/*
 * firmware_class.c - Multi purpose firmware loading support
 *
 * Copyright (c) 2003 Manuel Estrada Sainz
 *
 * Please see Documentation/firmware_class/ for more information.
 *
 */

#include <linux/capability.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/kthread.h>

#include <linux/firmware.h>
#include "base.h"

#define to_dev(obj) container_of(obj, struct device, kobj)

MODULE_AUTHOR("Manuel Estrada Sainz");
MODULE_DESCRIPTION("Multi purpose firmware loading support");
MODULE_LICENSE("GPL");

enum {
        FW_STATUS_LOADING,
        FW_STATUS_DONE,
        FW_STATUS_ABORT,
};

static int loading_timeout = 60;        /* In seconds */

/* fw_lock could be moved to 'struct firmware_priv' but since it is just
 * guarding for corner cases a global lock should be OK */
static DEFINE_MUTEX(fw_lock);

struct firmware_priv {
        char fw_id[FIRMWARE_NAME_MAX];
        struct completion completion;
        struct bin_attribute attr_data;
        struct firmware *fw;
        unsigned long status;
        int alloc_size;
        struct timer_list timeout;
};

#ifdef CONFIG_FW_LOADER
extern struct builtin_fw __start_builtin_fw[];
extern struct builtin_fw __end_builtin_fw[];
#else /* Module case. Avoid ifdefs later; it'll all optimise out */
static struct builtin_fw *__start_builtin_fw;
static struct builtin_fw *__end_builtin_fw;
#endif

static void
fw_load_abort(struct firmware_priv *fw_priv)
{
        set_bit(FW_STATUS_ABORT, &fw_priv->status);
        wmb();
        complete(&fw_priv->completion);
}

static ssize_t
firmware_timeout_show(struct class *class, char *buf)
{
        return sprintf(buf, "%d\n", loading_timeout);
}

/**
 * firmware_timeout_store - set number of seconds to wait for firmware
 * @class: device class pointer
 * @buf: buffer to scan for timeout value
 * @count: number of bytes in @buf
 *
 *      Sets the number of seconds to wait for the firmware.  Once
 *      this expires an error will be returned to the driver and no
 *      firmware will be provided.
 *
 *      Note: zero means 'wait forever'.
 **/
static ssize_t
firmware_timeout_store(struct class *class, const char *buf, size_t count)
{
        loading_timeout = simple_strtol(buf, NULL, 10);
        if (loading_timeout < 0)
                loading_timeout = 0;
        return count;
}

static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);

static void fw_dev_release(struct device *dev);

static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);

        if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
                return -ENOMEM;
        if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
                return -ENOMEM;

        return 0;
}

static struct class firmware_class = {
        .name           = "firmware",
        .dev_uevent     = firmware_uevent,
        .dev_release    = fw_dev_release,
};

static ssize_t firmware_loading_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
        int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
        return sprintf(buf, "%d\n", loading);
}

/**
 * firmware_loading_store - set value in the 'loading' control file
 * @dev: device pointer
 * @attr: device attribute pointer
 * @buf: buffer to scan for loading control value
 * @count: number of bytes in @buf
 *
 *      The relevant values are:
 *
 *       1: Start a load, discarding any previous partial load.
 *       0: Conclude the load and hand the data to the driver code.
 *      -1: Conclude the load with an error and discard any written data.
 **/
static ssize_t firmware_loading_store(struct device *dev,
                                      struct device_attribute *attr,
                                      const char *buf, size_t count)
{
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
        int loading = simple_strtol(buf, NULL, 10);

        switch (loading) {
        case 1:
                mutex_lock(&fw_lock);
                if (!fw_priv->fw) {
                        mutex_unlock(&fw_lock);
                        break;
                }
                vfree(fw_priv->fw->data);
                fw_priv->fw->data = NULL;
                fw_priv->fw->size = 0;
                fw_priv->alloc_size = 0;
                set_bit(FW_STATUS_LOADING, &fw_priv->status);
                mutex_unlock(&fw_lock);
                break;
        case 0:
                if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
                        complete(&fw_priv->completion);
                        clear_bit(FW_STATUS_LOADING, &fw_priv->status);
                        break;
                }
                /* fallthrough */
        default:
                dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
                /* fallthrough */
        case -1:
                fw_load_abort(fw_priv);
                break;
        }

        return count;
}

static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);

static ssize_t
firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
                   char *buffer, loff_t offset, size_t count)
{
        struct device *dev = to_dev(kobj);
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
        struct firmware *fw;
        ssize_t ret_count;

        mutex_lock(&fw_lock);
        fw = fw_priv->fw;
        if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
                ret_count = -ENODEV;
                goto out;
        }
        ret_count = memory_read_from_buffer(buffer, count, &offset,
                                                fw->data, fw->size);
out:
        mutex_unlock(&fw_lock);
        return ret_count;
}

static int
fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
{
        u8 *new_data;
        int new_size = fw_priv->alloc_size;

        if (min_size <= fw_priv->alloc_size)
                return 0;

        new_size = ALIGN(min_size, PAGE_SIZE);
        new_data = vmalloc(new_size);
        if (!new_data) {
                printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
                /* Make sure that we don't keep incomplete data */
                fw_load_abort(fw_priv);
                return -ENOMEM;
        }
        fw_priv->alloc_size = new_size;
        if (fw_priv->fw->data) {
                memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
                vfree(fw_priv->fw->data);
        }
        fw_priv->fw->data = new_data;
        BUG_ON(min_size > fw_priv->alloc_size);
        return 0;
}

