Line data    Source code

       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             : 
      10             : struct builtin_fw {
      11             :         char *name;
      12             :         void *data;
      13             :         unsigned long size;
      14             : };
      15             : 
      16             : extern struct builtin_fw __start_builtin_fw[];
      17             : extern struct builtin_fw __end_builtin_fw[];
      18             : 
      19           0 : static bool fw_copy_to_prealloc_buf(struct firmware *fw,
      20             :                                     void *buf, size_t size)
      21             : {
      22           0 :         if (!buf)
      23             :                 return true;
      24           0 :         if (size < fw->size)
      25             :                 return false;
      26           0 :         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             :  **/
      47           0 : bool firmware_request_builtin(struct firmware *fw, const char *name)
      48             : {
      49             :         struct builtin_fw *b_fw;
      50             : 
      51           0 :         if (!fw)
      52             :                 return false;
      53             : 
      54           0 :         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
      55           0 :                 if (strcmp(name, b_fw->name) == 0) {
      56           0 :                         fw->size = b_fw->size;
      57           0 :                         fw->data = b_fw->data;
      58           0 :                         return true;
      59             :                 }
      60             :         }
      61             : 
      62             :         return false;
      63             : }
      64             : EXPORT_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             :  **/
      86           0 : bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
      87             :                                   void *buf, size_t size)
      88             : {
      89           0 :         if (!firmware_request_builtin(fw, name))
      90             :                 return false;
      91             : 
      92           0 :         return fw_copy_to_prealloc_buf(fw, buf, size);
      93             : }
      94             : 
      95           0 : bool firmware_is_builtin(const struct firmware *fw)
      96             : {
      97             :         struct builtin_fw *b_fw;
      98             : 
      99           0 :         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
     100           0 :                 if (fw->data == b_fw->data)
     101             :                         return true;
     102             : 
     103             :         return false;
     104             : }
     105             : 
     106             : #endif