[PATCH v24 15/15] mmc: renesas_sdhi: Add HS400 enhanced strobe support for RZ/G3L

From: Biju Das <[email protected]>

RZ/G3L's HS400 enhanced strobe mode needs extra SCC register
programming beyond the standard HS400 path. Add a TMIO_MMC_HS400ES
flag (bit 17) for controllers that support it.

Add renesas_sdhi_hs400_enhanced_strobe(), registered as
host->ops.hs400_enhanced_strobe when the flag is set. On enable, it
clears DTSEL and TAPEN, programs TMPPORT3 and HWADJ2, sets the HS400
interface bit in SDIF_MODE, sets HS400EN2 in HS400MODE2, and sets
HS400EN plus the new HS400MODE1_ENHANCED_STROBE bit in TMPPORT2. On
disable, only the enhanced-strobe-related bits are cleared.

Also mask off HS400MODE1_ENHANCED_STROBE in
renesas_sdhi_reset_hs400_mode() when TMIO_MMC_HS400ES is set, for a
clean reset on mode exit.

Since a controller reset clears these SCC registers,
renesas_sdhi_reset() now re-invokes
renesas_sdhi_hs400_enhanced_strobe() after reset whenever
TMIO_MMC_HS400ES is set and the controller is currently in HS400
with enhanced strobe active, restoring the enhanced-strobe state
instead of losing it across a reset.

Enable TMIO_MMC_HS400ES in of_data_rzg3l to finalize RZ/G3L HS400
support.

Signed-off-by: Biju Das <[email protected]>
---
v23->v24:
 * No change.
v22->v23:
 * No change.
v21->v22:
 * Updated commit description.
 * Restored the patch after fixing inode corruption.
 * renesas_sdhi_reset() now restores data strobe register values
   after reset.
v20->v21:
 * Dropped the patch due to inode corruption during boot.
v19->v20:
 * SD_CLK_CTRL clk enable turned off before updating SCC_CKSEL_DTSEL
   register.
v18->v19:
 * Updated commit description.
 * HS400ES support is enabled based on of_data.
 * Fixed the space in HS400ES comment block.
v18:
 * New patch.
---
 drivers/mmc/host/renesas_sdhi_core.c          | 68 +++++++++++++++++--
 drivers/mmc/host/renesas_sdhi_internal_dmac.c |  2 +-
 include/linux/platform_data/tmio.h            |  3 +
 3 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 5d9d3c7dedf9..fc58f2188852 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -340,7 +340,8 @@ static int renesas_sdhi_card_busy(struct mmc_host *mmc)
 #define SH_MOBILE_SDHI_SCC_SMPCMP_CMD_REQUP	BIT(24)
 #define SH_MOBILE_SDHI_SCC_SMPCMP_CMD_ERR	(BIT(8) | BIT(24))
 
-#define SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN	BIT(31)
+#define SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN		BIT(31)
+#define SH_MOBILE_SDHI_SCC_HS400MODE1_ENHANCED_STROBE	BIT(30)
 
 /* Definitions for values the SH_MOBILE_SDHI_SCC_TMPPORT4 register */
 #define SH_MOBILE_SDHI_SCC_TMPPORT4_DLL_ACC_START	BIT(0)
@@ -636,6 +637,8 @@ static void renesas_sdhi_adjust_hs400_mode_disable(struct tmio_mmc_host *host)
 static void renesas_sdhi_reset_hs400_mode(struct tmio_mmc_host *host,
 					  struct renesas_sdhi *priv)
 {
+	u32 val = ~(SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN | host->pdata->osel_tmpout);
+
 	sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
 			sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
 
@@ -645,10 +648,11 @@ static void renesas_sdhi_reset_hs400_mode(struct tmio_mmc_host *host,
 
 	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_DT2FF, priv->scc_tappos);
 
+	if (host->pdata->flags & TMIO_MMC_HS400ES)
+		val &= ~SH_MOBILE_SDHI_SCC_HS400MODE1_ENHANCED_STROBE;
+
 	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2,
-		       ~(SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
-			 host->pdata->osel_tmpout) &
-			sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2));
+		       val & sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2));
 
 	if (host->pdata->flags & TMIO_MMC_HS400MODE2)
 		sd_scc_write32(host, priv, RZG3L_SDHI_SCC_HS400MODE2, 0x0);
@@ -679,6 +683,53 @@ static void renesas_sdhi_scc_reset(struct tmio_mmc_host *host, struct renesas_sd
 		       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
 }
 
