[PATCH 0/3] mmc: meson-gx: fixes for v4.14

[Jerome Brunet]

This patchset fixes the issues reported by Heiner [0] with the odroid-c2.
In a nutshell, this series does the following:

* Make sure the mmc clock rate is not set higher than what is requested
* Reset the tuning values on mmc power cycle instead of POWER_ON
* Add tuning of the tx phase to the tuning function.

This fixes the problem seen on the odroid-c2, both for hs200 and hs400.
To check for regression, this series has also been tested on the gxl
libretech-cc

Ulf, could you please pick this as fixes for v4.14 ?

[0]: https://lkml.kernel.org/r/e2171288-84ef-82db...@gmail.com

Jerome Brunet (3):
mmc: meson-gx: make sure the clock is rounded down
mmc: meson-gx: fix rx phase reset
mmc: meson-gx: include tx phase in the tuning process

drivers/mmc/host/meson-gx-mmc.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)

--
2.13.5

[Jerome Brunet]

Resetting the phase when POWER_ON is set the set_ios() call means that the
phase is reset almost every time the set_ios() is called, while the
expected behavior was to reset the phase on a power cycle.

This had gone unnoticed until now because in all mode (except hs400) the
tuning is done after the last to set_ios(). In such case, the tuning
result is used anyway. In HS400, there are a few calls to set_ios() after
the tuning is done, overwriting the tuning result.

Resetting the phase on POWER_UP instead of POWER_ON solve the problem.

Fixes: d341ca88eead ("mmc: meson-gx: rework tuning function")
Signed-off-by: Jerome Brunet <jbr...@baylibre.com>
---
drivers/mmc/host/meson-gx-mmc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 421c8719c202..08a55c2e96e1 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -745,6 +745,10 @@ static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
case MMC_POWER_UP:
if (!IS_ERR(mmc->supply.vmmc))
mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);
+
+ /* Reset rx phase */
+ clk_set_phase(host->rx_clk, 0);
+
break;

case MMC_POWER_ON:
@@ -758,8 +762,6 @@ static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
host->vqmmc_enabled = true;
}

- /* Reset rx phase */
- clk_set_phase(host->rx_clk, 0);
break;
}

--
2.13.5

[Jerome Brunet]

It has been reported that some platforms (odroid-c2) may require
a different tx phase setting to operate at high speed (hs200 and hs400)

To improve the situation, this patch includes tx phase in the tuning
process.

Fixes: d341ca88eead ("mmc: meson-gx: rework tuning function")

Reported-by: Heiner Kallweit <hkall...@gmail.com>

Signed-off-by: Jerome Brunet <jbr...@baylibre.com>
---

drivers/mmc/host/meson-gx-mmc.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 08a55c2e96e1..85745ef179e2 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -716,6 +716,22 @@ static int meson_mmc_clk_phase_tuning(struct mmc_host *mmc, u32 opcode,
static int meson_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
struct meson_host *host = mmc_priv(mmc);
+ int ret;
+
+ /*
+ * If this is the initial tuning, try to get a sane Rx starting
+ * phase before doing the actual tuning.
+ */
+ if (!mmc->doing_retune) {
+ ret = meson_mmc_clk_phase_tuning(mmc, opcode, host->rx_clk);
+
+ if (ret)
+ return ret;
+ }
+
+ ret = meson_mmc_clk_phase_tuning(mmc, opcode, host->tx_clk);
+ if (ret)
+ return ret;

return meson_mmc_clk_phase_tuning(mmc, opcode, host->rx_clk);
}
@@ -746,8 +762,9 @@ static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)

if (!IS_ERR(mmc->supply.vmmc))
mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, ios->vdd);

- /* Reset rx phase */

+ /* Reset phases */
clk_set_phase(host->rx_clk, 0);
+ clk_set_phase(host->tx_clk, 270);

break;

--
2.13.5

[Kevin Hilman]

Reviewed-by: Kevin Hilman <khi...@baylibre.com>