[U-Boot] [PATCH v5 02/18] rockchip: boot0: align to 0x20 for armv7 '_start'

[Kever Yang]

Andy,


On 11/09/2017 05:03 AM, Dr. Philipp Tomsich wrote:
> Andy,
>
> On 9 Nov 2017, at 13:59, Andy Yan <andy.yan at rock-chips.com> wrote:
>> Hi Phipipp, Kever:
>>
>>
>> On 2017年10月10日 22:21, Philipp Tomsich wrote:
>>> From: Kever Yang <kever.yang at rock-chips.com>
>>>
>>> The '_start' is using as vector table base address, and will write
>>> to VBAR register, so it needs to be aligned to 0x20 for armv7.
>>>
>>> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
>>> [Updated to current code base:]
>>> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
>>>
>>> ---
>>>
>>> Changes in v5: None
>>> Changes in v4: None
>>> Changes in v3: None
>>> Changes in v2: None
>>>
>>>   arch/arm/include/asm/arch-rockchip/boot0.h | 14 ++++++++++++--
>>>   1 file changed, 12 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/arm/include/asm/arch-rockchip/boot0.h b/arch/arm/include/asm/arch-rockchip/boot0.h
>>> index 455d842..f7c6146 100644
>>> --- a/arch/arm/include/asm/arch-rockchip/boot0.h
>>> +++ b/arch/arm/include/asm/arch-rockchip/boot0.h
>>> @@ -6,12 +6,13 @@
>>>     /*
>>>    * Execution starts on the instruction following this 4-byte header
>>> - * (containing the magic 'RK33').
>>> + * (containing the magic 'RK30', 'RK31', 'RK32' or 'RK33').  This
>>> + * magic constant will be written into the final image by the rkimage
>>> + * tool, but we need to reserve space for it here.
>>>    *
>>>    * To make life easier for everyone, we build the SPL binary with
>>>    * space for this 4-byte header already included in the binary.
>>>    */
>>> -
>>>   #ifdef CONFIG_SPL_BUILD
>>>   	/*
>>>   	 * We need to add 4 bytes of space for the 'RK33' at the
>>> @@ -26,6 +27,15 @@
>>>   	b reset	 /* may be overwritten --- should be 'nop' or a 'b reset' */
>>>   #endif
>>>   	b reset
>>      Do we really need the "b reset" here? the macro ARM_VECTORS already has a b reset.
>> Besides Joseph found  that the irq function will not work with this "b reset”
> The quoted code was from an older version of the series, but the ‘b reset’ is still there
> in the newer version.
>
> What IRQ function does not work?
> Shouldn't the IRQ be jumping into the ARM_VECTORS and never see the ‘b reset’?

We need the 'b reset' here,  this is not present at the same time with 
ARM_VECTORS,
I think what we need to handle is that we don't need boot0_hook in U-Boot,
let me send a patch to fix this.

Thanks,
- Kever
>
>>> +#if !defined(CONFIG_ARM64)
>>> +	/*
>>> +	 * For armv7, the addr '_start' will used as vector start address
>>> +	 * and write to VBAR register, which needs to aligned to 0x20.
>>> +	 */
>>> +	.align(5)
>>> +_start:
>>> +	ARM_VECTORS
>>> +#endif
>>>     #if defined(CONFIG_ROCKCHIP_RK3399) && defined(CONFIG_SPL_BUILD)
>>>   	.space CONFIG_ROCKCHIP_SPL_RESERVE_IRAM	/* space for the ATF data */
>>
>