/*
 *  Sony MemoryStick support
 *
 *  Copyright (C) 2007 Alex Dubov <oakad@yahoo.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.
 *
 * Special thanks to Carlos Corbacho for providing various MemoryStick cards
 * that made this driver possible.
 *
 */

#include <linux/memstick.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/slab.h>

#define DRIVER_NAME "memstick"

static unsigned int cmd_retries = 3;
module_param(cmd_retries, uint, 0644);

static struct workqueue_struct *workqueue;
static DEFINE_IDR(memstick_host_idr);
static DEFINE_SPINLOCK(memstick_host_lock);

static int memstick_dev_match(struct memstick_dev *card,
                              struct memstick_device_id *id)
{
        if (id->match_flags & MEMSTICK_MATCH_ALL) {
                if ((id->type == card->id.type)
                    && (id->category == card->id.category)
                    && (id->class == card->id.class))
                        return 1;
        }

        return 0;
}

static int memstick_bus_match(struct device *dev, struct device_driver *drv)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                 dev);
        struct memstick_driver *ms_drv = container_of(drv,
                                                      struct memstick_driver,
                                                      driver);
        struct memstick_device_id *ids = ms_drv->id_table;

        if (ids) {
                while (ids->match_flags) {
                        if (memstick_dev_match(card, ids))
                                return 1;
                        ++ids;
                }
        }
        return 0;
}

static int memstick_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                  dev);

        if (add_uevent_var(env, "MEMSTICK_TYPE=%02X", card->id.type))
                return -ENOMEM;

        if (add_uevent_var(env, "MEMSTICK_CATEGORY=%02X", card->id.category))
                return -ENOMEM;

        if (add_uevent_var(env, "MEMSTICK_CLASS=%02X", card->id.class))
                return -ENOMEM;

        return 0;
}

static int memstick_device_probe(struct device *dev)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                 dev);
        struct memstick_driver *drv = container_of(dev->driver,
                                                   struct memstick_driver,
                                                   driver);
        int rc = -ENODEV;

        if (dev->driver && drv->probe) {
                rc = drv->probe(card);
                if (!rc)
                        get_device(dev);
        }
        return rc;
}

static int memstick_device_remove(struct device *dev)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                  dev);
        struct memstick_driver *drv = container_of(dev->driver,
                                                   struct memstick_driver,
                                                   driver);

        if (dev->driver && drv->remove) {
                drv->remove(card);
                card->dev.driver = NULL;
        }

        put_device(dev);
        return 0;
}

#ifdef CONFIG_PM

static int memstick_device_suspend(struct device *dev, pm_message_t state)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                  dev);
        struct memstick_driver *drv = container_of(dev->driver,
                                                   struct memstick_driver,
                                                   driver);

        if (dev->driver && drv->suspend)
                return drv->suspend(card, state);
        return 0;
}

static int memstick_device_resume(struct device *dev)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                  dev);
        struct memstick_driver *drv = container_of(dev->driver,
                                                   struct memstick_driver,
                                                   driver);

        if (dev->driver && drv->resume)
                return drv->resume(card);
        return 0;
}

#else

#define memstick_device_suspend NULL
#define memstick_device_resume NULL

#endif /* CONFIG_PM */

#define MEMSTICK_ATTR(name, format)                                           \
static ssize_t name##_show(struct device *dev, struct device_attribute *attr, \
                            char *buf)                                        \
{                                                                             \
        struct memstick_dev *card = container_of(dev, struct memstick_dev,    \
                                                 dev);                        \
        return sprintf(buf, format, card->id.name);                           \
}

MEMSTICK_ATTR(type, "%02X");
MEMSTICK_ATTR(category, "%02X");
MEMSTICK_ATTR(class, "%02X");

#define MEMSTICK_ATTR_RO(name) __ATTR(name, S_IRUGO, name##_show, NULL)

static struct device_attribute memstick_dev_attrs[] = {
        MEMSTICK_ATTR_RO(type),
        MEMSTICK_ATTR_RO(category),
        MEMSTICK_ATTR_RO(class),
        __ATTR_NULL
};

static struct bus_type memstick_bus_type = {
        .name           = "memstick",
        .dev_attrs      = memstick_dev_attrs,
        .match          = memstick_bus_match,
        .uevent         = memstick_uevent,
        .probe          = memstick_device_probe,
        .remove         = memstick_device_remove,
        .suspend        = memstick_device_suspend,
        .resume         = memstick_device_resume
};

