On 7/22/20 10:02 AM, Cédric Le Goater wrote:
> On 7/21/20 9:57 PM, Guenter Roeck wrote:
>> On 7/21/20 10:36 AM, Cédric Le Goater wrote:
>>> Hello,
>>>
>>> On 2/6/20 7:32 PM, Guenter Roeck wrote:
>>>> When requesting JEDEC data using the JEDEC_READ command, the Linux kernel
>>>> always requests 6 bytes. The current implementation only returns three
>>>> bytes, and interprets the remaining three bytes as new commands.
>>>> While this does not matter most of the time, it is at the very least
>>>> confusing. To avoid the problem, always report up to 6 bytes of JEDEC
>>>> data. Fill remaining data with 0.
>>>>
>>>> Signed-off-by: Guenter Roeck <li...@roeck-us.net>
>>>> ---
>>>> v2: Split patch into two parts; improved decription
>>>>
>>>> hw/block/m25p80.c | 5 ++++-
>>>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
>>>> index 5ff8d270c4..53bf63856f 100644
>>>> --- a/hw/block/m25p80.c
>>>> +++ b/hw/block/m25p80.c
>>>> @@ -1040,8 +1040,11 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>>>> for (i = 0; i < s->pi->id_len; i++) {
>>>> s->data[i] = s->pi->id[i];
>>>> }
>>>> + for (; i < SPI_NOR_MAX_ID_LEN; i++) {
>>>> + s->data[i] = 0;
>>>> + }
>>>
>>> This is breaking an old firmware (Linux version 2.6.28.9) for a SuperMicro
>>> board :
>>>
>>> https://www.supermicro.com/en/products/motherboard/X11SSL-F
>>>
>>> which expects the flash ID to repeat. Erik solved the problem with the
>>> patch
>>> below and I think it makes sense to wrap around. Anyone knows what should
>>> be
>>> the expected behavior ?
>>>
>>
>> No idea what the expected behavior is, but I am fine with the code below
>> if it works.
>
> I checked on a few real systems and indeed the mx25l25635e behaves
> differently.
>
> AST2400
>
> [ 5.594176] aspeed-smc 1e620000.spi: reading JEDEC ID 20:BA:19:10:00:00
> [ 5.602226] aspeed-smc 1e620000.spi: n25q256a (32768 Kbytes)
> ...
> [ 6.174052] aspeed-smc 1e630000.spi: reading JEDEC ID C2:20:19:C2:20:19
> [ 6.181682] aspeed-smc 1e630000.spi: mx25l25635e (32768 Kbytes)
>
> AST2500
>
> [ 1.641317] aspeed-smc 1e620000.spi: reading JEDEC ID EF:40:19:00:00:00
> [ 1.648174] aspeed-smc 1e620000.spi: w25q256 (32768 Kbytes)
> ...
> [ 1.179214] aspeed-smc 1e630000.spi: reading JEDEC ID EF:40:19:00:00:00
> [ 1.186737] aspeed-smc 1e630000.spi: w25q256 (32768 Kbytes)
>
> AST2600
>
> [ 1.020255] aspeed-smc 1e620000.spi: reading JEDEC ID EF:40:20:00:00:00
> [ 1.027830] aspeed-smc 1e620000.spi: w25q512jv (65536 Kbytes)
> ...
> [ 1.884171] aspeed-smc 1e630000.spi: reading JEDEC ID EF:40:19:00:00:00
> [ 1.890937] aspeed-smc 1e630000.spi: w25q256 (32768 Kbytes)
FWIW QEMU models this one as 64KiB.
>
>
> I think we need a special case for it.
>
> C.
>
