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mmc: meson-gx: work around broken SDIO with certain WiFi chips

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There have been reports about SDIO failing with certain WiFi chips in
descriptor chain mode. SD / eMMC are working fine.

So let's fall back to bounce buffer mode for command SD_IO_RW_EXTENDED.
This was reported to fix the error.

Fixes: 79ed05e329 "mmc: meson-gx: add support for descriptor chain mode"
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Heiner Kallweit 2017-06-10 13:36:38 +02:00 committed by Ulf Hansson
parent 32c1431eea
commit 24835611a9
1 changed files with 9 additions and 0 deletions
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9
drivers/mmc/host/meson-gx-mmc.c
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@ -210,6 +210,15 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
int i;
bool use_desc_chain_mode = true;
/*
* Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been
* reported. For some strange reason this occurs in descriptor
* chain mode only. So let's fall back to bounce buffer mode
* for command SD_IO_RW_EXTENDED.
*/
if (mrq->cmd->opcode == SD_IO_RW_EXTENDED)
return;
for_each_sg(data->sg, sg, data->sg_len, i)
/* check for 8 byte alignment */
if (sg->offset & 7) {