mmc: dw_mmc: zx: Initial support for ZX mmc controller

This platform driver adds initial support for the DW host controller
found on ZTE SoCs.

It has been tested on ZX296718 EVB board currently. More support on
timing tuning will be added when hardware is available.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 241 insertions, 0 deletions

diff --git a/drivers/mmc/host/dw_mmc-zx.c b/drivers/mmc/host/dw_mmc-zx.c
new file mode 100644
index 000000000000..d38e94ae2b85
--- /dev/null
+++ b/drivers/mmc/host/dw_mmc-zx.c
@@ -0,0 +1,241 @@
+/*
+ * ZX Specific Extensions for Synopsys DW Multimedia Card Interface driver
+ *
+ * Copyright (C) 2016, Linaro Ltd.
+ * Copyright (C) 2016, ZTE Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "dw_mmc.h"
+#include "dw_mmc-pltfm.h"
+#include "dw_mmc-zx.h"
+
+struct dw_mci_zx_priv_data {
+	struct regmap	*sysc_base;
+};
+
+enum delay_type {
+	DELAY_TYPE_READ,	/* read dqs delay */
+	DELAY_TYPE_CLK,		/* clk sample delay */
+};
+
+static int dw_mci_zx_emmc_set_delay(struct dw_mci *host, unsigned int delay,
+				    enum delay_type dflag)
+{
+	struct dw_mci_zx_priv_data *priv = host->priv;
+	struct regmap *sysc_base = priv->sysc_base;
+	unsigned int clksel;
+	unsigned int loop = 1000;
+	int ret;
+
+	if (!sysc_base)
+		return -EINVAL;
+
+	ret = regmap_update_bits(sysc_base, LB_AON_EMMC_CFG_REG0,
+				 PARA_HALF_CLK_MODE | PARA_DLL_BYPASS_MODE |
+				 PARA_PHASE_DET_SEL_MASK |
+				 PARA_DLL_LOCK_NUM_MASK |
+				 DLL_REG_SET | PARA_DLL_START_MASK,
+				 PARA_DLL_START(4) | PARA_DLL_LOCK_NUM(4));
+	if (ret)
+		return ret;
+
+	ret = regmap_read(sysc_base, LB_AON_EMMC_CFG_REG1, &clksel);
+	if (ret)
+		return ret;
+
+	if (dflag == DELAY_TYPE_CLK) {
+		clksel &= ~CLK_SAMP_DELAY_MASK;
+		clksel |= CLK_SAMP_DELAY(delay);
+	} else {
+		clksel &= ~READ_DQS_DELAY_MASK;
+		clksel |= READ_DQS_DELAY(delay);
+	}
+
+	regmap_write(sysc_base, LB_AON_EMMC_CFG_REG1, clksel);
+	regmap_update_bits(sysc_base, LB_AON_EMMC_CFG_REG0,
+			   PARA_DLL_START_MASK | PARA_DLL_LOCK_NUM_MASK |
+			   DLL_REG_SET,
+			   PARA_DLL_START(4) | PARA_DLL_LOCK_NUM(4) |
+			   DLL_REG_SET);
+
+	do {
+		ret = regmap_read(sysc_base, LB_AON_EMMC_CFG_REG2, &clksel);
+		if (ret)
+			return ret;
+
+	} while (--loop && !(clksel & ZX_DLL_LOCKED));
+
+	if (!loop) {
+		dev_err(host->dev, "Error: %s dll lock fail\n", __func__);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int dw_mci_zx_emmc_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
+{
+	struct dw_mci *host = slot->host;
+	struct mmc_host *mmc = slot->mmc;
+	int ret, len = 0, start = 0, end = 0, delay, best = 0;
+
+	for (delay = 1; delay < 128; delay++) {
+		ret = dw_mci_zx_emmc_set_delay(host, delay, DELAY_TYPE_CLK);
+		if (!ret && mmc_send_tuning(mmc, opcode, NULL)) {
+			if (start >= 0) {
+				end = delay - 1;
+				/* check and update longest good range */
+				if ((end - start) > len) {
+					best = (start + end) >> 1;
+					len = end - start;
+				}
+			}
+			start = -1;
