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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20090315122759.3f48ba80@mjolnir.ossman.eu>
Date:	Sun, 15 Mar 2009 12:27:59 +0100
From:	Pierre Ossman <drzeus@...eus.cx>
To:	Wolfgang Mües <wolfgang.mues@...rswald.de>
Cc:	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Matt Fleming" <matt@...sole-pimps.org>,
	"David Brownell" <dbrownell@...rs.sourceforge.net>,
	"Mike Frysinger" <vapier.adi@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/7] mmc_spi: allow higher timeouts for SPI mode

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

> From: Wolfgang Muees <wolfgang.mues@...rswald.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@...rswald.de>
> 
> ---
> 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

  WARNING: This correspondence is being monitored by the
  Swedish government. Make sure your server uses encryption
  for SMTP traffic and consider using PGP for end-to-end
  encryption.

Download attachment "signature.asc" of type "application/pgp-signature" (199 bytes)