[PATCH 1/3] mmc: sunxi: Disable HS-DDR mode for H5 eMMC controller by default

Chen-Yu Tsai
2019-02-03T15:56:26Z

Some H5 boards seem to not have proper trace lengths for eMMC to be able
to use the default setting for the delay chains under HS-DDR mode. These
include the Bananapi M2+ H5 and NanoPi NEO Core2. However the Libre
Computer ALL-H3-CC-H5 works just fine.

For the H5 (at least for now), default to not enabling HS-DDR modes in
the driver, and expect the device tree to signal HS-DDR capability on
boards that work.

Reported-by: Chris Blake <chrisrblake93-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Fixes: 07bafc1e3536 ("mmc: sunxi: Use new timing mode for A64 eMMC controller")
Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Signed-off-by: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>
---
drivers/mmc/host/sunxi-mmc.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 279e326e397e..7415af8c8ff6 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -1399,7 +1399,16 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
MMC_CAP_ERASE | MMC_CAP_SDIO_IRQ;

- if (host->cfg->clk_delays || host->use_new_timings)
+ /*
+ * Some H5 devices do not have signal traces precise enough to
+ * use HS DDR mode for their eMMC chips.
+ *
+ * We still enable HS DDR modes for all the other controller
+ * variants that support them.
+ */
+ if ((host->cfg->clk_delays || host->use_new_timings) &&
+ !of_device_is_compatible(pdev->dev.of_node,
+ "allwinner,sun50i-h5-emmc"))
mmc->caps |= MMC_CAP_1_8V_DDR | MMC_CAP_3_3V_DDR;

ret = mmc_of_parse(mmc);
--
2.20.1