[U-Boot] [PATCH v2] sunxi_nand_spl: Be smarter about where to look for backup u-boot.bin

[Hans de Goede]

Hi,

On 21-09-15 12:22, Ian Campbell wrote:
> On Sun, 2015-09-20 at 15:39 -0400, Hans de Goede wrote:
>> We know when u-boot is written to its own partition, in this case the
>> layout always is:
>>
>> eb 0 spl
>> eb 1 spl-backup
>> eb 2 u-boot
>> eb 3 u-boot-backup
>>
>> eb: erase-block
>>
>> So if we cannot load u-boot from its primary offset we know exactly where
>> to look for it.
>
> Is it worth noting here (or perhaps in a code comment?) that the code
> currently assumes that the first four ebs are of uniform size?

The eraseblock size is a property of the nand, given a certain nand chip,
all eraseblocks on that chip always have the same size.

Regards,

Hans


>
>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> ---
>> Changes in v2:
>> -Add an eraseblock_size helper variable to make the calculation for
>> finding
>>   the backup u-boot easier to understand
>> ---
>>   drivers/mtd/nand/sunxi_nand_spl.c | 26 ++++++++++++++++++++------
>>   1 file changed, 20 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/sunxi_nand_spl.c
>> b/drivers/mtd/nand/sunxi_nand_spl.c
>> index 5985534..b0e07aa 100644
>> --- a/drivers/mtd/nand/sunxi_nand_spl.c
>> +++ b/drivers/mtd/nand/sunxi_nand_spl.c
>> @@ -356,18 +356,32 @@ static int nand_read_buffer(uint32_t offs, unsigned
>> int size, void *dest,
>>
>>   int nand_spl_load_image(uint32_t offs, unsigned int size, void *dest)
>>   {
>> +#if CONFIG_SYS_NAND_U_BOOT_OFFS == CONFIG_SPL_PAD_TO
>> +	/*
>> +	 * u-boot-dtb.bin appended to SPL, use syndrome (like the BROM
>> does)
>> +	 * and try different erase block sizes to find the backup.
>> +	 */
>>   	const uint32_t boot_offsets[] = {
>>   		0 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
>>   		1 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
>>   		2 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
>>   		4 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
>>   	};
>> -	int i, syndrome;
>> -
>> -	if (CONFIG_SYS_NAND_U_BOOT_OFFS == CONFIG_SPL_PAD_TO)
>> -		syndrome = 1; /* u-boot-dtb.bin appended to SPL */
>> -	else
>> -		syndrome = 0; /* u-boot-dtb.bin on its own partition */
>> +	const int syndrome = 1;
>> +#else
>> +	/*
>> +	 * u-boot-dtb.bin on its own partition, do not use syndrome, u
>> -boot
>> +	 * partition sits after 2 eraseblocks (spl, spl-backup), look
>> for
>> +	 * backup u-boot 1 erase block further.
>> +	 */
>> +	const uint32_t eraseblock_size = CONFIG_SYS_NAND_U_BOOT_OFFS /
>> 2;
>> +	const uint32_t boot_offsets[] = {
>> +		CONFIG_SYS_NAND_U_BOOT_OFFS,
>> +		CONFIG_SYS_NAND_U_BOOT_OFFS + eraseblock_size,
>> +	};
>> +	const int syndrome = 0;
>> +#endif
>> +	int i;
>>
>>   	if (offs == CONFIG_SYS_NAND_U_BOOT_OFFS) {
>>   		for (i = 0; i < ARRAY_SIZE(boot_offsets); i++) {