1// SPDX-License-Identifier: GPL-2.0
  2/* Builtin firmware support */
  3
  4#include <linux/firmware.h>
  5#include "../firmware.h"
  6
  7/* Only if FW_LOADER=y */
  8#ifdef CONFIG_FW_LOADER
  9
 10struct builtin_fw {
 11	char *name;
 12	void *data;
 13	unsigned long size;
 14};
 15
 16extern struct builtin_fw __start_builtin_fw[];
 17extern struct builtin_fw __end_builtin_fw[];
 18
 19static bool fw_copy_to_prealloc_buf(struct firmware *fw,
 20				    void *buf, size_t size)
 21{
 22	if (!buf)
 23		return true;
 24	if (size < fw->size)
 25		return false;
 26	memcpy(buf, fw->data, fw->size);
 27	return true;
 28}
 29
 30/**
 31 * firmware_request_builtin() - load builtin firmware
 32 * @fw: pointer to firmware struct
 33 * @name: name of firmware file
 34 *
 35 * Some use cases in the kernel have a requirement so that no memory allocator
 36 * is involved as these calls take place early in boot process. An example is
 37 * the x86 CPU microcode loader. In these cases all the caller wants is to see
 38 * if the firmware was built-in and if so use it right away. This can be used
 39 * for such cases.
 40 *
 41 * This looks for the firmware in the built-in kernel. Only if the kernel was
 42 * built-in with the firmware you are looking for will this return successfully.
 43 *
 44 * Callers of this API do not need to use release_firmware() as the pointer to
 45 * the firmware is expected to be provided locally on the stack of the caller.
 46 **/
 47bool firmware_request_builtin(struct firmware *fw, const char *name)
 48{
 49	struct builtin_fw *b_fw;
 50
 51	if (!fw)
 52		return false;
 53
 54	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 55		if (strcmp(name, b_fw->name) == 0) {
 56			fw->size = b_fw->size;
 57			fw->data = b_fw->data;
 58			return true;
 59		}
 60	}
 61
 62	return false;
 63}
 64EXPORT_SYMBOL_NS_GPL(firmware_request_builtin, TEST_FIRMWARE);
 65
 66/**
 67 * firmware_request_builtin_buf() - load builtin firmware into optional buffer
 68 * @fw: pointer to firmware struct
 69 * @name: name of firmware file
 70 * @buf: If set this lets you use a pre-allocated buffer so that the built-in
 71 *	firmware into is copied into. This field can be NULL. It is used by
 72 *	callers such as request_firmware_into_buf() and
 73 *	request_partial_firmware_into_buf()
 74 * @size: if buf was provided, the max size of the allocated buffer available.
 75 *	If the built-in firmware does not fit into the pre-allocated @buf this
 76 *	call will fail.
 77 *
 78 * This looks for the firmware in the built-in kernel. Only if the kernel was
 79 * built-in with the firmware you are looking for will this call possibly
 80 * succeed. If you passed a @buf the firmware will be copied into it *iff* the
 81 * built-in firmware fits into the pre-allocated buffer size specified in
 82 * @size.
 83 *
 84 * This caller is to be used internally by the firmware_loader only.
 85 **/
 86bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
 87				  void *buf, size_t size)
 88{
 89	if (!firmware_request_builtin(fw, name))
 90		return false;
 91
 92	return fw_copy_to_prealloc_buf(fw, buf, size);
 93}
 94
 95bool firmware_is_builtin(const struct firmware *fw)
 96{
 97	struct builtin_fw *b_fw;
 98
 99	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
100		if (fw->data == b_fw->data)
101			return true;
102
103	return false;
104}
105
106#endif