[PATCH v5 3/5] brcmfmac: sdio: Disable auto-tuning around commands expected to fail

From: Douglas Anderson
Date: Mon Jun 17 2019 - 14:04:08 EST

There are certain cases, notably when transitioning between sleep and
active state, when Broadcom SDIO WiFi cards will produce errors on the
SDIO bus. This is evident from the source code where you can see that
we try commands in a loop until we either get success or we've tried
too many times. The comment in the code reinforces this by saying
"just one write attempt may fail"

Unfortunately these failures sometimes end up causing an "-EILSEQ"
back to the core which triggers a retuning of the SDIO card and that
blocks all traffic to the card until it's done.

Let's disable retuning around the commands we expect might fail.

Commit notes:
Patches #2 - #5 will go through Ulf's tree.

This patch is still lacking Kalle Valo's Ack, which should probably be
received before landing in Ulf's tree.

Fixes: bd11e8bd03ca ("mmc: core: Flag re-tuning is needed on CRC errors")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Reviewed-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>

Changes in v5: None
Changes in v4:
- Adjust to API rename (Adrian, Ulf).

Changes in v3:
- Expect errors for all of brcmf_sdio_kso_control() (Adrian).

Changes in v2: None

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
index 4a750838d8cd..ee76593259a7 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
@@ -667,6 +667,8 @@ brcmf_sdio_kso_control(struct brcmf_sdio *bus, bool on)

brcmf_dbg(TRACE, "Enter: on=%d\n", on);

+ sdio_retune_crc_disable(bus->sdiodev->func1);
/* 1st KSO write goes to AOS wake up core if device is asleep */
brcmf_sdiod_writeb(bus->sdiodev, SBSDIO_FUNC1_SLEEPCSR, wr_val, &err);
@@ -727,6 +729,8 @@ brcmf_sdio_kso_control(struct brcmf_sdio *bus, bool on)
if (try_cnt > MAX_KSO_ATTEMPTS)
brcmf_err("max tries: rd_val=0x%x err=%d\n", rd_val, err);

+ sdio_retune_crc_enable(bus->sdiodev->func1);
return err;