[U-Boot, v3, 1/1] misc: fs_loader: Add request_firmware_into_buf_via_script() for flexible firmware loading via U-Boot script
Lucien.Jheng
lucienzx159 at gmail.com
Tue Jul 29 16:51:46 CEST 2025
This commit introduces a new API,
request_firmware_into_buf_via_script(), to the fs_loader framework.
This function allows firmware to be loaded into memory using
a user-defined U-Boot script, providing greater flexibility for
firmware loading scenarios that cannot be handled by static file
paths or device/partition selection alone.
Key features:
- The API runs a specified U-Boot script (by name), which is responsible
for loading the firmware into memory by any means (e.g., load from MMC, USB, network, etc.).
- The script must set two environment variables: 'fw_addr'
(the memory address where the firmware is loaded) and
'fw_size' (the size of the firmware in bytes).
- The function validates these variables, copies the firmware into a newly
allocated buffer (using memdup), and returns the pointer
via the provided double pointer argument.
- The maximum allowed firmware size is checked to prevent buffer overflows.
- The environment variables are cleared after use to avoid stale data.
- Detailed error messages are provided for all failure conditions to aid debugging.
Usage example:
1. Define a U-Boot script in the environment that loads the firmware
and sets the required variables:
=> env set my_fw_script 'load mmc 0:1 ${loadaddr} firmware.bin &&
env set fw_addr ${loadaddr} && env set fw_size ${filesize}'
2. In your code, call the new API:
void *fw_buf = NULL;
int ret = request_firmware_into_buf_via_script(&fw_buf, 0x46000000, "my_fw_script");
if (ret < 0)
return ret;
This approach allows board integrators and users to customize the firmware
loading process without modifying the source code,
simply by changing the script in the U-Boot environment.
Signed-off-by: Lucien.Jheng <lucienzx159 at gmail.com>
---
Change in PATCH v3:
air_en8811h.c:
* Use "fmt -w 72" to shrink the commit message to fit within 72 characters.
* expand the script en8811h_load_firmware to erase memory before loading firmware,
and to check the filesize after loading the first part of the firmware
Since the Airoha EN8811H requires MD32 firmware to be loaded via MDIO,
and U-Boot currently supports various FW loading methods (e.g., partition or rootfs for MMC),
I've followed Marek Vasut's advice [1] to implement this via U-Boot scripts.
[1] https://patchwork.ozlabs.org/project/uboot/patch/20250617081641.8385-5-marek.vasut+renesas@mailbox.org/
This commit expands the existing `fs_loader` concept by adding U-Boot script functionality.
This leverages U-Boot environment variables, providing significant flexibility
for FW loading without requiring CONFIG_* modifications or recompilations.
I've validated this API on the Banana Pi R3 Mini. Here are my test commands and logs:
1. `env set en8811h_load_firmware 'env set fw_addr 0x46000000 && env set fw_size 0x24000 && mw.b ${fw_addr} 0 ${fw_size} && load mmc 0:3 0x46000000 /boot/EthMD32.dm.bin && if test ${filesize} -eq 4000; then load mmc 0:3 0x46004000 /boot/EthMD32.DSP.bin; else echo "loading MD32 FW failed"; env set fw_size 0; exit 1;fi'`
````Test Log````
Net: 16384 bytes read in 1 ms (15.6 MiB/s)
131072 bytes read in 9 ms (13.9 MiB/s)
addr: 0x46000000, size: 0x24000
Found Airoha Firmware.
MD32 firmware version: 24112802
````End of Test Log````
2. `env set en8811h_load_firmware 'env set fw_addr 0x46000000 && env set fw_size 0x24000 && mmc partconf 0 1 2 2 && mmc read $fw_addr 0x0 0x120 && mmc partconf 0 1 1 0'`
````Test Log````
Net: MMC read: dev # 0, block # 0, count 288 ... 288 blocks read: OK
addr: 0x46000000, size: 0x24000
Found Airoha Firmware.
MD32 firmware version: 24112802
````End of Test Log````
Test Logs:
https://gist.github.com/bjxlucX123/6098f927c790861dbcebb87ea0059af5
drivers/misc/fs_loader.c | 72 ++++++++++++++++++++++++++++++++++++++++
include/fs_loader.h | 24 ++++++++++++++
2 files changed, 96 insertions(+)
diff --git a/drivers/misc/fs_loader.c b/drivers/misc/fs_loader.c
index 66803f4b997..202ee7c7bfb 100644
--- a/drivers/misc/fs_loader.c
+++ b/drivers/misc/fs_loader.c
@@ -228,6 +228,78 @@ int request_firmware_into_buf(struct udevice *dev,
return ret;
}
+/**
+ * request_firmware_into_buf_via_script() -
+ * Load firmware using a U-Boot script and copy to buffer
+ * @buf: Pointer to a void* that will receive a pointer to the copied firmware buffer.
