Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Claudiu Beznea]

On 28.11.2017 12:44, Bartosz Golaszewski wrote:
> 2017-11-28 11:25 GMT+01:00 Andy Shevchenko :
>> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>>> making it impossible to read it all.
>>>
>>> Fix it by manually adjusting the value in probe().
>>>
>>> This patch contains a temporary fix that is suitable for stable
>>> branches. Eventually we'll probably remove the call to ilog2() while
>>> converting the magic values to actual structs.
>>
>>> +   /*
>>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>>> while
>>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>>> +*
>>> +* Eventually we'll get rid of the magic values altoghether in 
>>> favor of
>>> +* real structs, but for now just manually set the right size.
>>> +*/
>>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>>
>> I didn't check, but do we need to test for len == 4 at all?
>>
>>> +   chip.byte_len = 6;
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
> 
> Yes, because the fix is only relevant for at24mac402 whose MAC byte
> array is 6 bytes long, while the one in at24mac602 is 8 bytes and the
> driver doesn't truncate the byte_len for it.
>From my point of view, I think all chips in at24_ids[] array should be checked
about restrictions regarding the size truncation (especially the ones from the
initial commit: "2b7a5056a0a7ff17d5d2 i2c: New-style EEPROM driver using device 
IDs"
which introduces AT24_DEVICE_MAGIC() macro)  and if none of them has such 
restrictions
we should get rid of the ilog2() restrictions.

Just my 2 cents...
Claudiu

> 
> Thanks,
> Bartosz
> 

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Claudiu Beznea]

On 28.11.2017 12:44, Bartosz Golaszewski wrote:
> 2017-11-28 11:25 GMT+01:00 Andy Shevchenko :
>> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>>> making it impossible to read it all.
>>>
>>> Fix it by manually adjusting the value in probe().
>>>
>>> This patch contains a temporary fix that is suitable for stable
>>> branches. Eventually we'll probably remove the call to ilog2() while
>>> converting the magic values to actual structs.
>>
>>> +   /*
>>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>>> while
>>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>>> +*
>>> +* Eventually we'll get rid of the magic values altoghether in 
>>> favor of
>>> +* real structs, but for now just manually set the right size.
>>> +*/
>>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>>
>> I didn't check, but do we need to test for len == 4 at all?
>>
>>> +   chip.byte_len = 6;
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
> 
> Yes, because the fix is only relevant for at24mac402 whose MAC byte
> array is 6 bytes long, while the one in at24mac602 is 8 bytes and the
> driver doesn't truncate the byte_len for it.
>From my point of view, I think all chips in at24_ids[] array should be checked
about restrictions regarding the size truncation (especially the ones from the
initial commit: "2b7a5056a0a7ff17d5d2 i2c: New-style EEPROM driver using device 
IDs"
which introduces AT24_DEVICE_MAGIC() macro)  and if none of them has such 
restrictions
we should get rid of the ilog2() restrictions.

Just my 2 cents...
Claudiu

> 
> Thanks,
> Bartosz
> 

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Heiner Kallweit]

Am 28.11.2017 um 13:09 schrieb Andy Shevchenko:
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>> making it impossible to read it all.
>>
>> Fix it by manually adjusting the value in probe().
>>
>> This patch contains a temporary fix that is suitable for stable
>> branches. Eventually we'll probably remove the call to ilog2() while
>> converting the magic values to actual structs.
>>
> 
> Reviewed-by: Andy Shevchenko 
> 
Looks good also to me.

>> Cc: sta...@vger.kernel.org
>> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
>> Signed-off-by: Bartosz Golaszewski 
>> ---
>>  drivers/misc/eeprom/at24.c | 10 ++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index e0b4b36ef010..783244b485cc 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -730,6 +730,16 @@ static int at24_probe(struct i2c_client *client, const 
>> struct i2c_device_id *id)
>> dev_warn(>dev,
>> "page_size looks suspicious (no power of 2)!\n");
>>
>> +   /*
>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>> while
>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>> +*
>> +* Eventually we'll get rid of the magic values altoghether in favor 
>> of
>> +* real structs, but for now just manually set the right size.
>> +*/
>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>> +   chip.byte_len = 6;
>> +
>> /* Use I2C operations unless we're stuck with SMBus extensions. */
>> if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
>> if (chip.flags & AT24_FLAG_ADDR16)
>> --
>> 2.15.0
>>
> 
> 
> 

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Heiner Kallweit]

Am 28.11.2017 um 13:09 schrieb Andy Shevchenko:
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>> making it impossible to read it all.
>>
>> Fix it by manually adjusting the value in probe().
>>
>> This patch contains a temporary fix that is suitable for stable
>> branches. Eventually we'll probably remove the call to ilog2() while
>> converting the magic values to actual structs.
>>
> 
> Reviewed-by: Andy Shevchenko 
> 
Looks good also to me.

>> Cc: sta...@vger.kernel.org
>> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
>> Signed-off-by: Bartosz Golaszewski 
>> ---
>>  drivers/misc/eeprom/at24.c | 10 ++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index e0b4b36ef010..783244b485cc 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -730,6 +730,16 @@ static int at24_probe(struct i2c_client *client, const 
>> struct i2c_device_id *id)
>> dev_warn(>dev,
>> "page_size looks suspicious (no power of 2)!\n");
>>
>> +   /*
>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>> while
>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>> +*
>> +* Eventually we'll get rid of the magic values altoghether in favor 
>> of
>> +* real structs, but for now just manually set the right size.
>> +*/
>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>> +   chip.byte_len = 6;
>> +
>> /* Use I2C operations unless we're stuck with SMBus extensions. */
>> if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
>> if (chip.flags & AT24_FLAG_ADDR16)
>> --
>> 2.15.0
>>
> 
> 
> 

