/*
 * 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/delay.h>
#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_device.h>
#include <linux/reset.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/gpio/consumer.h>

#include "sdhci-pltfm.h"

/* Tegra SDHOST controller vendor register definitions */
#define SDHCI_TEGRA_VENDOR_CLOCK_CTRL                   0x100
#define SDHCI_CLOCK_CTRL_TAP_MASK                       0x00ff0000
#define SDHCI_CLOCK_CTRL_TAP_SHIFT                      16
#define SDHCI_CLOCK_CTRL_SDR50_TUNING_OVERRIDE          BIT(5)
#define SDHCI_CLOCK_CTRL_PADPIPE_CLKEN_OVERRIDE         BIT(3)
#define SDHCI_CLOCK_CTRL_SPI_MODE_CLKEN_OVERRIDE        BIT(2)

#define SDHCI_TEGRA_VENDOR_MISC_CTRL            0x120
#define SDHCI_MISC_CTRL_ENABLE_SDR104           0x8
#define SDHCI_MISC_CTRL_ENABLE_SDR50            0x10
#define SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300   0x20
#define SDHCI_MISC_CTRL_ENABLE_DDR50            0x200

#define SDHCI_TEGRA_AUTO_CAL_CONFIG             0x1e4
#define SDHCI_AUTO_CAL_START                    BIT(31)
#define SDHCI_AUTO_CAL_ENABLE                   BIT(29)

#define NVQUIRK_FORCE_SDHCI_SPEC_200    BIT(0)
#define NVQUIRK_ENABLE_BLOCK_GAP_DET    BIT(1)
#define NVQUIRK_ENABLE_SDHCI_SPEC_300   BIT(2)
#define NVQUIRK_ENABLE_SDR50            BIT(3)
#define NVQUIRK_ENABLE_SDR104           BIT(4)
#define NVQUIRK_ENABLE_DDR50            BIT(5)
#define NVQUIRK_HAS_PADCALIB            BIT(6)

struct sdhci_tegra_soc_data {
        const struct sdhci_pltfm_data *pdata;
        u32 nvquirks;
};

struct sdhci_tegra {
        const struct sdhci_tegra_soc_data *soc_data;
        struct gpio_desc *power_gpio;
        bool ddr_signaling;
        bool pad_calib_required;

        struct reset_control *rst;
};

static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
        const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;

        if (unlikely((soc_data->nvquirks & NVQUIRK_FORCE_SDHCI_SPEC_200) &&
                        (reg == SDHCI_HOST_VERSION))) {
                /* Erratum: Version register is invalid in HW. */
                return SDHCI_SPEC_200;
        }

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

static void tegra_sdhci_writew(struct sdhci_host *host, u16 val, int reg)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);

        switch (reg) {
        case SDHCI_TRANSFER_MODE:
                /*
                 * Postpone this write, we must do it together with a
                 * command write that is down below.
                 */
                pltfm_host->xfer_mode_shadow = val;
                return;
        case SDHCI_COMMAND:
                writel((val << 16) | pltfm_host->xfer_mode_shadow,
                        host->ioaddr + SDHCI_TRANSFER_MODE);
                return;
        }

        writew(val, host->ioaddr + reg);
}

static void tegra_sdhci_writel(struct sdhci_host *host, u32 val, int reg)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
        const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;

        /* 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((soc_data->nvquirks & NVQUIRK_ENABLE_BLOCK_GAP_DET) &&
                        (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 *host)
{
        return mmc_gpio_get_ro(host->mmc);
}

static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
        const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;
        u32 misc_ctrl, clk_ctrl;

        sdhci_reset(host, mask);

        if (!(mask & SDHCI_RESET_ALL))
                return;

        misc_ctrl = sdhci_readl(host, SDHCI_TEGRA_VENDOR_MISC_CTRL);
        clk_ctrl = sdhci_readl(host, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);

        misc_ctrl &= ~(SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300 |
                       SDHCI_MISC_CTRL_ENABLE_SDR50 |
                       SDHCI_MISC_CTRL_ENABLE_DDR50 |
                       SDHCI_MISC_CTRL_ENABLE_SDR104);

        clk_ctrl &= ~SDHCI_CLOCK_CTRL_SPI_MODE_CLKEN_OVERRIDE;

