[PATCH] mmc: renesas_sdhi: Change HW adjustment register according to speed mode

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

From: Takeshi Saito <takeshi.saito.xv@renesas.com>

SCC is used for SDR104/HS200/HS400. We need to change SCC_DT2FF
according to the mode. If it is inappropriate, CRC error tends to occur.

This adds variable "tap_hs400" for HS400 mode and configures SCC_DT2FF
as needed.

Signed-off-by: Takeshi Saito <takeshi.saito.xv@renesas.com>
[wsa: rebased to upstream and updated commit message]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

I don't have a testcase currently, so I don't think this is stable material. If
this ever changes, we can have it added to stable later. But I am open for
other opinions here. Tested on Salvator-XS with Renesas R-Car M3N, no
regressions in both detecting HS400 and transferring large files.

 drivers/mmc/host/renesas_sdhi.h               | 2 ++
 drivers/mmc/host/renesas_sdhi_core.c          | 8 ++++++++
 drivers/mmc/host/renesas_sdhi_internal_dmac.c | 1 +
 3 files changed, 11 insertions(+)

diff --git a/drivers/mmc/host/renesas_sdhi.h b/drivers/mmc/host/renesas_sdhi.h
index da1e49c45bec..8394a7bb1fc1 100644
--- a/drivers/mmc/host/renesas_sdhi.h
+++ b/drivers/mmc/host/renesas_sdhi.h
@@ -15,6 +15,7 @@
 struct renesas_sdhi_scc {
 	unsigned long clk_rate;	/* clock rate for SDR104 */
 	u32 tap;		/* sampling clock position for SDR104 */
+	u32 tap_hs400;		/* sampling clock position for HS400 */
 };
 
 struct renesas_sdhi_of_data {
@@ -49,6 +50,7 @@ struct renesas_sdhi {
 	struct pinctrl_state *pins_default, *pins_uhs;
 	void __iomem *scc_ctl;
 	u32 scc_tappos;
+	u32 scc_tappos_hs400;
 };
 
 #define host_to_priv(host) \
diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 7e2a75c4f36f..71e13844df6c 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -337,6 +337,10 @@ static void renesas_sdhi_hs400_complete(struct tmio_mmc_host *host)
 	/* Set 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_DT2FF,
+		       priv->scc_tappos_hs400);
+
 	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2,
 		       (SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
 			SH_MOBILE_SDHI_SCC_TMPPORT2_HS400OSEL) |
@@ -396,6 +400,9 @@ static void renesas_sdhi_reset_hs400_mode(struct tmio_mmc_host *host,
 	/* 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_DT2FF, priv->scc_tappos);
+
 	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2,
 		       ~(SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
 			 SH_MOBILE_SDHI_SCC_TMPPORT2_HS400OSEL) &
@@ -786,6 +793,7 @@ int renesas_sdhi_probe(struct platform_device *pdev,
 			if (taps[i].clk_rate == 0 ||
 			    taps[i].clk_rate == host->mmc->f_max) {
 				priv->scc_tappos = taps->tap;
+				priv->scc_tappos_hs400 = taps->tap_hs400;
 				hit = true;
 				break;
 			}
diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
index 92c9b15252da..9dfafa2a90a3 100644
--- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
+++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -81,6 +81,7 @@ static struct renesas_sdhi_scc rcar_gen3_scc_taps[] = {
 	{
 		.clk_rate = 0,
 		.tap = 0x00000300,
+		.tap_hs400 = 0x00000704,
 	},
 };
 
-- 
2.11.0