Move the temporary buffer used by some sdio functions from sdio_func struct to
the mmc_host struct and make it dma-safe.
Signed-off-by: Marc Pignat <[email protected]>
---
There is no need to have this temporary buffer in every sdio_func, since all
access to it are serialized by sdio_[claim/release]_host.
I also think it should be ____cacheline_aligned to make sure we have no data
loss when doing dma syncing operations.
Comments welcome!
Regards
Marc
sdio-dma-tmpbuf-patch (against 2.6.24-rc5)
drivers/mmc/core/sdio_io.c | 20 ++++++++++++--------
include/linux/mmc/host.h | 3 +++
include/linux/mmc/sdio_func.h | 2 --
3 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 625b92c..e48663e 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -389,18 +389,19 @@ unsigned short sdio_readw(struct sdio_func *func, unsigned int addr,
int *err_ret)
{
int ret;
+ u8 *tmpbuf = func->card->host->tmpbuf;
if (err_ret)
*err_ret = 0;
- ret = sdio_memcpy_fromio(func, func->tmpbuf, addr, 2);
+ ret = sdio_memcpy_fromio(func, tmpbuf, addr, 2);
if (ret) {
if (err_ret)
*err_ret = ret;
return 0xFFFF;
}
- return le16_to_cpu(*(u16*)func->tmpbuf);
+ return le16_to_cpu(*(u16*)tmpbuf);
}
EXPORT_SYMBOL_GPL(sdio_readw);
@@ -419,10 +420,11 @@ void sdio_writew(struct sdio_func *func, unsigned short b, unsigned int addr,
int *err_ret)
{
int ret;
+ u8 *tmpbuf = func->card->host->tmpbuf;
- *(u16*)func->tmpbuf = cpu_to_le16(b);
+ *(u16*)tmpbuf = cpu_to_le16(b);
- ret = sdio_memcpy_toio(func, addr, func->tmpbuf, 2);
+ ret = sdio_memcpy_toio(func, addr, tmpbuf, 2);
if (err_ret)
*err_ret = ret;
}
@@ -443,18 +445,19 @@ unsigned long sdio_readl(struct sdio_func *func, unsigned int addr,
int *err_ret)
{
int ret;
+ u8 *tmpbuf = func->card->host->tmpbuf;
if (err_ret)
*err_ret = 0;
- ret = sdio_memcpy_fromio(func, func->tmpbuf, addr, 4);
+ ret = sdio_memcpy_fromio(func, tmpbuf, addr, 4);
if (ret) {
if (err_ret)
*err_ret = ret;
return 0xFFFFFFFF;
}
- return le32_to_cpu(*(u32*)func->tmpbuf);
+ return le32_to_cpu(*(u32*)tmpbuf);
}
EXPORT_SYMBOL_GPL(sdio_readl);
@@ -473,10 +476,11 @@ void sdio_writel(struct sdio_func *func, unsigned long b, unsigned int addr,
int *err_ret)
{
int ret;
+ u8 *tmpbuf = func->card->host->tmpbuf;
- *(u32*)func->tmpbuf = cpu_to_le32(b);
+ *(u32*)tmpbuf = cpu_to_le32(b);
- ret = sdio_memcpy_toio(func, addr, func->tmpbuf, 4);
+ ret = sdio_memcpy_toio(func, addr, tmpbuf, 4);
if (err_ret)
*err_ret = ret;
}
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 125eee1..8edb796 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -139,6 +139,9 @@ struct mmc_host {
struct led_trigger *led; /* activity led */
#endif
+ /* DMA:able scratch buffer */
+ u8 tmpbuf[4] ____cacheline_aligned;
+
unsigned long private[0] ____cacheline_aligned;
};
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index b050f4d..4a797a7 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -49,8 +49,6 @@ struct sdio_func {
unsigned int state; /* function state */
#define SDIO_STATE_PRESENT (1<<0) /* present in sysfs */
- u8 tmpbuf[4]; /* DMA:able scratch buffer */
-
unsigned num_info; /* number of info strings */
const char **info; /* info strings */
On Wed, 19 Dec 2007 11:55:25 +0100
Marc Pignat <[email protected]> wrote:
> Move the temporary buffer used by some sdio functions from sdio_func struct to
> the mmc_host struct and make it dma-safe.
>
> Signed-off-by: Marc Pignat <[email protected]>
> ---
>
> There is no need to have this temporary buffer in every sdio_func, since all
> access to it are serialized by sdio_[claim/release]_host.
>
I had some crazy idea about per function locking, but until that time this will do just fine.
> I also think it should be ____cacheline_aligned to make sure we have no data
> loss when doing dma syncing operations.
This is still voodoo to me, so I'll have to take your word for it. :)
>
> Comments welcome!
>
Looks good to me.
Rgds
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
On Wednesday 19 December 2007, Pierre Ossman wrote:
> On Wed, 19 Dec 2007 11:55:25 +0100
...
> This is still voodoo to me, so I'll have to take your word for it. :)
And almost voodoo to me... this is why I hope an ack from a DMA mentor!
Marc