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Date:   Fri, 15 Jul 2022 15:35:19 -0700
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Subject: Re: [PATCH] mtd: spi-nor: winbond: add support for W25Q512NW-IQ/IN
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From:   Jae Hyun Yoo <quic_jaehyoo@quicinc.com>
To:     Michael Walle <michael@walle.cc>
CC:     <clg@kaod.org>, <linux-kernel@vger.kernel.org>,
        <linux-mtd@lists.infradead.org>, <p.yadav@ti.com>,
        <quic_ggregory@quicinc.com>, <quic_jiles@quicinc.com>,
        <tudor.ambarus@microchip.com>
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Hi Michael,

On 7/15/2022 1:15 PM, Jae Hyun Yoo wrote:
> Hi Michael,
> 
> On 7/14/2022 7:30 AM, Jae Hyun Yoo wrote:
>> On 7/14/2022 7:21 AM, Michael Walle wrote:
>>> Am 2022-07-14 16:16, schrieb Michael Walle:
>>>> Am 2022-07-14 15:47, schrieb Jae Hyun Yoo:
>>>>> On 7/14/2022 12:41 AM, Michael Walle wrote:
>>>>>> What does "doesn't boot at all" mean? Are there any kernel startup
>>>>>> messages?
>>>>>
>>>>> I'm sharing the error messages below.
>>>>
>>>> Thanks.
>>>>
>>>>> [    0.748594] spi-nor spi0.0: w25q512nwq (65536 Kbytes)
>>>>> [    0.865216] spi-aspeed-smc 1e620000.spi: CE0 read buswidth:4 
>>>>> [0x406c0741]
>>>>> [    0.872833] ------------[ cut here ]------------
>>>>> [    0.877984] WARNING: CPU: 1 PID: 1 at drivers/mtd/mtdcore.c:583
>>>>> add_mtd_device+0x28c/0x53c
>>>>> [    0.887237] CPU: 1 PID: 1 Comm: swapper/0 Not tainted
>>>>> 5.15.43-AUTOINC-dirty-23801a6 #1
>>>>
>>>> Could you please try it on the latest (vanilla) linux-next?
>>>
>>> or spi-nor/next [1] as there are quite a lot of changes. The
>>> patches shall be based on that.
>>
>> Okay. Let me try that. I tested it using 5.15.43 with back-ported
>> spi-nor patches from the latest. I'll back-port more changes from
>> the spi-nor/next and will test the INFO(0xef6020, 0, 0, 0) setting
>> again.
> 
> I tested the setting again after cherry picking all SPI relating changes
> from the 'for-next' branch of
> git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi repository.
> 
> No luck! It's still making the same warning dump at 'add_mtd_device'
> since 'mtd->erasesize' is checked as 0.
> 
> I traced it further to check if the erasesize is properly parsed from
> the sfdp and checked that erase map seems parsed and initialized
> correctly in 'spi_nor_parse_bfpt' but problem is, a target
> mtd->erasesize is not properly selected in 'spi_nor_select_erase' since
> the 'wanted_size' variable is initialized as sector size of info table
> so a selected target mtd->erasesize is also 0 so looks like it's the
> reason why it can't initialize mtd device if we use
> INFO(0xef6020, 0, 0, 0).
> 
> Also, checked that the mtd->erasesize is set to 4096 if I enable
> CONFIG_MTD_SPI_NOR_USE_4K_SECTORS so the SPI flash can be initialized 
> with the INFO(0xef6020, 0, 0, 0) setting but, it should cover even when
> the configuration is not enabled. I think, this patch should go as it
> is. The erasesize selecting issue could be fixed using a separate
> patch.
> 
> Are you still sure that the INFO(0xef6020, 0, 0, 0) works in the
> latest spi-next?

I also tried to fix the issue and made a fix like below.

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 502967c76c5f..f8a020f80a56 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2117,7 +2117,7 @@ spi_nor_select_uniform_erase(struct 
spi_nor_erase_map *map,
                  * If the current erase size is the one, stop here:
                  * we have found the right uniform Sector Erase command.
                  */
-               if (tested_erase->size == wanted_size) {
+               if (wanted_size && tested_erase->size == wanted_size) {
                         erase = tested_erase;
                         break;
                 }

Tested that it makes the INFO(0xef6020, 0, 0, 0) setting work and a
selected mtd->erasesize is 65536 which is what I expected for this
device.

Not sure if it's a right fix or not. Please review and let me know if
it's good to submit or not.

Thanks,

Jae

> Thanks,
> 
> Jae
> 
>> -Jae
>>
>>> -michael
>>>
>>> [1] 
>>> git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git#spi-nor/next