[PATCH 5/8] sunxi: board: Save the chosen DT name in the SPL header

[Samuel Holland]

On 9/21/20 7:41 PM, André Przywara wrote:
> On 03/09/2020 06:07, Samuel Holland wrote:
>> This overwrites the name loaded from the SPL image. It will be different
>> if there was previously no name provided, or if a more accurate name was
>> determined by the board variant selection logic. This means that the DT> name in the SPL header now always matches the DT appended to U-Boot.
> 
> That's a nice way of preserving all this fancy DT selection choices for
> U-Boot proper!
> 
>> Signed-off-by: Samuel Holland <samuel at sholland.org>
> 
> One hint below, but nevertheless:
> 
> Reviewed-by: Andre Przywara <andre.przywara at arm.com>
> 
>> ---
>>  board/sunxi/board.c | 27 ++++++++++++++++++++++++++-
>>  1 file changed, 26 insertions(+), 1 deletion(-)
>>
>> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
>> index 3d64ed18664..eaa40a1ea96 100644
>> --- a/board/sunxi/board.c
>> +++ b/board/sunxi/board.c
>> @@ -331,6 +331,21 @@ static const char *get_spl_dt_name(void)
>>  	return NULL;
>>  }
>>  
>> +static void set_spl_dt_name(const char *name)
>> +{
>> +	struct boot_file_head *spl = get_spl_header(SPL_ENV_HEADER_VERSION);
>> +
>> +	if (spl == INVALID_SPL_HEADER)
>> +		return;
>> +
>> +	/* Promote the header version for U-Boot proper, if needed. */
>> +	if (spl->spl_signature[3] < SPL_DT_HEADER_VERSION)
>> +		spl->spl_signature[3] = SPL_DT_HEADER_VERSION;
>> +
>> +	strcpy((char *)&spl->string_pool, name);
> 
> Let's hope nobody ever optimises the strcpy() routine, as this might
> break (when doing unaligned accesses) on device memory, as in this case.

Why would any part of SRAM A1 be mapped as device memory? If U-Boot maps its own
code as device memory, and then implements a strcpy that requires aligned
multi-byte access (i.e. cannot handle arbitrary naturally-aligned char *), then
this code here isn't the bug.

Cheers,
Samuel

> Cheers,
> Andre.
> 
>> +	spl->dt_name_offset = offsetof(struct boot_file_head, string_pool);
>> +}
>> +
>>  int dram_init(void)
>>  {
>>  	struct boot_file_head *spl = get_spl_header(SPL_DRAM_HEADER_VERSION);
>> @@ -904,6 +919,7 @@ int ft_board_setup(void *blob, struct bd_info *bd)
>>  int board_fit_config_name_match(const char *name)
>>  {
>>  	const char *best_dt_name = get_spl_dt_name();
>> +	int ret;
>>  
>>  #ifdef CONFIG_DEFAULT_DEVICE_TREE
>>  	if (best_dt_name == NULL)
>> @@ -941,6 +957,15 @@ int board_fit_config_name_match(const char *name)
>>  	}
>>  #endif
>>  
>> -	return strcmp(name, best_dt_name);
>> +	ret = strcmp(name, best_dt_name);
>> +
>> +	/*
>> +	 * If one of the FIT configurations matches the most accurate DT name,
>> +	 * update the SPL header to provide that DT name to U-Boot proper.
>> +	 */
>> +	if (ret == 0)
>> +		set_spl_dt_name(best_dt_name);
>> +
>> +	return ret;
>>  }
>>  #endif
>>
>