The optee "/firmware" node is normally used to load the OP-TEE driver. SPL does not use it this way, but instead uses it to patch the kernel devicetree when booting OP-TEE. This seems weird, as OP-TEE -- which would run after SPL -- is capable of patching the devicetree and adding the required "/firmware" and "/reserved-memory" nodes.
However, OP-TEE's devicetree patching (CFG_DT=y) comes with a significant boot time penalty. Measurements put it between 700 to 1800 milliseconds. SPL can also do this patching, without incurring a measurable increase in boot time. This is the use case for falcon mode, which is the main reason to launch OP-TEE from SPL.
Although some OP-TEE configurations do not require any pre-patching of the devicetree, there are good use cases for doing so. As far as concerns with adding the nodes twice, OP-TEE will not add the node if it already-exists.
Add the "/firmware/optee" node the SPL devicetree.
Signed-off-by: Alexandru Gagniuc mr.nuke.me@gmail.com --- arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi index b314ce2dac..7deb0f5d70 100644 --- a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi +++ b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi @@ -33,6 +33,7 @@ optee { compatible = "linaro,optee-tz"; method = "smc"; + u-boot,dm-spl; }; };