Re: [PATCH v11 3/3] mtd: spi-nor: spansion: Add s25hl-t/s25hs-t IDs and fixups

[<Tudor.Ambarus@microchip.com>]

On 4/20/22 10:35, Tudor Ambarus - M18064 wrote:
> On 4/20/22 09:58, Takahiro Kuwano wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 4/20/2022 3:11 PM, Tudor.Ambarus@microchip.com wrote:
>>> On 4/20/22 08:34, Takahiro Kuwano wrote:
>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>
>>>> Hi Tudor,
>>>>
>>>> Thank you for your feedback.
>>>>
>>>> On 4/19/2022 6:32 PM, Tudor.Ambarus@microchip.com wrote:
>>>>> On 4/18/22 08:41, tkuw584924@gmail.com wrote:
>>>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>>>
>>>>>> From: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
>>>>>>
>>>>>> The S25HL-T/S25HS-T family is the Infineon SEMPER Flash with Quad SPI.
>>>>>>
>>>>>> For the single-die package parts (512Mb and 1Gb), only bottom 4KB and
>>>>>> uniform sector sizes are supported. This is due to missing or incorrect
>>>>>> entries in SMPT. Fixup for other sector sizes configurations will be
>>>>>> followed up as needed.
>>>>>>
>>>>>> Tested on Xilinx Zynq-7000 FPGA board.
>>>>>>
>>>>>> Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
>>>>>> ---
>>>>>> Changes in v11:
>>>>>>   - Cleanup fixups based on other patches in this series
>>>>>>
>>>>>> Changes in v10:
>>>>>>   - Cleanup fixups and ID table based on other patches in this series
>>>>>>
>>>>>> Changes in v9:
>>>>>>   - Use late_init() hook to fix mode clocks and writesize
>>>>>>   - Use PARSE_SFDP instead of NO_SFDP_FLAGS
>>>>>>   - Use MFR_FLAGS for USE_CLSR
>>>>>>   - Add comment block to explain about addr mode in post_bfpt_fixups()
>>>>>>
>>>>>> Changes in v8:
>>>>>>   - Call write_disable in error case only
>>>>>>   - Use spi_nor_read_reg() helper
>>>>>>   - Use nor->bouncebuf instead of variable on stack
>>>>>>   - Update ID table to use FLAGS macro
>>>>>>
>>>>>> Changes in v7:
>>>>>>   - Add missing device info table in v6
>>>>>>
>>>>>> Changes in v6:
>>>>>>   - Remove 2Gb multi die pacakge support
>>>>>>
>>>>>> Changes in v5:
>>>>>>   - Add NO_CHIP_ERASE flag to S25HL02GT and S25HS02GT
>>>>>>
>>>>>> Changes in v4:
>>>>>>   - Merge block comments about SMPT in s25hx_t_post_sfdp_fixups()
>>>>>>   - Remove USE_CLSR flags from S25HL02GT and S25HS02GT
>>>>>>
>>>>>> Changes in v3:
>>>>>>   - Remove S25HL256T and S25HS256T
>>>>>>   - Add S25HL02GT and S25HS02GT
>>>>>>   - Add support for multi-die package parts support
>>>>>>   - Remove erase_map fix for top/split sector layout
>>>>>>   - Set ECC data unit size (16B) to writesize
>>>>>>
>>>>>>  drivers/mtd/spi-nor/spansion.c | 54 ++++++++++++++++++++++++++++++++++
>>>>>>  1 file changed, 54 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
>>>>>> index 493240ebfd70..dd37b829efbc 100644
>>>>>> --- a/drivers/mtd/spi-nor/spansion.c
>>>>>> +++ b/drivers/mtd/spi-nor/spansion.c
>>>>>> @@ -208,6 +208,44 @@ static int cypress_nor_set_page_size(struct spi_nor *nor, u8 addr_width)
>>>>>>         return 0;
>>>>>>  }
>>>>>>
>>>>>> +static int
>>>>>> +s25hx_t_post_bfpt_fixups(struct spi_nor *nor,
>>>>>> +                        const struct sfdp_parameter_header *bfpt_header,
>>>>>> +                        const struct sfdp_bfpt *bfpt)
>>>>>> +{
>>>>>> +       int ret;
>>>>>> +
>>>>>> +       /*
>>>>>> +        * From BFPT, the nor->addr_width is set to 3. In Read Any Reg op, the
>>>>>> +        * Flash takes 3-byte or 4-byte addr depending current addr mode. Since
>>>>>> +        * Read Any Reg op is called in this hook and SMPT parse, we would sync
>>>>>
>>>>> Hi, Takahiro,
>>>>>
>>>>> I would like some details, please.
>>>>> 1/ with "this hook" you refer to cypress_nor_set_page_size(). Why can't you use a
>>>>> addr_width of value 3 when reading SPINOR_REG_CYPRESS_CFR3V?
>>>>>
>>>> If we are sure that the Flash is in 3-byte address mode, we can use the value 3
>>>> for reading CFR3V. However, the Flash's address mode may be changed prior to
>>>> Linux MTD probe in some use cases. Actually, in u-boot, it is set to 4-byte
>>>> address mode. We need to set the Flash's address mode in known state and update
>>>
>>> addr_width is set via CFR2Volatile, can we reset the flash at probe instead? Then
>>> you'll be sure that the flash is in its default state.
>>>
>> Resetting the Flash to revert back to default state should work for this. However,
> 
> good, let's do this.
> 
>> we still have SMPT issue below.
>>
>>>> nor->addr_width accordingly. Due to SMPT issue below, value of 4 would be better
>>>> choice.
>>>>
>>>>> 2/ Where in SMPT parse? I looked through the code and couldn't find the Read Any
>>>>> Reg op used. Why do you need an addr_width of value 4 in SMPT parse?
>>>>>
>>>> In the spi_nor_get_map_in_use(), the nor->read_opcode is set to 0x65 (=Read Any Reg).
>>>> The spi_nor_smpt_addr_width() returns the value of the nor->addr_width due to
>>>
>>> ok
>>>
>>>> SMPT_CMD_ADDRESS_LEN_USE_CURRENT. The nor->addr_width is set to 4 in the
>>>> spi_nor_parse_4bait() before SMPT parse. Therefore, the host issues Read Any Reg
>>>
>>> if 4bait is parsed before SMPT and nor->addr_width is already set to 4 in parse_4bait,
>>> then you don't have to do anything for SMPT, right?
>>>
>> Currently 4bait is parsed before SMPT. So, if we are sure the Flash is in 4-byte address
>> mode (by u-boot, for example), we don't have to do anything. If the Flash is in 3-byte
>> address mode (default), SMPT parse does not work correctly.
>>
>> Please see this about 4BAIT and SMPT issue.
>> https://patchwork.ozlabs.org/project/linux-mtd/patch/20201212115817.5122-1-vigneshr@ti.com/
>>
>> I introduced another workaround for SMPT issue in my previous series.
>> https://patchwork.ozlabs.org/project/linux-mtd/patch/9a2d323b2c18485d13f271e3bb213b96fea0e7e1.1649641729.git.Takahiro.Kuwano@infineon.com/
>> I withdrew this because this does not work if Flash address mode is not default state.
>> But if we can reset the Flash at probe, this should work.
> 
> Hmm. How about issuing spi_nor_set_4byte_addr_mode after parsing 4bait table,
> to solve this dependency?

