On 12/01/2016 06:52 PM, Ricardo Ribalda Delgado wrote:
> Hi Marek
Hi,
> Thanks for your review
>
> On Thu, Dec 1, 2016 at 5:05 PM, Marek Vasut <marek.va...@gmail.com> wrote:
>>
>> On 11/24/2016 05:56 PM, Ricardo Ribalda Delgado wrote:
>
>>> +#define SPI_S3AN BIT(10) /*
>>> + * Xilinx Spartan 3AN In-System Flash
>>> + * (MFR cannot be used for probing
>>> + * because it has the same value as
>>> + * ATMEL flashes)
>>> + */
>>
>> I have possibly off-topic question. Altera has something very similar --
>> EPCS/EPCQ flash which cannot be detected using standard READID .
>> Would this patch help with supporting those degenerate flashes too?
>>
>>> };
>>>
>
> I dont know, but I love the term degenerated flash, please let me use it :)
Hehe. It'd be great to know whether we don't have a possibility for a
generic usecase here. Can you briefly check that ?
>>> for (i = 0; i < len; ) {
>>> ssize_t written;
>>> + loff_t addr = to + i;
>>> +
>>> + if (hweight32(nor->page_size) == 1) {
>>> + page_offset = addr & (nor->page_size - 1);
>>> + } else {
>>> + uint64_t aux = addr;
>>>
>>> - page_offset = (to + i) & (nor->page_size - 1);
>>> + page_offset = do_div(aux, nor->page_size);
>>> + }
>>
>> Why is this part necessary ?
>
> If page_size is not a power of 2 (264,528), the & (size-1) operation
> for getting the offset does not work, you need to do a real modulus.
Aaah, now it makes sense. Ew, but all right, thanks for clarifying.
This could use a comment, somewhere along these lines.
>>> +
>>> + /* Flash in Power of 2 mode */
>>> + if (val & XSR_PAGESIZE) {
>>> + nor->page_size = (nor->page_size == 264) ? 256 : 512;
>>
>> 264 is due to some ECC ?
>
> The flash can be in standard mode or in power of two mode. You need to
> check the status register to know if the chip is in one mode or the
> other.
>
> The flash is in standard mode from factory, you can change the mode to
> power of two, but the data is corrupted and you cannot change back to
> standard mode.
>
> I guess they are using some bits reserved to ECC for data and that way
> you can squeeze some bits for user data.
OK, comment could help clarify this, so please add one.
>>> + nor->mtd.writebufsize = nor->page_size;
>>> + nor->mtd.size = 8 * nor->page_size * info->n_sectors;
>>> + nor->mtd.erasesize = 8 * nor->page_size;
>>> + } else {
>>> + nor->flags |= SNOR_F_S3AN_ADDR_DEFAULT;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>
>> [...]
>>
>> --
>> Best regards,
>> Marek Vasut
>
> Thanks Again
>
>
>
>
--
Best regards,
Marek Vasut
