/*
 *  linux/drivers/mmc/core/host.c
 *
 *  Copyright (C) 2003 Russell King, All Rights Reserved.
 *  Copyright (C) 2007-2008 Pierre Ossman
 *  Copyright (C) 2010 Linus Walleij
 *
 * 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.
 *
 *  MMC host class device management
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/pagemap.h>
#include <linux/export.h>
#include <linux/leds.h>
#include <linux/slab.h>

#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/slot-gpio.h>

#include "core.h"
#include "host.h"
#include "slot-gpio.h"
#include "pwrseq.h"

#define cls_dev_to_mmc_host(d)  container_of(d, struct mmc_host, class_dev)

static DEFINE_IDA(mmc_host_ida);
static DEFINE_SPINLOCK(mmc_host_lock);

static void mmc_host_classdev_release(struct device *dev)
{
        struct mmc_host *host = cls_dev_to_mmc_host(dev);
        spin_lock(&mmc_host_lock);
        ida_remove(&mmc_host_ida, host->index);
        spin_unlock(&mmc_host_lock);
        kfree(host);
}

static struct class mmc_host_class = {
        .name           = "mmc_host",
        .dev_release    = mmc_host_classdev_release,
};

int mmc_register_host_class(void)
{
        return class_register(&mmc_host_class);
}

void mmc_unregister_host_class(void)
{
        class_unregister(&mmc_host_class);
}

void mmc_retune_enable(struct mmc_host *host)
{
        host->can_retune = 1;
        if (host->retune_period)
                mod_timer(&host->retune_timer,
                          jiffies + host->retune_period * HZ);
}

/*
 * Pause re-tuning for a small set of operations.  The pause begins after the
 * next command and after first doing re-tuning.
 */
void mmc_retune_pause(struct mmc_host *host)
{
        if (!host->retune_paused) {
                host->retune_paused = 1;
                mmc_retune_needed(host);
                mmc_retune_hold(host);
        }
}
EXPORT_SYMBOL(mmc_retune_pause);

void mmc_retune_unpause(struct mmc_host *host)
{
        if (host->retune_paused) {
                host->retune_paused = 0;
                mmc_retune_release(host);
        }
}
EXPORT_SYMBOL(mmc_retune_unpause);

void mmc_retune_disable(struct mmc_host *host)
{
        mmc_retune_unpause(host);
        host->can_retune = 0;
        del_timer_sync(&host->retune_timer);
        host->retune_now = 0;
        host->need_retune = 0;
}

void mmc_retune_timer_stop(struct mmc_host *host)
{
        del_timer_sync(&host->retune_timer);
}
EXPORT_SYMBOL(mmc_retune_timer_stop);

void mmc_retune_hold(struct mmc_host *host)
{
        if (!host->hold_retune)
                host->retune_now = 1;
        host->hold_retune += 1;
}

void mmc_retune_release(struct mmc_host *host)
{
        if (host->hold_retune)
                host->hold_retune -= 1;
        else
                WARN_ON(1);
}

int mmc_retune(struct mmc_host *host)
{
        bool return_to_hs400 = false;
        int err;

        if (host->retune_now)
                host->retune_now = 0;
        else
                return 0;

        if (!host->need_retune || host->doing_retune || !host->card)
                return 0;

        host->need_retune = 0;

        host->doing_retune = 1;

        if (host->ios.timing == MMC_TIMING_MMC_HS400) {
                err = mmc_hs400_to_hs200(host->card);
                if (err)
                        goto out;

                return_to_hs400 = true;

                if (host->ops->prepare_hs400_tuning)
                        host->ops->prepare_hs400_tuning(host, &host->ios);
        }

        err = mmc_execute_tuning(host->card);
        if (err)
                goto out;

        if (return_to_hs400)
                err = mmc_hs200_to_hs400(host->card);
out:
        host->doing_retune = 0;

        return err;
}

static void mmc_retune_timer(unsigned long data)
{
        struct mmc_host *host = (struct mmc_host *)data;

        mmc_retune_needed(host);
}

/**
 *      mmc_of_parse() - parse host's device-tree node
 *      @host: host whose node should be parsed.
 *
 * To keep the rest of the MMC subsystem unaware of whether DT has been
 * used to to instantiate and configure this host instance or not, we
 * parse the properties and set respective generic mmc-host flags and
 * parameters.
 */
int mmc_of_parse(struct mmc_host *host)
{
        struct device_node *np;
        u32 bus_width;
        int ret;
        bool cd_cap_invert, cd_gpio_invert = false;
        bool ro_cap_invert, ro_gpio_invert = false;

        if (!host->parent || !host->parent->of_node)
                return 0;

        np = host->parent->of_node;

