Subject: [PATCH 5/5] mmc: dw_mmc: Add support DW SD/MMC driver on SOCFPGA

From: [email-masked] (Jaehoon Chung)
Date: Wed, 15 May 2013 13:28:16 +0900

On 05/15/2013 07:52 AM, dinguyen at altera.com wrote:
> From: Dinh Nguyen <[email-masked]>
> 
> Add platform specific functionality for the DW SD/MMC driver for
> SoCFPGA. Move SDMMC_CMD_USE_HOLD_REG to dw_mmc.h so other platforms
> can use this define.
> 
> Signed-off-by: Dinh Nguyen <[email-masked]>
> CC: Seungwon Jeon <[email-masked]>
> CC: Jaehoon Chung <[email-masked]>
> CC: Arnd Bergmann <[email-masked]>
> CC: Olof Johansson <[email-masked]>
> CC: Pavel Machek <[email-masked]>
> CC: linux-mmc at vger.kernel.org
> ---
>  drivers/mmc/host/Kconfig          |    8 +++
>  drivers/mmc/host/Makefile         |    1 +
>  drivers/mmc/host/dw_mmc-exynos.c  |    2 -
>  drivers/mmc/host/dw_mmc-socfpga.c |  141 +++++++++++++++++++++++++++++++++++++
>  drivers/mmc/host/dw_mmc.h         |    1 +
>  5 files changed, 151 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/mmc/host/dw_mmc-socfpga.c
> 
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 9ab8f8d..1be2289 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -556,6 +556,14 @@ config MMC_DW_EXYNOS
>  	  Synopsys DesignWare Memory Card Interface driver. Select this option
>  	  for platforms based on Exynos4 and Exynos5 SoC's.
>  
> +config MMC_DW_SOCFPGA
SOCFPGA? I think good that should be changed more generic.
> +	tristate "SOCFPGA specific extensions for Synopsys DW Memory Card Interface"
> +	depends on MMC_DW
> +	select MMC_DW_PLTFM
> +	help
> +	  This selects support for Altera SoCFPGA specific extensions to the
> +	  Synopsys DesignWare Memory Card Interface driver.
> +
>  config MMC_DW_PCI
>  	tristate "Synopsys Designware MCI support on PCI bus"
>  	depends on MMC_DW && PCI
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index cd32280..67718c1 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -42,6 +42,7 @@ 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-$(CONFIG_MMC_DW_SOCFPGA)	+= dw_mmc-socfpga.o
>  obj-$(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
> index f013e7e..866edef 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.c
> +++ b/drivers/mmc/host/dw_mmc-exynos.c
> @@ -31,8 +31,6 @@
>  					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
>  
> diff --git a/drivers/mmc/host/dw_mmc-socfpga.c b/drivers/mmc/host/dw_mmc-socfpga.c
> new file mode 100644
> index 0000000..7eb3163
> --- /dev/null
> +++ b/drivers/mmc/host/dw_mmc-socfpga.c
> @@ -0,0 +1,141 @@
> +/*
> + * Altera SoCFPGA Specific Extensions for Synopsys DW Multimedia Card Interface driver
> + *
> + *  Copyright (C) 2012, Samsung Electronics Co., Ltd.
> + *  Copyright (C) 2013 Altera Corporation
> + *
> + * 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.
> + *
> + * Taken from dw_mmc_exynos.c
> + */
> +#include <linux/clk.h>
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/dw_mmc.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +
> +#include "dw_mmc.h"
> +#include "dw_mmc-pltfm.h"
> +
> +#define SYSMGR_SDMMCGRP_CTRL_OFFSET		0x108
Is it vendor specific register offset?
> +#define DRV_CLK_PHASE_SHIFT_SEL_MASK	0x7
> +#define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel)		\
> +	((((drvsel) << 0) & 0x7) | (((smplsel) << 3) & 0x38))
Change more readable. ((drvsel & 0x7) << 0 | (smplsel & 0x7) << 3)?
