path: root/drivers/base/firmware_loader/main.c

// SPDX-License-Identifier: GPL-2.0
/*
 * main.c - Multi purpose firmware loading support
 *
 * Copyright (c) 2003 Manuel Estrada Sainz
 *
 * Please see Documentation/driver-api/firmware/ for more information.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/device.h>
#include <linux/kernel_read_file.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/highmem.h>
#include <linux/firmware.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/async.h>
#include <linux/pm.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/reboot.h>
#include <linux/security.h>
#include <linux/zstd.h>
#include <linux/xz.h>

#include <generated/utsrelease.h>

#include "../base.h"
#include "firmware.h"
#include "fallback.h"

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

struct firmware_cache {
	/* firmware_buf instance will be added into the below list */
	spinlock_t lock;
	struct list_head head;
	int state;

#ifdef CONFIG_FW_CACHE
	/*
	 * Names of firmware images which have been cached successfully
	 * will be added into the below list so that device uncache
	 * helper can trace which firmware images have been cached
	 * before.
	 */
	spinlock_t name_lock;
	struct list_head fw_names;

	struct delayed_work work;

	struct notifier_block   pm_notify;
#endif
};

struct fw_cache_entry {
	struct list_head list;
	const char *name;
};

struct fw_name_devm {
	unsigned long magic;
	const char *name;
};

static inline struct fw_priv *to_fw_priv(struct kref *ref)
{
	return container_of(ref, struct fw_priv, ref);
}

#define	FW_LOADER_NO_CACHE	0
#define	FW_LOADER_START_CACHE	1

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

struct firmware_cache fw_cache;

void fw_state_init(struct fw_priv *fw_priv)
{
	struct fw_state *fw_st = &fw_priv->fw_st;

	init_completion(&fw_st->completion);
	fw_st->status = FW_STATUS_UNKNOWN;
}

static inline int fw_state_wait(struct fw_priv *fw_priv)
{
	return __fw_state_wait_common(fw_priv, MAX_SCHEDULE_TIMEOUT);
}

static void fw_cache_piggyback_on_request(struct fw_priv *fw_priv);

static struct fw_priv *__allocate_fw_priv(const char *fw_name,
					  struct firmware_cache *fwc,
					  void *dbuf,
					  size_t size,
					  size_t offset,
					  u32 opt_flags)
{
	struct fw_priv *fw_priv;

	/* For a partial read, the buffer must be preallocated. */
	if ((opt_flags & FW_OPT_PARTIAL) && !dbuf)
		return NULL;

	/* Only partial reads are allowed to use an offset. */
	if (offset != 0 && !(opt_flags & FW_OPT_PARTIAL))
		return NULL;

	fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
	if (!fw_priv)
		return NULL;

	fw_priv->fw_name = kstrdup_const(fw_name, GFP_ATOMIC);
	if (!fw_priv->fw_name) {
		kfree(fw_priv);
		return NULL;
	}

	kref_init(&fw_priv->ref);
	fw_priv->fwc = fwc;
	fw_priv->data = dbuf;
	fw_priv->allocated_size = size;
	fw_priv->offset = offset;
	fw_priv->opt_flags = opt_flags;
	fw_state_init(fw_priv);
#ifdef CONFIG_FW_LOADER_USER_HELPER
	INIT_LIST_HEAD(&fw_priv->pending_list);
#endif

	pr_debug("%s: fw-%s fw_priv=%p\n", __func__, fw_name, fw_priv);

	return fw_priv;
}

static struct fw_priv *__lookup_fw_priv(const char *fw_name)
{
	struct fw_priv *tmp;
	struct firmware_cache *fwc = &fw_cache;

	list_for_each_entry(tmp, &fwc->head, list)
		if (!strcmp(tmp->fw_name, fw_name))
			return tmp;
	return NULL;
}

/* Returns 1 for batching firmware requests with the same name */
int alloc_lookup_fw_priv(const char *fw_name, struct firmware_cache *fwc,
			 struct fw_priv **fw_priv, void *dbuf, size_t size,
			 size_t offset, u32 opt_flags)
{
	struct fw_priv *tmp;

	spin_lock(&fwc->lock);
	/*
	 * Do not merge requests that are marked to be non-cached or
	 * are performing partial reads.
	 */
	if (!(opt_flags & (FW_OPT_NOCACHE | FW_OPT_PARTIAL))) {
		tmp = __lookup_fw_priv(fw_name);
		if (tmp) {
			kref_get(&tmp->ref);
			spin_unlock(&fwc->lock);
			*fw_priv = tmp;
			pr_debug("batched request - sharing the same struct fw_priv and lookup for multiple requests\n");
			return 1;
		}
	}

	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, offset, opt_flags);
	if (tmp) {
		INIT_LIST_HEAD(&tmp->list);
		if (!(opt_flags & FW_OPT_NOCACHE))
			list_add(&tmp->list, &fwc->head);
	}
	spin_unlock(&fwc->lock);

	*fw_priv = tmp;

	return tmp ? 0 : -ENOMEM;
}

static void __free_fw_priv(struct kref *ref)
	__releases(&fwc->lock)
{
	struct fw_priv *fw_priv = to_fw_priv(ref);
	struct firmware_cache *fwc = fw_priv->fwc;

	pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
		 __func__, fw_p