/*
 * Copyright (C) 2010 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/module.h>

#include <asm/gpio.h>

#include <mach/gpio-tegra.h>
#include <mach/sdhci.h>

#include "sdhci-pltfm.h"

static u32 tegra_sdhci_readl(struct sdhci_host *host, int reg)
{
	u32 val;

	if (unlikely(reg == SDHCI_PRESENT_STATE)) {
		/* Use wp_gpio here instead? */
		val = readl(host->ioaddr + reg);
		return val | SDHCI_WRITE_PROTECT;
	}

	return readl(host->ioaddr + reg);
}

static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
{
	if (unlikely(reg == SDHCI_HOST_VERSION)) {
		/* Erratum: Version register is invalid in HW. */
		return SDHCI_SPEC_200;
	}

	return readw(host->ioaddr + reg);
}

static void tegra_sdhci_writel(struct sdhci_host *host, u32 val, int reg)
{
	/* Seems like we're getting spurious timeout and crc errors, so
	 * disable signalling of them. In case of real errors software
	 * timers should take care of eventually detecting them.
	 */
	if (unlikely(reg == SDHCI_SIGNAL_ENABLE))
		val &= ~(SDHCI_INT_TIMEOUT|SDHCI_INT_CRC);

	writel(val, host->ioaddr + reg);

	if (unlikely(reg == SDHCI_INT_ENABLE)) {
		/* Erratum: Must enable block gap interrupt detection */
		u8 gap_ctrl = readb(host->ioaddr + SDHCI_BLOCK_GAP_CONTROL);
		if (val & SDHCI_INT_CARD_INT)
			gap_ctrl |= 0x8;
		else
			gap_ctrl &= ~0x8;
		writeb(gap_ctrl, host->ioaddr + SDHCI_BLOCK_GAP_CONTROL);
	}
}

static unsigned int tegra_sdhci_get_ro(struct sdhci_host *sdhci)
{
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(sdhci);
	struct tegra_sdhci_platform_data *plat = pltfm_host->priv;

	if (!gpio_is_valid(plat->wp_gpio))
		return -1;

	return gpio_get_value(plat->wp_gpio);
}

static irqreturn_t carddetect_irq(int irq, void *data)
{
	struct sdhci_host *sdhost = (struct sdhci_host *)data;

	tasklet_schedule(&sdhost->card_tasklet);
	return IRQ_HANDLED;
};

static int tegra_sdhci_8bit(struct sdhci_host *host, int bus_width)
{
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct tegra_sdhci_platform_data *plat = pltfm_host->priv;
	u32 ctrl;

	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
	if (plat->is_8bit && bus_width == MMC_BUS_WIDTH_8) {
		ctrl &= ~SDHCI_CTRL_4BITBUS;
		ctrl |= SDHCI_CTRL_8BITBUS;
	} else {
		ctrl &= ~SDHCI_CTRL_8BITBUS;
		if (bus_width == MMC_BUS_WIDTH_4)
			ctrl |= SDHCI_CTRL_4BITBUS;
		else
			ctrl &= ~SDHCI_CTRL_4BITBUS;
	}
	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
	return 0;
}

static struct sdhci_ops tegra_sdhci_ops = {
	.get_ro     = tegra_sdhci_get_ro,
	.read_l     = tegra_sdhci_readl,
	.read_w     = tegra_sdhci_readw,
	.write_l    = tegra_sdhci_writel,
	.platform_8bit_width = tegra_sdhci_8bit,
};

static struct sdhci_pltfm_data sdhci_tegra_pdata = {
	.quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
		  SDHCI_QUIRK_SINGLE_POWER_WRITE |
		  SDHCI_QUIRK_NO_HISPD_BIT |
		  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC,
	.ops  = &tegra_sdhci_ops,
};

static const struct of_device_id sdhci_tegra_dt_match[] __devinitdata = {
	{ .compatible = "nvidia,tegra20-sdhci", },
	{}
};
MODULE_DEVICE_TABLE(of, sdhci_dt_ids);

static struct tegra_sdhci_platform_data * __devinit sdhci_tegra_dt_parse_pdata(
						struct platform_device *pdev)
{
	struct tegra_sdhci_platform_data *plat;
	struct device_node *np = pdev->dev.of_node;

	if (!np)
		return NULL;

	plat = devm_kzalloc(&pdev->dev, sizeof(*plat), GFP_KERNEL);
	if (!plat) {
		dev_err(&pdev->dev, "Can't allocate platform data\n");
		return NULL;
	}

	plat->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
	plat->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
	plat->power_gpio = of_get_named_gpio(np, "power-gpios", 0);
	if (of_find_property(np, "support-8bit", NULL))
		plat->is_8bit = 1;

	return plat;
}

static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
{
	struct sdhci_pltfm_host *pltfm_host;
	struct tegra_sdhci_platform_data *plat;
	struct sdhci_host *host;
	struct clk *clk;
	int rc;

	host = sdhci_pltfm_init(pdev, &sdhci_tegra_pdata);
	if (IS_ERR(host))
		return PTR_ERR(host);

	pltfm_host = sdhci_priv(host);

	plat = pdev->dev.platform_data;

