mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
188cc0424e
Extend current sysfs access to ext_csd rpmb parameters (RPMB partition size) and rel_sector information. Signed-off-by: Loic Pallardy <loic.pallardy@stericsson.com> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Johan Rudholm <johan.rudholm@stericsson.com> Acked-by: Krishna Konda <kkonda@codeaurora.org> Signed-off-by: Chris Ball <cjb@laptop.org>
84 lines
3.1 KiB
Plaintext
84 lines
3.1 KiB
Plaintext
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
|
|
raw_rpmb_size_mult RPMB partition size
|
|
rel_sectors Reliable write sector count
|
|
|
|
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.
|
|
|
|
Note on raw_rpmb_size_mult:
|
|
"raw_rpmb_size_mult" is a mutliple of 128kB block.
|
|
RPMB size in byte is calculated by using the following equation:
|
|
RPMB partition size = 128kB x raw_rpmb_size_mult
|
|
|
|
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
|