[PATCH 0/2] Proper MMC command classes support

[PATCH 0/2] Proper MMC command classes support

[Pierre Ossman]

The MMC block layer currently contains an if-clause which only seems to
serve the purpose of killing forward compatibility:

	if (card->csd.cmdclass & ~0x1ff)
		return -ENODEV;

This checks for (what I presume) command classes that were undefined
when this code was written. Since these are now starting to be used,
this code is causing a lot of problems. The following two patches tries
to make a more sane check of the command classes.

(Note. The new command class is for high speed cards to allow higher
transfer rates than normal)

Rgds
Pierre

[PATCH 1/2] Proper MMC command classes support

[Pierre Ossman]

[-- Attachment #1: Type: text/plain, Size: 137 bytes --]

Defines for the different command classes as defined in the MMC and SD
specifications.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>


[-- Attachment #2: mmc-ccc.patch --]
[-- Type: text/x-patch, Size: 1548 bytes --]

Index: linux-wbsd/include/linux/mmc/protocol.h
===================================================================
--- linux-wbsd/include/linux/mmc/protocol.h	(revision 134)
+++ linux-wbsd/include/linux/mmc/protocol.h	(working copy)
@@ -209,6 +209,33 @@
 #define CSD_SPEC_VER_2      2           /* Implements system specification 2.0 - 2.2 */
 #define CSD_SPEC_VER_3      3           /* Implements system specification 3.1 */
 
+/*
+ * Card Command Classes (CCC)
+ */
+#define CCC_BASIC		(1<<0)	/* (0) Basic protocol functions */
+					/* (CMD0,1,2,3,4,7,9,10,12,13,15) */
+#define CCC_STREAM_READ		(1<<1)	/* (1) Stream read commands */
+					/* (CMD11) */
+#define CCC_BLOCK_READ		(1<<2)	/* (2) Block read commands */
+					/* (CMD16,17,18) */
+#define CCC_STREAM_WRITE	(1<<3)	/* (3) Stream write commands */
+					/* (CMD20) */
+#define CCC_BLOCK_WRITE		(1<<4)	/* (4) Block write commands */
+					/* (CMD16,24,25,26,27) */
+#define CCC_ERASE		(1<<5)	/* (5) Ability to erase blocks */
+					/* (CMD32,33,34,35,36,37,38,39) */
+#define CCC_WRITE_PROT		(1<<6)	/* (6) Able to write protect blocks */
+					/* (CMD28,29,30) */
+#define CCC_LOCK_CARD		(1<<7)	/* (7) Able to lock down card */
+					/* (CMD16,CMD42) */
+#define CCC_APP_SPEC		(1<<8)	/* (8) Application specific */
+					/* (CMD55,56,57,ACMD*) */
+#define CCC_IO_MODE		(1<<9)	/* (9) I/O mode */
+					/* (CMD5,39,40,52,53) */
+#define CCC_SWITCH		(1<<10)	/* (10) High speed switch */
+					/* (CMD6,34,35,36,37,50) */
+					/* (11) Reserved */
+					/* (CMD?) */
 
 /*
  * SD bus widths

[PATCH 2/2] Proper MMC command classes support

[Pierre Ossman]

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Removes the check for high command classes and instead checks that the
command classes needed are present.
Previous solution killed forward compatibility at no apparent gain.

Signed-of-by: Pierre Ossman <drzeus@drzeus.cx>

This patch only checks for CCC_BLOCK_READ even though CCC_BLOCK_WRITE is
also needed. My intention is to make the card read-only if the write
command class is unavailable. But such a patch will conflict with the SD
patches previously submitted. So I need to know which version should be
used as a base.


[-- Attachment #2: mmc-block-ccc.patch --]
[-- Type: text/x-patch, Size: 493 bytes --]

Index: linux-wbsd/drivers/mmc/mmc_block.c
===================================================================
--- linux-wbsd/drivers/mmc/mmc_block.c	(revision 134)
+++ linux-wbsd/drivers/mmc/mmc_block.c	(working copy)
@@ -443,7 +443,10 @@
 	struct mmc_blk_data *md;
 	int err;
 
-	if (card->csd.cmdclass & ~0x1ff)
+	/*
+	 * Check that the card supports the command class(es) we need.
+	 */
+	if (!(card->csd.cmdclass & CCC_BLOCK_READ))
 		return -ENODEV;
 
 	if (card->csd.read_blkbits < 9) {