        /*
         * If the board does not define a regulator for the SDHCI
         * IO voltage, then don't advertise support for UHS modes
         * even if the device supports it because the IO voltage
         * cannot be configured.
         */
        if (!IS_ERR(host->mmc->supply.vqmmc)) {
                /* Erratum: Enable SDHCI spec v3.00 support */
                if (soc_data->nvquirks & NVQUIRK_ENABLE_SDHCI_SPEC_300)
                        misc_ctrl |= SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300;
                /* Advertise UHS modes as supported by host */
                if (soc_data->nvquirks & NVQUIRK_ENABLE_SDR50)
                        misc_ctrl |= SDHCI_MISC_CTRL_ENABLE_SDR50;
                if (soc_data->nvquirks & NVQUIRK_ENABLE_DDR50)
                        misc_ctrl |= SDHCI_MISC_CTRL_ENABLE_DDR50;
                if (soc_data->nvquirks & NVQUIRK_ENABLE_SDR104)
                        misc_ctrl |= SDHCI_MISC_CTRL_ENABLE_SDR104;
                if (soc_data->nvquirks & SDHCI_MISC_CTRL_ENABLE_SDR50)
                        clk_ctrl |= SDHCI_CLOCK_CTRL_SDR50_TUNING_OVERRIDE;
        }

        sdhci_writel(host, misc_ctrl, SDHCI_TEGRA_VENDOR_MISC_CTRL);
        sdhci_writel(host, clk_ctrl, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);

        if (soc_data->nvquirks & NVQUIRK_HAS_PADCALIB)
                tegra_host->pad_calib_required = true;

        tegra_host->ddr_signaling = false;
}

static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
{
        u32 val;

        mdelay(1);

        val = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
        val |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
        sdhci_writel(host,val, SDHCI_TEGRA_AUTO_CAL_CONFIG);
}

static void tegra_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
        unsigned long host_clk;

        if (!clock)
                return sdhci_set_clock(host, clock);

        host_clk = tegra_host->ddr_signaling ? clock * 2 : clock;
        clk_set_rate(pltfm_host->clk, host_clk);
        host->max_clk = clk_get_rate(pltfm_host->clk);

        sdhci_set_clock(host, clock);

        if (tegra_host->pad_calib_required) {
                tegra_sdhci_pad_autocalib(host);
                tegra_host->pad_calib_required = false;
        }
}

static void tegra_sdhci_set_uhs_signaling(struct sdhci_host *host,
                                          unsigned timing)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);

        if (timing == MMC_TIMING_UHS_DDR50)
                tegra_host->ddr_signaling = true;

        sdhci_set_uhs_signaling(host, timing);
}

static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host *host)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);

        /*
         * DDR modes require the host to run at double the card frequency, so
         * the maximum rate we can support is half of the module input clock.
         */
        return clk_round_rate(pltfm_host->clk, UINT_MAX) / 2;
}

static void tegra_sdhci_set_tap(struct sdhci_host *host, unsigned int tap)
{
        u32 reg;

        reg = sdhci_readl(host, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
        reg &= ~SDHCI_CLOCK_CTRL_TAP_MASK;
        reg |= tap << SDHCI_CLOCK_CTRL_TAP_SHIFT;
        sdhci_writel(host, reg, SDHCI_TEGRA_VENDOR_CLOCK_CTRL);
}

static int tegra_sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
{
        unsigned int min, max;

        /*
         * Start search for minimum tap value at 10, as smaller values are
         * may wrongly be reported as working but fail at higher speeds,
         * according to the TRM.
         */
        min = 10;
        while (min < 255) {
                tegra_sdhci_set_tap(host, min);
                if (!mmc_send_tuning(host->mmc, opcode, NULL))
                        break;
                min++;
        }

        /* Find the maximum tap value that still passes. */
        max = min + 1;
        while (max < 255) {
                tegra_sdhci_set_tap(host, max);
                if (mmc_send_tuning(host->mmc, opcode, NULL)) {
                        max--;
                        break;
                }
                max++;
        }

