/*
 * drivers/mmc/host/sdhci-msm.c - Qualcomm SDHCI Platform driver
 *
 * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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/module.h>
#include <linux/of_device.h>
#include <linux/regulator/consumer.h>
#include <linux/delay.h>

#include "sdhci-pltfm.h"

#define CORE_HC_MODE		0x78
#define HC_MODE_EN		0x1
#define CORE_POWER		0x0
#define CORE_SW_RST		BIT(7)


struct sdhci_msm_host {
	struct platform_device *pdev;
	void __iomem *core_mem;	/* MSM SDCC mapped address */
	struct clk *clk;	/* main SD/MMC bus clock */
	struct clk *pclk;	/* SDHC peripheral bus clock */
	struct clk *bus_clk;	/* SDHC bus voter clock */
	struct mmc_host *mmc;
	struct sdhci_pltfm_data sdhci_msm_pdata;
};

/* Platform specific tuning */
static int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
{
	/*
	 * Tuning is required for SDR104, HS200 and HS400 cards and if the clock
	 * frequency greater than 100MHz in those modes. The standard tuning
	 * procedure should not be executed, but a custom implementation will be
	 * added here instead.
	 */
	return 0;
}

static const struct of_device_id sdhci_msm_dt_match[] = {
	{ .compatible = "qcom,sdhci-msm-v4" },
	{},
};

MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);

static struct sdhci_ops sdhci_msm_ops = {
	.platform_execute_tuning = sdhci_msm_execute_tuning,
};

static int sdhci_msm_probe(struct platform_device *pdev)
{
	struct sdhci_host *host;
	struct sdhci_pltfm_host *pltfm_host;
	struct sdhci_msm_host *msm_host;
	struct resource *core_memres;
	int ret;
	u16 host_version;

	msm_host = devm_kzalloc(&pdev->dev, sizeof(*msm_host), GFP_KERNEL);
	if (!msm_host)
		return -ENOMEM;

	msm_host->sdhci_msm_pdata.ops = &sdhci_msm_ops;
	host = sdhci_pltfm_init(pdev, &msm_host->sdhci_msm_pdata, 0);
	if (IS_ERR(host))
		return PTR_ERR(host);

	pltfm_host = sdhci_priv(host);
	pltfm_host->priv = msm_host;
	msm_host->mmc = host->mmc;
	msm_host->pdev = pdev;

	ret = mmc_of_parse(host->mmc);
	if (ret)
		goto pltfm_free;

	sdhci_get_of_property(pdev);

	/* Setup SDCC bus voter clock. */
	msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
	if (!IS_ERR(msm_host->bus_clk)) {
		/* Vote for max. clk rate for max. performance */
		ret = clk_set_rate(msm_host->bus_clk, INT_MAX);
		if (ret)
			goto pltfm_free;
		ret = clk_prepare_enable(msm_host->bus_clk);
		if (ret)
			goto pltfm_free;
	}

	/* Setup main peripheral bus clock */
	msm_host->pclk = devm_clk_get(&pdev->dev, "iface");
	if (IS_ERR(msm_host->pclk)) {
		ret = PTR_ERR(msm_host->pclk);
		dev_err(&pdev->dev, "Perpheral clk setup failed (%d)\n", ret);
		goto bus_clk_disable;
	}

	ret = clk_prepare_enable(msm_host->pclk);
	if (ret)
		goto bus_clk_disable;

	/* Setup SDC MMC clock */
	msm_host->clk = devm_clk_get(&pdev->dev, "core");
	if (IS_ERR(msm_host->clk)) {
		ret = PTR_ERR(msm_host->clk);
		dev_err(&pdev->dev, "SDC MMC clk setup failed (%d)\n", ret);
		goto pclk_disable;
	}

	ret = clk_prepare_enable(msm_host->clk);
	if (ret)
		goto pclk_disable;

	core_memres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	msm_host->core_mem = devm_ioremap_resource(&pdev->dev, core_memres);

	if (IS_ERR(msm_host->core_mem)) {
		dev_err(&pdev->dev, "Failed to remap registers\n");
		ret = PTR_ERR(msm_host->core_mem);
		goto clk_disable;
	}

	/* Reset the core and Enable SDHC mode */
	writel_relaxed(readl_relaxed(msm_host->core_mem + CORE_POWER) |
		       CORE_SW_RST, msm_host->core_mem + CORE_POWER);

	/* SW reset can take upto 10HCLK + 15MCLK cycles. (min 40us) */
	usleep_range(1000, 5000);
	if (readl(msm_host->core_mem + CORE_POWER) & CORE_SW_RST) {
		dev_err(&pdev->dev, "Stuck in reset\n");
		ret = -ETIMEDOUT;
		goto clk_disable;
	}

	/* Set HC_MODE_EN bit in HC_MODE register */
	writel_relaxed(HC_MODE_EN, (msm_host->core_mem + CORE_HC_MODE));

	host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
	host->quirks |= SDHCI_QUIRK_SINGLE_POWER_WRITE;

	host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));
	dev_dbg(&pdev->dev, "Host Version: 0x%x Vendor Version 0x%x\n",
		host_version, ((host_version & SDHCI_VENDOR_VER_MASK) >>
			       SDHCI_VENDOR_VER_SHIFT));

	ret = sdhci_add_host(host);
	if (ret)
		goto clk_disable;

	return 0;

clk_disable:
	clk_disable_unprepare(msm_host->clk);
pclk_disable:
	clk_disable_unprepare(msm_host->pclk);
bus_clk_disable:
	if (!IS_ERR(msm_host->bus_clk))
		clk_disable_unprepare(msm_host->bus_clk);
pltfm_free:
	sdhci_pltfm_free(pdev);
	return ret;
}

static int sdhci_msm_remove(struct platform_device *pdev)
{
	struct sdhci_host *host = platform_get_drvdata(pdev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct sdhci_msm_host *msm_host = pltfm_host->priv;
	int dead = (readl_relaxed(host->ioaddr + SDHCI_INT_STATUS) ==
		    0xffffffff);

	sdhci_remove_host(host, dead);
	sdhci_pltfm_free(pdev);
	clk_disable_unprepare(msm_host->clk);
	clk_disable_unprepare(msm_host->pclk);
	if (!IS_ERR(msm_host->bus_clk))
		clk_disable_unprepare(msm_host->bus_clk);
	return 0;
}

static struct platform_driver sdhci_msm_driver = {
	.probe = sdhci_msm_probe,
	.remove = sdhci_msm_remove,
	.driver = {
		   .name = "sdhci_msm",
		   .owner = THIS_MODULE,
		   .of_match_table = sdhci_msm_dt_match,
	},
};

module_platform_driver(sdhci_msm_driver);

MODULE_DESCRIPTION("Qualcomm Secure Digital Host Controller Interface driver");
MODULE_LICENSE("GPL v2");