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Old 01-25-2010, 06:26 PM
Stefan Bader
 
Default SRU: ath5k: Fix eeprom checksum check for custom sized eeproms

SRU justification:

Impact: Upstream 2.6.31.9 contained a patch that added a check for bogus
EEPROM checksums to the ath5k driver but it seems to have missed the fact
that custom EEPROMs might be different in size.

Fix: Upstream patch which was added to 2.6.32.4 but not carried over to
2.6.31.y adds code to query and work with differently sized EEPROMS.

Testcase: Bring up certain hw with custom EEPROM. Verified in the report.

-Stefan

---
 
Old 01-25-2010, 11:39 PM
Tim Gardner
 
Default SRU: ath5k: Fix eeprom checksum check for custom sized eeproms

Stefan Bader wrote:
> SRU justification:
>
> Impact: Upstream 2.6.31.9 contained a patch that added a check for bogus
> EEPROM checksums to the ath5k driver but it seems to have missed the fact
> that custom EEPROMs might be different in size.
>
> Fix: Upstream patch which was added to 2.6.32.4 but not carried over to
> 2.6.31.y adds code to query and work with differently sized EEPROMS.
>
> Testcase: Bring up certain hw with custom EEPROM. Verified in the report.
>
> -Stefan
>
> ---
>
> From e6efac7b7c4ce45d40f5e07d3105e07704e95673 Mon Sep 17 00:00:00 2001
> From: Luis R. Rodriguez <lrodriguez@atheros.com>
> Date: Mon, 4 Jan 2010 10:40:39 -0500
> Subject: [PATCH] ath5k: Fix eeprom checksum check for custom sized eeproms
>
> BugLink: http://bugs.launchpad.net/bugs/506180
>
> commit 359207c687cc8f4f9845c8dadd0d6dabad44e584 upstream.
>
> Commit 8bf3d79bc401ca417ccf9fc076d3295d1a71dbf5 enabled EEPROM
> checksum checks to avoid bogus bug reports but failed to address
> updating the code to consider devices with custom EEPROM sizes.
> Devices with custom sized EEPROMs have the upper limit size stuffed
> in the EEPROM. Use this as the upper limit instead of the static
> default size. In case of a checksum error also provide back the
> max size and whether or not this was the default size or a custom
> one. If the EEPROM is busted we add a failsafe check to ensure
> we don't loop forever or try to read bogus areas of hardware.
>
> This closes bug 14874
>
> http://bugzilla.kernel.org/show_bug.cgi?id=14874
>
> Cc: David Quan <david.quan@atheros.com>
> Cc: Stephen Beahm <stephenbeahm@comcast.net>
> Reported-by: Joshua Covington <joshuacov@googlemail.com>
> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
> Signed-off-by: John W. Linville <linville@tuxdriver.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
> ---
> drivers/net/wireless/ath/ath5k/eeprom.c | 32 ++++++++++++++++++++++++++++--
> drivers/net/wireless/ath/ath5k/eeprom.h | 8 +++++++
> 2 files changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath5k/eeprom.c b/drivers/net/wireless/ath/ath5k/eeprom.c
> index 7918852..9a96550 100644
> --- a/drivers/net/wireless/ath/ath5k/eeprom.c
> +++ b/drivers/net/wireless/ath/ath5k/eeprom.c
> @@ -97,7 +97,7 @@ ath5k_eeprom_init_header(struct ath5k_hw *ah)
> struct ath5k_eeprom_info *ee = &ah->ah_capabilities.cap_eeprom;
> int ret;
> u16 val;
> - u32 cksum, offset;
> + u32 cksum, offset, eep_max = AR5K_EEPROM_INFO_MAX;
>
> /*
> * Read values from EEPROM and store them in the capability structure
> @@ -116,12 +116,38 @@ ath5k_eeprom_init_header(struct ath5k_hw *ah)
> * Validate the checksum of the EEPROM date. There are some
> * devices with invalid EEPROMs.
> */
> - for (cksum = 0, offset = 0; offset < AR5K_EEPROM_INFO_MAX; offset++) {
> + AR5K_EEPROM_READ(AR5K_EEPROM_SIZE_UPPER, val);
> + if (val) {
> + eep_max = (val & AR5K_EEPROM_SIZE_UPPER_MASK) <<
> + AR5K_EEPROM_SIZE_ENDLOC_SHIFT;
> + AR5K_EEPROM_READ(AR5K_EEPROM_SIZE_LOWER, val);
> + eep_max = (eep_max | val) - AR5K_EEPROM_INFO_BASE;
> +
> + /*
> + * Fail safe check to prevent stupid loops due
> + * to busted EEPROMs. XXX: This value is likely too
> + * big still, waiting on a better value.
> + */
> + if (eep_max > (3 * AR5K_EEPROM_INFO_MAX)) {
> + ATH5K_ERR(ah->ah_sc, "Invalid max custom EEPROM size: "
> + "%d (0x%04x) max expected: %d (0x%04x)
",
> + eep_max, eep_max,
> + 3 * AR5K_EEPROM_INFO_MAX,
> + 3 * AR5K_EEPROM_INFO_MAX);
> + return -EIO;
> + }
> + }
> +
> + for (cksum = 0, offset = 0; offset < eep_max; offset++) {
> AR5K_EEPROM_READ(AR5K_EEPROM_INFO(offset), val);
> cksum ^= val;
> }
> if (cksum != AR5K_EEPROM_INFO_CKSUM) {
> - ATH5K_ERR(ah->ah_sc, "Invalid EEPROM checksum 0x%04x
", cksum);
> + ATH5K_ERR(ah->ah_sc, "Invalid EEPROM "
> + "checksum: 0x%04x eep_max: 0x%04x (%s)
",
> + cksum, eep_max,
> + eep_max == AR5K_EEPROM_INFO_MAX ?
> + "default size" : "custom size");
> return -EIO;
> }
>
> diff --git a/drivers/net/wireless/ath/ath5k/eeprom.h b/drivers/net/wireless/ath/ath5k/eeprom.h
> index 0123f35..473a483 100644
> --- a/drivers/net/wireless/ath/ath5k/eeprom.h
> +++ b/drivers/net/wireless/ath/ath5k/eeprom.h
> @@ -37,6 +37,14 @@
> #define AR5K_EEPROM_RFKILL_POLARITY_S 1
>
> #define AR5K_EEPROM_REG_DOMAIN 0x00bf /* EEPROM regdom */
> +
> +/* FLASH(EEPROM) Defines for AR531X chips */
> +#define AR5K_EEPROM_SIZE_LOWER 0x1b /* size info -- lower */
> +#define AR5K_EEPROM_SIZE_UPPER 0x1c /* size info -- upper */
> +#define AR5K_EEPROM_SIZE_UPPER_MASK 0xfff0
> +#define AR5K_EEPROM_SIZE_UPPER_SHIFT 4
> +#define AR5K_EEPROM_SIZE_ENDLOC_SHIFT 12
> +
> #define AR5K_EEPROM_CHECKSUM 0x00c0 /* EEPROM checksum */
> #define AR5K_EEPROM_INFO_BASE 0x00c0 /* EEPROM header */
> #define AR5K_EEPROM_INFO_MAX (0x400 - AR5K_EEPROM_INFO_BASE)

Acked-by: Tim Gardner <tim.gardner@canonical.com>

--
Tim Gardner tim.gardner@canonical.com

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