mmc: Add support for Qualcomm SDHCI controller

Add support for SD/eMMC controller present on some Qualcomm Snapdragon
devices. This controller implements SDHCI 2.0 interface but requires
vendor-specific initialization.
Driver works in PIO mode as ADMA is not supported by U-Boot (yet).

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

doc/device-tree-bindings/mmc/msm_sdhci.txt

@@ -0,0 +1,25 @@
+Qualcomm Snapdragon SDHCI controller
+
+Required properties:
+- compatible : "qcom,sdhci-msm-v4"
+- reg: Base address and length of registers:
+	- Host controller registers (SDHCI)
+	- SD Core registers
+- clock: interface clock (must accept SD bus clock as a frequency)
+
+Optional properties:
+- index: If there is more than one controller - controller index (required
+	by generic SDHCI code).
+- bus_width: Width of SD/eMMC bus (default 4)
+- clock-frequency: Frequency of SD/eMMC bus (default 400 kHz)
+
+Example:
+
+sdhci@07864000 {
+	compatible = "qcom,sdhci-msm-v4";
+	reg = <0x7864900 0x11c 0x7864000 0x800>;
+	index = <0x1>;
+	bus-width = <0x4>;
+	clock = <&clkc 1>;
+	clock-frequency = <200000000>;
+};

drivers/mmc/Kconfig

@@ -16,6 +16,15 @@ config DM_MMC
 	  appear as block devices in U-Boot and can support filesystems such
 	  as EXT4 and FAT.
 
+config MSM_SDHCI
+	bool "Qualcomm SDHCI controller"
+	depends on DM_MMC
+	help
+	  Enables support for SDHCI 2.0 controller present on some Qualcomm
+          Snapdragon devices. This device is compatible with eMMC v4.5 and
+          SD 3.0 specifications. Both SD and eMMC devices are supported.
+	  Card-detect gpios are not supported.
+
 config ROCKCHIP_DWMMC
 	bool "Rockchip SD/MMC controller support"
 	depends on DM_MMC && OF_CONTROL

drivers/mmc/Makefile

@@ -50,3 +50,4 @@ else
 obj-$(CONFIG_GENERIC_MMC) += mmc_write.o
 endif
 obj-$(CONFIG_PIC32_SDHCI) += pic32_sdhci.o
+obj-$(CONFIG_MSM_SDHCI) += msm_sdhci.o