        /* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
        if (of_property_read_u32(np, "bus-width", &bus_width) < 0) {
                dev_dbg(host->parent,
                        "\"bus-width\" property is missing, assuming 1 bit.\n");
                bus_width = 1;
        }

        switch (bus_width) {
        case 8:
                host->caps |= MMC_CAP_8_BIT_DATA;
                /* Hosts capable of 8-bit transfers can also do 4 bits */
        case 4:
                host->caps |= MMC_CAP_4_BIT_DATA;
                break;
        case 1:
                break;
        default:
                dev_err(host->parent,
                        "Invalid \"bus-width\" value %u!\n", bus_width);
                return -EINVAL;
        }

        /* f_max is obtained from the optional "max-frequency" property */
        of_property_read_u32(np, "max-frequency", &host->f_max);

        /*
         * Configure CD and WP pins. They are both by default active low to
         * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the
         * mmc-gpio helpers are used to attach, configure and use them. If
         * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH
         * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the
         * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability
         * is set. If the "non-removable" property is found, the
         * MMC_CAP_NONREMOVABLE capability is set and no card-detection
         * configuration is performed.
         */

        /* Parse Card Detection */
        if (of_property_read_bool(np, "non-removable")) {
                host->caps |= MMC_CAP_NONREMOVABLE;
        } else {
                cd_cap_invert = of_property_read_bool(np, "cd-inverted");

                if (of_property_read_bool(np, "broken-cd"))
                        host->caps |= MMC_CAP_NEEDS_POLL;

                ret = mmc_gpiod_request_cd(host, "cd", 0, true,
                                           0, &cd_gpio_invert);
                if (!ret)
                        dev_info(host->parent, "Got CD GPIO\n");
                else if (ret != -ENOENT && ret != -ENOSYS)
                        return ret;

                /*
                 * There are two ways to flag that the CD line is inverted:
                 * through the cd-inverted flag and by the GPIO line itself
                 * being inverted from the GPIO subsystem. This is a leftover
                 * from the times when the GPIO subsystem did not make it
                 * possible to flag a line as inverted.
                 *
                 * If the capability on the host AND the GPIO line are
                 * both inverted, the end result is that the CD line is
                 * not inverted.
                 */
                if (cd_cap_invert ^ cd_gpio_invert)
                        host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
        }

        /* Parse Write Protection */
        ro_cap_invert = of_property_read_bool(np, "wp-inverted");

        ret = mmc_gpiod_request_ro(host, "wp", 0, false, 0, &ro_gpio_invert);
        if (!ret)
                dev_info(host->parent, "Got WP GPIO\n");
        else if (ret != -ENOENT && ret != -ENOSYS)
                return ret;

        if (of_property_read_bool(np, "disable-wp"))
                host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;

        /* See the comment on CD inversion above */
        if (ro_cap_invert ^ ro_gpio_invert)
                host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;

        if (of_property_read_bool(np, "cap-sd-highspeed"))
                host->caps |= MMC_CAP_SD_HIGHSPEED;
        if (of_property_read_bool(np, "cap-mmc-highspeed"))
                host->caps |= MMC_CAP_MMC_HIGHSPEED;
        if (of_property_read_bool(np, "sd-uhs-sdr12"))
                host->caps |= MMC_CAP_UHS_SDR12;
        if (of_property_read_bool(np, "sd-uhs-sdr25"))
                host->caps |= MMC_CAP_UHS_SDR25;
        if (of_property_read_bool(np, "sd-uhs-sdr50"))
                host->caps |= MMC_CAP_UHS_SDR50;
        if (of_property_read_bool(np, "sd-uhs-sdr104"))
                host->caps |= MMC_CAP_UHS_SDR104;
        if (of_property_read_bool(np, "sd-uhs-ddr50"))
                host->caps |= MMC_CAP_UHS_DDR50;
        if (of_property_read_bool(np, "cap-power-off-card"))
                host->caps |= MMC_CAP_POWER_OFF_CARD;
        if (of_property_read_bool(np, "cap-mmc-hw-reset"))
                host->caps |= MMC_CAP_HW_RESET;
        if (of_property_read_bool(np, "cap-sdio-irq"))
                host->caps |= MMC_CAP_SDIO_IRQ;
        if (of_property_read_bool(np, "full-pwr-cycle"))
                host->caps2 |= MMC_CAP2_FULL_PWR_CYCLE;
        if (of_property_read_bool(np, "keep-power-in-suspend"))
                host->pm_caps |= MMC_PM_KEEP_POWER;
        if (of_property_read_bool(np, "wakeup-source") ||
            of_property_read_bool(np, "enable-sdio-wakeup")) /* legacy */
                host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
        if (of_property_read_bool(np, "mmc-ddr-1_8v"))
                host->caps |= MMC_CAP_1_8V_DDR;
        if (of_property_read_bool(np, "mmc-ddr-1_2v"))
                host->caps |= MMC_CAP_1_2V_DDR;
        if (of_property_read_bool(np, "mmc-hs200-1_8v"))
                host->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
        if (of_property_read_bool(np, "mmc-hs200-1_2v"))
                host->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
        if (of_property_read_bool(np, "mmc-hs400-1_8v"))
                host->caps2 |= MMC_CAP2_HS400_1_8V | MMC_CAP2_HS200_1_8V_SDR;
        if (of_property_read_bool(np, "mmc-hs400-1_2v"))
                host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR;
        if (of_property_read_bool(np, "mmc-hs400-enhanced-strobe"))
                host->caps2 |= MMC_CAP2_HS400_ES;
        if (of_property_read_bool(np, "no-sdio"))
                host->caps2 |= MMC_CAP2_NO_SDIO;
        if (of_property_read_bool(np, "no-sd"))
                host->caps2 |= MMC_CAP2_NO_SD;
        if (of_property_read_bool(np, "no-mmc"))
                host->caps2 |= MMC_CAP2_NO_MMC;

