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 this error.
Fixes: 79ed05e329c3 "mmc: meson-gx: add support for descriptor chain mode"
Cc: <stable@xxxxxxxxxxxxxxx> # 4.12.x
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
drivers/mmc/host/meson-gx-mmc.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 1842ed34..4cdbe3c0 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -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 AP6335-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) {
--
2.13.0
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