[U-Boot] [PATCH] mmc: fix OCR Polling

[Andrew Gabbasov <andrew_gabbasov@mentor.com>]

Hi Peng,

> From: Peng Fan [mailto:Peng.Fan at freescale.com]
> Sent: Saturday, March 21, 2015 1:34 PM
> To: Gabbasov, Andrew; u-boot at lists.denx.de
> Subject: Re: [U-Boot] [PATCH] mmc: fix OCR Polling
> 
> [skipped]
> 
> > After this patch, if the busy flag is indeed already set (so that the
> > loop body is not executed), and it is not an SPI case
> > (mmc_host_is_spi(mmc) is false), the "cmd" structure (which is local
> > to mmc_complete_op_cond() function) is left uninitialized, and using
> > cmd.response[0] later in the function becomes incorrect. And the OCR
> > register value and the high capacity flag may be set incorrectly.
> Yeah. you are right.
> Maybe the following piece of code should be added to replace mmc->ocr =
> cmd.response[0]:
> "
> if (mmc_host_is_spi(mmc))
>      mmc->ocr = cmd.response[0];
> else
>      mmc->ocr = mmc->op_cond_response;
> "
> Thanks for correcting me.

Well, there can be several ways to correct that. The easiest would be
something
similar to what you propose, but, just to avoid extra "if", we could add
    mmc->op_cond_response = cmd.response[0];
to the end of existing "if(mmc_host_is_spi(mmc))" and change
    mmc->ocr = cmd.response[0];
to
    mmc->ocr = mmc->op_cond_response;
at the end of function. Since op_cond_response should be already set from
the function beginning, this can be used immediately.

And, going further, since op_cond_response is actually the same contents
as mmc->ocr, we could combine them and use mmc->ocr at once, from
the beginning of polling loops. This is a little more complex, but makes
the code cleaner. This is what is done in one of other patches in my series
;-)

Thanks.

Best regards,
Andrew