Re: relation between mmc_request, mmc_data and mmc_command

From: Pierre Ossman
Date: Tue Dec 25 2007 - 08:36:01 EST


On Sun, 23 Dec 2007 23:25:26 -0800
"raki john" <raki4652@xxxxxxxxx> wrote:

>
> Does mmc_requeest->stop is equal to mmc_request->data->stop ?
>
> Does mmc_request is equal to mmc_request->data->mrq ?
>
> Does mmc_request->data is equal to mmc_request->cmd->data ?
>
> Does mmc_request is equal to mmc_request->cmd->mrq ?
>

Yes on all accounts. I don't know the reason for this extreme redundancy. It was there long before I got involved.

>
> I think Stop command which is part of mmc_request is used for sending stop
> command after Multi Block write. is this correct. If stop command fails(CRC
> fail, timeout), does this mean card write failed.
>

It is correct that it is used for multi block writes. But also other open ended transfers.

If the stop command fails, then the card will be in an unknown state. The write should have been completed though.

Rgds
Pierre

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