mmc: dw_mmc: add support for exynos specific implementation of dw-mshc
authorThomas Abraham <thomas.ab@samsung.com>
Mon, 17 Sep 2012 18:16:43 +0000 (18:16 +0000)
committerChris Ball <cjb@laptop.org>
Wed, 3 Oct 2012 14:05:20 +0000 (10:05 -0400)
Samsung Exynos SoC's extend the dw-mshc controller for additional clock
and bus control. Add support for these extensions and include provide
device tree based discovery suppory as well.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt [new file with mode: 0644]
drivers/mmc/host/Kconfig
drivers/mmc/host/Makefile
drivers/mmc/host/dw_mmc-exynos.c [new file with mode: 0644]
include/linux/mmc/dw_mmc.h

diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
new file mode 100644 (file)
index 0000000..7927689
--- /dev/null
@@ -0,0 +1,87 @@
+* Samsung Exynos specific extensions to the Synopsis Designware Mobile
+  Storage Host Controller
+
+The Synopsis designware mobile storage host controller is used to interface
+a SoC with storage medium such as eMMC or SD/MMC cards. This file documents
+differences between the core Synopsis dw mshc controller properties described
+by synposis-dw-mshc.txt and the properties used by the Samsung Exynos specific
+extensions to the Synopsis Designware Mobile Storage Host Controller.
+
+Required Properties:
+
+* compatible: should be
+       - "samsung,exynos4210-dw-mshc": for controllers with Samsung Exynos4210
+         specific extentions.
+       - "samsung,exynos4412-dw-mshc": for controllers with Samsung Exynos4412
+         specific extentions.
+       - "samsung,exynos5250-dw-mshc": for controllers with Samsung Exynos5250
+         specific extentions.
+
+* samsung,dw-mshc-ciu-div: Specifies the divider value for the card interface
+  unit (ciu) clock. This property is applicable only for Exynos5 SoC's and
+  ignored for Exynos4 SoC's. The valid range of divider value is 0 to 7.
+
+* samsung,dw-mshc-sdr-timing: Specifies the value of CIU clock phase shift value
+  in transmit mode and CIU clock phase shift value in receive mode for single
+  data rate mode operation. Refer notes below for the order of the cells and the
+  valid values.
+
+* samsung,dw-mshc-ddr-timing: Specifies the value of CUI clock phase shift value
+  in transmit mode and CIU clock phase shift value in receive mode for double
+  data rate mode operation. Refer notes below for the order of the cells and the
+  valid values.
+
+  Notes for the sdr-timing and ddr-timing values:
+
+    The order of the cells should be
+      - First Cell: CIU clock phase shift value for tx mode.
+      - Second Cell: CIU clock phase shift value for rx mode.
+
+    Valid values for SDR and DDR CIU clock timing for Exynos5250:
+      - valid value for tx phase shift and rx phase shift is 0 to 7.
+      - when CIU clock divider value is set to 3, all possible 8 phase shift
+        values can be used.
+      - if CIU clock divider value is 0 (that is divide by 1), both tx and rx
+        phase shift clocks should be 0.
+
+Required properties for a slot:
+
+* gpios: specifies a list of gpios used for command, clock and data bus. The
+  first gpio is the command line and the second gpio is the clock line. The
+  rest of the gpios (depending on the bus-width property) are the data lines in
+  no particular order. The format of the gpio specifier depends on the gpio
+  controller.
+
+Example:
+
+  The MSHC controller node can be split into two portions, SoC specific and
+  board specific portions as listed below.
