From: Adrian Hunter <adrian.hunter@nokia.com>
To: Philip Rakity <prakity@marvell.com>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Nicolas Pitre <nico@marvell.com>,
Lennert Buijtenhek <buytenh@marvell.com>,
"pierre@ossman.eu" <pierre@ossman.eu>
Subject: Re: Patch: eMMC boot partition needs to be deactivated for linux to find user partitions
Date: Mon, 15 Mar 2010 10:08:02 +0200 [thread overview]
Message-ID: <4B9DEAE2.3030707@nokia.com> (raw)
In-Reply-To: <53E1B390-48DD-4E33-B51F-1B039AFD13A2@marvell.com>
Philip Rakity wrote:
> Some eMMC chips have a boot partition that is meant to be used to load in low level boot code.
> This partition is available when the chip is powered up. Normally the boot loader would disable
> access to the partition once boot code was loaded in before passing control to linux.
>
> if booting occurs from another device (not the eMMC chip) the partition will not be disabled by
> the boot loader and control will be passed to linux. This will cause linux to not recognize user
> partitions on the chip unless access to the boot partition is deactivated.
>
> See JEDEC Standard 84-A44 (eMMC 4.4 spec) -- Page 139
Page 139 doesn't say anything about why you need that switch command.
Please provide a more useful reference or delete this.
Boot mode is terminated by CMD1, so that switch command should not
be needed. Please explain why it is needed in more detail.
That switch command should not be used for devices that do not
support it e.g. eMMC 4.3 and before.
>
> signed off by: Philip Rakity <prakity@marvell.com>
> diff -ru linux-2.6.32.8/drivers/mmc/core/mmc.c linux-2.6.32.8 copy/drivers/mmc/core/mmc.c
> --- linux-2.6.32.8/drivers/mmc/core/mmc.c 2010-02-09 04:57:19.000000000 -0800
> +++ linux-2.6.32.8 copy/drivers/mmc/core/mmc.c 2010-03-12 20:56:16.000000000 -0800
> @@ -430,6 +432,13 @@
> }
>
> /*
> + * ensure eMMC private booting PARTITION is not enabled
> + * see JEDEC Standard No. 84-A44 - Page 139
> + */
> + mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> + EXT_CSD_BOOT_CONFIG, 0x0);
> +
> + /*
> * Compute bus speed.
> */
> max_dtr = (unsigned int)-1;
> diff -ru linux-2.6.32.8/include/linux/mmc/mmc.h linux-2.6.32.8 copy/include/linux/mmc/mmc.h
> --- linux-2.6.32.8/include/linux/mmc/mmc.h 2010-02-09 04:57:19.000000000 -0800
> +++ linux-2.6.32.8 copy/include/linux/mmc/mmc.h 2010-03-12 20:53:48.000000000 -0800
> @@ -251,6 +252,7 @@
> * EXT_CSD fields
> */
>
> +#define EXT_CSD_BOOT_CONFIG 179 /* R/W */
> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
> #define EXT_CSD_HS_TIMING 185 /* R/W */
> #define EXT_CSD_CARD_TYPE 196 /* RO */
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
next prev parent reply other threads:[~2010-03-15 8:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-12 5:17 RE: Bug in mmc.c == stops eMMC toshiba from working - sector check not good (PATCH) Philip Rakity
2010-03-13 5:09 ` Patch: eMMC boot partition needs to be deactivated for linux to find user partitions Philip Rakity
2010-03-15 8:08 ` Adrian Hunter [this message]
2010-03-15 18:32 ` Features vs versions (Was: Patch: eMMC boot partition needs to be deactivated for linux to find user partitions) Edward Falk
2010-03-15 18:54 ` Johnson, Charles F
2010-03-16 1:44 ` Patch: eMMC boot partition needs to be deactivated for linux to find user partitions Philip Rakity
2010-03-20 5:12 ` Philip Rakity
2010-03-22 8:25 ` Adrian Hunter
[not found] ` <639D1595-D908-473C-9A41-71B493DCD0C0@marvell.com>
2010-03-29 7:12 ` Adrian Hunter
2010-09-19 21:46 ` [PATCH] sdhci: add quirk for controllers that don't support write only detect Philip Rakity
2010-09-20 6:14 ` Wolfram Sang
2010-09-20 16:00 ` Philip Rakity
2010-09-21 5:43 ` [PATCH] sdhci: allow for eMMC 74 clock generation by controller Philip Rakity
2010-09-21 6:04 ` Adrian Hunter
2010-09-21 15:06 ` Philip Rakity
2010-09-21 16:58 ` Wolfram Sang
[not found] ` <15EE115E-4B8A-4314-BD7A-3FB24A1F1BB6@marvell.com>
2010-09-22 8:56 ` Wolfram Sang
2010-09-22 7:57 ` Adrian Hunter
2010-09-22 22:25 ` [PATCH] sdhci: print out controller name for register debug Philip Rakity
2010-09-22 23:08 ` Chris Ball
2010-09-23 8:39 ` Wolfram Sang
2010-09-23 16:12 ` Chris Ball
2010-09-23 17:11 ` Wolfram Sang
2010-09-21 6:48 ` [PATCH] sdhci: allow for eMMC 74 clock generation by controller Wolfram Sang
2010-09-23 15:24 ` Philip Rakity
2010-09-23 15:49 ` Subject: [PATCH] sdhci: Show SD Command when doing debug printks Philip Rakity
2010-10-07 23:58 ` [PATCH] sdhci: allow for eMMC 74 clock generation by controller Chris Ball
[not found] ` <763CD352-8557-46F1-89D6-5596C40C435E@marvell.com>
2010-09-24 4:49 ` [PATCH] sdhci: add quirk for controllers that don't support write only detect Wolfram Sang
2010-09-24 9:34 ` Philip Rakity
2010-03-16 20:25 ` Bug in mmc.c == stops eMMC toshiba from working - sector check not good (REPOST) (PATCH) Philip Rakity
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