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mmc: renesas_sdhi: Add manual correction 

This patch adds a manual correction mechanism for SDHI. Currently, SDHI
uses automatic TAP position correction. However, TAP position can also
be corrected manually via correction error status flags.

Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20191217114034.13290-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Takeshi Saito 2019-12-17 12:40:31 +01:00 committed by Ulf Hansson
parent 44f54e7012
commit 11a219606a
2 changed files with 52 additions and 10 deletions
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1
drivers/mmc/host/renesas_sdhi.h
View File

@ -57,6 +57,7 @@ struct renesas_sdhi {
void __iomem *scc_ctl;
u32 scc_tappos;
u32 scc_tappos_hs400;
bool doing_tune;
};
#define host_to_priv(host) \

61
drivers/mmc/host/renesas_sdhi_core.c
View File

@ -263,6 +263,8 @@ static int renesas_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
#define SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN BIT(0)
/* Definitions for values the SH_MOBILE_SDHI_SCC_RVSREQ register */
#define SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR BIT(2)
#define SH_MOBILE_SDHI_SCC_RVSREQ_REQTAPUP BIT(1)
#define SH_MOBILE_SDHI_SCC_RVSREQ_REQTAPDOWN BIT(0)
/* Definitions for values the SH_MOBILE_SDHI_SCC_TMPPORT2 register */
#define SH_MOBILE_SDHI_SCC_TMPPORT2_HS400OSEL BIT(4)
#define SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN BIT(31)
@ -321,6 +323,8 @@ static void renesas_sdhi_prepare_tuning(struct tmio_mmc_host *host,
{
struct renesas_sdhi *priv = host_to_priv(host);
priv->doing_tune = true;
/* Set sampling clock position */
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET, tap);
}
@ -426,6 +430,8 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
unsigned long ntap; /* temporary counter of tuning success */
unsigned long i;
priv->doing_tune = false;
/* Clear SCC_RVSREQ */
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
@ -485,6 +491,47 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
return 0;
}
static bool renesas_sdhi_manual_correction(struct tmio_mmc_host *host, bool use_4tap)
{
struct renesas_sdhi *priv = host_to_priv(host);
u32 val;
val = sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ);
if (!val)
return false;
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
/* Change TAP position according to correction status */
if (val & SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR)
return true; /* Need re-tune */
else if (val & SH_MOBILE_SDHI_SCC_RVSREQ_REQTAPUP)
host->tap_set = (host->tap_set + 1) % host->tap_num;
else if (val & SH_MOBILE_SDHI_SCC_RVSREQ_REQTAPDOWN)
host->tap_set = (host->tap_set - 1) % host->tap_num;
else
return false;
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TAPSET,
host->tap_set / (use_4tap ? 2 : 1));
return false;
}
static bool renesas_sdhi_auto_correction(struct tmio_mmc_host *host)
{
struct renesas_sdhi *priv = host_to_priv(host);
/* Check SCC error */
if (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ) &
SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR) {
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
return true;
}
return false;
}
static bool renesas_sdhi_check_scc_error(struct tmio_mmc_host *host)
{
struct renesas_sdhi *priv = host_to_priv(host);
@ -499,20 +546,14 @@ static bool renesas_sdhi_check_scc_error(struct tmio_mmc_host *host)
!(host->mmc->ios.timing == MMC_TIMING_MMC_HS400 && !use_4tap))
return false;
if (mmc_doing_retune(host->mmc))
if (mmc_doing_retune(host->mmc) || priv->doing_tune)
return false;
/* Check SCC error */
if (sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL) &
SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN &&
sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ) &
SH_MOBILE_SDHI_SCC_RVSREQ_RVSERR) {
/* Clear SCC error */
sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_RVSREQ, 0);
return true;
}
SH_MOBILE_SDHI_SCC_RVSCNTL_RVSEN)
return renesas_sdhi_auto_correction(host);
return false;
return renesas_sdhi_manual_correction(host, use_4tap);
}
static void renesas_sdhi_hw_reset(struct tmio_mmc_host *host)