/**
 * firmware_data_write - write method for firmware
 * @kobj: kobject for the device
 * @bin_attr: bin_attr structure
 * @buffer: buffer being written
 * @offset: buffer offset for write in total data store area
 * @count: buffer size
 *
 *      Data written to the 'data' attribute will be later handed to
 *      the driver as a firmware image.
 **/
static ssize_t
firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
                    char *buffer, loff_t offset, size_t count)
{
        struct device *dev = to_dev(kobj);
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
        struct firmware *fw;
        ssize_t retval;

        if (!capable(CAP_SYS_RAWIO))
                return -EPERM;

        mutex_lock(&fw_lock);
        fw = fw_priv->fw;
        if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
                retval = -ENODEV;
                goto out;
        }
        retval = fw_realloc_buffer(fw_priv, offset + count);
        if (retval)
                goto out;

        memcpy((u8 *)fw->data + offset, buffer, count);

        fw->size = max_t(size_t, offset + count, fw->size);
        retval = count;
out:
        mutex_unlock(&fw_lock);
        return retval;
}

static struct bin_attribute firmware_attr_data_tmpl = {
        .attr = {.name = "data", .mode = 0644},
        .size = 0,
        .read = firmware_data_read,
        .write = firmware_data_write,
};

static void fw_dev_release(struct device *dev)
{
        struct firmware_priv *fw_priv = dev_get_drvdata(dev);

        kfree(fw_priv);
        kfree(dev);

        module_put(THIS_MODULE);
}

static void
firmware_class_timeout(u_long data)
{
        struct firmware_priv *fw_priv = (struct firmware_priv *) data;
        fw_load_abort(fw_priv);
}

static int fw_register_device(struct device **dev_p, const char *fw_name,
                              struct device *device)
{
        int retval;
        struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
                                                GFP_KERNEL);
        struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);

        *dev_p = NULL;

        if (!fw_priv || !f_dev) {
                dev_err(device, "%s: kmalloc failed\n", __func__);
                retval = -ENOMEM;
                goto error_kfree;
        }

        init_completion(&fw_priv->completion);
        fw_priv->attr_data = firmware_attr_data_tmpl;
        strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);

        fw_priv->timeout.function = firmware_class_timeout;
        fw_priv->timeout.data = (u_long) fw_priv;
        init_timer(&fw_priv->timeout);

        dev_set_name(f_dev, dev_name(device));
        f_dev->parent = device;
        f_dev->class = &firmware_class;
        dev_set_drvdata(f_dev, fw_priv);
        dev_set_uevent_suppress(f_dev, 1);
        retval = device_register(f_dev);
        if (retval) {
                dev_err(device, "%s: device_register failed\n", __func__);
                goto error_kfree;
        }
        *dev_p = f_dev;
        return 0;

error_kfree:
        kfree(fw_priv);
        kfree(f_dev);
        return retval;
}

static int fw_setup_device(struct firmware *fw, struct device **dev_p,
                           const char *fw_name, struct device *device,
                           int uevent)
{
        struct device *f_dev;
        struct firmware_priv *fw_priv;
        int retval;

        *dev_p = NULL;
        retval = fw_register_device(&f_dev, fw_name, device);
        if (retval)
                goto out;

        /* Need to pin this module until class device is destroyed */
        __module_get(THIS_MODULE);

        fw_priv = dev_get_drvdata(f_dev);

        fw_priv->fw = fw;
        retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
        if (retval) {
                dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
                goto error_unreg;
        }

        retval = device_create_file(f_dev, &dev_attr_loading);
        if (retval) {
                dev_err(device, "%s: device_create_file failed\n", __func__);
                goto error_unreg;
        }

        if (uevent)
                dev_set_uevent_suppress(f_dev, 0);
        *dev_p = f_dev;
        goto out;

error_unreg:
        device_unregister(f_dev);
out:
        return retval;
}

static int
_request_firmware(const struct firmware **firmware_p, const char *name,
                 struct device *device, int uevent)
{
        struct device *f_dev;
        struct firmware_priv *fw_priv;
        struct firmware *firmware;
        struct builtin_fw *builtin;
        int retval;

        if (!firmware_p)
                return -EINVAL;

