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)
I think we need a special case for it.
C.
