Autoloading of mmc_block for SD/MMC interfaces

Autoloading of mmc_block for SD/MMC interfaces

[Matthew Garrett]

Hi,

Currently, mmc_block isn't autoloaded when an MMC or SD card is 
inserted. On card insertion, /sys/bus/mmc/devices/mmc0:0001 (or similar) 
is created. In this is a file called csd, which is a dump of 128 bits of 
card specific data. According to drivers/mmc/mmc.c, the 12 bits starting 
at bit 84 define the commands that the card will respond to. 
include/linux/mmc/protocol.h specifies these - if bit 2 is set 
(BLOCK_READ), then mmc_block should be loaded.

Sample dump:

tyrosine% cat /sys/bus/mmc/devices/mmc0:0001/csd
8c7f002a1f5983d3f6da8fff9e600000
         ^^^

12 bits - 0x95f

100101011111
         ^ CCC_BLOCK_READ
-- 
Matthew Garrett | mjg59@srcf.ucam.org


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Re: Autoloading of mmc_block for SD/MMC interfaces

[Marco d'Itri]

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On Jan 31, Matthew Garrett <mjg59@srcf.ucam.org> wrote:

> Currently, mmc_block isn't autoloaded when an MMC or SD card is 
> inserted. On card insertion, /sys/bus/mmc/devices/mmc0:0001 (or similar) 
If there also other drivers for MMC cards exist then looks like they
should use $MODALIAS.

-- 
ciao,
Marco

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