linux-stable/drivers/mmc
Philip Rakity 08ee80cc39 mmc: core: eMMC bus width may not work on all platforms
CMD19 -- The offical way to validate bus widths from the JEDEC spec
does not work on all platforms.  Some platforms that use PCI/PCIe
to connect their SD controllers are known to fail.

If the quirk MMC_BUS_WIDTH_TEST is not defined we try to figure out
the bus width by reading the ext_csd at different bus widths and
compare this against the ext_csd read in 1 bit mode.  If no ext_csd
is available we default to 1 bit operations.

Code has been tested on mmp2 against 8 bit eMMC and Transcend 2GB
card that is known to not work in 4 bit mode.  The physical pins
on the card are not present to support 4 bit operation.

Signed-off-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-05-25 16:52:32 -04:00
..
card mmc: core: Block CMD23 support for UHS104/SDXC cards. 2011-05-25 16:49:03 -04:00
core mmc: core: eMMC bus width may not work on all platforms 2011-05-25 16:52:32 -04:00
host mmc: sdhci: Auto-CMD23 fixes. 2011-05-25 16:52:26 -04:00
Kconfig mmc: explicitly mention SDIO support in Kconfig 2008-10-12 11:04:36 +02:00
Makefile mmc: Makefile: Fix EXTRA_CFLAGS assignment 2010-10-23 21:11:15 +08:00