Regression: at24 eeprom writing times out on sama5d3

Peter Rosin peda at axentia.se
Thu Jun 30 00:44:31 PDT 2022 

Hi again.

2022-06-10 at 22:51, Peter Rosin wrote:
> Hi!
> 
> 2022-06-10 at 09:35, Codrin.Ciubotariu at microchip.com wrote:
>> On 09.06.2022 17:28, Peter Rosin wrote:
>>> Hi!
>>
>> Hi Peter,
>>
>>>
>>> I have not actually bisected this issue but reverting the effects of
>>> patch a4bd8da893a3 ("ARM: dts: at91: sama5d3: add i2c gpio pinctrl")
>>> makes the problem go away.
>>>
>>> I.e. I need something like this in my dts
>>>
>>> &i2c2 {
>>>          status = "okay";
>>>
>>>          pinctrl-names = "default";
>>>          /delete-property/ pinctrl-1;
>>>          /delete-property/ sda-gpios;
>>>          /delete-property/ scl-gpios;
>>>
>>>          eeprom at 50 {
>>>                  compatible = "st,24c64", "atmel,24c64";
>>>                  reg = <0x50>;
>>>                  wp-gpios = <&filter_gpio 7 GPIO_ACTIVE_HIGH>;
>>>          };
>>> };
>>>
>>> for multi-page eeprom writes to not time out (a page is 32 bytes on this
>>> eeprom).
>>>
>>> For reference, the current defaults for this SoC/I2C-bus, that I modify,
>>> are:
>>>
>>>          pinctrl-names = "default", "gpio";
>>>          pinctrl-0 = <&pinctrl_i2c2>;
>>>          pinctrl-1 = <&pinctrl_i2c2_gpio>;
>>>          sda-gpios = <&pioA 18 GPIO_ACTIVE_HIGH>;
>>>          scl-gpios = <&pioA 19 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
>>>
>>> I suspect that the underlying reason is that the bus recovery takes
>>> too long and that the at24 eeprom driver gives up prematurely. I doubt
>>> that this is chip specific, but I don't know that.
>>>
>>> I can work around the issue in user space with by writing in 4 byte
>>> chunks, like so
>>>
>>> dd if=source.file of=/sys/bus/i2c/devices/2-0050/eeprom obs=4
>>>
>>> but that is really ugly and gets slow too, about 20 seconds to program
>>> the full 8kB eeprom. With the above in my dts it takes a second or
>>> so (a bit more with dynamic debug active).
>>>
>>>
>>> If I run
>>>
>>> dd if=source.file of=/sys/bus/i2c/devices/2-0050/eeprom
>>>
>>> with a source.file of 8kB and the upstream dts properties in place, I can
>>> collect the following debug output from at24, i2c-core and i2c-at91:
>>>
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 0 --> 0 (-23170)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 32 --> -121 (-23169)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 32 --> 0 (-23168)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 64 --> -121 (-23168)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 64 --> 0 (-23167)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -121 (-23167)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: controller timed out
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -110 (-23155)
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:56:34 me20 kernel: at91_i2c f801c000.i2c: controller timed out
>>> Jun  9 15:56:34 me20 kernel: i2c i2c-2: Trying i2c bus recovery
>>> Jun  9 15:56:34 me20 kernel: at24 2-0050: write 32 at 96 --> -110 (-23143)
>>>
>>> And then there is no more action. I.e. only a couple of 32 byte pages
>>> are written.
>>>
>>> With the above mentioned dts override in place I instead get this, which is
>>> a lot more sensible:
>>>
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 0 --> 0 (753629)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 32 --> -121 (753629)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 32 --> 0 (753630)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 64 --> -121 (753630)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 64 --> 0 (753631)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 96 --> -121 (753631)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 96 --> 0 (753632)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 128 --> -121 (753632)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 128 --> 0 (753633)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 160 --> -121 (753633)
>>> Jun  9 15:48:53 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:53 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:53 me20 kernel: at24 2-0050: write 32 at 160 --> 0 (753634)
>>> ... snip ...
>>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8128 --> -121 (753883)
>>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8128 --> 0 (753884)
>>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: received nack
>>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8160 --> -121 (753884)
>>> Jun  9 15:48:55 me20 kernel: i2c i2c-2: at91_xfer: processing 1 messages:
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer: write 34 bytes.
>>> Jun  9 15:48:55 me20 kernel: at91_i2c f801c000.i2c: transfer complete
>>> Jun  9 15:48:55 me20 kernel: at24 2-0050: write 32 at 8160 --> 0 (753885)
>>
>> could you please apply this patch-set [1] and let us know if it 
>> addresses your issue?
>>
>> Thanks and best regards,
>> Codrin
>>
>> https://patchwork.ozlabs.org/project/linux-i2c/list/?series=255408
> 
> That series does indeed help! I'll reply with a tested-by etc on the
> first two patches, I can't test patch 3/3 with my sama5d3 board...
> 
> Thank you very much!

Since replying to the actual patches do not work for me, I'm writing here
instead. Sorry about that. As stated above, it /seems/ to work much better
with these patches. But I fooled myself and there is still some remaining
trouble. It is not uncommon that the second (32-byte) page in the eeprom
is not written correctly for whatever reason. I do not know why it's
always the second page that gets corrupted, but this is a bad problem since
the failure is completely silent.

Cheers,
Peter

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