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/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/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);

static struct firmware_cache fw_cache;

/* Builtin firmware support */

#ifdef CONFIG_FW_LOADER

extern struct builtin_fw __start_builtin_fw[];
extern struct builtin_fw __end_builtin_fw[];

static void fw_copy_to_prealloc_buf(struct firmware *fw,
				    void *buf, size_t size)
{
	if (!buf || size < fw->size)
		return;
	memcpy(buf, fw->data, fw->size);
}

static bool fw_get_builtin_firmware(struct firmware *fw, const char *name,
				    void *buf, size_t size)
{
	struct builtin_fw *b_fw;

	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
		if (strcmp(name, b_fw->name) == 0) {
			fw->size = b_fw->size;
			fw->data = b_fw->data;
			fw_copy_to_prealloc_buf(fw, buf, size);

			return true;
		}
	}

	return false;
}

static bool fw_is_builtin_firmware(const struct firmware *fw)
{
	struct builtin_fw *b_fw;

	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
		if (fw->data == b_fw->data)
			return true;

	return false;
}

#else /* Module case - no builtin firmware support */

static inline bool fw_get_builtin_firmware(struct firmware *fw,
					   const char *name, void *buf,
					   size_t size)
{
	return false;
}

static inline bool fw_is_builtin_firmware(const struct firmware *fw)
{
	return false;
}
#endif

static 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 int fw_cache_piggyback_on_request(const char *name);

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 */
static 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(&