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

[David Brownell <david-b@pacbell.net>]

On Wednesday 11 March 2009, Wolfgang Mües wrote:
> From: Wolfgang Muees <wolfgang.mues@auerswald.de>
> 
> 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@auerswald.de>

Acked-by: David Brownell <dbrownell@users.sourceforge.net>


> ---
> 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);
> 
> ---
> regards
> 
> i. A. Wolfgang Mües
> -- 
> Auerswald GmbH & Co. KG
> Hardware Development
> Telefon: +49 (0)5306 9219 0
> Telefax: +49 (0)5306 9219 94 
> E-Mail: Wolfgang.Mues@Auerswald.de
> Web: http://www.auerswald.de
>  
> --------------------------------------------------------------
> Auerswald GmbH & Co. KG, Vor den Grashöfen 1, 38162 Cremlingen
> Registriert beim AG Braunschweig HRA 13289
> p.h.G Auerswald Geschäftsführungsges. mbH
> Registriert beim AG Braunschweig HRB 7463
> Geschäftsführer: Dipl-Ing. Gerhard Auerswald
> 
>