is completed.
> For a command with R1b response, the proper software sequence
> is to poll the DLA for R1b commands to determine busy
> state completion. The DLA polling is not working properly for
> the ESDHC module. This is relevant for all eSDHC ports (eSDHC1-4 ports)
> 
> DLA bit in PRSSTAT register cannot be
> polled to wait for busy state completion.
> 
> Updated block guide to reflect that DLA is not applicable to detect
> busy state, instead, should poll bit 24 in PRSSTAT register (DLSL[0] bit)
> to check that wait busy state is over.

I'll give it a try in the -next branch. The patch looks as if it is safe
on other SoCs, but let's see.

Sascha

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