Hi,
On Tue, Mar 20, 2018 at 01:59:03PM +0100, Patrick Delaunay wrote:
Add minimal PSCI support for Linux.
Signed-off-by: Patrick Delaunay patrick.delaunay@st.com
+int __secure psci_features(unsigned int psci_fid) +{
- switch (psci_fid) {
- case ARM_PSCI_0_2_FN_PSCI_VERSION:
- case ARM_PSCI_0_2_FN_CPU_ON:
- case ARM_PSCI_0_2_FN_CPU_OFF:
- case ARM_PSCI_0_2_FN_SYSTEM_RESET:
return 0x0;- }
- return ARM_PSCI_RET_NI;
+}
+unsigned int __secure psci_version(void) +{
- return ARM_PSCI_VER_1_0;
+}
I'm a bit worried, because while PSCI_VERSION reports PSCI 1.0, this does not appear to be conformant with teh PSCI 1.0 spec, as some mandatory functions are missing:
* AFFINITY_INFO -- Linux relies on this to ensure that CPUs have exited the kernel when calling CPU_OFF (e.g. so that we don't free any data / code that said CPU may be using on the path to calling CPU_OFF).
* SYSTEM_OFF -- Can you implement this similarly to SYSTEM_RESET?
+int __secure psci_cpu_on(u32 __always_unused unused, u32 mpidr, u32 pc) +{
What about the context_id? PSCI 0.2+ mandates it, and some project rely upon it (though Linux currently does not).
- u32 cpu = (mpidr & 0x3);
- /* store target PC */
- psci_save_target_pc(cpu, pc);
- /* write entrypoint in backup RAM register */
- writel((u32)&psci_cpu_entry, TAMP_BACKUP_BRANCH_ADDRESS);
- /* write magic number in backup register */
- writel(BOOT_API_A7_CORE1_MAGIC_NUMBER, TAMP_BACKUP_MAGIC_NUMBER);
- stm32mp_smp_kick_all_cpus();
- return ARM_PSCI_RET_SUCCESS;
Does some other part of U-Boot do some state tracking? What happens if this is called for a CPU that's already online?
Thanks, Mark.