source: src/linux/laguna/linux-3.1/drivers/mmc/host/sdhci-cns3xxx.c @ 17837

/*
 * SDHCI support for CNS3xxx SoC
 *
 * Copyright 2008 Cavium Networks
 * Copyright 2010 MontaVista Software, LLC.
 *
 * Authors: Scott Shu
 *          Anton Vorontsov <avorontsov@mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/mmc/host.h>
#include <mach/cns3xxx.h>
#include "sdhci-pltfm.h"

static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
{
        return 150000000;
}

static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
{
        struct device *dev = mmc_dev(host->mmc);
        int div = 1;
        u16 clk;
        unsigned long timeout;

        if (clock == host->clock)
                return;

        sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);

        if (clock == 0)
                goto out;

        while (host->max_clk / div > clock) {
                /*
                 * On CNS3xxx divider grows linearly up to 4, and then
                 * exponentially up to 256.
                 */
                if (div < 4)
                        div += 1;
                else if (div < 256)
                        div *= 2;
                else
                        break;
        }

        dev_dbg(dev, "desired SD clock: %d, actual: %d\n",
                clock, host->max_clk / div);

        /* Divide by 3 is special. */
        if (div != 3)
                div >>= 1;

        clk = div << SDHCI_DIVIDER_SHIFT;
        clk |= SDHCI_CLOCK_INT_EN;
        sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);

        timeout = 20;
        while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
                        & SDHCI_CLOCK_INT_STABLE)) {
                if (timeout == 0) {
                        dev_warn(dev, "clock is unstable");
                        break;
                }
                timeout--;
                mdelay(1);
        }

        clk |= SDHCI_CLOCK_CARD_EN;
        sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
out:
        host->clock = clock;
}

static struct sdhci_ops sdhci_cns3xxx_ops = {
        .get_max_clock  = sdhci_cns3xxx_get_max_clk,
        .set_clock      = sdhci_cns3xxx_set_clock,
};

static struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
        .ops = &sdhci_cns3xxx_ops,
        .quirks = SDHCI_QUIRK_BROKEN_DMA |
                  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
//                SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
                  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
                  SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
                  SDHCI_QUIRK_NONSTANDARD_CLOCK |
                  SDHCI_QUIRK_BROKEN_CARD_DETECTION,
};

static int __devinit sdhci_cns3xxx_probe(struct platform_device *pdev)
{
        return sdhci_pltfm_register(pdev, &sdhci_cns3xxx_pdata);
}

static int __devexit sdhci_cns3xxx_remove(struct platform_device *pdev)
{
        return sdhci_pltfm_unregister(pdev);
}

static struct platform_driver sdhci_cns3xxx_driver = {
        .driver         = {
                .name   = "sdhci-cns3xxx",
                .owner  = THIS_MODULE,
        },
        .probe          = sdhci_cns3xxx_probe,
        .remove         = __devexit_p(sdhci_cns3xxx_remove),
#ifdef CONFIG_PM
        .suspend        = sdhci_pltfm_suspend,
        .resume         = sdhci_pltfm_resume,
#endif
};

static int __init sdhci_cns3xxx_init(void)
{
        return platform_driver_register(&sdhci_cns3xxx_driver);
}
module_init(sdhci_cns3xxx_init);

static void __exit sdhci_cns3xxx_exit(void)
{
        platform_driver_unregister(&sdhci_cns3xxx_driver);
}
module_exit(sdhci_cns3xxx_exit);

MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
MODULE_AUTHOR("Scott Shu, "
              "Anton Vorontsov <avorontsov@mvista.com>");
MODULE_LICENSE("GPL v2");