* [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
@ 2017-03-29 20:56 ` Heiner Kallweit
0 siblings, 0 replies; 6+ messages in thread
From: Heiner Kallweit @ 2017-03-29 20:56 UTC (permalink / raw)
To: Ulf Hansson; +Cc: linux-mmc, linux-amlogic, Helmut Klein, Kevin Hilman
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.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Helmut Klein <hgkr.klein@gmail.com>
---
v2:
- switch to much simpler version as suggested by Kevin Hilman <khilman@baylibre.com>
- adjust commit message
---
include/linux/mmc/sdio_func.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index aab032a6..65d90f76 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -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 */
--
2.12.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
@ 2017-03-29 20:56 ` Heiner Kallweit
0 siblings, 0 replies; 6+ messages in thread
From: Heiner Kallweit @ 2017-03-29 20:56 UTC (permalink / raw)
To: linus-amlogic
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.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Helmut Klein <hgkr.klein@gmail.com>
---
v2:
- switch to much simpler version as suggested by Kevin Hilman <khilman@baylibre.com>
- adjust commit message
---
include/linux/mmc/sdio_func.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index aab032a6..65d90f76 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -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 */
--
2.12.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
2017-03-29 20:56 ` Heiner Kallweit
@ 2017-03-29 22:58 ` Kevin Hilman
-1 siblings, 0 replies; 6+ messages in thread
From: Kevin Hilman @ 2017-03-29 22:58 UTC (permalink / raw)
To: Heiner Kallweit; +Cc: Ulf Hansson, linux-mmc, linux-amlogic, Helmut Klein
Heiner Kallweit <hkallweit1@gmail.com> writes:
> 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.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> Tested-by: Helmut Klein <hgkr.klein@gmail.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Kevin
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
@ 2017-03-29 22:58 ` Kevin Hilman
0 siblings, 0 replies; 6+ messages in thread
From: Kevin Hilman @ 2017-03-29 22:58 UTC (permalink / raw)
To: linus-amlogic
Heiner Kallweit <hkallweit1@gmail.com> writes:
> 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.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> Tested-by: Helmut Klein <hgkr.klein@gmail.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Kevin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
2017-03-29 20:56 ` Heiner Kallweit
@ 2017-04-13 20:54 ` Heiner Kallweit
-1 siblings, 0 replies; 6+ messages in thread
From: Heiner Kallweit @ 2017-04-13 20:54 UTC (permalink / raw)
To: Ulf Hansson; +Cc: linux-mmc, linux-amlogic, Helmut Klein, Kevin Hilman
Am 29.03.2017 um 22:56 schrieb 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_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.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> Tested-by: Helmut Klein <hgkr.klein@gmail.com>
> ---
> v2:
> - switch to much simpler version as suggested by Kevin Hilman <khilman@baylibre.com>
> - adjust commit message
> ---
> include/linux/mmc/sdio_func.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
> index aab032a6..65d90f76 100644
> --- a/include/linux/mmc/sdio_func.h
> +++ b/include/linux/mmc/sdio_func.h
> @@ -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
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func
@ 2017-04-13 20:54 ` Heiner Kallweit
0 siblings, 0 replies; 6+ messages in thread
From: Heiner Kallweit @ 2017-04-13 20:54 UTC (permalink / raw)
To: linus-amlogic
Am 29.03.2017 um 22:56 schrieb 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_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.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> Tested-by: Helmut Klein <hgkr.klein@gmail.com>
> ---
> v2:
> - switch to much simpler version as suggested by Kevin Hilman <khilman@baylibre.com>
> - adjust commit message
> ---
> include/linux/mmc/sdio_func.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
> index aab032a6..65d90f76 100644
> --- a/include/linux/mmc/sdio_func.h
> +++ b/include/linux/mmc/sdio_func.h
> @@ -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
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-04-13 20:55 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2017-03-29 20:56 [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func Heiner Kallweit
2017-03-29 20:56 ` Heiner Kallweit
2017-03-29 22:58 ` Kevin Hilman
2017-03-29 22:58 ` Kevin Hilman
2017-04-13 20:54 ` Heiner Kallweit
2017-04-13 20:54 ` Heiner Kallweit
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