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Diffstat (limited to 'Documentation/mmc/mmc-dev-attrs.txt')
| -rw-r--r-- | Documentation/mmc/mmc-dev-attrs.txt | 76 |
1 files changed, 0 insertions, 76 deletions
diff --git a/Documentation/mmc/mmc-dev-attrs.txt b/Documentation/mmc/mmc-dev-attrs.txt deleted file mode 100644 index 22ae844..0000000 --- a/Documentation/mmc/mmc-dev-attrs.txt +++ /dev/null @@ -1,76 +0,0 @@ -SD and MMC Block Device Attributes -================================== - -These attributes are defined for the block devices associated with the -SD or MMC device. - -The following attributes are read/write. - - force_ro Enforce read-only access even if write protect switch is off. - -SD and MMC Device Attributes -============================ - -All attributes are read-only. - - cid Card Identifaction Register - csd Card Specific Data Register - scr SD Card Configuration Register (SD only) - date Manufacturing Date (from CID Register) - fwrev Firmware/Product Revision (from CID Register) (SD and MMCv1 only) - hwrev Hardware/Product Revision (from CID Register) (SD and MMCv1 only) - manfid Manufacturer ID (from CID Register) - name Product Name (from CID Register) - oemid OEM/Application ID (from CID Register) - serial Product Serial Number (from CID Register) - erase_size Erase group size - preferred_erase_size Preferred erase size - -Note on Erase Size and Preferred Erase Size: - - "erase_size" is the minimum size, in bytes, of an erase - operation. For MMC, "erase_size" is the erase group size - reported by the card. Note that "erase_size" does not apply - to trim or secure trim operations where the minimum size is - always one 512 byte sector. For SD, "erase_size" is 512 - if the card is block-addressed, 0 otherwise. - - SD/MMC cards can erase an arbitrarily large area up to and - including the whole card. When erasing a large area it may - be desirable to do it in smaller chunks for three reasons: - 1. A single erase command will make all other I/O on - the card wait. This is not a problem if the whole card - is being erased, but erasing one partition will make - I/O for another partition on the same card wait for the - duration of the erase - which could be a several - minutes. - 2. To be able to inform the user of erase progress. - 3. The erase timeout becomes too large to be very - useful. Because the erase timeout contains a margin - which is multiplied by the size of the erase area, - the value can end up being several minutes for large - areas. - - "erase_size" is not the most efficient unit to erase - (especially for SD where it is just one sector), - hence "preferred_erase_size" provides a good chunk - size for erasing large areas. - - For MMC, "preferred_erase_size" is the high-capacity - erase size if a card specifies one, otherwise it is - based on the capacity of the card. - - For SD, "preferred_erase_size" is the allocation unit - size specified by the card. - - "preferred_erase_size" is in bytes. - -SD/MMC/SDIO Clock Gating Attribute -================================== - -Read and write access is provided to following attribute. -This attribute appears only if CONFIG_MMC_CLKGATE is enabled. - - clkgate_delay Tune the clock gating delay with desired value in milliseconds. - -echo <desired delay> > /sys/class/mmc_host/mmcX/clkgate_delay |