[U-Boot] [PATCH 2/2] armv8: fsl-layerscape: SMP support for loading 32-bit OS

[Alexander Graf]

On 13.05.16 10:40, Alison Wang wrote:
> Spin-table method is used for secondary cores to load 32-bit OS. The
> architecture information will be got through checking FIT image and
> saved in the os_arch element of spin-table, then the secondary cores
> will check os_arch and jump to 32-bit OS or 64-bit OS automatically.
> 
> Signed-off-by: Alison Wang <alison.wang at nxp.com>
> Signed-off-by: Chenhui Zhao <chenhui.zhao at nxp.com>
> ---
>  arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S  | 21 +++++++++++++++++++++
>  arch/arm/cpu/armv8/fsl-layerscape/mp.c        | 10 ++++++++++
>  arch/arm/include/asm/arch-fsl-layerscape/mp.h |  6 ++++++
>  arch/arm/lib/bootm.c                          |  5 +++++
>  4 files changed, 42 insertions(+)
> 
> diff --git a/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S b/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S
> index 04831ca..85d1d4b 100644
> --- a/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S
> +++ b/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S
> @@ -13,6 +13,7 @@
>  #ifdef CONFIG_MP
>  #include <asm/arch/mp.h>
>  #endif
> +#include <asm/u-boot.h>
>  
>  ENTRY(lowlevel_init)
>  	mov	x29, lr			/* Save LR */
> @@ -320,6 +321,11 @@ ENTRY(secondary_boot_func)
>          gic_wait_for_interrupt_m x0, w1
>  #endif
>  
> +	ldr	x5, [x11, #24]
> +	ldr	x6, =IH_ARCH_DEFAULT
> +	cmp	x6, x5
> +	b.ne	slave_cpu
> +
>  	bl secondary_switch_to_el2
>  #ifdef CONFIG_ARMV8_SWITCH_TO_EL1
>  	bl secondary_switch_to_el1
> @@ -337,6 +343,21 @@ slave_cpu:
>  	tbz     x1, #25, cpu_is_le
>  	rev     x0, x0                  /* BE to LE conversion */
>  cpu_is_le:
> +
> +	ldr	x5, [x11, #24]
> +	ldr	x6, =IH_ARCH_DEFAULT
> +	cmp	x6, x5
> +	b.eq	1f
> +
> +#ifdef CONFIG_ARMV8_SWITCH_TO_EL1
> +	bl	secondary_switch_to_el2
> +	ldr	x0, [x11]
> +	bl	armv8_switch_to_el1_aarch32
> +#else
> +	bl	armv8_switch_to_el2_aarch32
> +#endif

Ah, so conditionally you also need to invoke the aarch64 variant. Why
not just make it an actual runtime parameter to the existing function?

Also as a side remark, the "clean" solution would obviously be to
support PSCI and just check which mode the caller was in.


Alex