[U-Boot] [PATCH v2 08/15] sf: Respect maximum SPI write size

[Simon Glass]

Hi Jagan,

On Tue, Apr 23, 2013 at 1:44 PM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> Hi Simon,
>
> On Mon, Mar 11, 2013 at 9:38 PM, Simon Glass <sjg at chromium.org> wrote:
>> Some SPI flash controllers (e.g. Intel ICH) have a limit on the number of
>> bytes that can be in a write transaction. Support this by breaking the
>> writes into multiple transactions.
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
>> ---
>> Changes in v2: None
>>
>>  drivers/mtd/spi/spi_flash.c | 10 ++++++++--
>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
>> index 17f3d3c..b82011d 100644
>> --- a/drivers/mtd/spi/spi_flash.c
>> +++ b/drivers/mtd/spi/spi_flash.c
>> @@ -87,6 +87,9 @@ int spi_flash_cmd_write_multi(struct spi_flash *flash, u32 offset,
>>         for (actual = 0; actual < len; actual += chunk_len) {
>>                 chunk_len = min(len - actual, page_size - byte_addr);
>>
>> +               if (flash->spi->max_write_size)
>> +                       chunk_len = min(chunk_len, flash->spi->max_write_size);
>> +
>>                 cmd[1] = page_addr >> 8;
>>                 cmd[2] = page_addr;
>>                 cmd[3] = byte_addr;
>> @@ -111,8 +114,11 @@ int spi_flash_cmd_write_multi(struct spi_flash *flash, u32 offset,
>>                 if (ret)
>>                         break;
>>
>> -               page_addr++;
>> -               byte_addr = 0;
>> +               byte_addr += chunk_len;
>> +               if (byte_addr == page_size) {
>> +                       page_addr++;
>> +                       byte_addr = 0;
>> +               }
>
> Does this change required to handle < page_size writes, means if the
> user is giving an offset other than
> multiples of page_sizes?

I'm not quite sure what you are saying, but let me try to response.

I believe what should happen is that byte_addr should become aligned
to the page_size after the first transfer, and from then on it should
start at 0 for each page.

Are you seeing a problem?

Regards,
Simon

>
> Thanks,
> Jagan.