// SPDX-License-Identifier: GPL-2.0

#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <linux/types.h>

#include "sysfs.h"

/*
 * sysfs support for firmware loader
 */

void __fw_load_abort(struct fw_priv *fw_priv)
{
        /*
         * There is a small window in which user can write to 'loading'
         * between loading done/aborted and disappearance of 'loading'
         */
        if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
                return;

        fw_state_aborted(fw_priv);
}

#ifdef CONFIG_FW_LOADER_USER_HELPER
static ssize_t timeout_show(const struct class *class, const struct class_attribute *attr,
                            char *buf)
{
        return sysfs_emit(buf, "%d\n", __firmware_loading_timeout());
}

/**
 * timeout_store() - set number of seconds to wait for firmware
 * @class: device class pointer
 * @attr: device attribute 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 timeout_store(const struct class *class, const struct class_attribute *attr,
                             const char *buf, size_t count)
{
        int tmp_loading_timeout;

        if (kstrtoint(buf, 10, &tmp_loading_timeout))
                return -EINVAL;

        if (tmp_loading_timeout < 0)
                tmp_loading_timeout = 0;

        __fw_fallback_set_timeout(tmp_loading_timeout);

        return count;
}
static CLASS_ATTR_RW(timeout);

static struct attribute *firmware_class_attrs[] = {
        &class_attr_timeout.attr,
        NULL,
};
ATTRIBUTE_GROUPS(firmware_class);

static int do_firmware_uevent(const struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
{
        if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
                return -ENOMEM;
        if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
                return -ENOMEM;
        if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
                return -ENOMEM;

        return 0;
}

static int firmware_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
        const struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
        int err = 0;

        mutex_lock(&fw_lock);
        if (fw_sysfs->fw_priv)
                err = do_firmware_uevent(fw_sysfs, env);
        mutex_unlock(&fw_lock);
        return err;
}
#endif /* CONFIG_FW_LOADER_USER_HELPER */

static void fw_dev_release(struct device *dev)
{
        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);

        if (fw_sysfs->fw_upload_priv)
                fw_upload_free(fw_sysfs);

        kfree(fw_sysfs);
}

static struct class firmware_class = {
        .name           = "firmware",
#ifdef CONFIG_FW_LOADER_USER_HELPER
        .class_groups   = firmware_class_groups,
        .dev_uevent     = firmware_uevent,
#endif
        .dev_release    = fw_dev_release,
};

int register_sysfs_loader(void)
{
        int ret = class_register(&firmware_class);

        if (ret != 0)
                return ret;
        return register_firmware_config_sysctl();
}

void unregister_sysfs_loader(void)
{
        unregister_firmware_config_sysctl();
        class_unregister(&firmware_class);
}

static ssize_t firmware_loading_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
        int loading = 0;

        mutex_lock(&fw_lock);
        if (fw_sysfs->fw_priv)
                loading = fw_state_is_loading(fw_sysfs->fw_priv);
        mutex_unlock(&fw_lock);

        return sysfs_emit(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 fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
        struct fw_priv *fw_priv;
        ssize_t written = count;
        int loading;

        if (kstrtoint(buf, 10, &loading))
                return -EINVAL;

        mutex_lock(&fw_lock);
        fw_priv = fw_sysfs->fw_priv;
        if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
                goto out;

        switch (loading) {
        case 1:
                /* discarding any previous partial load */
                fw_free_paged_buf(fw_priv);
                fw_state_start(fw_priv);
                break;
        case 0:
                if (fw_state_is_loading(fw_priv)) {
                        int rc;

                        /*
                         * Several loading requests may be pending on
                         * one same firmware buf, so let all requests
                         * see the mapped 'buf->data' once the loading
                         * is completed.
                         */
                        rc = fw_map_paged_buf(fw_priv);
                        if (rc)
                                dev_err(dev, "%s: map pages failed\n",
                                        __func__);
                        else
                                rc = security_kernel_post_load_data(fw_priv->data,
                                                                    fw_priv->size,
                                                                    LOADING_FIRMWARE,
                                                                    "blob");

                        /*
                         * Same logic as fw_load_abort, only the DONE bit
                         * is ignored and we set ABORT only on failure.
                         */
                        if (rc) {
                                fw_state_aborted(fw_priv);
                                written = rc;
                        } else {
                                fw_state_done(fw_priv);