drivers/mmc/msm_sdhci.c

@@ -0,0 +1,180 @@
+/*
+ * Qualcomm SDHCI driver - SD/eMMC controller
+ *
+ * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
+ *
+ * Based on Linux driver
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <sdhci.h>
+#include <wait_bit.h>
+#include <asm/io.h>
+#include <linux/bitops.h>
+
+/* Non-standard registers needed for SDHCI startup */
+#define SDCC_MCI_POWER   0x0
+#define SDCC_MCI_POWER_SW_RST BIT(7)
+
+/* This is undocumented register */
+#define SDCC_MCI_VERSION             0x50
+#define SDCC_MCI_VERSION_MAJOR_SHIFT 28
+#define SDCC_MCI_VERSION_MAJOR_MASK  (0xf << SDCC_MCI_VERSION_MAJOR_SHIFT)
+#define SDCC_MCI_VERSION_MINOR_MASK  0xff
+
+#define SDCC_MCI_STATUS2 0x6C
+#define SDCC_MCI_STATUS2_MCI_ACT 0x1
+#define SDCC_MCI_HC_MODE 0x78
+
+/* Offset to SDHCI registers */
+#define SDCC_SDHCI_OFFSET 0x900
+
+/* Non standard (?) SDHCI register */
+#define SDHCI_VENDOR_SPEC_CAPABILITIES0  0x11c
+
+struct msm_sdhc {
+	struct sdhci_host host;
+	void *base;
+};
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int msm_sdc_clk_init(struct udevice *dev)
+{
+	uint clk_rate = fdtdec_get_uint(gd->fdt_blob, dev->of_offset,
+					"clock-frequency", 400000);
+	uint clkd[2]; /* clk_id and clk_no */
+	int clk_offset;
+	struct udevice *clk;
+	int ret;
+
+	ret = fdtdec_get_int_array(gd->fdt_blob, dev->of_offset, "clock", clkd,
+				   2);
+	if (ret)
+		return ret;
+
+	clk_offset = fdt_node_offset_by_phandle(gd->fdt_blob, clkd[0]);
+	if (clk_offset < 0)
+		return clk_offset;
+
+	ret = uclass_get_device_by_of_offset(UCLASS_CLK, clk_offset, &clk);
+	if (ret)
+		return ret;
+
+	ret = clk_set_periph_rate(clk, clkd[1], clk_rate);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int msm_sdc_probe(struct udevice *dev)
+{
+	struct msm_sdhc *prv = dev_get_priv(dev);
+	struct sdhci_host *host = &prv->host;
+	u32 core_version, core_minor, core_major;
+	int ret;
+
+	host->quirks = SDHCI_QUIRK_WAIT_SEND_CMD | SDHCI_QUIRK_BROKEN_R1B;
+
+	/* Init clocks */
+	ret = msm_sdc_clk_init(dev);
+	if (ret)
+		return ret;
+
+	/* Reset the core and Enable SDHC mode */
+	writel(readl(prv->base + SDCC_MCI_POWER) | SDCC_MCI_POWER_SW_RST,
+	       prv->base + SDCC_MCI_POWER);
+
+
+	/* Wait for reset to be written to register */
+	if (wait_for_bit(__func__, prv->base + SDCC_MCI_STATUS2,
+			 SDCC_MCI_STATUS2_MCI_ACT, false, 10, false)) {
+		printf("msm_sdhci: reset request failed\n");
+		return -EIO;
+	}
+
+	/* SW reset can take upto 10HCLK + 15MCLK cycles. (min 40us) */
+	if (wait_for_bit(__func__, prv->base + SDCC_MCI_POWER,
+			 SDCC_MCI_POWER_SW_RST, false, 2, false)) {
+		printf("msm_sdhci: stuck in reset\n");
+		return -ETIMEDOUT;
+	}
+
+	/* Enable host-controller mode */
+	writel(1, prv->base + SDCC_MCI_HC_MODE);
+
+	core_version = readl(prv->base + SDCC_MCI_VERSION);
+
+	core_major = (core_version & SDCC_MCI_VERSION_MAJOR_MASK);
+	core_major >>= SDCC_MCI_VERSION_MAJOR_SHIFT;
+
+	core_minor = core_version & SDCC_MCI_VERSION_MINOR_MASK;
+
+	/*
+	 * Support for some capabilities is not advertised by newer
+	 * controller versions and must be explicitly enabled.
+	 */
+	if (core_major >= 1 && core_minor != 0x11 && core_minor != 0x12) {
+		u32 caps = readl(host->ioaddr + SDHCI_CAPABILITIES);
+		caps |= SDHCI_CAN_VDD_300 | SDHCI_CAN_DO_8BIT;
+		writel(caps, host->ioaddr + SDHCI_VENDOR_SPEC_CAPABILITIES0);
+	}
+
+	/* Set host controller version */
+	host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
+
+	/* automatically detect max and min speed */
+	return add_sdhci(host, 0, 0);
+}
+
+static int msm_sdc_remove(struct udevice *dev)
+{
+	struct msm_sdhc *priv = dev_get_priv(dev);
+
+	 /* Disable host-controller mode */
+	writel(0, priv->base + SDCC_MCI_HC_MODE);
+
+	return 0;
+}
+
+static int msm_ofdata_to_platdata(struct udevice *dev)
+{
+	struct udevice *parent = dev->parent;
+	struct msm_sdhc *priv = dev_get_priv(dev);
+	struct sdhci_host *host = &priv->host;
+
+	host->name = strdup(dev->name);
+	host->ioaddr = (void *)dev_get_addr(dev);
+	host->bus_width = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+					 "bus-width", 4);
+	host->index = fdtdec_get_uint(gd->fdt_blob, dev->of_offset, "index", 0);
+	priv->base = (void *)fdtdec_get_addr_size_auto_parent(gd->fdt_blob,
+							      parent->of_offset,
+							      dev->of_offset,
+							      "reg", 1, NULL);
+	if (priv->base == (void *)FDT_ADDR_T_NONE ||
+	    host->ioaddr == (void *)FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct udevice_id msm_mmc_ids[] = {
+	{ .compatible = "qcom,sdhci-msm-v4" },
+	{ }
+};
+
+U_BOOT_DRIVER(msm_sdc_drv) = {
+	.name		= "msm_sdc",
+	.id		= UCLASS_MMC,
+	.of_match	= msm_mmc_ids,
+	.ofdata_to_platdata = msm_ofdata_to_platdata,
+	.probe		= msm_sdc_probe,
+	.remove		= msm_sdc_remove,
+	.priv_auto_alloc_size = sizeof(struct msm_sdhc),
+};