+static void renesas_sdhi_hs400_enhanced_strobe(struct mmc_host *mmc,
+					       struct mmc_ios *ios)
+{
+	struct tmio_mmc_host *host = mmc_priv(mmc);
+	struct renesas_sdhi *priv = host_to_priv(host);
+	u32 val = sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2);
+
+	if (!(host->pdata->flags & TMIO_MMC_HS400ES))
+		return;
+
+	if (ios->enhanced_strobe) {
+		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_CKSEL,
+			       ~SH_MOBILE_SDHI_SCC_CKSEL_DTSEL &
+			       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_CKSEL));
+
+		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));
+
+		sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT3, BIT(8) | BIT(9));
+		sd_scc_write32(host, priv, RZG3L_SDHI_SCC_HWADJ2, 0xFF);
+		sd_ctrl_write16(host, CTL_SDIF_MODE, SDIF_MODE_HS400 |
+				sd_ctrl_read16(host, CTL_SDIF_MODE));
+		sd_scc_write32(host, priv, RZG3L_SDHI_SCC_HS400MODE2,
+			       RZG3L_SDHI_SCC_HS400MODE2_HS400EN2);
+
+		val |= SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
+		       SH_MOBILE_SDHI_SCC_HS400MODE1_ENHANCED_STROBE;
+	} else {
+		val &= ~(SH_MOBILE_SDHI_SCC_TMPPORT2_HS400EN |
+			 SH_MOBILE_SDHI_SCC_HS400MODE1_ENHANCED_STROBE);
+
+		sd_ctrl_write16(host, CTL_SDIF_MODE, ~SDIF_MODE_HS400 &
+				sd_ctrl_read16(host, CTL_SDIF_MODE));
+
+		sd_scc_write32(host, priv, RZG3L_SDHI_SCC_HS400MODE2, 0);
+	}
+
+	sd_scc_write32(host, priv, SH_MOBILE_SDHI_SCC_TMPPORT2, val);
+}
+
 /* only populated for TMIO_MMC_MIN_RCAR2 */
 static void renesas_sdhi_reset(struct tmio_mmc_host *host, bool preserve)
 {
@@ -703,6 +754,13 @@ static void renesas_sdhi_reset(struct tmio_mmc_host *host, bool preserve)
 			/* Unknown why but without polling reset status, it will hang */
 			read_poll_timeout(reset_control_status, ret, ret == 0, 1, 100,
 					  false, priv->rstc);
+
+			/* Restore data strobe registers */
+			if ((host->pdata->flags & TMIO_MMC_HS400ES) &&
+			    host->mmc->ios.timing == MMC_TIMING_MMC_HS400 &&
+			    host->mmc->ios.enhanced_strobe)
+				renesas_sdhi_hs400_enhanced_strobe(host->mmc, &host->mmc->ios);
+
 			/* At least SDHI_VER_GEN2_SDR50 needs manual release of reset */
 			sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
 			if (priv->rdev)
@@ -1410,6 +1468,8 @@ int renesas_sdhi_probe(struct platform_device *pdev,
 		host->ops.prepare_hs400_tuning = renesas_sdhi_prepare_hs400_tuning;
 		host->ops.hs400_downgrade = renesas_sdhi_disable_scc;
 		host->ops.hs400_complete = renesas_sdhi_hs400_complete;
+		if (host->pdata->flags & TMIO_MMC_HS400ES)
+			host->ops.hs400_enhanced_strobe = renesas_sdhi_hs400_enhanced_strobe;
 	}
 
 	sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask_all);
diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
index afe259c1566d..c64993ee3ec5 100644
--- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
+++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -179,7 +179,7 @@ static const struct renesas_sdhi_of_data of_data_rzg3l = {
 			  TMIO_MMC_HAVE_CBSY | TMIO_MMC_MIN_RCAR2 |
 			  TMIO_MMC_64BIT_DATA_PORT | TMIO_MMC_TUNING_DELAY |
 			  TMIO_MMC_INTERNAL_DIVIDER | TMIO_MMC_HWADJ |
-			  TMIO_MMC_HS400MODE2,
+			  TMIO_MMC_HS400MODE2 | TMIO_MMC_HS400ES,
 	.capabilities	= MMC_CAP_SD_HIGHSPEED | MMC_CAP_SDIO_IRQ |
 			  MMC_CAP_CMD23 | MMC_CAP_WAIT_WHILE_BUSY,
 	.capabilities2	= MMC_CAP2_NO_WRITE_PROTECT | MMC_CAP2_MERGE_CAPABLE,
diff --git a/include/linux/platform_data/tmio.h b/include/linux/platform_data/tmio.h
index 88a3744f965a..ca1435441628 100644
--- a/include/linux/platform_data/tmio.h
+++ b/include/linux/platform_data/tmio.h
@@ -62,6 +62,9 @@
 /* Some controllers have HS400MODE2 */
 #define TMIO_MMC_HS400MODE2		BIT(16)
 
+/* Some controllers have HS400ES */
+#define TMIO_MMC_HS400ES		BIT(17)
+
 struct tmio_mmc_data {
 	void				*chan_priv_tx;
 	void				*chan_priv_rx;
-- 
2.43.0