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| author | Jithu Joseph <jithu.joseph@intel.com> | 2020-04-27 16:15:14 -0700 |
|---|---|---|
| committer | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2020-05-05 20:27:44 +0300 |
| commit | 2d30fcdd439f766fa984df3854fd57c3c5daba7e (patch) | |
| tree | 63642a7f6a8a578d31be7cb148b58be957d79c0f /Documentation/ABI | |
| parent | 3ce2db608ec362bb01b821fb74a8e75989d54376 (diff) | |
| download | linux-2d30fcdd439f766fa984df3854fd57c3c5daba7e.tar.bz2 | |
platform/x86: Add Slim Bootloader firmware update signaling driver
Slim Bootloader(SBL) is a small open-source boot firmware,
designed for running on certain Intel platforms. SBL can be
thought-of as fulfilling the role of a minimal BIOS
implementation, i.e initializing the hardware and booting
Operating System.
Since SBL is not UEFI compliant, firmware update cannot be triggered
using standard UEFI runtime services. Further considering performance
impact, SBL doesn't look for a firmware update image on every reset
and does so only when firmware update signal is asserted.
SBL exposes an ACPI-WMI device which comes up in sysfs as
/sys/bus/wmi/44FADEB1xxx and this driver adds a
"firmware_update_request" device attribute. This attribute normally
has a value of 0 and userspace can signal SBL to update firmware,
on next reboot, by writing a value of 1 like:
echo 1 > /sys/bus/wmi/devices/44FADEB1xxx/firmware_update_request
This driver only implements a signaling mechanism, the actual firmware
update process and various details like firmware update image format,
firmware image location etc are defined by SBL and are not in the
scope of this driver.
DocLink: https://slimbootloader.github.io/security/firmware-update.html
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-platform-intel-wmi-sbl-fw-update | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-platform-intel-wmi-sbl-fw-update b/Documentation/ABI/testing/sysfs-platform-intel-wmi-sbl-fw-update new file mode 100644 index 000000000000..5aa618987cad --- /dev/null +++ b/Documentation/ABI/testing/sysfs-platform-intel-wmi-sbl-fw-update @@ -0,0 +1,12 @@ +What: /sys/bus/wmi/devices/44FADEB1-B204-40F2-8581-394BBDC1B651/firmware_update_request +Date: April 2020 +KernelVersion: 5.7 +Contact: "Jithu Joseph" <jithu.joseph@intel.com> +Description: + Allow user space entities to trigger update of Slim + Bootloader (SBL). This attribute normally has a value + of 0 and userspace can signal SBL to update firmware, + on next reboot, by writing a value of 1. + There are two available states: + * 0 -> Skip firmware update while rebooting + * 1 -> Attempt firmware update on next reboot |