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[linux-2.6.22.y-op.git] / drivers / base / firmware_class.c

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

#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 <asm/semaphore.h>

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

MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
MODULE_DESCRIPTION("Multi purpose firmware loading support");
MODULE_LICENSE("GPL");

enum {
        FW_STATUS_LOADING,
        FW_STATUS_DONE,
        FW_STATUS_ABORT,
        FW_STATUS_READY,
};

static int loading_timeout = 10;        /* 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 DECLARE_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;
};

static inline 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:
 * Description:
 *      Sets the number of seconds to wait for the firmware.  Once
 *      this expires an error will be return to the driver and no
 *      firmware will be provided.
 *
 *      Note: zero means 'wait for ever'
 *
 **/
static ssize_t
firmware_timeout_store(struct class *class, const char *buf, size_t count)
{
        loading_timeout = simple_strtol(buf, NULL, 10);
        return count;
}

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

static void  fw_class_dev_release(struct class_device *class_dev);
int firmware_class_hotplug(struct class_device *dev, char **envp,
                           int num_envp, char *buffer, int buffer_size);

static struct class firmware_class = {
        .name           = "firmware",
        .hotplug        = firmware_class_hotplug,
        .release        = fw_class_dev_release,
};

int
firmware_class_hotplug(struct class_device *class_dev, char **envp,
                       int num_envp, char *buffer, int buffer_size)
{
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);
        int i = 0, len = 0;

        if (!test_bit(FW_STATUS_READY, &fw_priv->status))
                return -ENODEV;

        if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
                        "FIRMWARE=%s", fw_priv->fw_id))
                return -ENOMEM;
        if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
                        "TIMEOUT=%i", loading_timeout))
                return -ENOMEM;

        envp[i] = NULL;

        return 0;
}

static ssize_t
firmware_loading_show(struct class_device *class_dev, char *buf)
{
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);
        int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
        return sprintf(buf, "%d\n", loading);
}

/**
 * firmware_loading_store: - loading control file
 * Description:
 *      The relevant values are:
 *
 *       1: Start a load, discarding any previous partial load.
 *       0: Conclude the load and handle 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 class_device *class_dev,
                       const char *buf, size_t count)
{
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);
        int loading = simple_strtol(buf, NULL, 10);

        switch (loading) {
        case 1:
                down(&fw_lock);
                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);
                up(&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:
                printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
                       loading);
                /* fallthrough */
        case -1:
                fw_load_abort(fw_priv);
                break;
        }

        return count;
}

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

static ssize_t
firmware_data_read(struct kobject *kobj,
                   char *buffer, loff_t offset, size_t count)
{
        struct class_device *class_dev = to_class_dev(kobj);
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);
        struct firmware *fw;
        ssize_t ret_count = count;

        down(&fw_lock);
        fw = fw_priv->fw;
        if (test_bit(FW_STATUS_DONE, &fw_priv->status)) {
                ret_count = -ENODEV;
                goto out;
        }
        if (offset > fw->size) {
                ret_count = 0;
                goto out;
        }
        if (offset + ret_count > fw->size)
                ret_count = fw->size - offset;

        memcpy(buffer, fw->data + offset, ret_count);
out:
        up(&fw_lock);
        return ret_count;
}
static int
fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
{
        u8 *new_data;

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

        new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
        if (!new_data) {
                printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
                /* Make sure that we don't keep incomplete data */
                fw_load_abort(fw_priv);
                return -ENOMEM;
        }
        fw_priv->alloc_size += PAGE_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:
 *
 * Description:
 *
 *      Data written to the 'data' attribute will be later handled to
 *      the driver as a firmware image.
 **/
static ssize_t
firmware_data_write(struct kobject *kobj,
                    char *buffer, loff_t offset, size_t count)
{
        struct class_device *class_dev = to_class_dev(kobj);
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);
        struct firmware *fw;
        ssize_t retval;

        if (!capable(CAP_SYS_RAWIO))
                return -EPERM;
        down(&fw_lock);
        fw = fw_priv->fw;
        if (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(fw->data + offset, buffer, count);

        fw->size = max_t(size_t, offset + count, fw->size);
        retval = count;
out:
        up(&fw_lock);
        return retval;
}
static struct bin_attribute firmware_attr_data_tmpl = {
        .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
        .size = 0,
        .read = firmware_data_read,
        .write = firmware_data_write,
};

static void
fw_class_dev_release(struct class_device *class_dev)
{
        struct firmware_priv *fw_priv = class_get_devdata(class_dev);

        kfree(fw_priv);
        kfree(class_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 inline void
fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
{
        /* XXX warning we should watch out for name collisions */
        strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
}

static int
fw_register_class_device(struct class_device **class_dev_p,
                         const char *fw_name, struct device *device)
{
        int retval;
        struct firmware_priv *fw_priv = kmalloc(sizeof (struct firmware_priv),
                                                GFP_KERNEL);
        struct class_device *class_dev = kmalloc(sizeof (struct class_device),
                                                 GFP_KERNEL);

