Re: [PATCH 5/7] mmc_spi: allow higher timeouts for SPI mode

[Pierre Ossman]

On Wed, 11 Mar 2009 14:28:39 +0100
Wolfgang MÃes <wolfgang.mues@xxxxxxxxxxxx> wrote:

> From: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
> 
> o Some SD cards have very high timeouts in SPI mode.
>   So adjust the timeouts from theory to practice.
> 
> Signed-off-by: Wolfgang Muees <wolfgang.mues@xxxxxxxxxxxx>
> 
> ---
> This is one of a line of patches to enhance the usability of
> the mmc spi host port driver from "don't work with most SD cards"
> to "work with nearly all SD cards" (including those ugly cards
> with non-byte-aligned responses).
> 
> diff -uprN 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/core/core.c 2_6_29_rc7_patch5_extra_spi_timeouts/drivers/mmc/core/core.c
> --- 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/core/core.c	2009-03-04 02:05:22.000000000 +0100
> +++ 2_6_29_rc7_patch5_extra_spi_timeouts/drivers/mmc/core/core.c	2009-03-10 12:06:16.000000000 +0100
> @@ -297,6 +297,21 @@ void mmc_set_data_timeout(struct mmc_dat
>  			data->timeout_clks = 0;
>  		}
>  	}
> +	/*
> +	 * Some cards need very high timeouts if driven in SPI mode.
> +	 * The worst observed timeout was 900ms after writing a
> +	 * continuous stream of data until the internal logic
> +	 * overflowed.
> +	 */
> +	if (mmc_host_is_spi(card->host)) {
> +		if (data->flags & MMC_DATA_WRITE) {
> +			if (data->timeout_ns < 1000000000)
> +				data->timeout_ns = 1000000000;	/* 1s */
> +		} else {
> +			if (data->timeout_ns < 100000000)
> +				data->timeout_ns =  100000000;	/* 100ms */
> +		}
> +	}
>  }
>  EXPORT_SYMBOL(mmc_set_data_timeout);
> 

In the future, there are macros called NSEC_PER_SEC and similar that
can be used to increase readability instead of the comments.

Rgds
-- 
     -- Pierre Ossman

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