2011-03-18 12:53:20

by Ido Yariv

Subject: [PATCH] wl12xx: Clamp byte mode transfers for 128x chips

On wl128x based devices, when TX packets are aggregated, each packet
size must be aligned to the SDIO block size, and sent using block mode
transfers.

The block size is set to 256 bytes, which is less than the maximum
possible byte transfer. Thus, if two small packets (< 256 bytes) are
aggregated, the aggregation buffer size would be 512, and will be sent
using byte mode transfers. This can have undesired side effects.

Fix this by setting the MMC_QUIRK_BLKSZ_FOR_BYTE_MODE mmc card quirk.
For 127x chips this has no effect, as the block size is set to 512
bytes.

Signed-off-by: Arik Nemtsov <[email protected]>
Signed-off-by: Ido Yariv <[email protected]>
---
drivers/net/wireless/wl12xx/sdio.c | 3 +++
drivers/net/wireless/wl12xx/sdio_test.c | 3 +++
2 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/net/wireless/wl12xx/sdio.c b/drivers/net/wireless/wl12xx/sdio.c
index ff77361..26dcd44 100644
--- a/drivers/net/wireless/wl12xx/sdio.c
+++ b/drivers/net/wireless/wl12xx/sdio.c
@@ -246,6 +246,9 @@ static int __devinit wl1271_probe(struct sdio_func *func,
/* Grab access to FN0 for ELP reg. */
func->card->quirks |= MMC_QUIRK_LENIENT_FN0;

+ /* Use block mode for transferring over one block size of data */
+ func->card->quirks |= MMC_QUIRK_BLKSZ_FOR_BYTE_MODE;
+
wlan_data = wl12xx_get_platform_data();
if (IS_ERR(wlan_data)) {
ret = PTR_ERR(wlan_data);
diff --git a/drivers/net/wireless/wl12xx/sdio_test.c b/drivers/net/wireless/wl12xx/sdio_test.c
index 968249a..f289153 100644
--- a/drivers/net/wireless/wl12xx/sdio_test.c
+++ b/drivers/net/wireless/wl12xx/sdio_test.c
@@ -417,6 +417,9 @@ static int __devinit wl1271_probe(struct sdio_func *func,
/* Grab access to FN0 for ELP reg. */
func->card->quirks |= MMC_QUIRK_LENIENT_FN0;

+ /* Use block mode for transferring over one block size of data */
+ func->card->quirks |= MMC_QUIRK_BLKSZ_FOR_BYTE_MODE;
+
wlan_data = wl12xx_get_platform_data();
if (IS_ERR(wlan_data)) {
ret = PTR_ERR(wlan_data);
--
1.7.1

2011-03-21 14:01:30

by Luciano Coelho

Subject: Re: [PATCH] wl12xx: Clamp byte mode transfers for 128x chips

On Fri, 2011-03-18 at 14:49 +0200, Arik Nemtsov wrote:
> On wl128x based devices, when TX packets are aggregated, each packet
> size must be aligned to the SDIO block size, and sent using block mode
> transfers.
>
> The block size is set to 256 bytes, which is less than the maximum
> possible byte transfer. Thus, if two small packets (< 256 bytes) are
> aggregated, the aggregation buffer size would be 512, and will be sent
> using byte mode transfers. This can have undesired side effects.
>
> Fix this by setting the MMC_QUIRK_BLKSZ_FOR_BYTE_MODE mmc card quirk.
> For 127x chips this has no effect, as the block size is set to 512
> bytes.
>
> Signed-off-by: Arik Nemtsov <[email protected]>
> Signed-off-by: Ido Yariv <[email protected]>
> ---

Thanks! Applied and fixed Arik's email address, which was corrupted (or
rather Ido-ized :P)

--
Cheers,
Luca.