From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: linux-mmc@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
Takeshi Saito <takeshi.saito.xv@renesas.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>
Subject: [RFC PATCH 1/2] mmc: renesas_sdhi: Add manual correction
Date: Tue, 3 Dec 2019 21:32:59 +0100 [thread overview]
Message-ID: <20191203203301.2202-2-wsa+renesas@sang-engineering.com> (raw)
In-Reply-To: <20191203203301.2202-1-wsa+renesas@sang-engineering.com>
From: Takeshi Saito <takeshi.saito.xv@renesas.com>
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>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
Pretty much like the BSP patch. Just some rebasing, refactorization and
updates of the commit message. I especially changed the original
calculation from:
+ host->tap_set = (host->tap_set +
+ host->tap_num + 1) % host->tap_num;
to:
+ host->tap_set = (host->tap_set + 1) % host->tap_num;
(same for -1). Because "+ tap_num % tap_num" is a NOOP. Or did I miss
something?
drivers/mmc/host/renesas_sdhi.h | 1 +
drivers/mmc/host/renesas_sdhi_core.c | 62 +++++++++++++++++++++++-----
2 files changed, 52 insertions(+), 11 deletions(-)
diff --git a/drivers/mmc/host/renesas_sdhi.h b/drivers/mmc/host/renesas_sdhi.h
index f524251d5113..11a0b2bca3aa 100644
--- a/drivers/mmc/host/renesas_sdhi.h
+++ b/drivers/mmc/host/renesas_sdhi.h
@@ -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) \
diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 282c133defd6..903da3ba399b 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -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);
@@ -485,12 +491,52 @@ 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);
bool use_4tap = priv->quirks && priv->quirks->hs400_4taps;
-
/*
* Skip checking SCC errors when running on 4 taps in HS400 mode as
* any retuning would still result in the same 4 taps being used.
@@ -500,20 +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)
--
2.20.1
next prev parent reply other threads:[~2019-12-03 20:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 20:32 [RFC PATCH 0/2] mmc: renesas_sdhi: add manual correction Wolfram Sang
2019-12-03 20:32 ` Wolfram Sang [this message]
2019-12-04 9:44 ` [RFC PATCH 1/2] mmc: renesas_sdhi: Add " Geert Uytterhoeven
2019-12-10 22:28 ` Wolfram Sang
2019-12-11 7:43 ` Geert Uytterhoeven
2019-12-13 16:18 ` Wolfram Sang
2019-12-09 6:42 ` Yoshihiro Shimoda
2019-12-03 20:33 ` [RFC PATCH 2/2] mmc: renesas_sdhi: enfore manual correction for Gen3 Wolfram Sang
2019-12-04 9:39 ` Geert Uytterhoeven
2019-12-09 7:00 ` Yoshihiro Shimoda
2019-12-03 20:33 ` [RFC PATCH 3/2] mmc: renesas_sdhi: remove double clear of automatic correction Wolfram Sang
2019-12-09 7:01 ` Yoshihiro Shimoda
2019-12-10 22:32 ` [RFC PATCH 0/2] mmc: renesas_sdhi: add manual correction Wolfram Sang
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