        /* The TRM states the ideal tap value is at 75% in the passing range. */
        tegra_sdhci_set_tap(host, min + ((max - min) * 3 / 4));

        return mmc_send_tuning(host->mmc, opcode, NULL);
}

static void tegra_sdhci_voltage_switch(struct sdhci_host *host)
{
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
        const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;

        if (soc_data->nvquirks & NVQUIRK_HAS_PADCALIB)
                tegra_host->pad_calib_required = true;
}

static const struct sdhci_ops tegra_sdhci_ops = {
        .get_ro     = tegra_sdhci_get_ro,
        .read_w     = tegra_sdhci_readw,
        .write_l    = tegra_sdhci_writel,
        .set_clock  = tegra_sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .reset      = tegra_sdhci_reset,
        .platform_execute_tuning = tegra_sdhci_execute_tuning,
        .set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
        .voltage_switch = tegra_sdhci_voltage_switch,
        .get_max_clock = tegra_sdhci_get_max_clock,
};

static const struct sdhci_pltfm_data sdhci_tegra20_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .ops  = &tegra_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra20 = {
        .pdata = &sdhci_tegra20_pdata,
        .nvquirks = NVQUIRK_FORCE_SDHCI_SPEC_200 |
                    NVQUIRK_ENABLE_BLOCK_GAP_DET,
};

static const struct sdhci_pltfm_data sdhci_tegra30_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
        .ops  = &tegra_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra30 = {
        .pdata = &sdhci_tegra30_pdata,
        .nvquirks = NVQUIRK_ENABLE_SDHCI_SPEC_300 |
                    NVQUIRK_ENABLE_SDR50 |
                    NVQUIRK_ENABLE_SDR104 |
                    NVQUIRK_HAS_PADCALIB,
};

static const struct sdhci_ops tegra114_sdhci_ops = {
        .get_ro     = tegra_sdhci_get_ro,
        .read_w     = tegra_sdhci_readw,
        .write_w    = tegra_sdhci_writew,
        .write_l    = tegra_sdhci_writel,
        .set_clock  = tegra_sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .reset      = tegra_sdhci_reset,
        .platform_execute_tuning = tegra_sdhci_execute_tuning,
        .set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
        .voltage_switch = tegra_sdhci_voltage_switch,
        .get_max_clock = tegra_sdhci_get_max_clock,
};

static const struct sdhci_pltfm_data sdhci_tegra114_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
        .ops  = &tegra114_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra114 = {
        .pdata = &sdhci_tegra114_pdata,
};

static const struct sdhci_pltfm_data sdhci_tegra124_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
                   /*
                    * The TRM states that the SD/MMC controller found on
                    * Tegra124 can address 34 bits (the maximum supported by
                    * the Tegra memory controller), but tests show that DMA
                    * to or from above 4 GiB doesn't work. This is possibly
                    * caused by missing programming, though it's not obvious
                    * what sequence is required. Mark 64-bit DMA broken for
                    * now to fix this for existing users (e.g. Nyan boards).
                    */
                   SDHCI_QUIRK2_BROKEN_64_BIT_DMA,
        .ops  = &tegra114_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra124 = {
        .pdata = &sdhci_tegra124_pdata,
};

static const struct sdhci_pltfm_data sdhci_tegra210_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
        .ops  = &tegra114_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra210 = {
        .pdata = &sdhci_tegra210_pdata,
};

static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
        .quirks = SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
                  SDHCI_QUIRK_SINGLE_POWER_WRITE |
                  SDHCI_QUIRK_NO_HISPD_BIT |
                  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
        .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
                   /* SDHCI controllers on Tegra186 support 40-bit addressing.
                    * IOVA addresses are 48-bit wide on Tegra186.
                    * With 64-bit dma mask used for SDHCI, accesses can
                    * be broken. Disable 64-bit dma, which would fall back
                    * to 32-bit dma mask. Ideally 40-bit dma mask would work,
                    * But it is not supported as of now.
                    */
                   SDHCI_QUIRK2_BROKEN_64_BIT_DMA,
        .ops  = &tegra114_sdhci_ops,
};