        *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
        if (!firmware) {
                dev_err(device, "%s: kmalloc(struct firmware) failed\n",
                        __func__);
                retval = -ENOMEM;
                goto out;
        }

        for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
             builtin++) {
                if (strcmp(name, builtin->name))
                        continue;
                dev_info(device, "firmware: using built-in firmware %s\n",
                         name);
                firmware->size = builtin->size;
                firmware->data = builtin->data;
                return 0;
        }

        if (uevent)
                dev_info(device, "firmware: requesting %s\n", name);

        retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
        if (retval)
                goto error_kfree_fw;

        fw_priv = dev_get_drvdata(f_dev);

        if (uevent) {
                if (loading_timeout > 0) {
                        fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
                        add_timer(&fw_priv->timeout);
                }

                kobject_uevent(&f_dev->kobj, KOBJ_ADD);
                wait_for_completion(&fw_priv->completion);
                set_bit(FW_STATUS_DONE, &fw_priv->status);
                del_timer_sync(&fw_priv->timeout);
        } else
                wait_for_completion(&fw_priv->completion);

        mutex_lock(&fw_lock);
        if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
                retval = -ENOENT;
                release_firmware(fw_priv->fw);
                *firmware_p = NULL;
        }
        fw_priv->fw = NULL;
        mutex_unlock(&fw_lock);
        device_unregister(f_dev);
        goto out;

error_kfree_fw:
        kfree(firmware);
        *firmware_p = NULL;
out:
        return retval;
}

/**
 * request_firmware: - send firmware request and wait for it
 * @firmware_p: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 *
 *      @firmware_p will be used to return a firmware image by the name
 *      of @name for device @device.
 *
 *      Should be called from user context where sleeping is allowed.
 *
 *      @name will be used as $FIRMWARE in the uevent environment and
 *      should be distinctive enough not to be confused with any other
 *      firmware image for this or any other device.
 **/
int
request_firmware(const struct firmware **firmware_p, const char *name,
                 struct device *device)
{
        int uevent = 1;
        return _request_firmware(firmware_p, name, device, uevent);
}

/**
 * release_firmware: - release the resource associated with a firmware image
 * @fw: firmware resource to release
 **/
void
release_firmware(const struct firmware *fw)
{
        struct builtin_fw *builtin;

        if (fw) {
                for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
                     builtin++) {
                        if (fw->data == builtin->data)
                                goto free_fw;
                }
                vfree(fw->data);
        free_fw:
                kfree(fw);
        }
}

/* Async support */
struct firmware_work {
        struct work_struct work;
        struct module *module;
        const char *name;
        struct device *device;
        void *context;
        void (*cont)(const struct firmware *fw, void *context);
        int uevent;
};

static int
request_firmware_work_func(void *arg)
{
        struct firmware_work *fw_work = arg;
        const struct firmware *fw;
        int ret;
        if (!arg) {
                WARN_ON(1);
                return 0;
        }
        ret = _request_firmware(&fw, fw_work->name, fw_work->device,
                fw_work->uevent);
        if (ret < 0)
                fw_work->cont(NULL, fw_work->context);
        else {
                fw_work->cont(fw, fw_work->context);
                release_firmware(fw);
        }
        module_put(fw_work->module);
        kfree(fw_work);
        return ret;
}

/**
 * request_firmware_nowait: asynchronous version of request_firmware
 * @module: module requesting the firmware
 * @uevent: sends uevent to copy the firmware image if this flag
 *      is non-zero else the firmware copy must be done manually.
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 * @context: will be passed over to @cont, and
 *      @fw may be %NULL if firmware request fails.
 * @cont: function will be called asynchronously when the firmware
 *      request is over.
 *
 *      Asynchronous variant of request_firmware() for contexts where
 *      it is not possible to sleep.
 **/
int
request_firmware_nowait(
        struct module *module, int uevent,
        const char *name, struct device *device, void *context,
        void (*cont)(const struct firmware *fw, void *context))
{
        struct task_struct *task;
        struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
                                                GFP_ATOMIC);

        if (!fw_work)
                return -ENOMEM;
        if (!try_module_get(module)) {
                kfree(fw_work);
                return -EFAULT;
        }

        *fw_work = (struct firmware_work) {
                .module = module,
                .name = name,
                .device = device,
                .context = context,
                .cont = cont,
                .uevent = uevent,
        };

        task = kthread_run(request_firmware_work_func, fw_work,
                            "firmware/%s", name);

        if (IS_ERR(task)) {
                fw_work->cont(NULL, fw_work->context);
                module_put(fw_work->module);
                kfree(fw_work);
                return PTR_ERR(task);
        }
        return 0;
}

static int __init
firmware_class_init(void)
{
        int error;
        error = class_register(&firmware_class);
        if (error) {
                printk(KERN_ERR "%s: class_register failed\n", __func__);
                return error;
        }
        error = class_create_file(&firmware_class, &class_attr_timeout);
        if (error) {
                printk(KERN_ERR "%s: class_create_file failed\n",
                       __func__);
                class_unregister(&firmware_class);
        }
        return error;

}
static void __exit
firmware_class_exit(void)
{
        class_unregister(&firmware_class);
}

fs_initcall(firmware_class_init);
module_exit(firmware_class_exit);

EXPORT_SYMBOL(release_firmware);
EXPORT_SYMBOL(request_firmware);
EXPORT_SYMBOL(request_firmware_nowait);