On Wed, 2 Oct 2024 at 03:57, Patrick Rudolph patrick.rudolph@9elements.com wrote:
When ACPI is enabled over FDT the APs cannot be brought out of reset by the OS using the "FDT spin-table" mechanism, as no FDT is provided to the OS. The APs must be released out of reset in u-boot and then brought up in an ACPI compliant fashion.
When ARMV8_MULTIENTRY is specified, the APs are released from reset and will enter U-Boot after it has been relocated as well.
By default ARMV8_MULTIENTRY is not selected, keeping existing behaviour.
TEST: All APs enter U-Boot when run on qemu-system-aarch64 and on real hardware.
Signed-off-by: Patrick Rudolph patrick.rudolph@9elements.com Cc: Matthias Brugger mbrugger@suse.com Cc: Peter Robinson pbrobinson@gmail.com Cc: Tom Rini trini@konsulko.com
Changelog v2:
- Drop CPU code from board
- Add CPU driver to release APs from reset
Changelog v4:
- Use the generic armv8 CPU driver
- Probe all CPUs
- Release secondary CPUs in the probe function
- Use of_to_plat() to parse DT
- Drop udelay()
- Select the GICv2 driver
Changelog v5:
- Cosmetic fixes
- Drop arch_early_init_r()
Changelog v6:
- Update header order
- Drop ifdef
arch/arm/Kconfig | 1 + arch/arm/mach-bcm283x/Kconfig | 5 +- drivers/cpu/Makefile | 2 +- drivers/cpu/bcm283x_cpu.c | 214 ++++++++++++++++++++++++++++++++++ 4 files changed, 220 insertions(+), 2 deletions(-) create mode 100644 drivers/cpu/bcm283x_cpu.c
Reviewed-by: Simon Glass sjg@chromium.org