static const struct sdhci_tegra_soc_data soc_data_tegra186 = {
        .pdata = &sdhci_tegra186_pdata,
};

static const struct of_device_id sdhci_tegra_dt_match[] = {
        { .compatible = "nvidia,tegra186-sdhci", .data = &soc_data_tegra186 },
        { .compatible = "nvidia,tegra210-sdhci", .data = &soc_data_tegra210 },
        { .compatible = "nvidia,tegra124-sdhci", .data = &soc_data_tegra124 },
        { .compatible = "nvidia,tegra114-sdhci", .data = &soc_data_tegra114 },
        { .compatible = "nvidia,tegra30-sdhci", .data = &soc_data_tegra30 },
        { .compatible = "nvidia,tegra20-sdhci", .data = &soc_data_tegra20 },
        {}
};
MODULE_DEVICE_TABLE(of, sdhci_tegra_dt_match);

static int sdhci_tegra_probe(struct platform_device *pdev)
{
        const struct of_device_id *match;
        const struct sdhci_tegra_soc_data *soc_data;
        struct sdhci_host *host;
        struct sdhci_pltfm_host *pltfm_host;
        struct sdhci_tegra *tegra_host;
        struct clk *clk;
        int rc;

        match = of_match_device(sdhci_tegra_dt_match, &pdev->dev);
        if (!match)
                return -EINVAL;
        soc_data = match->data;

        host = sdhci_pltfm_init(pdev, soc_data->pdata, sizeof(*tegra_host));
        if (IS_ERR(host))
                return PTR_ERR(host);
        pltfm_host = sdhci_priv(host);

        tegra_host = sdhci_pltfm_priv(pltfm_host);
        tegra_host->ddr_signaling = false;
        tegra_host->pad_calib_required = false;
        tegra_host->soc_data = soc_data;

        rc = mmc_of_parse(host->mmc);
        if (rc)
                goto err_parse_dt;

        if (tegra_host->soc_data->nvquirks & NVQUIRK_ENABLE_DDR50)
                host->mmc->caps |= MMC_CAP_1_8V_DDR;

        tegra_host->power_gpio = devm_gpiod_get_optional(&pdev->dev, "power",
                                                         GPIOD_OUT_HIGH);
        if (IS_ERR(tegra_host->power_gpio)) {
                rc = PTR_ERR(tegra_host->power_gpio);
                goto err_power_req;
        }

        clk = devm_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_prepare_enable(clk);
        pltfm_host->clk = clk;

        tegra_host->rst = devm_reset_control_get_exclusive(&pdev->dev,
                                                           "sdhci");
        if (IS_ERR(tegra_host->rst)) {
                rc = PTR_ERR(tegra_host->rst);
                dev_err(&pdev->dev, "failed to get reset control: %d\n", rc);
                goto err_rst_get;
        }

        rc = reset_control_assert(tegra_host->rst);
        if (rc)
                goto err_rst_get;

        usleep_range(2000, 4000);

        rc = reset_control_deassert(tegra_host->rst);
        if (rc)
                goto err_rst_get;

        usleep_range(2000, 4000);

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

        return 0;

err_add_host:
        reset_control_assert(tegra_host->rst);
err_rst_get:
        clk_disable_unprepare(pltfm_host->clk);
err_clk_get:
err_power_req:
err_parse_dt:
        sdhci_pltfm_free(pdev);
        return rc;
}

static int 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 sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);

        sdhci_remove_host(host, 0);

        reset_control_assert(tegra_host->rst);
        usleep_range(2000, 4000);
        clk_disable_unprepare(pltfm_host->clk);

        sdhci_pltfm_free(pdev);

        return 0;
}

static struct platform_driver sdhci_tegra_driver = {
        .driver         = {
                .name   = "sdhci-tegra",
                .of_match_table = sdhci_tegra_dt_match,
                .pm     = &sdhci_pltfm_pmops,
        },
        .probe          = sdhci_tegra_probe,
        .remove         = sdhci_tegra_remove,
};

module_platform_driver(sdhci_tegra_driver);

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