[PATCH 3/4] mmc: dw_mmc: Add quirk for extended data read timeout

["Mårten Lindahl" <marten.lindahl@axis.com>]

Current dw_mci driver supports a TMOUT register which consists of a 24
bit field (TMOUT[31:8]) for the DATA_TIMEOUT. The maximum value of this
field is 0xFFFFFF, which with a 200MHz clock will give a full DRTO of:

0xFFFFFF / 200000000 => ~84 ms

However, the ARTPEC-8 SoC DWMMC IP version has a TMOUT register with an
extended DATA_TIMEOUT field, which supports longer timers for the DRTO.
In this version the DATA_TIMEOUT field is split into two, which with the
same 200MHz clock as above will allow a maximum timeout of:

((TMOUT[10:8] -1) * 0xFFFFFF + TMOUT[31:11] * 8) / 200000000 => ~587 ms

Add a quirk to support this. The quirk is enabled for ARTPEC-8 SoCs.

Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
---
 drivers/mmc/host/dw_mmc-exynos.c |  5 +++++
 drivers/mmc/host/dw_mmc.c        | 33 ++++++++++++++++++++++++++++----
 drivers/mmc/host/dw_mmc.h        |  7 +++++++
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index cae7c94b5d6e..6ae9c0ec1282 100644
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -127,6 +127,11 @@ static int dw_mci_exynos_priv_init(struct dw_mci *host)
 				DQS_CTRL_GET_RD_DELAY(priv->saved_strobe_ctrl);
 	}
 
+	if (priv->ctrl_type == DW_MCI_TYPE_ARTPEC8) {
+		/* Quirk needed for ARTPEC-8 SoCs */
+		host->quirks |= DW_MMC_QUIRK_EXTENDED_TMOUT;
+	}
+
 	host->bus_hz /= (priv->ciu_div + 1);
 
 	return 0;
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index f2a14a434bef..45ea9fd97a6a 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1289,6 +1289,7 @@ static void dw_mci_set_data_timeout(struct dw_mci *host,
 {
 	u32 clk_div, tmout;
 	u64 tmp;
+	unsigned int tmp2;
 
 	clk_div = (mci_readl(host, CLKDIV) & 0xFF) * 2;
 	if (clk_div == 0)
@@ -1301,10 +1302,28 @@ static void dw_mci_set_data_timeout(struct dw_mci *host,
 	tmout = 0xFF; /* Set maximum */
 
 	/* TMOUT[31:8] (DATA_TIMEOUT) */
-	if (!tmp || tmp > 0xFFFFFF)
-		tmout |= (0xFFFFFF << 8);
-	else
-		tmout |= (tmp & 0xFFFFFF) << 8;
+	if (host->quirks & DW_MMC_QUIRK_EXTENDED_TMOUT) {
+		/*
+		 * Extended HW timer (max = 0x6FFFFF2):
+		 * ((TMOUT[10:8] - 1) * 0xFFFFFF + TMOUT[31:11] * 8)
+		 */
+		if (!tmp || tmp > 0x6FFFFF2)
+			tmout |= (0xFFFFFF << 8);
+		else {
+			/* TMOUT[10:8] */
+			tmp2 = (((unsigned int)tmp / 0xFFFFFF) + 1) & 0x7;
+			tmout |= tmp2 << 8;
+
+			/* TMOUT[31:11] */
+			tmp = tmp - ((tmp2 - 1) * 0xFFFFFF);
+			tmout |= (tmp & 0xFFFFF8) << 8;
+		}
+	} else {
+		if (!tmp || tmp > 0xFFFFFF)
+			tmout |= (0xFFFFFF << 8);
+		else
+			tmout |= (tmp & 0xFFFFFF) << 8;
+	}
 
 	mci_writel(host, TMOUT, tmout);
 	dev_dbg(host->dev, "timeout_ns: %u => TMOUT[31:8]: 0x%#08x",
@@ -2005,9 +2024,15 @@ static void dw_mci_set_drto(struct dw_mci *host)
 	if (drto_div == 0)
 		drto_div = 1;
 
+	if (host->quirks & DW_MMC_QUIRK_EXTENDED_TMOUT)
+		drto_clks = (((drto_clks & 0x7) - 1) * 0xFFFFFF) +
+			((drto_clks & 0xFFFFF8));
+
 	drto_ms = DIV_ROUND_UP_ULL((u64)MSEC_PER_SEC * drto_clks * drto_div,
 				   host->bus_hz);
 
+	dev_dbg(host->dev, "drto_ms: %u\n", drto_ms);
+
 	/* add a bit spare time */
 	drto_ms += 10;
 
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 771d5afa3136..071f4479f166 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -118,6 +118,7 @@ struct dw_mci_dma_slave {
  * @part_buf: Simple buffer for partial fifo reads/writes.
  * @push_data: Pointer to FIFO push function.
  * @pull_data: Pointer to FIFO pull function.
+ * @quirks: Set of quirks that apply to specific versions of the IP.
  * @vqmmc_enabled: Status of vqmmc, should be true or false.
  * @irq_flags: The flags to be passed to request_irq.
  * @irq: The irq value to be passed to request_irq.
@@ -223,6 +224,9 @@ struct dw_mci {
 	void (*push_data)(struct dw_mci *host, void *buf, int cnt);
 	void (*pull_data)(struct dw_mci *host, void *buf, int cnt);
 
+	/* Workaround flags */
+	u32			quirks;
+
 	bool			vqmmc_enabled;
 	unsigned long		irq_flags; /* IRQ flags */
 	int			irq;
@@ -274,6 +278,9 @@ struct dw_mci_board {
 	struct dma_pdata *data;
 };
 
+/* Support for longer data read timeout */
+#define DW_MMC_QUIRK_EXTENDED_TMOUT	(1<<0)
+
 #define DW_MMC_240A		0x240a
 #define DW_MMC_280A		0x280a
 
-- 
2.20.1