[U-Boot] [PATCH v4 04/14] ARM: Factor out reusable psci_cpu_entry

[Marc Zyngier <marc.zyngier@arm.com>]

On Fri, 27 Feb 2015 13:28:03 +0000
Jan Kiszka <jan.kiszka@siemens.com> wrote:

> _sunxi_cpu_entry can be converted completely into a reusable
> psci_cpu_entry. Tegra124 will use it as well.
> 
> CC: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  arch/arm/cpu/armv7/psci.S       | 18 ++++++++++++++++++
>  arch/arm/cpu/armv7/sunxi/psci.S | 20 ++------------------
>  2 files changed, 20 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
> index d688607..315c20b 100644
> --- a/arch/arm/cpu/armv7/psci.S
> +++ b/arch/arm/cpu/armv7/psci.S
> @@ -170,4 +170,22 @@ ENTRY(psci_cpu_off_common)
>  	bx	lr
>  ENDPROC(psci_cpu_off_common)
>  
> +ENTRY(psci_cpu_entry)
> +	@ Set SMP bit
> +	mrc	p15, 0, r0, c1, c0, 1		@ ACTLR
> +	orr	r0, r0, #(1 << 6)		@ Set SMP bit
> +	mcr	p15, 0, r0, c1, c0, 1		@ ACTLR
> +	isb
> +
> +	bl	_nonsec_init
> +
> +	adr	r0, _psci_target_pc
> +	ldr	r0, [r0]
> +	b	_do_nonsec_entry
> +ENDPROC(psci_cpu_entry)

I'd add a *big* comment at the top of this. ACTLR is implementation
dependent, and while sticking the SMP bit at this location is fairly
common among ARM cores, it is by no mean a strong guarantee (this is
not an architectural feature).

I'd recommend making it override-able.

> +.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 bb3d4ef..9ea3ce8 100644
> --- a/arch/arm/cpu/armv7/sunxi/psci.S
> +++ b/arch/arm/cpu/armv7/sunxi/psci.S
> @@ -139,7 +139,7 @@ out:	mcr	p15, 0, r7, c1, c1, 0
>  	@ r2 = target PC
>  .globl	psci_cpu_on
>  psci_cpu_on:
> -	adr	r0, _target_pc
> +	ldr	r0, =_psci_target_pc
>  	str	r2, [r0]
>  	dsb
>  
> @@ -151,7 +151,7 @@ psci_cpu_on:
>  	mov	r4, #1
>  	lsl	r4, r4, r1
>  
> -	adr	r6, _sunxi_cpu_entry
> +	ldr	r6, =psci_cpu_entry
>  	str	r6, [r0, #0x1a4] @ PRIVATE_REG (boot vector)
>  
>  	@ Assert reset on target CPU
> @@ -197,22 +197,6 @@ psci_cpu_on:
>  	mov	r0, #ARM_PSCI_RET_SUCCESS	@ Return
> PSCI_RET_SUCCESS mov	pc, lr
>  
> -_target_pc:
> -	.word	0
> -
> -_sunxi_cpu_entry:
> -	@ Set SMP bit
> -	mrc	p15, 0, r0, c1, c0, 1
> -	orr	r0, r0, #0x40
> -	mcr	p15, 0, r0, c1, c0, 1
> -	isb
> -
> -	bl	_nonsec_init
> -
> -	adr	r0, _target_pc
> -	ldr	r0, [r0]
> -	b	_do_nonsec_entry
> -
>  .globl	psci_cpu_off
>  psci_cpu_off:
>  	bl	psci_cpu_off_common



-- 
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