+			end = 0;
+			continue;
+		}
+		if (start < 0)
+			start = delay;
+	}
+
+	if (start >= 0) {
+		end = delay - 1;
+		if ((end - start) > len) {
+			best = (start + end) >> 1;
+			len = end - start;
+		}
+	}
+	if (best < 0)
+		return -EIO;
+
+	dev_info(host->dev, "%s best range: start %d end %d\n", __func__,
+		 start, end);
+	return dw_mci_zx_emmc_set_delay(host, best, DELAY_TYPE_CLK);
+}
+
+static int dw_mci_zx_prepare_hs400_tuning(struct dw_mci *host,
+					  struct mmc_ios *ios)
+{
+	int ret;
+
+	/* config phase shift as 90 degree */
+	ret = dw_mci_zx_emmc_set_delay(host, 32, DELAY_TYPE_READ);
+	if (ret < 0)
+		return -EIO;
+
+	return 0;
+}
+
+static int dw_mci_zx_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
+{
+	struct dw_mci *host = slot->host;
+
+	if (host->verid == 0x290a) /* only for emmc */
+		return dw_mci_zx_emmc_execute_tuning(slot, opcode);
+	/* TODO: Add 0x210a dedicated tuning for sd/sdio */
+
+	return 0;
+}
+
+static int dw_mci_zx_parse_dt(struct dw_mci *host)
+{
+	struct device_node *np = host->dev->of_node;
+	struct device_node *node;
+	struct dw_mci_zx_priv_data *priv;
+	struct regmap *sysc_base;
+	int ret;
+
+	/* syscon is needed only by emmc */
+	node = of_parse_phandle(np, "zte,aon-syscon", 0);
+	if (node) {
+		sysc_base = syscon_node_to_regmap(node);
+		of_node_put(node);
+
+		if (IS_ERR(sysc_base)) {
+			ret = PTR_ERR(sysc_base);
+			if (ret != -EPROBE_DEFER)
+				dev_err(host->dev, "Can't get syscon: %d\n",
+					ret);
+			return ret;
+		}
+	} else {
+		return 0;
+	}
+
+	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	priv->sysc_base = sysc_base;
+	host->priv = priv;
+
+	return 0;
+}
+
+static unsigned long zx_dwmmc_caps[3] = {
+	MMC_CAP_CMD23,
+	MMC_CAP_CMD23,
+	MMC_CAP_CMD23,
+};
+
+static const struct dw_mci_drv_data zx_drv_data = {
+	.caps			= zx_dwmmc_caps,
+	.execute_tuning		= dw_mci_zx_execute_tuning,
+	.prepare_hs400_tuning	= dw_mci_zx_prepare_hs400_tuning,
+	.parse_dt               = dw_mci_zx_parse_dt,
+};
+
+static const struct of_device_id dw_mci_zx_match[] = {
+	{ .compatible = "zte,zx296718-dw-mshc", .data = &zx_drv_data},
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_mci_zx_match);
+
+static int dw_mci_zx_probe(struct platform_device *pdev)
+{
+	const struct dw_mci_drv_data *drv_data;
+	const struct of_device_id *match;
+
+	match = of_match_node(dw_mci_zx_match, pdev->dev.of_node);
+	drv_data = match->data;
+
+	return dw_mci_pltfm_register(pdev, drv_data);
+}
+
+static const struct dev_pm_ops dw_mci_zx_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
+			   dw_mci_runtime_resume,
+			   NULL)
+};
+
+static struct platform_driver dw_mci_zx_pltfm_driver = {
+	.probe		= dw_mci_zx_probe,
+	.remove		= dw_mci_pltfm_remove,
+	.driver		= {
+		.name		= "dwmmc_zx",
+		.of_match_table	= dw_mci_zx_match,
+		.pm		= &dw_mci_zx_dev_pm_ops,
+	},
+};
+
+module_platform_driver(dw_mci_zx_pltfm_driver);
+
+MODULE_DESCRIPTION("ZTE emmc/sd driver");
+MODULE_LICENSE("GPL v2");