On Wed, Oct 11, 2017 at 10:35:37AM +0200, Niklas Söderlund wrote:
> Hi Simon,
>
> On 2017-10-11 09:36:48 +0200, Simon Horman wrote:
> > On Wed, Oct 11, 2017 at 02:08:14AM +0200, Niklas Söderlund wrote:
> > > The commit 43b0b361b0170030 ("mmc: tmio: always get number of taps")
> > > changed the behavior of the tuning. Before the commit the SCC was only
> > > enabled for the first tuning attempt (host->init_tuning(host)), if that
> > > failed the hardware where reset and tuning retried. In the second
> > > attempt the SCC where never configured and tuning would succeed for some
> > > stubborn cards. This patch restore this behavior which allows a troubled
> > > card I have to be used.
> >
> > Hi Wolfram,
> >
> > Is tuning retried if the card is changed, f.e. ejected and a different card
> > inserted?
>
> I'd say tuning is retried every time a card is inserted, based on my
> tests bellow. Which would make the change in 43b0b361b0170030 correct as
> the number of taps should be reread each time but the fallback to try
> tuning without the SCC clock changed restored (if that is correct
> behavior?).
Presumably rereading the number of taps each time is the correct behaviour
- though my initial assumption was otherwise when I added the code to
mainline.
I think that in theory there is a chance that tuning could fail at some
time and succeed later - f.e. if the board warms up. But in I also
think your solution makes a lot of sense in practice.
Reviewed-by: Simon Horman <[email protected]>
> The register write which breaks my stubborn card tuning is
> in renesas_sdhi_init_tuning() in drivers/mmc/host/renesas_sdhi_core.c:
>
> # I assume this write is just to unlock writing to
> # SH_MOBILE_SDHI_SCC_CKSEL ?
> sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
> sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
>
> # This register change starts to produce the timeout for CMD19 with
> # my stubborn card. In renesas_sdhi_hw_reset() this register is
> # reset and tuning then works.
> sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
> SH_MOBILE_SDHI_SCC_CKSEL_DTSEL |
> sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));
>
> # I as above assume this just locks the register write again ?
> sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
> sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
>
Looking at the above I am reminded of a patch I recently came across in the
BSP when looking at enabling HS400.
https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas-bsp.git/commit/?h=v4.9/rcar-3.5.8&id=313b1462fb380d8c414853e98ab99e42b73668e5
>From 313b1462fb380d8c414853e98ab99e42b73668e5 Mon Sep 17 00:00:00 2001
From: Masaharu Hayakawa <[email protected]>
Date: Thu, 26 Jan 2017 18:21:12 +0900
Subject: [PATCH] mmc: sh_mobile_sdhi: Fix HS400 mode tuning
The order of register setting was changed according to the tuning flow.
Tuning result of 8TAP replace on the position of the 4TAP.
Added function sh_mobile_sdhi_reset_hs400_mode() to return to HS200 mode
for retuning.
Signed-off-by: Masaharu Hayakawa <[email protected]>
diff --git a/drivers/mmc/host/sh_mobile_sdhi.c
b/drivers/mmc/host/sh_mobile_sdhi.c
index 847db8b9d403..83aabfefd56f 100644
--- a/drivers/mmc/host/sh_mobile_sdhi.c
+++ b/drivers/mmc/host/sh_mobile_sdhi.c
@@ -348,33 +348,30 @@ static unsigned int sh_mobile_sdhi_init_tuning(struct
tmio_mmc_host *host)
priv = host_to_priv(host);
- /* set sampling clock selection range */
- sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
- 0x8 << SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT);
-
/* Initialize SCC */
sd_ctrl_write32_as_16_and_16(host, CTL_STATUS, 0x0);
- sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
- SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN |
- sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL));
-
sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+ /* set sampling clock selection range */
+ sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL,
+ SH_MOBILE_SDHI_SCC_DTCNTL_TAPEN |
+ 0x8 << SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT);
+
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL,
SH_MOBILE_SDHI_SCC_CKSEL_DTSEL |
sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));
- sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
- sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
-
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
~SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &
sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DT2FF, host->scc_tappos);
+ sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
+ sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
/* Read TAPNUM */
return (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_DTCNTL) >>
SH_MOBILE_SDHI_SCC_DTCNTL_TAPNUM_SHIFT) &
@@ -415,17 +412,46 @@ static void sh_mobile_sdhi_prepare_hs400_tuning(struct
mmc_host *mmc,
SH_MOBILE_SDHI_SCC_TMPPORT2_HS400OSEL) |
sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2));
+ sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, host->tap_set/2);
+
sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
}
+static void sh_mobile_sdhi_reset_hs400_mode(struct mmc_host *mmc)
+{
+ struct tmio_mmc_host *host = mmc_priv(mmc);
+ struct sh_mobile_sdhi *priv = host_to_priv(host);
+
+ if (!(host->mmc->caps2 & MMC_CAP2_HS200_1_8V_SDR) &&
+ !(host->mmc->caps2 & (MMC_CAP2_HS400_1_8V |
+ MMC_CAP2_HS200_1_8V_SDR)))
+ return;
+
+ if (!priv->scc_ctl)
+ return;
+
+ sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
+ sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+
+ /* Reset HS400 mode */
+ sd_ctrl_write16(host, CTL_SDIF_MODE, ~0x0001 &
+ sd_ctrl_read16(host, CTL_SDIF_MODE));
+ sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2,
+ ~(SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
+ SH_MOBILE_SDHI_SCC_TMPPORT2_HS400OSEL) &
+ sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2));
+
+ sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
+ sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
+}
+
#define SH_MOBILE_SDHI_MAX_TAP 3
static int sh_mobile_sdhi_select_tuning(struct tmio_mmc_host *host)
{
struct sh_mobile_sdhi *priv = host_to_priv(host);
unsigned long tap_cnt; /* counter of tuning success */
- unsigned long tap_set; /* tap position */
unsigned long tap_start;/* start position of tuning success */
unsigned long tap_end; /* end position of tuning success */
unsigned long ntap; /* temporary counter of tuning success */
@@ -510,12 +536,12 @@ static int sh_mobile_sdhi_select_tuning(struct
tmio_mmc_host *host)
select = true;
if (select)
- tap_set = (tap_start + tap_end) / 2 % host->tap_num;
+ host->tap_set = (tap_start + tap_end) / 2 % host->tap_num;
else
return -EIO;
/* Set SCC */
- sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap_set);
+ sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, host->tap_set);
/* Enable auto re-tuning */
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL,
@@ -732,6 +758,7 @@ static int sh_mobile_sdhi_probe(struct platform_device
*pdev)
host->hw_reset = sh_mobile_sdhi_hw_reset;
host->prepare_hs400_tuning =
sh_mobile_sdhi_prepare_hs400_tuning;
+ host->reset_hs400_mode = sh_mobile_sdhi_reset_hs400_mode;
}
/* Orginally registers were 16 bit apart, could be 32 or 64 nowadays */
--
2.11.0
