Hi, Shawn

Sorry I replied late. I added comments below.

On 6 March 2016 at 22:16, Shawn Lin [off-list ref] wrote:

On 2016/3/6 16:47, Guodong Xu wrote:

quoted

mmc registers may in abnormal state if mmc is used in bootloader,
eg. to support booting from eMMC. So we need reset mmc registers
when kernel boots up, instead of assuming mmc is in clean state.

With this patch, user can add a 'resets' property into dw_mmc dts
node. When driver parse_dt and probe, it calls reset API to
deassert the 'reset' of dw_mmc host controller. When probe error or
remove, it calls reset API to assert it.

Please also refer to Documentation/devicetree/bindings/reset/reset.txt

Signed-off-by: Guodong Xu <redacted>
Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>

Really should V2 and add the changelog.

Yes, will do. next version I sent will be labelled as V3.

---

quoted

  drivers/mmc/host/dw_mmc.c | 22 +++++++++++++++++++++-
  1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 242f9a0..281ea9c 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c

@@ -2878,6 +2878,14 @@ static struct dw_mci_board *dw_mci_parse_dt(struct

dw_mci *host)
        if (!pdata)
                return ERR_PTR(-ENOMEM);

+       /* find reset controller when exist */
+       pdata->rstc = devm_reset_control_get_optional(dev, NULL);
+       if (IS_ERR(pdata->rstc)) {
+               if (PTR_ERR(pdata->rstc) == -EPROBE_DEFER)
+                       return ERR_PTR(-EPROBE_DEFER);
+               pdata->rstc = NULL;

maybe we can remove "pdata->rstc = NULL", and directly
use IS_ERR(..) for the following "if (host->pdata->rstc != NULL)"
statement

Yes, will do.
I see your point, other lines in this file are using IS_ERR(!..), I will
use this style too.

+       }

quoted

+
        /* find out number of slots supported */
        of_property_read_u32(np, "num-slots", &pdata->num_slots);

@@ -2949,7 +2957,9 @@ int dw_mci_probe(struct dw_mci *host)

        if (!host->pdata) {
                host->pdata = dw_mci_parse_dt(host);
-               if (IS_ERR(host->pdata)) {
+               if (PTR_ERR(host->pdata) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;

please fix the coding style here.

Do you mean to add additional {} for this 'if' , like this?

+               if (PTR_ERR(host->pdata) == -EPROBE_DEFER) {

+                       return -EPROBE_DEFER;

   +                }

I will add {}.

+               else if (IS_ERR(host->pdata)) {

quoted

                        dev_err(host->dev, "platform data not
available\n");
                        return -EINVAL;
                }

@@ -3012,6 +3022,9 @@ int dw_mci_probe(struct dw_mci *host)
                }
        }

+       if (host->pdata->rstc != NULL)
+               reset_control_deassert(host->pdata->rstc);
+

sorry, I can't follow your intention here. Shouldn't it be something
like "assert mmc -> may need delay -> deassert mmc". As your current
code, nothing happend right?

The chip exits from bootloader with this bit asserted. And when entering
kernel, we only need to deassert.

In my current code, the driver deassert mmc in _probe(), and assert mmc in
_remove().

        setup_timer(&host->cmd11_timer,

quoted

                    dw_mci_cmd11_timer, (unsigned long)host);

@@ -3164,6 +3177,9 @@ err_dmaunmap:
        if (host->use_dma && host->dma_ops->exit)
                host->dma_ops->exit(host);

+       if (host->pdata->rstc != NULL)
+               reset_control_assert(host->pdata->rstc);
+
  err_clk_ciu:
        if (!IS_ERR(host->ciu_clk))
                clk_disable_unprepare(host->ciu_clk);

@@ -3196,11 +3212,15 @@ void dw_mci_remove(struct dw_mci *host)
        if (host->use_dma && host->dma_ops->exit)
                host->dma_ops->exit(host);

+       if (host->pdata->rstc != NULL)
+               reset_control_assert(host->pdata->rstc);
+
        if (!IS_ERR(host->ciu_clk))
                clk_disable_unprepare(host->ciu_clk);

        if (!IS_ERR(host->biu_clk))
                clk_disable_unprepare(host->biu_clk);
+
  }

unnecessary new line here.

Will fix.

-Guodong

  EXPORT_SYMBOL(dw_mci_remove);

quoted

--
Best Regards
Shawn Lin