	if (plat == NULL)
		plat = sdhci_tegra_dt_parse_pdata(pdev);

	if (plat == NULL) {
		dev_err(mmc_dev(host->mmc), "missing platform data\n");
		rc = -ENXIO;
		goto err_no_plat;
	}

	pltfm_host->priv = plat;

	if (gpio_is_valid(plat->power_gpio)) {
		rc = gpio_request(plat->power_gpio, "sdhci_power");
		if (rc) {
			dev_err(mmc_dev(host->mmc),
				"failed to allocate power gpio\n");
			goto err_power_req;
		}
		tegra_gpio_enable(plat->power_gpio);
		gpio_direction_output(plat->power_gpio, 1);
	}

	if (gpio_is_valid(plat->cd_gpio)) {
		rc = gpio_request(plat->cd_gpio, "sdhci_cd");
		if (rc) {
			dev_err(mmc_dev(host->mmc),
				"failed to allocate cd gpio\n");
			goto err_cd_req;
		}
		tegra_gpio_enable(plat->cd_gpio);
		gpio_direction_input(plat->cd_gpio);

		rc = request_irq(gpio_to_irq(plat->cd_gpio), carddetect_irq,
				 IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
				 mmc_hostname(host->mmc), host);

		if (rc)	{
			dev_err(mmc_dev(host->mmc), "request irq error\n");
			goto err_cd_irq_req;
		}

	}

	if (gpio_is_valid(plat->wp_gpio)) {
		rc = gpio_request(plat->wp_gpio, "sdhci_wp");
		if (rc) {
			dev_err(mmc_dev(host->mmc),
				"failed to allocate wp gpio\n");
			goto err_wp_req;
		}
		tegra_gpio_enable(plat->wp_gpio);
		gpio_direction_input(plat->wp_gpio);
	}

	clk = clk_get(mmc_dev(host->mmc), NULL);
	if (IS_ERR(clk)) {
		dev_err(mmc_dev(host->mmc), "clk err\n");
		rc = PTR_ERR(clk);
		goto err_clk_get;
	}
	clk_enable(clk);
	pltfm_host->clk = clk;

	host->mmc->pm_caps = plat->pm_flags;

	if (plat->is_8bit)
		host->mmc->caps |= MMC_CAP_8_BIT_DATA;

	rc = sdhci_add_host(host);
	if (rc)
		goto err_add_host;

	return 0;

err_add_host:
	clk_disable(pltfm_host->clk);
	clk_put(pltfm_host->clk);
err_clk_get:
	if (gpio_is_valid(plat->wp_gpio)) {
		tegra_gpio_disable(plat->wp_gpio);
		gpio_free(plat->wp_gpio);
	}
err_wp_req:
	if (gpio_is_valid(plat->cd_gpio))
		free_irq(gpio_to_irq(plat->cd_gpio), host);
err_cd_irq_req:
	if (gpio_is_valid(plat->cd_gpio)) {
		tegra_gpio_disable(plat->cd_gpio);
		gpio_free(plat->cd_gpio);
	}
err_cd_req:
	if (gpio_is_valid(plat->power_gpio)) {
		tegra_gpio_disable(plat->power_gpio);
		gpio_free(plat->power_gpio);
	}
err_power_req:
err_no_plat:
	sdhci_pltfm_free(pdev);
	return rc;
}

static int __devexit sdhci_tegra_remove(struct platform_device *pdev)
{
	struct sdhci_host *host = platform_get_drvdata(pdev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct tegra_sdhci_platform_data *plat = pltfm_host->priv;
	int dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff);

	sdhci_remove_host(host, dead);

	if (gpio_is_valid(plat->wp_gpio)) {
		tegra_gpio_disable(plat->wp_gpio);
		gpio_free(plat->wp_gpio);
	}

	if (gpio_is_valid(plat->cd_gpio)) {
		free_irq(gpio_to_irq(plat->cd_gpio), host);
		tegra_gpio_disable(plat->cd_gpio);
		gpio_free(plat->cd_gpio);
	}

	if (gpio_is_valid(plat->power_gpio)) {
		tegra_gpio_disable(plat->power_gpio);
		gpio_free(plat->power_gpio);
	}

	clk_disable(pltfm_host->clk);
	clk_put(pltfm_host->clk);

	sdhci_pltfm_free(pdev);

	return 0;
}

static struct platform_driver sdhci_tegra_driver = {
	.driver		= {
		.name	= "sdhci-tegra",
		.owner	= THIS_MODULE,
		.of_match_table = sdhci_tegra_dt_match,
		.pm	= SDHCI_PLTFM_PMOPS,
	},
	.probe		= sdhci_tegra_probe,
	.remove		= __devexit_p(sdhci_tegra_remove),
};

static int __init sdhci_tegra_init(void)
{
	return platform_driver_register(&sdhci_tegra_driver);
}
module_init(sdhci_tegra_init);

static void __exit sdhci_tegra_exit(void)
{
	platform_driver_unregister(&sdhci_tegra_driver);
}
module_exit(sdhci_tegra_exit);

MODULE_DESCRIPTION("SDHCI driver for Tegra");
MODULE_AUTHOR(" Google, Inc.");
MODULE_LICENSE("GPL v2");