static void memstick_free(struct device *dev)
{
        struct memstick_host *host = container_of(dev, struct memstick_host,
                                                  dev);
        kfree(host);
}

static struct class memstick_host_class = {
        .name        = "memstick_host",
        .dev_release = memstick_free
};

static void memstick_free_card(struct device *dev)
{
        struct memstick_dev *card = container_of(dev, struct memstick_dev,
                                                 dev);
        kfree(card);
}

static int memstick_dummy_check(struct memstick_dev *card)
{
        return 0;
}

/**
 * memstick_detect_change - schedule media detection on memstick host
 * @host - host to use
 */
void memstick_detect_change(struct memstick_host *host)
{
        queue_work(workqueue, &host->media_checker);
}
EXPORT_SYMBOL(memstick_detect_change);

/**
 * memstick_next_req - called by host driver to obtain next request to process
 * @host - host to use
 * @mrq - pointer to stick the request to
 *
 * Host calls this function from idle state (*mrq == NULL) or after finishing
 * previous request (*mrq should point to it). If previous request was
 * unsuccessful, it is retried for predetermined number of times. Return value
 * of 0 means that new request was assigned to the host.
 */
int memstick_next_req(struct memstick_host *host, struct memstick_request **mrq)
{
        int rc = -ENXIO;

        if ((*mrq) && (*mrq)->error && host->retries) {
                (*mrq)->error = rc;
                host->retries--;
                return 0;
        }

        if (host->card && host->card->next_request)
                rc = host->card->next_request(host->card, mrq);

        if (!rc)
                host->retries = cmd_retries > 1 ? cmd_retries - 1 : 1;
        else
                *mrq = NULL;

        return rc;
}
EXPORT_SYMBOL(memstick_next_req);

/**
 * memstick_new_req - notify the host that some requests are pending
 * @host - host to use
 */
void memstick_new_req(struct memstick_host *host)
{
        if (host->card) {
                host->retries = cmd_retries;
                INIT_COMPLETION(host->card->mrq_complete);
                host->request(host);
        }
}
EXPORT_SYMBOL(memstick_new_req);

/**
 * memstick_init_req_sg - set request fields needed for bulk data transfer
 * @mrq - request to use
 * @tpc - memstick Transport Protocol Command
 * @sg - TPC argument
 */
void memstick_init_req_sg(struct memstick_request *mrq, unsigned char tpc,
                          const struct scatterlist *sg)
{
        mrq->tpc = tpc;
        if (tpc & 8)
                mrq->data_dir = WRITE;
        else
                mrq->data_dir = READ;

        mrq->sg = *sg;
        mrq->long_data = 1;

        if (tpc == MS_TPC_SET_CMD || tpc == MS_TPC_EX_SET_CMD)
                mrq->need_card_int = 1;
        else
                mrq->need_card_int = 0;
}
EXPORT_SYMBOL(memstick_init_req_sg);

/**
 * memstick_init_req - set request fields needed for short data transfer
 * @mrq - request to use
 * @tpc - memstick Transport Protocol Command
 * @buf - TPC argument buffer
 * @length - TPC argument size
 *
 * The intended use of this function (transfer of data items several bytes
 * in size) allows us to just copy the value between request structure and
 * user supplied buffer.
 */
void memstick_init_req(struct memstick_request *mrq, unsigned char tpc,
                       const void *buf, size_t length)
{
        mrq->tpc = tpc;
        if (tpc & 8)
                mrq->data_dir = WRITE;
        else
                mrq->data_dir = READ;

        mrq->data_len = length > sizeof(mrq->data) ? sizeof(mrq->data) : length;
        if (mrq->data_dir == WRITE)
                memcpy(mrq->data, buf, mrq->data_len);

        mrq->long_data = 0;

        if (tpc == MS_TPC_SET_CMD || tpc == MS_TPC_EX_SET_CMD)
                mrq->need_card_int = 1;
        else
                mrq->need_card_int = 0;
}
EXPORT_SYMBOL(memstick_init_req);