        *class_dev_p = NULL;

        if (!fw_priv || !class_dev) {
                printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
                retval = -ENOMEM;
                goto error_kfree;
        }
        memset(fw_priv, 0, sizeof (*fw_priv));
        memset(class_dev, 0, sizeof (*class_dev));

        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);

        fw_setup_class_device_id(class_dev, device);
        class_dev->dev = device;
        class_dev->class = &firmware_class;
        class_set_devdata(class_dev, fw_priv);
        retval = class_device_register(class_dev);
        if (retval) {
                printk(KERN_ERR "%s: class_device_register failed\n",
                       __FUNCTION__);
                goto error_kfree;
        }
        *class_dev_p = class_dev;
        return 0;

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

static int
fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
                      const char *fw_name, struct device *device)
{
        struct class_device *class_dev;
        struct firmware_priv *fw_priv;
        int retval;

        *class_dev_p = NULL;
        retval = fw_register_class_device(&class_dev, fw_name, device);
        if (retval)
                goto out;

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

        fw_priv = class_get_devdata(class_dev);

        fw_priv->fw = fw;
        retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
        if (retval) {
                printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
                       __FUNCTION__);
                goto error_unreg;
        }

        retval = class_device_create_file(class_dev,
                                          &class_device_attr_loading);
        if (retval) {
                printk(KERN_ERR "%s: class_device_create_file failed\n",
                       __FUNCTION__);
                goto error_unreg;
        }

        set_bit(FW_STATUS_READY, &fw_priv->status);
        *class_dev_p = class_dev;
        goto out;

error_unreg:
        class_device_unregister(class_dev);
out:
        return retval;
}

/**
 * request_firmware: - request firmware to hotplug and wait for it
 * Description:
 *      @firmware 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 use as $FIRMWARE in the hotplug 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)
{
        struct class_device *class_dev;
        struct firmware_priv *fw_priv;
        struct firmware *firmware;
        int retval;

        if (!firmware_p)
                return -EINVAL;

        *firmware_p = firmware = kmalloc(sizeof (struct firmware), GFP_KERNEL);
        if (!firmware) {
                printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
                       __FUNCTION__);
                retval = -ENOMEM;
                goto out;
        }
        memset(firmware, 0, sizeof (*firmware));

        retval = fw_setup_class_device(firmware, &class_dev, name, device);
        if (retval)
                goto error_kfree_fw;

        fw_priv = class_get_devdata(class_dev);

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

        kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
        wait_for_completion(&fw_priv->completion);
        set_bit(FW_STATUS_DONE, &fw_priv->status);

        del_timer_sync(&fw_priv->timeout);

        down(&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;
        up(&fw_lock);
        class_device_unregister(class_dev);
        goto out;

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

/**
 * release_firmware: - release the resource associated with a firmware image
 **/
void
release_firmware(const struct firmware *fw)
{
        if (fw) {
                vfree(fw->data);
                kfree(fw);
        }
}

/**
 * register_firmware: - provide a firmware image for later usage
 *
 * Description:
 *      Make sure that @data will be available by requesting firmware @name.
 *
 *      Note: This will not be possible until some kind of persistence
 *      is available.
 **/
void
register_firmware(const char *name, const u8 *data, size_t size)
{
        /* This is meaningless without firmware caching, so until we
         * decide if firmware caching is reasonable just leave it as a
         * noop */
}

/* 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);
};

static int
request_firmware_work_func(void *arg)
{
        struct firmware_work *fw_work = arg;
        const struct firmware *fw;
        if (!arg) {
                WARN_ON(1);
                return 0;
        }
        daemonize("%s/%s", "firmware", fw_work->name);
        request_firmware(&fw, fw_work->name, fw_work->device);
        fw_work->cont(fw, fw_work->context);
        release_firmware(fw);
        module_put(fw_work->module);
        kfree(fw_work);
        return 0;
}

/**
 * request_firmware_nowait:
 *
 * Description:
 *      Asynchronous variant of request_firmware() for contexts where
 *      it is not possible to sleep.
 *
 *      @cont will be called asynchronously when the firmware request is over.
 *
 *      @context will be passed over to @cont.
 *
 *      @fw may be %NULL if firmware request fails.
 *
 **/
int
request_firmware_nowait(
        struct module *module,
        const char *name, struct device *device, void *context,
        void (*cont)(const struct firmware *fw, void *context))
{
        struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
                                                GFP_ATOMIC);
        int ret;

        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,
        };

        ret = kernel_thread(request_firmware_work_func, fw_work,
                            CLONE_FS | CLONE_FILES);

        if (ret < 0) {
                fw_work->cont(NULL, fw_work->context);
                return ret;
        }
        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", __FUNCTION__);
                return error;
        }
        error = class_create_file(&firmware_class, &class_attr_timeout);
        if (error) {
                printk(KERN_ERR "%s: class_create_file failed\n",
                       __FUNCTION__);
                class_unregister(&firmware_class);
        }
        return error;

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

module_init(firmware_class_init);
module_exit(firmware_class_exit);

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