or maybe we can add a smpt hook where you interrogate the state of addr mode
from CR2V and use the add_width from CR2V instead of relying on what we get
from SMPT_CMD_ADDRESS_LEN_USE_CURRENT. This will avoid changing the state
of the flash at parse time.
 
> 
>>
>>
>>>> with 4-byte address. We need to set the Flash into 4-byte address mode in advance.
>>>>
>>>>>
>>>>>> +        * Flash's addr mode and nor->addr_width here.
>>>>>> +        */
>>>>>> +       ret = spi_nor_set_4byte_addr_mode(nor, true);
>>>>>> +       if (ret)
>>>>>> +               return ret;
>>>>>> +       nor->addr_width = 4;
>>>>>> +
>>>>>> +       /* Replace Quad Enable with volatile version */
>>>>>> +       nor->params->quad_enable = cypress_nor_quad_enable_volatile;
>>>>>> +
>>>>>> +       return cypress_nor_set_page_size(nor, nor->addr_width);
>>>>>> +}
>>>>>> +
>>>>>> +void s25hx_t_late_init(struct spi_nor *nor)
>>>>>> +{
>>>>>> +       /* Fast Read 4B requires mode cycles */
>>>>>> +       nor->params->reads[SNOR_CMD_READ_FAST].num_mode_clocks = 8;
>>>>>
>>>>> Isn't this info already handled in BFPT? What value of num_mode_clocks
>>>>> do you obtain from BFPT for the non-4B opcode?
>>>>>
>>>> There is no parameter in BFPT that describes about Fast Read 1-1-1 op
>>>> (as we can see 'struct sfdp_bfpt_read' in sfdp.c).
>>>> The value of num_mode_clocks for Fast Read 1-1-1 is set to 0 in
>>>> spi_nor_init_default_params().
>>>>
>>>
>>> I see, thanks!
>>
>> Thanks,
>> Takahiro
> 

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