mmc: sdio: fix alignment issue in struct sdio_func
Subsystems (2)
PATCH v2 1/1 mmc: sdio: fix alignment issue in struct sdio_func
Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be used for DMA to be 8-byte-aligned. struct sdio_func has an embedded small DMA buffer not meeting this requirement.
Testing an extension to meson-gx driver for switching to descriptor chain mode broke SDIO therefore. Aligning tmpbuf to a 8-byte boundary fixed the driver behavior.
---
v2:
- switch to much simpler version as suggested by Kevin Hilman <[email protected]>
- adjust commit message
--- include/linux/mmc/sdio_func.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
include/linux/mmc/sdio_func.h +2 -1
@@ -53,7 +53,8 @@ struct sdio_func {unsigned int state;/* function state */ #define SDIO_STATE_PRESENT (1<<0)/* present in sysfs */ -u8 tmpbuf[4 ];/* DMA:able scratch buffer */ +/* take care of proper alignment for DMA on certain 64-bit systems */ +u8 __aligned(8) tmpbuf[4 ];/* DMA:able scratch buffer */ unsigned num_info;/* number of info strings */ const char **info;/* info strings */
Signature · 1 line
2.12.1
Kevin Hilman
maintainerPATCH v2 1/1 mmc: sdio: fix alignment issue in struct sdio_func
Quoted 9 lines · Heiner Kallweit
Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be used for DMA to be 8-byte-aligned. struct
sdio_funchas an embedded small DMA buffer not meeting this requirement.
Testing an extension to meson-gx driver for switching to descriptor chain mode broke SDIO therefore. Aligning tmpbuf to a 8-byte boundary fixed the driver behavior.Signed-off-by Heiner Kallweit <[email protected]>Tested-by Helmut Klein <[email protected]>
Kevin
PATCH v2 1/1 mmc: sdio: fix alignment issue in struct sdio_func
In reply to Heiner KallweitAm 29.03.2017 um 22:56 schrieb Heiner Kallweit:
Quoted 23 lines
Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be used for DMA to be 8-byte-aligned. struct
sdio_funchas an embedded small DMA buffer not meeting this requirement.
Testing an extension to meson-gx driver for switching to descriptor chain mode broke SDIO therefore. Aligning tmpbuf to a 8-byte boundary fixed the driver behavior.Signed-off-by Heiner Kallweit <[email protected]>Tested-by Helmut Klein <[email protected]>---
v2:
- switch to much simpler version as suggested by Kevin Hilman <[email protected]>
- adjust commit message--- include/linux/mmc/sdio_func.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)include/linux/mmc/sdio_func.h +0
-0
include/linux/mmc/sdio_func.h struct sdio_func { · line 60
Quoted 9 lines
include/linux/mmc/sdio_func.h +2
-1@@ -53,7 +53,8 @@ struct sdio_func {unsigned int state;/* function state */ #define SDIO_STATE_PRESENT (1<<0)/* present in sysfs */ -u8 tmpbuf[4 ];/* DMA:able scratch buffer */ +/* take care of proper alignment for DMA on certain 64-bit systems */ +u8 __aligned(8) tmpbuf[4 ];/* DMA:able scratch buffer */ unsigned num_info;/* number of info strings */ const char **info;/* info strings */
Ulf, do you have an opinion on this one? A related patch was just applied to the brcmfmac WiFi driver -> https://patchwork.kernel.org/patch/9665425/
In sum WiFi over SDIO would be ok an systems requiring 8 byte aligned DMA buffers (at least systems using the brcmfmac driver). OK here means that no fallback to bounce buffer mode is necessary.
Rgds, Heiner