[PATCH v2] mci: dwcmshc-sdhci: add support for Kalray Coolidge v2 SoC eMMC controller

[Yann Sionneau <ysionneau@kalrayinc.com>]

Kalray Coolidge v2 SoC eMMC controller needs static tx delay tuning even
for basic standard or high speed modes.

Add vendor specific callback mechanism for init and implement it for
Coolidge v2 SoC.

Signed-off-by: Yann Sionneau <ysionneau@kalrayinc.com>
---

Notes:

V1 -> V2:
 - Fixed comment style
 - Removed unused set_ios callback
 - rephrased commit message

 drivers/mci/dwcmshc-sdhci.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/mci/dwcmshc-sdhci.c b/drivers/mci/dwcmshc-sdhci.c
index d9c51752db..b3432d500b 100644
--- a/drivers/mci/dwcmshc-sdhci.c
+++ b/drivers/mci/dwcmshc-sdhci.c
@@ -9,11 +9,16 @@
 #include <dma.h>
 #include <malloc.h>
 #include <mci.h>
+#include <of_device.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 
 #include "sdhci.h"
 
+#define tx_delay_static_cfg(delay)      (delay << 5)
+#define tx_tuning_clk_sel(delay)        (delay)
+
+#define DWCMSHC_GPIO_OUT  0x34 /* offset from vendor specific area */
 #define CARD_STATUS_MASK (0x1e00)
 #define CARD_STATUS_TRAN (4 << 9)
 
@@ -22,6 +27,12 @@ static int do_send_cmd(struct mci_host *mci, struct mci_cmd *cmd, struct mci_dat
 struct dwcmshc_host {
 	struct mci_host mci;
 	struct sdhci sdhci;
+	int vendor_specific_area;
+	const struct dwcmshc_callbacks *cb;
+};
+
+struct dwcmshc_callbacks {
+	void (*init)(struct mci_host *mci, struct device *dev);
 };
 
 static inline struct dwcmshc_host *priv_from_mci_host(struct mci_host *h)
@@ -253,6 +264,9 @@ static int dwcmshc_mci_init(struct mci_host *mci, struct device *dev)
 	dev_dbg(host->mci.hw_dev, "host version4: %s\n",
 		ctrl2 & SDHCI_CTRL_V4_MODE ? "enabled" : "disabled");
 
+	if (host->cb && host->cb->init)
+		host->cb->init(mci, dev);
+
 	return 0;
 }
 
@@ -284,6 +298,8 @@ static void dwcmshc_set_dma_mask(struct device *dev)
 
 static int dwcmshc_probe(struct device *dev)
 {
+	const struct dwcmshc_callbacks *dwcmshc_cb =
+			of_device_get_match_data(dev);
 	struct dwcmshc_host *host;
 	struct resource *iores;
 	struct mci_host *mci;
@@ -309,6 +325,7 @@ static int dwcmshc_probe(struct device *dev)
 	host->sdhci.base = IOMEM(iores->start);
 	host->sdhci.mci = mci;
 	host->sdhci.max_clk = clk_get_rate(clk);
+	host->cb = dwcmshc_cb;
 
 	mci->hw_dev = dev;
 	mci->init = dwcmshc_mci_init;
@@ -337,6 +354,10 @@ static int dwcmshc_probe(struct device *dev)
 	dev_dbg(host->mci.hw_dev, "host controller version: %u\n",
 		host->sdhci.version);
 
+	host->vendor_specific_area = sdhci_read32(&host->sdhci,
+						   SDHCI_P_VENDOR_SPEC_AREA);
+	host->vendor_specific_area &= SDHCI_P_VENDOR_SPEC_AREA_MASK;
+
 	ret = mci_register(&host->mci);
 	if (ret)
 		goto err_register;
@@ -354,8 +375,23 @@ static int dwcmshc_probe(struct device *dev)
 	return ret;
 }
 
+static void dwcmshc_coolidgev2_init(struct mci_host *mci, struct device *dev)
+{
+	struct dwcmshc_host *host = priv_from_mci_host(mci);
+
+	/* configure TX delay to set correct setup/hold for Coolidge V2 */
+	sdhci_write32(&host->sdhci,
+		      host->vendor_specific_area + DWCMSHC_GPIO_OUT,
+		      tx_delay_static_cfg(0xf) | tx_tuning_clk_sel(4));
+}
+
+struct dwcmshc_callbacks kalray_coolidgev2_callbacks = {
+	.init = dwcmshc_coolidgev2_init,
+};
+
 static struct of_device_id dwcmshc_dt_ids[] = {
 	{ .compatible = "snps,dwcmshc-sdhci", },
+	{ .compatible = "kalray,coolidge-v2-dwcmshc-sdhci", .data = &kalray_coolidgev2_callbacks },
 	{ }
 };
 
-- 
2.43.0