> +
> +extern void __iomem *sys_manager_base_addr;
> +
> +/* SOCFPGA implementation specific driver private data */
> +struct dw_mci_socfpga_priv_data {
> +	u8	ciu_div;
> +	u32	hs_timing;
> +};
> +
> +static int dw_mci_socfpga_priv_init(struct dw_mci *host)
> +{
> +	struct dw_mci_socfpga_priv_data *priv;
> +	struct device *dev = host->dev;
> +	int pwr_en;
> +
> +	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv) {
> +		dev_err(host->dev, "mem alloc failed for private data\n");
> +		return -ENOMEM;
> +	}
> +
> +	host->priv = priv;
> +
> +	if (of_property_read_u32(dev->of_node, "pwr-en", &pwr_en)) {
> +		dev_info(dev, "couldn't determine pwr-en, assuming pwr-en = 0\n");
> +		pwr_en = 0;
> +	}
> +
> +	/* Set PWREN bit */
> +	mci_writel(host, PWREN, pwr_en);
What is this setting? In dw-mmc.c, PWREN register should be set.
> +
> +	return 0;
> +}
> +
> +static int dw_mci_socfpga_setup_clock(struct dw_mci *host)
> +{
> +	struct dw_mci_socfpga_priv_data *priv = host->priv;
> +
> +	clk_disable(host->ciu_clk);
> +	writel(priv->hs_timing, sys_manager_base_addr +
> +		SYSMGR_SDMMCGRP_CTRL_OFFSET);
> +	clk_enable(host->ciu_clk);
Why do you use the clk_disable/enable at this point?
> +
> +	host->bus_hz /= priv->ciu_div;
Didn't consider the "divide by zero"?
> +	return 0;
> +}
> +
> +static void dw_mci_socfpga_prepare_command(struct dw_mci *host, u32 *cmdr)
> +{
> +	struct dw_mci_socfpga_priv_data *priv = host->priv;
> +
> +	if (priv->hs_timing & DRV_CLK_PHASE_SHIFT_SEL_MASK)
> +		*cmdr |= SDMMC_CMD_USE_HOLD_REG;
> +}
> +
> +static int dw_mci_socfpga_parse_dt(struct dw_mci *host)
> +{
> +	struct dw_mci_socfpga_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, "altr,dw-mshc-ciu-div", &div);
> +	priv->ciu_div = div;
> +
> +	ret = of_property_read_u32_array(np,
> +			"altr,dw-mshc-sdr-timing", timing, 2);
> +	if (ret)
> +		return ret;
> +
> +	priv->hs_timing = SYSMGR_SDMMC_CTRL_SET(timing[0], timing[1]);
> +	return 0;
> +}
> +
> +static const struct dw_mci_drv_data socfpga_drv_data = {
> +	.init			= dw_mci_socfpga_priv_init,
> +	.setup_clock		= dw_mci_socfpga_setup_clock,
> +	.prepare_command	= dw_mci_socfpga_prepare_command,
> +	.parse_dt		= dw_mci_socfpga_parse_dt,
> +};
> +
> +static const struct of_device_id dw_mci_socfpga_match[] = {
> +	{ .compatible = "altr,socfpga-dw-mshc",
> +			.data = &socfpga_drv_data, },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, dw_mci_socfpga_match);
> +
> +int dw_mci_socfpga_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_socfpga_match, pdev->dev.of_node);
> +	drv_data = match->data;
> +	return dw_mci_pltfm_register(pdev, drv_data);
> +}
> +
> +static struct platform_driver dw_mci_socfpga_pltfm_driver = {
> +	.probe		= dw_mci_socfpga_probe,
> +	.remove		= __exit_p(dw_mci_pltfm_remove),
> +	.driver		= {
> +		.name		= "dwmmc_socfpga",
> +		.of_match_table	= of_match_ptr(dw_mci_socfpga_match),
> +		.pm		= &dw_mci_pltfm_pmops,
> +	},
> +};
> +
> +module_platform_driver(dw_mci_socfpga_pltfm_driver);
> +
> +MODULE_DESCRIPTION("Altera SOCFPGA Specific DW-MSHC Driver Extension");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:dwmmc-socfpga");
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 0b74189..3700cb2 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -111,6 +111,7 @@
>  #define SDMMC_INT_ERROR			0xbfc2
>  /* Command register defines */
>  #define SDMMC_CMD_START			BIT(31)
> +#define SDMMC_CMD_USE_HOLD_REG	BIT(29)
>  #define SDMMC_CMD_CCS_EXP		BIT(23)
>  #define SDMMC_CMD_CEATA_RD		BIT(22)
>  #define SDMMC_CMD_UPD_CLK		BIT(21)
>