Hi Wolfram-san,
Thank you for the patch!
> From: Wolfram Sang, Sent: Tuesday, March 9, 2021 6:24 PM
>
> All recent SDHI instances can be reset via the reset controller. If one
> is found, use it instead of the open coded reset. This is to get a
> future-proof sane reset state.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> ---
<snip>
> @@ -561,9 +563,16 @@ static int renesas_sdhi_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_io
> static void renesas_sdhi_reset(struct tmio_mmc_host *host)
> {
> struct renesas_sdhi *priv = host_to_priv(host);
> + int ret;
> u16 val;
>
> - if (priv->scc_ctl) {
> + if (priv->rstc) {
> + reset_control_reset(priv->rstc);
> + /* Unknown why but without polling reset status, it will hang */
> + read_poll_timeout(reset_control_status, ret, ret == 0, 1, 100,
> + false, priv->rstc);
> + priv->needs_adjust_hs400 = false;
After we did hard reset here, sometimes tmio_mmc_reset_work() cannot recover
again with "mmcblk0: recovery failed!" message... So, I investigated this
issue and I found a reason.
> + } else if (priv->scc_ctl) {
> renesas_sdhi_disable_scc(host->mmc);
I realized this renesas_sdhi_disable_scc() will set CLK_CTL_SCLKEN.
So, the previous code can issue CMD13 after tmio_mmc_reset_work() was called.
But, after we applied this patch, the CMD13 failed because the clock was disabled.
# In other words, if a controller doesn't have scc, the previous code cannot issue
# CMD13 in such a case, I guess.
So, before we apply this patch, we have to add ->set_clock() calling in
tmio_mmc_reset_work() like below:
---
diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index eca767dcabba..a05ccfc7aa0d 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -222,6 +222,7 @@ static void tmio_mmc_reset_work(struct work_struct *work)
spin_unlock_irqrestore(&host->lock, flags);
tmio_mmc_reset(host);
+ host->set_clock(host, host->clk_cache);
/* Ready for new calls */
host->mrq = NULL;
---
Best regards,
Yoshihiro Shimoda
