Hi, Andreas Actually the owl_v7_invalidate_l1 is not needed, and the headsmp-owl.S file can be removed if pen release staff is not used. The CPUx can jump to secondary_startup directly by setting OWL_CPUx_ADDR register.
Because S900 is aarch64 architecture, it cannot boot CPUx simply by setting SPS register. It depends on the low-level arm-trusted-firmware. Linux kernel can boot up CPUx by PSCI interface, and the arm-trusted-firmware will power on CPUx, initialize EL3 register and jump to EL2 entry in Linux kernel. Best Regards, David Liu -----Original Message----- From: Andreas Färber [mailto:afaer...@suse.de] Sent: Sunday, July 02, 2017 3:57 AM To: 刘炜 Cc: Arnd Bergmann; Thomas Liau; Linux ARM; mp-cs; 张东风; 张天益; 96boa...@ucrobotics.com; supp...@lemaker.org; Linux Kernel Mailing List; Russell King Subject: Re: 答复: [PATCH v4 20/28] ARM: owl: Implement CPU enable-method for S500 Hi David, Am 01.07.2017 um 06:42 schrieb 刘炜: > OWL_CPUx_ADDR is the physical address of CPUx wakeup function. > OWL_CPUx_FLAG is a valid flag of OWL_CPUx_ADDR. > > After CPUxs are wakeuped by SEV instruction, they will check their own > OWL_CPUx_FLAG register. If the register vlaue is 0x55aa, CPUx will jump to > OWL_CPUx_ADDR to boot up, otherwize go to sleep by WFE. > > So the pen release staff is not necessary, you can remove these code safely. Thank you for the quick confirmation! I have just tested a patch, and it appears to work. Is owl_v7_invalidate_l1 necessary? mach-sunxi (that Arnd pointed to as example) uses secondary_startup directly, without custom assembler code. https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm/mach-actions/headsmp.S > BTW: CPU2/3 must exit the power gate state before wakeup, and CPU1 is always > power on and has no power gate control. Yes, the S500 SPS was luckily documented in the manual. The power-gating for CPU2/3 is already implemented: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm/mach-actions/platsmp.c For S900 however SPS is sadly not documented... If you know who at Actions Semi could help there, please also take a look at: https://github.com/96boards/documentation/issues/59 Best regards, Andreas -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg)
