2 Commits

Author SHA1 Message Date
Uwe Kleine-König
2b329f5694 platform/x86: wmi: Make remove callback return void
The driver core ignores the return value of struct bus_type::remove()
(and so wmi_dev_remove()) because there is only little that can be done.

To simplify the quest to make this function return void, let struct
wmi_driver::remove() return void, too. All implementers of this callback
return 0 already and this way it should be obvious to driver authors
that returning an error code is a bad idea.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20210301160404.1677064-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2021-03-08 11:33:39 +01:00
Jithu Joseph
2d30fcdd43 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>
2020-05-05 20:27:44 +03:00