[U-Boot] [PATCH v7 07/17] ARM: Put target PC for PSCI CPU_ON on per-CPU stack

[Wang Dongsheng]

> -----Original Message-----
> From: U-Boot [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Jan Kiszka
> Sent: Tuesday, April 21, 2015 1:19 PM
> To: U-Boot Mailing List; Tom Rini
> Cc: Marc Zyngier; Tom Warren; Paul Walmsley; Ian Campbell; Thierry Reding
> Subject: [U-Boot] [PATCH v7 07/17] ARM: Put target PC for PSCI CPU_ON on per-CPU
> stack
> 
> Use a per-CPU variable for saving the target PC during CPU_ON operations. This
> allows us to run this service independently on targets that have more than 2
> cores and also core-local power control.
> 
> CC: Marc Zyngier <marc.zyngier at arm.com>
> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> Reviewed-by: Tom Rini <trini at konsulko.com>
> Reviewed-by: Thierry Reding <treding at nvidia.com>
> Tested-by: Thierry Reding <treding at nvidia.com>
> Tested-by: Ian Campbell <ijc at hellion.org.uk>
> ---
>  arch/arm/cpu/armv7/psci.S       | 11 +++++------
>  arch/arm/cpu/armv7/sunxi/psci.S |  9 ++++++---
>  2 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S index
> 18d85c4..87c0c0b 100644
> --- a/arch/arm/cpu/armv7/psci.S
> +++ b/arch/arm/cpu/armv7/psci.S
> @@ -17,6 +17,7 @@
> 
>  #include <config.h>
>  #include <linux/linkage.h>
> +#include <asm/macro.h>
>  #include <asm/psci.h>
> 
>  	.pushsection ._secure.text, "ax"
> @@ -202,6 +203,7 @@ ENTRY(psci_get_cpu_stack_top)
>  	add	r5, r5, #0x2000			@ Skip two pages
>  	lsr	r5, r5, #12			@ Align to start of page
>  	lsl	r5, r5, #12
> +	sub	r5, r5, #4			@ reserve 1 word for target PC
>  	sub	r0, r5, r0			@ here's our stack!
> 
>  	bx	lr
> @@ -212,13 +214,10 @@ ENTRY(psci_cpu_entry)
> 
>  	bl	_nonsec_init
> 
> -	adr	r0, _psci_target_pc
> -	ldr	r0, [r0]
> +	bl	psci_get_cpu_id			@ CPU ID => r0
> +	bl	psci_get_cpu_stack_top		@ stack top => r0
> +	ldr	r0, [r0]			@ target PC at stack top
>  	b	_do_nonsec_entry
>  ENDPROC(psci_cpu_entry)
> 
> -.globl _psci_target_pc
> -_psci_target_pc:
> -	.word	0
> -
>  	.popsection
> diff --git a/arch/arm/cpu/armv7/sunxi/psci.S b/arch/arm/cpu/armv7/sunxi/psci.S
> index dd583b2..7ec0500 100644
> --- a/arch/arm/cpu/armv7/sunxi/psci.S
> +++ b/arch/arm/cpu/armv7/sunxi/psci.S
> @@ -139,8 +139,11 @@ out:	mcr	p15, 0, r7, c1, c1, 0
>  	@ r2 = target PC
>  .globl	psci_cpu_on
>  psci_cpu_on:
> -	ldr	r0, =_psci_target_pc
> -	str	r2, [r0]
> +	push	{lr}
> +
> +	mov	r0, r1
> +	bl	psci_get_cpu_stack_top	@ get stack top of target CPU
> +	str	r2, [r0]		@ store target PC at stack top

Base on target PC will be saved in stack. The cpu(r1) should be mask firstly.
Because r1 value is 0xf0x, and it is not what we expected cpu value(0x1 or ...).
If not, the stack address is incorrect.

When I develop LS1021a PSCI code, I found this issue. So I think sunxi also has this
issue.

http://patchwork.ozlabs.org/patch/471695/

Regards,
-Dongsheng