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Andy Shevchenko]

On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
> making it impossible to read it all.
>
> Fix it by manually adjusting the value in probe().
>
> This patch contains a temporary fix that is suitable for stable
> branches. Eventually we'll probably remove the call to ilog2() while
> converting the magic values to actual structs.
>

Reviewed-by: Andy Shevchenko 

> Cc: sta...@vger.kernel.org
> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
> Signed-off-by: Bartosz Golaszewski 
> ---
>  drivers/misc/eeprom/at24.c | 10 ++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index e0b4b36ef010..783244b485cc 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -730,6 +730,16 @@ static int at24_probe(struct i2c_client *client, const 
> struct i2c_device_id *id)
> dev_warn(>dev,
> "page_size looks suspicious (no power of 2)!\n");
>
> +   /*
> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
> while
> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
> +*
> +* Eventually we'll get rid of the magic values altoghether in favor 
> of
> +* real structs, but for now just manually set the right size.
> +*/
> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
> +   chip.byte_len = 6;
> +
> /* Use I2C operations unless we're stuck with SMBus extensions. */
> if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> if (chip.flags & AT24_FLAG_ADDR16)
> --
> 2.15.0
>



-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Andy Shevchenko]

On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
> making it impossible to read it all.
>
> Fix it by manually adjusting the value in probe().
>
> This patch contains a temporary fix that is suitable for stable
> branches. Eventually we'll probably remove the call to ilog2() while
> converting the magic values to actual structs.
>

Reviewed-by: Andy Shevchenko 

> Cc: sta...@vger.kernel.org
> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
> Signed-off-by: Bartosz Golaszewski 
> ---
>  drivers/misc/eeprom/at24.c | 10 ++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index e0b4b36ef010..783244b485cc 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -730,6 +730,16 @@ static int at24_probe(struct i2c_client *client, const 
> struct i2c_device_id *id)
> dev_warn(>dev,
> "page_size looks suspicious (no power of 2)!\n");
>
> +   /*
> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
> while
> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
> +*
> +* Eventually we'll get rid of the magic values altoghether in favor 
> of
> +* real structs, but for now just manually set the right size.
> +*/
> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
> +   chip.byte_len = 6;
> +
> /* Use I2C operations unless we're stuck with SMBus extensions. */
> if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> if (chip.flags & AT24_FLAG_ADDR16)
> --
> 2.15.0
>



-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Bartosz Golaszewski]

2017-11-28 11:25 GMT+01:00 Andy Shevchenko :
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>> making it impossible to read it all.
>>
>> Fix it by manually adjusting the value in probe().
>>
>> This patch contains a temporary fix that is suitable for stable
>> branches. Eventually we'll probably remove the call to ilog2() while
>> converting the magic values to actual structs.
>
>> +   /*
>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>> while
>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>> +*
>> +* Eventually we'll get rid of the magic values altoghether in favor 
>> of
>> +* real structs, but for now just manually set the right size.
>> +*/
>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>
> I didn't check, but do we need to test for len == 4 at all?
>
>> +   chip.byte_len = 6;
>
> --
> With Best Regards,
> Andy Shevchenko

Yes, because the fix is only relevant for at24mac402 whose MAC byte
array is 6 bytes long, while the one in at24mac602 is 8 bytes and the
driver doesn't truncate the byte_len for it.

Thanks,
Bartosz

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Bartosz Golaszewski]

2017-11-28 11:25 GMT+01:00 Andy Shevchenko :
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
>> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
>> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
>> making it impossible to read it all.
>>
>> Fix it by manually adjusting the value in probe().
>>
>> This patch contains a temporary fix that is suitable for stable
>> branches. Eventually we'll probably remove the call to ilog2() while
>> converting the magic values to actual structs.
>
>> +   /*
>> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
>> while
>> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
>> +*
>> +* Eventually we'll get rid of the magic values altoghether in favor 
>> of
>> +* real structs, but for now just manually set the right size.
>> +*/
>> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
>
> I didn't check, but do we need to test for len == 4 at all?
>
>> +   chip.byte_len = 6;
>
> --
> With Best Regards,
> Andy Shevchenko

Yes, because the fix is only relevant for at24mac402 whose MAC byte
array is 6 bytes long, while the one in at24mac602 is 8 bytes and the
driver doesn't truncate the byte_len for it.

Thanks,
Bartosz

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Andy Shevchenko]

On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
> making it impossible to read it all.
>
> Fix it by manually adjusting the value in probe().
>
> This patch contains a temporary fix that is suitable for stable
> branches. Eventually we'll probably remove the call to ilog2() while
> converting the magic values to actual structs.

> +   /*
> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
> while
> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
> +*
> +* Eventually we'll get rid of the magic values altoghether in favor 
> of
> +* real structs, but for now just manually set the right size.
> +*/
> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)

I didn't check, but do we need to test for len == 4 at all?

> +   chip.byte_len = 6;

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] eeprom: at24: correctly set the size for at24mac402

[Andy Shevchenko]

On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski  wrote:
> There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down
> the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6,
> making it impossible to read it all.
>
> Fix it by manually adjusting the value in probe().
>
> This patch contains a temporary fix that is suitable for stable
> branches. Eventually we'll probably remove the call to ilog2() while
> converting the magic values to actual structs.

> +   /*
> +* REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, 
> while
> +* the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
> +*
> +* Eventually we'll get rid of the magic values altoghether in favor 
> of
> +* real structs, but for now just manually set the right size.
> +*/
> +   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)

I didn't check, but do we need to test for len == 4 at all?

> +   chip.byte_len = 6;

-- 
With Best Regards,
Andy Shevchenko