[U-Boot] [PATCH 1/5] ARM: socfpga: Add boot trampoline for Arria10

[Marek Vasut]

On 04/17/2018 10:40 AM, See, Chin Liang wrote:
> Hi Marek,
> 
> On Sun, 2018-04-15 at 15:37 +0200, Marek Vasut wrote:
>> The Arria10 uses slightly different boot image header than the Gen5
>> SoCs,
>> in particular the header itself contains an offset from the start of
>> the
>> header to which the Arria10 jumps. This offset must not be negative,
>> yet
>> the header is placed at offset 0x40 of the bootable binary.
>> Therefore, to
>> jump into U-Boot, add a trampoline just past the Arria10 boot header
>> and
>> point to this trampoline at fixed offset from the header generated
>> using
>> the mkimage -T socfpgaimage_v1 . Note that it is not needed to jump
>> back
>> to offset 0x0 of the image, it is possible to jump directly at the
>> reset
>> label and save processing two instructions.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> Cc: Dinh Nguyen <dinguyen at kernel.org>
>> Cc: Chin Liang See <chin.liang.see at intel.com>
>> ---
>>  arch/arm/mach-socfpga/include/mach/boot0.h | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/mach-socfpga/include/mach/boot0.h
>> b/arch/arm/mach-socfpga/include/mach/boot0.h
>> index d6b9435d33..06bbe27d2c 100644
>> --- a/arch/arm/mach-socfpga/include/mach/boot0.h
>> +++ b/arch/arm/mach-socfpga/include/mach/boot0.h
>> @@ -18,10 +18,10 @@ _start:
>>  	.word	0xcafec0d3;	/* Checksum, zero-pad */
>>  	nop;
>>  
>> -	b reset;		/* SoCFPGA jumps here */
>> -	nop;
>> +	b reset;		/* SoCFPGA Gen5 jumps here */
>>  	nop;
>>  	nop;
>> +	b reset;		/* SoCFPGA Gen10 trampoline */
> 
> Our mkpimage tools from SOCEDS is using 0x14 as offset. Wonder can we
> standardize that by using 0x14 instead of proposed 0x18 in this patch?

What difference does it make, the entire image is generated during the
build anyway ? This patch uses offset 0x1c, but what is the reason for
address 0x14 in your proprietary tool, is there one ?

-- 
Best regards,
Marek Vasut