[U-Boot] [PATCH] driver/mxc_i2c: Move static data structure to global_data

[Troy Kisky]

On 2/10/2014 7:34 PM, York Sun wrote:
> On 02/10/2014 02:02 PM, York Sun wrote:
>> This driver needs a data structure in SRAM before SDRAM is available.
>> This is not alway the case using .data section. Moving this data
>> structure to global_data guarantees it is writable.
>>
>> Signed-off-by: York Sun <yorksun at freescale.com>
>> CC: Troy Kisky <troy.kisky at boundarydevices.com>
>> ---
>>   drivers/i2c/mxc_i2c.c             |   18 ++++++++----------
>>   include/asm-generic/global_data.h |    3 +++
>>   2 files changed, 11 insertions(+), 10 deletions(-)
>>
> Troy,
>
> Following Tom's suggestion, I am trying to use linker script to put the srdata
> into SRAM. But I still have a concern regarding initializing the srdata. I don't
> see it is initialized anywhere. Do you presume the data is wiped out before the
> driver runs? If that's the case, I need to clear the data somewhere in my code.
>
> York
>
> .
>
As I understand it, the .data section follows the .text section and is 
relocated with it. Thus,
if your program is loaded into sram, the .data will be there as well. 
The .data section
also contains the initial value, so no need for code to initialize it. 
If later your code
is relocated to sdram, the .data section should be relocated as well. 
But if the data
has pointers initialized in code to point at sram, those will not be 
relocated and
will need some kind of fixup routine. I'm not very familiar with the SPL 
code
so take whatever I say with a grain of salt.

Troy