1==================================
2SD and MMC Block Device Attributes
3==================================
4
5These attributes are defined for the block devices associated with the
6SD or MMC device.
7
8The following attributes are read/write.
9
10	========		===============================================
11	force_ro		Enforce read-only access even if write protect 					switch is off.
12	========		===============================================
13
14SD and MMC Device Attributes
15============================
16
17All attributes are read-only.
18
19	======================	===============================================
20	cid			Card Identification Register
21	csd			Card Specific Data Register
22	scr			SD Card Configuration Register (SD only)
23	date			Manufacturing Date (from CID Register)
24	fwrev			Firmware/Product Revision (from CID Register)
25				(SD and MMCv1 only)
26	hwrev			Hardware/Product Revision (from CID Register)
27				(SD and MMCv1 only)
28	manfid			Manufacturer ID (from CID Register)
29	name			Product Name (from CID Register)
30	oemid			OEM/Application ID (from CID Register)
31	prv			Product Revision (from CID Register)
32				(SD and MMCv4 only)
33	serial			Product Serial Number (from CID Register)
34	erase_size		Erase group size
35	preferred_erase_size	Preferred erase size
36	raw_rpmb_size_mult	RPMB partition size
37	rel_sectors		Reliable write sector count
38	ocr 			Operation Conditions Register
39	dsr			Driver Stage Register
40	cmdq_en			Command Queue enabled:
41
42					1 => enabled, 0 => not enabled
43	======================	===============================================
44
45Note on Erase Size and Preferred Erase Size:
46
47	"erase_size" is the  minimum size, in bytes, of an erase
48	operation.  For MMC, "erase_size" is the erase group size
49	reported by the card.  Note that "erase_size" does not apply
50	to trim or secure trim operations where the minimum size is
51	always one 512 byte sector.  For SD, "erase_size" is 512
52	if the card is block-addressed, 0 otherwise.
53
54	SD/MMC cards can erase an arbitrarily large area up to and
55	including the whole card.  When erasing a large area it may
56	be desirable to do it in smaller chunks for three reasons:
57
58	     1. A single erase command will make all other I/O on
59		the card wait.  This is not a problem if the whole card
60		is being erased, but erasing one partition will make
61		I/O for another partition on the same card wait for the
62		duration of the erase - which could be a several
63		minutes.
64	     2. To be able to inform the user of erase progress.
65	     3. The erase timeout becomes too large to be very
66		useful.  Because the erase timeout contains a margin
67		which is multiplied by the size of the erase area,
68		the value can end up being several minutes for large
69		areas.
70
71	"erase_size" is not the most efficient unit to erase
72	(especially for SD where it is just one sector),
73	hence "preferred_erase_size" provides a good chunk
74	size for erasing large areas.
75
76	For MMC, "preferred_erase_size" is the high-capacity
77	erase size if a card specifies one, otherwise it is
78	based on the capacity of the card.
79
80	For SD, "preferred_erase_size" is the allocation unit
81	size specified by the card.
82
83	"preferred_erase_size" is in bytes.
84
85Note on raw_rpmb_size_mult:
86
87	"raw_rpmb_size_mult" is a multiple of 128kB block.
88
89	RPMB size in byte is calculated by using the following equation:
90
91		RPMB partition size = 128kB x raw_rpmb_size_mult
92