                                /*
                                 * If this is a user-initiated firmware upload
                                 * then start the upload in a worker thread now.
                                 */
                                rc = fw_upload_start(fw_sysfs);
                                if (rc)
                                        written = rc;
                        }
                        break;
                }
                fallthrough;
        default:
                dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
                fallthrough;
        case -1:
                fw_load_abort(fw_sysfs);
                if (fw_sysfs->fw_upload_priv)
                        fw_state_init(fw_sysfs->fw_priv);

                break;
        }
out:
        mutex_unlock(&fw_lock);
        return written;
}

DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);

static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
                             loff_t offset, size_t count, bool read)
{
        if (read)
                memcpy(buffer, fw_priv->data + offset, count);
        else
                memcpy(fw_priv->data + offset, buffer, count);
}

static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
                        loff_t offset, size_t count, bool read)
{
        while (count) {
                int page_nr = offset >> PAGE_SHIFT;
                int page_ofs = offset & (PAGE_SIZE - 1);
                int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);

                if (read)
                        memcpy_from_page(buffer, fw_priv->pages[page_nr],
                                         page_ofs, page_cnt);
                else
                        memcpy_to_page(fw_priv->pages[page_nr], page_ofs,
                                       buffer, page_cnt);

                buffer += page_cnt;
                offset += page_cnt;
                count -= page_cnt;
        }
}

static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
                                  const struct bin_attribute *bin_attr,
                                  char *buffer, loff_t offset, size_t count)
{
        struct device *dev = kobj_to_dev(kobj);
        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
        struct fw_priv *fw_priv;
        ssize_t ret_count;

        mutex_lock(&fw_lock);
        fw_priv = fw_sysfs->fw_priv;
        if (!fw_priv || fw_state_is_done(fw_priv)) {
                ret_count = -ENODEV;
                goto out;
        }
        if (offset > fw_priv->size) {
                ret_count = 0;
                goto out;
        }
        if (count > fw_priv->size - offset)
                count = fw_priv->size - offset;

        ret_count = count;

        if (fw_priv->data)
                firmware_rw_data(fw_priv, buffer, offset, count, true);
        else
                firmware_rw(fw_priv, buffer, offset, count, true);

out:
        mutex_unlock(&fw_lock);
        return ret_count;
}

static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
{
        int err;

        err = fw_grow_paged_buf(fw_sysfs->fw_priv,
                                PAGE_ALIGN(min_size) >> PAGE_SHIFT);
        if (err)
                fw_load_abort(fw_sysfs);
        return err;
}

/**
 * firmware_data_write() - write method for firmware
 * @filp: open sysfs file
 * @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 file *filp, struct kobject *kobj,
                                   const struct bin_attribute *bin_attr,
                                   char *buffer, loff_t offset, size_t count)
{
        struct device *dev = kobj_to_dev(kobj);
        struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
        struct fw_priv *fw_priv;
        ssize_t retval;

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

        mutex_lock(&fw_lock);
        fw_priv = fw_sysfs->fw_priv;
        if (!fw_priv || fw_state_is_done(fw_priv)) {
                retval = -ENODEV;
                goto out;
        }

        if (fw_priv->data) {
                if (offset + count > fw_priv->allocated_size) {
                        retval = -ENOMEM;
                        goto out;
                }
                firmware_rw_data(fw_priv, buffer, offset, count, false);
                retval = count;
        } else {
                retval = fw_realloc_pages(fw_sysfs, offset + count);
                if (retval)
                        goto out;

                retval = count;
                firmware_rw(fw_priv, buffer, offset, count, false);
        }

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

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

static struct attribute *fw_dev_attrs[] = {
        &dev_attr_loading.attr,
#ifdef CONFIG_FW_UPLOAD
        &dev_attr_cancel.attr,
        &dev_attr_status.attr,
        &dev_attr_error.attr,
        &dev_attr_remaining_size.attr,
#endif
        NULL
};

static const struct bin_attribute *const fw_dev_bin_attrs[] = {
        &firmware_attr_data,
        NULL
};

static const struct attribute_group fw_dev_attr_group = {
        .attrs = fw_dev_attrs,
        .bin_attrs = fw_dev_bin_attrs,
#ifdef CONFIG_FW_UPLOAD
        .is_visible = fw_upload_is_visible,
#endif
};

static const struct attribute_group *fw_dev_attr_groups[] = {
        &fw_dev_attr_group,
        NULL
};

struct fw_sysfs *
fw_create_instance(struct firmware *firmware, const char *fw_name,
                   struct device *device, u32 opt_flags)
{
        struct fw_sysfs *fw_sysfs;
        struct device *f_dev;

        fw_sysfs = kzalloc_obj(*fw_sysfs);
        if (!fw_sysfs) {
                fw_sysfs = ERR_PTR(-ENOMEM);
                goto exit;
        }

        fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
        fw_sysfs->fw = firmware;
        f_dev = &fw_sysfs->dev;

        device_initialize(f_dev);
        dev_set_name(f_dev, "%s", fw_name);
        f_dev->parent = device;
        f_dev->class = &firmware_class;
        f_dev->groups = fw_dev_attr_groups;
exit:
        return fw_sysfs;
}