+
+       dwmmc0@12200000 {
+               compatible = "samsung,exynos5250-dw-mshc";
+               reg = <0x12200000 0x1000>;
+               interrupts = <0 75 0>;
+               #address-cells = <1>;
+               #size-cells = <0>;
+       };
+
+       dwmmc0@12200000 {
+               num-slots = <1>;
+               supports-highspeed;
+               broken-cd;
+               fifo-depth = <0x80>;
+               card-detect-delay = <200>;
+               samsung,dw-mshc-ciu-div = <3>;
+               samsung,dw-mshc-sdr-timing = <2 3>;
+               samsung,dw-mshc-ddr-timing = <1 2>;
+
+               slot@0 {
+                       reg = <0>;
+                       bus-width = <8>;
+                       gpios = <&gpc0 0 2 0 3>, <&gpc0 1 2 0 3>,
+                               <&gpc1 0 2 3 3>, <&gpc1 1 2 3 3>,
+                               <&gpc1 2 2 3 3>, <&gpc1 3 2 3 3>,
+                               <&gpc0 3 2 3 3>, <&gpc0 4 2 3 3>,
+                               <&gpc0 5 2 3 3>, <&gpc0 6 2 3 3>;
+               };
+       };
index aa131b32e3b2981231ef0144398dce93c71c0ccc..9bf10e7bbfaffaafed7a373cb320cfb76c5e7fce 100644 (file)
@@ -540,6 +540,15 @@ config MMC_DW_PLTFM
 
          If unsure, say Y.
 
+config MMC_DW_EXYNOS
+       tristate "Exynos specific extentions for Synopsys DW Memory Card Interface"
+       depends on MMC_DW
+       select MMC_DW_PLTFM
+       help
+         This selects support for Samsung Exynos SoC specific extensions to the
+         Synopsys DesignWare Memory Card Interface driver. Select this option
+         for platforms based on Exynos4 and Exynos5 SoC's.
+
 config MMC_DW_PCI
        tristate "Synopsys Designware MCI support on PCI bus"
        depends on MMC_DW && PCI
index 8922b06be9256d3b1c9f24117e5b47f29b054dc6..17ad0a7ba40b4bfcb79c665df49c4798747cece3 100644 (file)
@@ -39,6 +39,7 @@ obj-$(CONFIG_MMC_VIA_SDMMC)   += via-sdmmc.o
 obj-$(CONFIG_SDH_BFIN)         += bfin_sdh.o
 obj-$(CONFIG_MMC_DW)           += dw_mmc.o
 obj-$(CONFIG_MMC_DW_PLTFM)     += dw_mmc-pltfm.o
+obj-$(CONFIG_MMC_DW_EXYNOS)    += dw_mmc-exynos.o
 obj-$(CONFIG_MMC_DW_PCI)       += dw_mmc-pci.o
 obj-$(CONFIG_MMC_SH_MMCIF)     += sh_mmcif.o
 obj-$(CONFIG_MMC_JZ4740)       += jz4740_mmc.o
diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
new file mode 100644 (file)
index 0000000..660bbc5
--- /dev/null
@@ -0,0 +1,253 @@
+/*
+ * Exynos Specific Extensions for Synopsys DW Multimedia Card Interface driver
+ *
+ * Copyright (C) 2012, Samsung Electronics Co., Ltd.
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/dw_mmc.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+
+#include "dw_mmc.h"
+#include "dw_mmc-pltfm.h"
+
+#define NUM_PINS(x)                    (x + 2)
+
+#define SDMMC_CLKSEL                   0x09C
+#define SDMMC_CLKSEL_CCLK_SAMPLE(x)    (((x) & 7) << 0)
+#define SDMMC_CLKSEL_CCLK_DRIVE(x)     (((x) & 7) << 16)
+#define SDMMC_CLKSEL_CCLK_DIVIDER(x)   (((x) & 7) << 24)
+#define SDMMC_CLKSEL_GET_DRV_WD3(x)    (((x) >> 16) & 0x7)
+#define SDMMC_CLKSEL_TIMING(x, y, z)   (SDMMC_CLKSEL_CCLK_SAMPLE(x) |  \
+                                       SDMMC_CLKSEL_CCLK_DRIVE(y) |    \
+                                       SDMMC_CLKSEL_CCLK_DIVIDER(z))
+
+#define SDMMC_CMD_USE_HOLD_REG         BIT(29)
+
+#define EXYNOS4210_FIXED_CIU_CLK_DIV   2
+#define EXYNOS4412_FIXED_CIU_CLK_DIV   4
+
+/* Variations in Exynos specific dw-mshc controller */
+enum dw_mci_exynos_type {
+       DW_MCI_TYPE_EXYNOS4210,
+       DW_MCI_TYPE_EXYNOS4412,
+       DW_MCI_TYPE_EXYNOS5250,
+};
+
+/* Exynos implementation specific driver private data */
+struct dw_mci_exynos_priv_data {
+       enum dw_mci_exynos_type         ctrl_type;
+       u8                              ciu_div;
+       u32                             sdr_timing;
