When 'use_rp_mutex' (default = 0) is set in the device tree, a root
port mutex will be added. This mutex is used in _ON and _OFF method,
where the GPIO reset and/or enable GPIO value is changed. The
companion driver, such as WWAN driver, needs to acquire this root
port mutex when accessing the same GPIO pins. Using this common mutex
prevents those invoked methods from being called from different thread
while one is not completed.
An example is that WWAN driver calling _RST method to reset the device
and does remove/rescan for the device while the pm runtime work might
call RTD3 _OFF.
For those root port without additional driver, this mutex is not needed.
BRANCH=firmware-brya-14505.B
TEST=boot to OS and check the generated SSDT table for the root port.
The RPMX mutex should be generated and _ON and _OFF should use this
mutex.
Signed-off-by: Cliff Huang <cliff.huang@intel.com>
Change-Id: Ibc077528692b2d7076132384fb7bd441be502511
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73380
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Bora Guvendik <bora.guvendik@intel.com>
69564f3de5