summaryrefslogtreecommitdiffstats
path: root/Documentation/driver-api/firmware/fw_upload.rst
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /Documentation/driver-api/firmware/fw_upload.rst
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/driver-api/firmware/fw_upload.rst')
-rw-r--r--Documentation/driver-api/firmware/fw_upload.rst126
1 files changed, 126 insertions, 0 deletions
diff --git a/Documentation/driver-api/firmware/fw_upload.rst b/Documentation/driver-api/firmware/fw_upload.rst
new file mode 100644
index 000000000..76922591e
--- /dev/null
+++ b/Documentation/driver-api/firmware/fw_upload.rst
@@ -0,0 +1,126 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+Firmware Upload API
+===================
+
+A device driver that registers with the firmware loader will expose
+persistent sysfs nodes to enable users to initiate firmware updates for
+that device. It is the responsibility of the device driver and/or the
+device itself to perform any validation on the data received. Firmware
+upload uses the same *loading* and *data* sysfs files described in the
+documentation for firmware fallback. It also adds additional sysfs files
+to provide status on the transfer of the firmware image to the device.
+
+Register for firmware upload
+============================
+
+A device driver registers for firmware upload by calling
+firmware_upload_register(). Among the parameter list is a name to
+identify the device under /sys/class/firmware. A user may initiate a
+firmware upload by echoing a 1 to the *loading* sysfs file for the target
+device. Next, the user writes the firmware image to the *data* sysfs
+file. After writing the firmware data, the user echos 0 to the *loading*
+sysfs file to signal completion. Echoing 0 to *loading* also triggers the
+transfer of the firmware to the lower-lever device driver in the context
+of a kernel worker thread.
+
+To use the firmware upload API, write a driver that implements a set of
+ops. The probe function calls firmware_upload_register() and the remove
+function calls firmware_upload_unregister() such as::
+
+ static const struct fw_upload_ops m10bmc_ops = {
+ .prepare = m10bmc_sec_prepare,
+ .write = m10bmc_sec_write,
+ .poll_complete = m10bmc_sec_poll_complete,
+ .cancel = m10bmc_sec_cancel,
+ .cleanup = m10bmc_sec_cleanup,
+ };
+
+ static int m10bmc_sec_probe(struct platform_device *pdev)
+ {
+ const char *fw_name, *truncate;
+ struct m10bmc_sec *sec;
+ struct fw_upload *fwl;
+ unsigned int len;
+
+ sec = devm_kzalloc(&pdev->dev, sizeof(*sec), GFP_KERNEL);
+ if (!sec)
+ return -ENOMEM;
+
+ sec->dev = &pdev->dev;
+ sec->m10bmc = dev_get_drvdata(pdev->dev.parent);
+ dev_set_drvdata(&pdev->dev, sec);
+
+ fw_name = dev_name(sec->dev);
+ truncate = strstr(fw_name, ".auto");
+ len = (truncate) ? truncate - fw_name : strlen(fw_name);
+ sec->fw_name = kmemdup_nul(fw_name, len, GFP_KERNEL);
+
+ fwl = firmware_upload_register(sec->dev, sec->fw_name, &m10bmc_ops, sec);
+ if (IS_ERR(fwl)) {
+ dev_err(sec->dev, "Firmware Upload driver failed to start\n");
+ kfree(sec->fw_name);
+ return PTR_ERR(fwl);
+ }
+
+ sec->fwl = fwl;
+ return 0;
+ }
+
+ static int m10bmc_sec_remove(struct platform_device *pdev)
+ {
+ struct m10bmc_sec *sec = dev_get_drvdata(&pdev->dev);
+
+ firmware_upload_unregister(sec->fwl);
+ kfree(sec->fw_name);
+ return 0;
+ }
+
+firmware_upload_register
+------------------------
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.c
+ :identifiers: firmware_upload_register
+
+firmware_upload_unregister
+--------------------------
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.c
+ :identifiers: firmware_upload_unregister
+
+Firmware Upload Ops
+-------------------
+.. kernel-doc:: include/linux/firmware.h
+ :identifiers: fw_upload_ops
+
+Firmware Upload Progress Codes
+------------------------------
+The following progress codes are used internally by the firmware loader.
+Corresponding strings are reported through the status sysfs node that
+is described below and are documented in the ABI documentation.
+
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.h
+ :identifiers: fw_upload_prog
+
+Firmware Upload Error Codes
+---------------------------
+The following error codes may be returned by the driver ops in case of
+failure:
+
+.. kernel-doc:: include/linux/firmware.h
+ :identifiers: fw_upload_err
+
+Sysfs Attributes
+================
+
+In addition to the *loading* and *data* sysfs files, there are additional
+sysfs files to monitor the status of the data transfer to the target
+device and to determine the final pass/fail status of the transfer.
+Depending on the device and the size of the firmware image, a firmware
+update could take milliseconds or minutes.
+
+The additional sysfs files are:
+
+* status - provides an indication of the progress of a firmware update
+* error - provides error information for a failed firmware update
+* remaining_size - tracks the data transfer portion of an update
+* cancel - echo 1 to this file to cancel the update