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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-16 12:21:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-16 12:21:41 -0700
commitc309b6f24222246c18a8b65d3950e6e755440865 (patch)
tree11893170f5c246bb0dee8066e85878af04162ab0 /Documentation/driver-api/mmc/mmc-dev-attrs.rst
parent3e859477a1db52a0435d06a55fdb54f62d69c292 (diff)
parent168869492e7009b6861b615f1d030c99bc805e83 (diff)
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Merge tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull rst conversion of docs from Mauro Carvalho Chehab: "As agreed with Jon, I'm sending this big series directly to you, c/c him, as this series required a special care, in order to avoid conflicts with other trees" * tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits) docs: kbuild: fix build with pdf and fix some minor issues docs: block: fix pdf output docs: arm: fix a breakage with pdf output docs: don't use nested tables docs: gpio: add sysfs interface to the admin-guide docs: locking: add it to the main index docs: add some directories to the main documentation index docs: add SPDX tags to new index files docs: add a memory-devices subdir to driver-api docs: phy: place documentation under driver-api docs: serial: move it to the driver-api docs: driver-api: add remaining converted dirs to it docs: driver-api: add xilinx driver API documentation docs: driver-api: add a series of orphaned documents docs: admin-guide: add a series of orphaned documents docs: cgroup-v1: add it to the admin-guide book docs: aoe: add it to the driver-api book docs: add some documentation dirs to the driver-api book docs: driver-model: move it to the driver-api book docs: lp855x-driver.rst: add it to the driver-api book ...
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+==================================
+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 Identification 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)
+ prv Product Revision (from CID Register)
+ (SD and MMCv4 only)
+ 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
+ ocr Operation Conditions Register
+ dsr Driver Stage Register
+ cmdq_en Command Queue enabled:
+
+ 1 => enabled, 0 => not enabled
+ ====================== ===============================================
+
+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 multiple of 128kB block.
+
+ RPMB size in byte is calculated by using the following equation:
+
+ RPMB partition size = 128kB x raw_rpmb_size_mult