        host->dsr_req = !of_property_read_u32(np, "dsr", &host->dsr);
        if (host->dsr_req && (host->dsr & ~0xffff)) {
                dev_err(host->parent,
                        "device tree specified broken value for DSR: 0x%x, ignoring\n",
                        host->dsr);
                host->dsr_req = 0;
        }

        return mmc_pwrseq_alloc(host);
}

EXPORT_SYMBOL(mmc_of_parse);

/**
 *      mmc_alloc_host - initialise the per-host structure.
 *      @extra: sizeof private data structure
 *      @dev: pointer to host device model structure
 *
 *      Initialise the per-host structure.
 */
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
        int err;
        struct mmc_host *host;

        host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
        if (!host)
                return NULL;

        /* scanning will be enabled when we're ready */
        host->rescan_disable = 1;

again:
        if (!ida_pre_get(&mmc_host_ida, GFP_KERNEL)) {
                kfree(host);
                return NULL;
        }

        spin_lock(&mmc_host_lock);
        err = ida_get_new(&mmc_host_ida, &host->index);
        spin_unlock(&mmc_host_lock);

        if (err == -EAGAIN) {
                goto again;
        } else if (err) {
                kfree(host);
                return NULL;
        }

        dev_set_name(&host->class_dev, "mmc%d", host->index);

        host->parent = dev;
        host->class_dev.parent = dev;
        host->class_dev.class = &mmc_host_class;
        device_initialize(&host->class_dev);
        device_enable_async_suspend(&host->class_dev);

        if (mmc_gpio_alloc(host)) {
                put_device(&host->class_dev);
                return NULL;
        }

        spin_lock_init(&host->lock);
        init_waitqueue_head(&host->wq);
        INIT_DELAYED_WORK(&host->detect, mmc_rescan);
        setup_timer(&host->retune_timer, mmc_retune_timer, (unsigned long)host);

        /*
         * By default, hosts do not support SGIO or large requests.
         * They have to set these according to their abilities.
         */
        host->max_segs = 1;
        host->max_seg_size = PAGE_SIZE;

        host->max_req_size = PAGE_SIZE;
        host->max_blk_size = 512;
        host->max_blk_count = PAGE_SIZE / 512;

        return host;
}

EXPORT_SYMBOL(mmc_alloc_host);

/**
 *      mmc_add_host - initialise host hardware
 *      @host: mmc host
 *
 *      Register the host with the driver model. The host must be
 *      prepared to start servicing requests before this function
 *      completes.
 */
int mmc_add_host(struct mmc_host *host)
{
        int err;

        WARN_ON((host->caps & MMC_CAP_SDIO_IRQ) &&
                !host->ops->enable_sdio_irq);

        err = device_add(&host->class_dev);
        if (err)
                return err;

        led_trigger_register_simple(dev_name(&host->class_dev), &host->led);

#ifdef CONFIG_DEBUG_FS
        mmc_add_host_debugfs(host);
#endif

        mmc_start_host(host);
        mmc_register_pm_notifier(host);

        return 0;
}

EXPORT_SYMBOL(mmc_add_host);

/**
 *      mmc_remove_host - remove host hardware
 *      @host: mmc host
 *
 *      Unregister and remove all cards associated with this host,
 *      and power down the MMC bus. No new requests will be issued
 *      after this function has returned.
 */
void mmc_remove_host(struct mmc_host *host)
{
        mmc_unregister_pm_notifier(host);
        mmc_stop_host(host);

#ifdef CONFIG_DEBUG_FS
        mmc_remove_host_debugfs(host);
#endif

        device_del(&host->class_dev);

        led_trigger_unregister_simple(host->led);
}

EXPORT_SYMBOL(mmc_remove_host);

/**
 *      mmc_free_host - free the host structure
 *      @host: mmc host
 *
 *      Free the host once all references to it have been dropped.
 */
void mmc_free_host(struct mmc_host *host)
{
        mmc_pwrseq_free(host);
        put_device(&host->class_dev);
}

EXPORT_SYMBOL(mmc_free_host);