arm-trusted-firmware

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Author	SHA1	Message	Date
Andre Przywara	f240728b76	qemu: Move and generalise FDT PSCI fixup The QEMU platform port scans its device tree to advertise PSCI as the CPU enable method. It does this by scanning every node in the DT and check whether its compatible string starts with "arm,cortex-a". Then it sets the enable-method to PSCI, if it doesn't already have one. Other platforms might want to use this functionality as well, so let's move it out of the QEMU platform directory and make it more robust by fixing some shortcomings: - A compatible string starting with a certain prefix is not a good way to find the CPU nodes. For instance a "arm,cortex-a72-pmu" node will match as well and is in turn favoured with an enable-method. - If the DT already has an enable-method, we won't change this to PSCI. Those two issues will for instance fail on the Raspberry Pi 4 DT. To fix those problems, we adjust the scanning method: The DT spec says that all CPU nodes are subnodes of the mandatory /cpus node, which is a subnode of the root node. Also each CPU node has to have a device_type = "cpu" property. So we find the /cpus node, then scan for a subnode with the proper device_type, forcing the enable-method to "psci". We have to restart this search after a property has been patched, as the node offsets might have changed meanwhile. This allows this routine to be reused for the Raspberry Pi 4 later. Change-Id: I00cae16cc923d9f8bb96a9b2a2933b9a79b06139 Signed-off-by: Andre Przywara <andre.przywara@arm.com>	5 years ago

Author

SHA1

Message

Date

Andre Przywara

f240728b76

qemu: Move and generalise FDT PSCI fixup

The QEMU platform port scans its device tree to advertise PSCI as the
CPU enable method. It does this by scanning *every* node in the DT and
check whether its compatible string starts with "arm,cortex-a". Then it
sets the enable-method to PSCI, if it doesn't already have one.

Other platforms might want to use this functionality as well, so let's
move it out of the QEMU platform directory and make it more robust by
fixing some shortcomings:
- A compatible string starting with a certain prefix is not a good way
to find the CPU nodes. For instance a "arm,cortex-a72-pmu" node will
match as well and is in turn favoured with an enable-method.
- If the DT already has an enable-method, we won't change this to PSCI.

Those two issues will for instance fail on the Raspberry Pi 4 DT.
To fix those problems, we adjust the scanning method:
The DT spec says that all CPU nodes are subnodes of the mandatory
/cpus node, which is a subnode of the root node. Also each CPU node has
to have a device_type = "cpu" property. So we find the /cpus node, then
scan for a subnode with the proper device_type, forcing the
enable-method to "psci".
We have to restart this search after a property has been patched, as the
node offsets might have changed meanwhile.

This allows this routine to be reused for the Raspberry Pi 4 later.

Change-Id: I00cae16cc923d9f8bb96a9b2a2933b9a79b06139
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

5 years ago

1 Commits (f240728b76c05ac507189a37375b120379eda650)