+ * @max_size: Maximum allowed size for the firmware to be loaded.
+ * @script_name: Name of the U-Boot script to execute for firmware loading.
+ *
+ * Executes a U-Boot script (@script_name) that loads firmware into
+ * memory and sets the environment variables 'fw_addr' (address) and
+ * 'fw_size' (size in bytes). Allocates a buffer, copies the firmware
+ * from the given address, and returns the pointer via @buf.
+ *
+ * The script must set these environment variables:
+ * fw_addr - Address where firmware is loaded in memory
+ * fw_size - Size of the firmware in bytes
+ *
+ * The script should be defined in the U-Boot environment, for example:
+ * env set script_name 'load mmc 0:1 ${loadaddr} firmware.bin &&
+ * env set fw_addr ${loadaddr} && env set fw_size ${filesize}
+ * Return: 0 on success, negative value on error.
+ */
+int request_firmware_into_buf_via_script(void **buf, size_t max_size,
+ const char *script_name)
+{
+ ulong addr, size;
+ int ret;
+ char cmd[32];
+
+ if (!buf || !script_name || !max_size)
+ return -EINVAL;
+
+ /* Create command to run the firmware loading script */
+ snprintf(cmd, sizeof(cmd), "run %s", script_name);
+
+ /* Run the firmware loading script */
+ ret = run_command_list(cmd, -1, 0);
+ if (ret) {
+ log_err("Firmware loading script '%s' not defined or failed.\n",
+ script_name);
+ return -EINVAL;
+ }
+
+ /* Find out where the firmware got loaded and how long it is */
+ addr = env_get_hex("fw_addr", 0);
+ size = env_get_hex("fw_size", 0);
+
+ /* Clear the variables set by the firmware loading script */
+ env_set("fw_addr", NULL);
+ env_set("fw_size", NULL);
+
+ if (!addr || !size) {
+ log_err("Firmware address (0x%lx) or size (0x%lx) are invalid.\n",
+ addr, size);
+ return -EINVAL;
+ }
+
+ /* Validate the firmware size against the buffer size */
+ if (size > max_size) {
+ log_err("Firmware size (0x%lx) exceeds buffer size (0x%zx).\n",
+ size, max_size);
+ return -EINVAL;
+ }
+
+ *buf = (void *)memdup((void *)addr, size);
+ if (!*buf) {
+ log_err("Failed to allocate memory for firmware copy.\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
static int fs_loader_of_to_plat(struct udevice *dev)
{
u32 phandlepart[2];
diff --git a/include/fs_loader.h b/include/fs_loader.h
index 5eb5b7ab4a1..97ed4cc2af0 100644
--- a/include/fs_loader.h
+++ b/include/fs_loader.h
@@ -64,4 +64,28 @@ int request_firmware_into_buf(struct udevice *dev,
* Return: 0 on success, negative value on error
*/
int get_fs_loader(struct udevice **dev);
+
+/**
+ * request_firmware_into_buf_via_script() -
+ * Load firmware using a U-Boot script and copy to buffer
+ * @buf: Pointer to a void* that will receive a pointer to the copied firmware buffer.
+ * @max_size: Maximum allowed size for the firmware to be loaded.
+ * @script_name: Name of the U-Boot script to execute for firmware loading.
+ *
+ * Executes a U-Boot script (@script_name) that loads firmware into
+ * memory and sets the environment variables 'fw_addr' (address) and
+ * 'fw_size' (size in bytes). Allocates a buffer, copies the firmware
+ * from the given address, and returns the pointer via @buf.
+ *
+ * The script must set these environment variables:
+ * fw_addr - Address where firmware is loaded in memory
+ * fw_size - Size of the firmware in bytes
+ *
+ * The script should be defined in the U-Boot environment, for example:
+ * env set script_name 'load mmc 0:1 ${loadaddr} firmware.bin &&
+ * env set fw_addr ${loadaddr} && env set fw_size ${filesize}
+ * Return: 0 on success, negative value on error.
+ */
+int request_firmware_into_buf_via_script(void **buf, size_t max_size,
+ const char *script_name);
#endif
--
2.34.1
More information about the U-Boot
mailing list