Re: [PATCH v4 6/6] mtd: spi-nor: spansion: Add s25hl-t/s25hs-t IDs and fixups

[<Tudor.Ambarus@microchip.com>]

Hi,

On 4/9/21 5:05 AM, Takahiro Kuwano wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 4/8/2021 7:03 PM, Tudor.Ambarus@microchip.com wrote:
>> On 4/8/21 11:21 AM, Takahiro Kuwano wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> Hi Tudor,
>>>
>>> On 4/8/2021 2:06 PM, Tudor.Ambarus@microchip.com wrote:
>>>> Hi,
>>>>
>>>> On 3/19/21 8:58 AM, tkuw584924@gmail.com wrote:
>>>>> +static int
>>>>> +s25hx_t_post_bfpt_fixups(struct spi_nor *nor,
>>>>> +                        const struct sfdp_parameter_header *bfpt_header,
>>>>> +                        const struct sfdp_bfpt *bfpt,
>>>>> +                        struct spi_nor_flash_parameter *params)
>>>>> +{
>>>>> +       int ret;
>>>>> +       u32 addr;
>>>>> +       u8 cfr3v;
>>>>> +
>>>>> +       ret = spi_nor_set_4byte_addr_mode(nor, true);
>>>>> +       if (ret)
>>>>> +               return ret;
>>>>> +       nor->addr_width = 4;
>>>>
>>>> Takahiro, you are bypassing the core functions. spansion_set_4byte_addr_mode()
>>>> will be called at set_4byte_addr_mode() time, resulting in an illegal op?
>>>>
>>> Since the spansion_post_sfdp_fixups() adds the SNOR_F_4B_OPCODES flag,
>>> spansion_set_4byte_addr_mode() is not called actually.
>>
>> right. Do we have to undo this somewhere, i.e, call
>> spi_nor_set_4byte_addr_mode(nor, false); ?
>>
> No. The Read/Write Any Register commands take 3 or 4 byte address depending
> on the Flash's current addr mode. Since the spansion_read/write_any_reg()
> use nor->addr_width which is always 4, the Flash's addr mode must always be
> in 4 byte mode.

If you reboot your board via cmdline, and the flash doesn't have a reset opcode,
the flash will remain in 4 byte mode when the driver loads again. Wouldn't that
affect the read sfdp command, since it is sent in 3 byte mode? Can you try a
"reboot" cmd and check what happens?

Cheers,
ta
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