/*
 * Functions prefixed with "h_" are protocol callbacks. They can be called from
 * interrupt context. Return value of 0 means that request processing is still
 * ongoing, while special error value of -EAGAIN means that current request is
 * finished (and request processor should come back some time later).
 */

static int h_memstick_read_dev_id(struct memstick_dev *card,
                                  struct memstick_request **mrq)
{
        struct ms_id_register id_reg;

        if (!(*mrq)) {
                memstick_init_req(&card->current_mrq, MS_TPC_READ_REG, NULL,
                                  sizeof(struct ms_id_register));
                *mrq = &card->current_mrq;
                return 0;
        } else {
                if (!(*mrq)->error) {
                        memcpy(&id_reg, (*mrq)->data, sizeof(id_reg));
                        card->id.match_flags = MEMSTICK_MATCH_ALL;
                        card->id.type = id_reg.type;
                        card->id.category = id_reg.category;
                        card->id.class = id_reg.class;
                        dev_dbg(&card->dev, "if_mode = %02x\n", id_reg.if_mode);
                }
                complete(&card->mrq_complete);
                return -EAGAIN;
        }
}

static int h_memstick_set_rw_addr(struct memstick_dev *card,
                                  struct memstick_request **mrq)
{
        if (!(*mrq)) {
                memstick_init_req(&card->current_mrq, MS_TPC_SET_RW_REG_ADRS,
                                  (char *)&card->reg_addr,
                                  sizeof(card->reg_addr));
                *mrq = &card->current_mrq;
                return 0;
        } else {
                complete(&card->mrq_complete);
                return -EAGAIN;
        }
}

/**
 * memstick_set_rw_addr - issue SET_RW_REG_ADDR request and wait for it to
 *                        complete
 * @card - media device to use
 */
int memstick_set_rw_addr(struct memstick_dev *card)
{
        card->next_request = h_memstick_set_rw_addr;
        memstick_new_req(card->host);
        wait_for_completion(&card->mrq_complete);

        return card->current_mrq.error;
}
EXPORT_SYMBOL(memstick_set_rw_addr);

static struct memstick_dev *memstick_alloc_card(struct memstick_host *host)
{
        struct memstick_dev *card = kzalloc(sizeof(struct memstick_dev),
                                            GFP_KERNEL);
        struct memstick_dev *old_card = host->card;
        struct ms_id_register id_reg;

        if (card) {
                card->host = host;
                dev_set_name(&card->dev, "%s", dev_name(&host->dev));
                card->dev.parent = &host->dev;
                card->dev.bus = &memstick_bus_type;
                card->dev.release = memstick_free_card;
                card->check = memstick_dummy_check;

                card->reg_addr.r_offset = offsetof(struct ms_register, id);
                card->reg_addr.r_length = sizeof(id_reg);
                card->reg_addr.w_offset = offsetof(struct ms_register, id);
                card->reg_addr.w_length = sizeof(id_reg);

                init_completion(&card->mrq_complete);

                host->card = card;
                if (memstick_set_rw_addr(card))
                        goto err_out;

                card->next_request = h_memstick_read_dev_id;
                memstick_new_req(host);
                wait_for_completion(&card->mrq_complete);

                if (card->current_mrq.error)
                        goto err_out;
        }
        host->card = old_card;
        return card;
err_out:
        host->card = old_card;
        kfree(card);
        return NULL;
}

static int memstick_power_on(struct memstick_host *host)
{
        int rc = host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_ON);

        if (!rc)
                rc = host->set_param(host, MEMSTICK_INTERFACE, MEMSTICK_SERIAL);

        return rc;
}

static void memstick_check(struct work_struct *work)
{
        struct memstick_host *host = container_of(work, struct memstick_host,
                                                  media_checker);
        struct memstick_dev *card;

        dev_dbg(&host->dev, "memstick_check started\n");
        mutex_lock(&host->lock);
        if (!host->card) {
                if (memstick_power_on(host))
                        goto out_power_off;
        } else if (host->card->stop)
                host->card->stop(host->card);

        card = memstick_alloc_card(host);

        if (!card) {
                if (host->card) {
                        device_unregister(&host->card->dev);
                        host->card = NULL;
                }
        } else {
                dev_dbg(&host->dev, "new card %02x, %02x, %02x\n",
                        card->id.type, card->id.category, card->id.class);
                if (host->card) {
                        if (memstick_set_rw_addr(host->card)
                            || !memstick_dev_match(host->card, &card->id)
                            || !(host->card->check(host->card))) {
                                device_unregister(&host->card->dev);
                                host->card = NULL;
                        } else if (host->card->start)
                                host->card->start(host->card);
                }

                if (!host->card) {
                        host->card = card;
                        if (device_register(&card->dev)) {
                                put_device(&card->dev);
                                kfree(host->card);
                                host->card = NULL;
                        }
                } else
                        kfree(card);
        }

out_power_off:
        if (!host->card)
                host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF);

        mutex_unlock(&host->lock);
        dev_dbg(&host->dev, "memstick_check finished\n");
}