+       u32                             ddr_timing;
+};
+
+static struct dw_mci_exynos_compatible {
+       char                            *compatible;
+       enum dw_mci_exynos_type         ctrl_type;
+} exynos_compat[] = {
+       {
+               .compatible     = "samsung,exynos4210-dw-mshc",
+               .ctrl_type      = DW_MCI_TYPE_EXYNOS4210,
+       }, {
+               .compatible     = "samsung,exynos4412-dw-mshc",
+               .ctrl_type      = DW_MCI_TYPE_EXYNOS4412,
+       }, {
+               .compatible     = "samsung,exynos5250-dw-mshc",
+               .ctrl_type      = DW_MCI_TYPE_EXYNOS5250,
+       },
+};
+
+static int dw_mci_exynos_priv_init(struct dw_mci *host)
+{
+       struct dw_mci_exynos_priv_data *priv;
+       int idx;
+
+       priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv) {
+               dev_err(host->dev, "mem alloc failed for private data\n");
+               return -ENOMEM;
+       }
+
+       for (idx = 0; idx < ARRAY_SIZE(exynos_compat); idx++) {
+               if (of_device_is_compatible(host->dev->of_node,
+                                       exynos_compat[idx].compatible))
+                       priv->ctrl_type = exynos_compat[idx].ctrl_type;
+       }
+
+       host->priv = priv;
+       return 0;
+}
+
+static int dw_mci_exynos_setup_clock(struct dw_mci *host)
+{
+       struct dw_mci_exynos_priv_data *priv = host->priv;
+
+       if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS5250)
+               host->bus_hz /= (priv->ciu_div + 1);
+       else if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4412)
+               host->bus_hz /= EXYNOS4412_FIXED_CIU_CLK_DIV;
+       else if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4210)
+               host->bus_hz /= EXYNOS4210_FIXED_CIU_CLK_DIV;
+
+       return 0;
+}
+
+static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
+{
+       /*
+        * Exynos4412 and Exynos5250 extends the use of CMD register with the
+        * use of bit 29 (which is reserved on standard MSHC controllers) for
+        * optionally bypassing the HOLD register for command and data. The
+        * HOLD register should be bypassed in case there is no phase shift
+        * applied on CMD/DATA that is sent to the card.
+        */
+       if (SDMMC_CLKSEL_GET_DRV_WD3(mci_readl(host, CLKSEL)))
+               *cmdr |= SDMMC_CMD_USE_HOLD_REG;
+}
+
+static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
+{
+       struct dw_mci_exynos_priv_data *priv = host->priv;
+
+       if (ios->timing == MMC_TIMING_UHS_DDR50)
+               mci_writel(host, CLKSEL, priv->ddr_timing);
+       else
+               mci_writel(host, CLKSEL, priv->sdr_timing);
+}
+
+static int dw_mci_exynos_parse_dt(struct dw_mci *host)
+{
+       struct dw_mci_exynos_priv_data *priv = host->priv;
+       struct device_node *np = host->dev->of_node;
+       u32 timing[2];
+       u32 div = 0;
+       int ret;
+
+       of_property_read_u32(np, "samsung,dw-mshc-ciu-div", &div);
+       priv->ciu_div = div;
+
+       ret = of_property_read_u32_array(np,
+                       "samsung,dw-mshc-sdr-timing", timing, 2);
+       if (ret)
+               return ret;
+
+       priv->sdr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);
+
+       ret = of_property_read_u32_array(np,
+                       "samsung,dw-mshc-ddr-timing", timing, 2);
+       if (ret)
+               return ret;
+
+       priv->ddr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);
+       return 0;
+}
+
+static int dw_mci_exynos_setup_bus(struct dw_mci *host,
+                               struct device_node *slot_np, u8 bus_width)
+{
+       int idx, gpio, ret;
+
+       if (!slot_np)
+               return -EINVAL;
+
+       /* cmd + clock + bus-width pins */
