Commit c3665006 authored by Thomas Abraham's avatar Thomas Abraham Committed by Chris Ball
Browse files

mmc: dw_mmc: add support for exynos specific implementation of dw-mshc 



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: default avatarThomas Abraham <thomas.abraham@linaro.org>
Acked-by: default avatarWill Newton <will.newton@imgtec.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 800d78bf

Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt

0 → 100644
+87 −0
Original line number Diff line number Diff line 
* 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>;

		};

	};

drivers/mmc/host/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -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

drivers/mmc/host/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/mmc/host/dw_mmc-exynos.c

0 → 100644
+253 −0
Original line number Diff line number Diff line 
/*

 * 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");

include/linux/mmc/dw_mmc.h

+1 −1
Original line number Diff line number Diff line
@@ -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 */