/**
 * memstick_alloc_host - allocate a memstick_host structure
 * @extra: size of the user private data to allocate
 * @dev: parent device of the host
 */
struct memstick_host *memstick_alloc_host(unsigned int extra,
                                          struct device *dev)
{
        struct memstick_host *host;

        host = kzalloc(sizeof(struct memstick_host) + extra, GFP_KERNEL);
        if (host) {
                mutex_init(&host->lock);
                INIT_WORK(&host->media_checker, memstick_check);
                host->dev.class = &memstick_host_class;
                host->dev.parent = dev;
                device_initialize(&host->dev);
        }
        return host;
}
EXPORT_SYMBOL(memstick_alloc_host);

/**
 * memstick_add_host - start request processing on memstick host
 * @host - host to use
 */
int memstick_add_host(struct memstick_host *host)
{
        int rc;

        while (1) {
                if (!idr_pre_get(&memstick_host_idr, GFP_KERNEL))
                        return -ENOMEM;

                spin_lock(&memstick_host_lock);
                rc = idr_get_new(&memstick_host_idr, host, &host->id);
                spin_unlock(&memstick_host_lock);
                if (!rc)
                        break;
                else if (rc != -EAGAIN)
                        return rc;
        }

        dev_set_name(&host->dev, "memstick%u", host->id);

        rc = device_add(&host->dev);
        if (rc) {
                spin_lock(&memstick_host_lock);
                idr_remove(&memstick_host_idr, host->id);
                spin_unlock(&memstick_host_lock);
                return rc;
        }

        host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF);
        memstick_detect_change(host);
        return 0;
}
EXPORT_SYMBOL(memstick_add_host);

/**
 * memstick_remove_host - stop request processing on memstick host
 * @host - host to use
 */
void memstick_remove_host(struct memstick_host *host)
{
        flush_workqueue(workqueue);
        mutex_lock(&host->lock);
        if (host->card)
                device_unregister(&host->card->dev);
        host->card = NULL;
        host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF);
        mutex_unlock(&host->lock);

        spin_lock(&memstick_host_lock);
        idr_remove(&memstick_host_idr, host->id);
        spin_unlock(&memstick_host_lock);
        device_del(&host->dev);
}
EXPORT_SYMBOL(memstick_remove_host);

/**
 * memstick_free_host - free memstick host
 * @host - host to use
 */
void memstick_free_host(struct memstick_host *host)
{
        mutex_destroy(&host->lock);
        put_device(&host->dev);
}
EXPORT_SYMBOL(memstick_free_host);

/**
 * memstick_suspend_host - notify bus driver of host suspension
 * @host - host to use
 */
void memstick_suspend_host(struct memstick_host *host)
{
        mutex_lock(&host->lock);
        host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF);
        mutex_unlock(&host->lock);
}
EXPORT_SYMBOL(memstick_suspend_host);

/**
 * memstick_resume_host - notify bus driver of host resumption
 * @host - host to use
 */
void memstick_resume_host(struct memstick_host *host)
{
        int rc = 0;

        mutex_lock(&host->lock);
        if (host->card)
                rc = memstick_power_on(host);
        mutex_unlock(&host->lock);

        if (!rc)
                memstick_detect_change(host);
}
EXPORT_SYMBOL(memstick_resume_host);

int memstick_register_driver(struct memstick_driver *drv)
{
        drv->driver.bus = &memstick_bus_type;

        return driver_register(&drv->driver);
}
EXPORT_SYMBOL(memstick_register_driver);

void memstick_unregister_driver(struct memstick_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL(memstick_unregister_driver);


static int __init memstick_init(void)
{
        int rc;

        workqueue = create_freezable_workqueue("kmemstick");
        if (!workqueue)
                return -ENOMEM;

        rc = bus_register(&memstick_bus_type);
        if (!rc)
                rc = class_register(&memstick_host_class);

        if (!rc)
                return 0;

        bus_unregister(&memstick_bus_type);
        destroy_workqueue(workqueue);

        return rc;
}

static void __exit memstick_exit(void)
{
        class_unregister(&memstick_host_class);
        bus_unregister(&memstick_bus_type);
        destroy_workqueue(workqueue);
        idr_destroy(&memstick_host_idr);
}

module_init(memstick_init);
module_exit(memstick_exit);

MODULE_AUTHOR("Alex Dubov");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Sony MemoryStick core driver");