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sdio: add MMC_QUIRK_LENIENT_FN0

PATCH In review Ohad Ben-Cohen 2 participants 3 messages Aug 26, 2009 – Aug 27, 2009 MMC, SD and SDIO

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Ohad Ben-Cohen

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PATCH 2/2 sdio: add MMC_QUIRK_LENIENT_FN0

From: Ohad Ben-Cohen <[email protected]>

Normally writes to SDIO function 0 outside the vendor specific CCCR registers are prohibited. To support embedded devices that require writes to SDIO function 0 outside this range (e.g. TI WL127x embedded sdio wifi device), MMC_QUIRK_LENIENT_FN0 is introduced.

Signed-off-by Ohad Ben-Cohen <[email protected]>
---
 drivers/mmc/core/sdio_io.c |    2 +-
 include/linux/mmc/card.h   |    3 +++
 2 files changed, 4 insertions(+), 1 deletions(-)
drivers/mmc/core/sdio_io.c +1 -1
index f61fc2d..f9aa8a7 100644
@@ -624,7 +624,7 @@ void sdio_f0_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
 
 	BUG_ON(!func);
 
-	if (addr < 0xF0 || addr > 0xFF) {
+	if ((addr < 0xF0 || addr > 0xFF) && (!mmc_card_lenient_fn0(func->card))) {
 		if (err_ret)
 			*err_ret = -EINVAL;
 		return;
include/linux/mmc/card.h +3 -0
index eac86fe..bff96cf 100644
@@ -95,6 +95,7 @@ struct mmc_card {
 #define MMC_STATE_HIGHSPEED	(1<<2)		/* card is in high speed mode */
 #define MMC_STATE_BLOCKADDR	(1<<3)		/* card uses block-addressing */
 	unsigned int		quirks; 	/* card quirks */
+#define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */
 
 	u32			raw_cid[4];	/* raw card CID */
 	u32			raw_csd[4];	/* raw card CSD */

@@ -130,6 +131,8 @@ struct mmc_card {
 #define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
 #define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
 
+#define mmc_card_lenient_fn0(c)	((c)->quirks & MMC_QUIRK_LENIENT_FN0)
+
 #define mmc_card_name(c)	((c)->cid.prod_name)
 #define mmc_card_id(c)		(dev_name(&(c)->dev))
Signature · 1 line
1.5.4.3
#1 lore raw
Quoted 8 lines · On Wed, 26 Aug 2009 04:10:01 +0300 Ohad Ben-Cohen <[email protected]> wrote:

From: Ohad Ben-Cohen <[email protected]>

Normally writes to SDIO function 0 outside the vendor specific CCCR registers are prohibited. To support embedded devices that require writes to SDIO function 0 outside this range (e.g. TI WL127x embedded sdio wifi device), MMC_QUIRK_LENIENT_FN0 is introduced.

It hardly seems worthwhile doing this in two separate patches so I rolled them together and fiddled the changelog a bit.

Quoted 26 lines
drivers/mmc/core/sdio_io.c +1 -1
index f61fc2d..f9aa8a7 100644
@@ -624,7 +624,7 @@ void sdio_f0_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
 
 	BUG_ON(!func);
 
-	if (addr < 0xF0 || addr > 0xFF) {
+	if ((addr < 0xF0 || addr > 0xFF) && (!mmc_card_lenient_fn0(func->card))) {
 		if (err_ret)
 			*err_ret = -EINVAL;
 		return;
include/linux/mmc/card.h +1 -0
index eac86fe..bff96cf 100644
@@ -95,6 +95,7 @@ struct mmc_card {
 #define MMC_STATE_HIGHSPEED	(1<<2)		/* card is in high speed mode */
 #define MMC_STATE_BLOCKADDR	(1<<3)		/* card uses block-addressing */
 	unsigned int		quirks; 	/* card quirks */
+#define MMC_QUIRK_LENIENT_FN0	(1<<0)		/* allow SDIO FN0 writes outside of the VS CCCR range */
 
 	u32			raw_cid[4];	/* raw card CID */
 	u32			raw_csd[4];	/* raw card CSD */

include/linux/mmc/card.h struct mmc_card { · line 137

Quoted 7 lines
include/linux/mmc/card.h +2 -0
@@ -130,6 +131,8 @@ struct mmc_card {
 #define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
 #define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
 
+#define mmc_card_lenient_fn0(c)	((c)->quirks & MMC_QUIRK_LENIENT_FN0)
+
 #define mmc_card_name(c)	((c)->cid.prod_name)
 #define mmc_card_id(c)		(dev_name(&(c)->dev))

No, please don't use macros unless the function HAS to be implemented in a macro. If it simply cannot be implemented in C.

The code you have there will silently compile if passed the address of any struct which contains a field called "quirks". That's bad. Using a C function provides typechecking.

include/linux/mmc/card.h renamed from include/linux/mmc/card.h~sdio-add-mmc_quirk_lenient_fn0-fix +4 -1
@@ -134,7 +134,10 @@ struct mmc_card {
 #define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)
 #define mmc_card_set_blockaddr(c) ((c)->state |= MMC_STATE_BLOCKADDR)
 
-#define mmc_card_lenient_fn0(c)	((c)->quirks & MMC_QUIRK_LENIENT_FN0)
+static inline int mmc_card_lenient_fn0(const struct mmc_card *c)
+{
+	return c->quirks & MMC_QUIRK_LENIENT_FN0;
+}
 
 #define mmc_card_name(c)	((c)->cid.prod_name)
 #define mmc_card_id(c)		(dev_name(&(c)->dev))

_

A nice side-effect of using C is that for some reason people are more likely to document C functions than with macros. Although in this case the MMC_QUIRK_LENIENT_FN0 documentation suffices.