+       for (idx = 0; idx < NUM_PINS(bus_width); idx++) {
+               gpio = of_get_gpio(slot_np, idx);
+               if (!gpio_is_valid(gpio)) {
+                       dev_err(host->dev, "invalid gpio: %d\n", gpio);
+                       return -EINVAL;
+               }
+
+               ret = devm_gpio_request(host->dev, gpio, "dw-mci-bus");
+               if (ret) {
+                       dev_err(host->dev, "gpio [%d] request failed\n", gpio);
+                       return -EBUSY;
+               }
+       }
+
+       gpio = of_get_named_gpio(slot_np, "wp-gpios", 0);
+       if (gpio_is_valid(gpio)) {
+               if (devm_gpio_request(host->dev, gpio, "dw-mci-wp"))
+                       dev_info(host->dev, "gpio [%d] request failed\n",
+                                               gpio);
+       } else {
+               dev_info(host->dev, "wp gpio not available");
+               host->pdata->quirks |= DW_MCI_QUIRK_NO_WRITE_PROTECT;
+       }
+
+       if (host->pdata->quirks & DW_MCI_QUIRK_BROKEN_CARD_DETECTION)
+               return 0;
+
+       gpio = of_get_named_gpio(slot_np, "samsung,cd-pinmux-gpio", 0);
+       if (gpio_is_valid(gpio)) {
+               if (devm_gpio_request(host->dev, gpio, "dw-mci-cd"))
+                       dev_err(host->dev, "gpio [%d] request failed\n", gpio);
+       } else {
+               dev_info(host->dev, "cd gpio not available");
+       }
+
+       return 0;
+}
+
+/* Exynos5250 controller specific capabilities */
+static unsigned long exynos5250_dwmmc_caps[4] = {
+       MMC_CAP_UHS_DDR50 | MMC_CAP_1_8V_DDR |
+               MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
+       MMC_CAP_CMD23,
+       MMC_CAP_CMD23,
+       MMC_CAP_CMD23,
+};
+
+static struct dw_mci_drv_data exynos5250_drv_data = {
+       .caps                   = exynos5250_dwmmc_caps,
+       .init                   = dw_mci_exynos_priv_init,
+       .setup_clock            = dw_mci_exynos_setup_clock,
+       .prepare_command        = dw_mci_exynos_prepare_command,
+       .set_ios                = dw_mci_exynos_set_ios,
+       .parse_dt               = dw_mci_exynos_parse_dt,
+       .setup_bus              = dw_mci_exynos_setup_bus,
+};
+
+static const struct of_device_id dw_mci_exynos_match[] = {
+       { .compatible = "samsung,exynos5250-dw-mshc",
+                       .data = (void *)&exynos5250_drv_data, },
+       {},
+};
+MODULE_DEVICE_TABLE(of, dw_mci_pltfm_match);
+
+int dw_mci_exynos_probe(struct platform_device *pdev)
+{
+       struct dw_mci_drv_data *drv_data;
+       const struct of_device_id *match;
+
+       match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node);
+       drv_data = match->data;
+       return dw_mci_pltfm_register(pdev, drv_data);
+}
+
+static struct platform_driver dw_mci_exynos_pltfm_driver = {
+       .probe          = dw_mci_exynos_probe,
+       .remove         = __exit_p(dw_mci_pltfm_remove),
+       .driver         = {
+               .name           = "dwmmc_exynos",
+               .of_match_table = of_match_ptr(dw_mci_exynos_match),
+               .pm             = &dw_mci_pltfm_pmops,
+       },
+};
+
+module_platform_driver(dw_mci_exynos_pltfm_driver);
+
+MODULE_DESCRIPTION("Samsung Specific DW-MSHC Driver Extension");
+MODULE_AUTHOR("Thomas Abraham <thomas.ab@samsung.com");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dwmmc-exynos");
index 6cb043e48953d8caec00d890882b8e66e055e5e3..7c6a1139d8faf9ad54af671c68cd81ea3dcebf2f 100644 (file)
@@ -227,7 +227,7 @@ struct dw_mci_board {
        u32 num_slots;
 
        u32 quirks; /* Workaround / Quirk flags */
-       unsigned int bus_hz; /* Bus speed */
+       unsigned int bus_hz; /* Clock speed at the cclk_in pad */
 
        unsigned int caps;      /* Capabilities */
        unsigned int caps2;     /* More capabilities */