* [PATCH] eeprom: at24: correctly set the size for at24mac402
@ 2017-11-27 21:06 Bartosz Golaszewski
2017-11-28 10:25 ` Andy Shevchenko
2017-11-28 12:09 ` Andy Shevchenko
0 siblings, 2 replies; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-11-27 21:06 UTC (permalink / raw)
To: Heiner Kallweit, Claudiu Beznea
Cc: linux-i2c, linux-kernel, Bartosz Golaszewski, stable
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.
Cc: stable@vger.kernel.org
Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
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(&client->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
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] eeprom: at24: correctly set the size for at24mac402
2017-11-27 21:06 [PATCH] eeprom: at24: correctly set the size for at24mac402 Bartosz Golaszewski
@ 2017-11-28 10:25 ` Andy Shevchenko
2017-11-28 10:44 ` Bartosz Golaszewski
2017-11-28 12:09 ` Andy Shevchenko
1 sibling, 1 reply; 6+ messages in thread
From: Andy Shevchenko @ 2017-11-28 10:25 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Heiner Kallweit, Claudiu Beznea, linux-i2c,
linux-kernel@vger.kernel.org, stable
On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski <brgl@bgdev.pl> 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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] eeprom: at24: correctly set the size for at24mac402
2017-11-28 10:25 ` Andy Shevchenko
@ 2017-11-28 10:44 ` Bartosz Golaszewski
2017-12-04 12:36 ` Claudiu Beznea
0 siblings, 1 reply; 6+ messages in thread
From: Bartosz Golaszewski @ 2017-11-28 10:44 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Heiner Kallweit, Claudiu Beznea, linux-i2c,
linux-kernel@vger.kernel.org, stable
2017-11-28 11:25 GMT+01:00 Andy Shevchenko <andy.shevchenko@gmail.com>:
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski <brgl@bgdev.pl> 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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] eeprom: at24: correctly set the size for at24mac402
2017-11-28 10:44 ` Bartosz Golaszewski
@ 2017-12-04 12:36 ` Claudiu Beznea
0 siblings, 0 replies; 6+ messages in thread
From: Claudiu Beznea @ 2017-12-04 12:36 UTC (permalink / raw)
To: Bartosz Golaszewski, Andy Shevchenko
Cc: Heiner Kallweit, linux-i2c, linux-kernel@vger.kernel.org, stable
On 28.11.2017 12:44, Bartosz Golaszewski wrote:
> 2017-11-28 11:25 GMT+01:00 Andy Shevchenko <andy.shevchenko@gmail.com>:
>> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski <brgl@bgdev.pl> 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
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] eeprom: at24: correctly set the size for at24mac402
2017-11-27 21:06 [PATCH] eeprom: at24: correctly set the size for at24mac402 Bartosz Golaszewski
2017-11-28 10:25 ` Andy Shevchenko
@ 2017-11-28 12:09 ` Andy Shevchenko
2017-11-28 19:39 ` Heiner Kallweit
1 sibling, 1 reply; 6+ messages in thread
From: Andy Shevchenko @ 2017-11-28 12:09 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Heiner Kallweit, Claudiu Beznea, linux-i2c,
linux-kernel@vger.kernel.org, stable
On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski <brgl@bgdev.pl> 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 <andy.shevchenko@gmail.com>
> Cc: stable@vger.kernel.org
> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
> 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(&client->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
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] eeprom: at24: correctly set the size for at24mac402
2017-11-28 12:09 ` Andy Shevchenko
@ 2017-11-28 19:39 ` Heiner Kallweit
0 siblings, 0 replies; 6+ messages in thread
From: Heiner Kallweit @ 2017-11-28 19:39 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: Andy Shevchenko, Claudiu Beznea, linux-i2c,
linux-kernel@vger.kernel.org, stable
Am 28.11.2017 um 13:09 schrieb Andy Shevchenko:
> On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski <brgl@bgdev.pl> 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 <andy.shevchenko@gmail.com>
>
Looks good also to me.
>> Cc: stable@vger.kernel.org
>> Fixes: 0b813658c115 ("eeprom: at24: add support for at24mac series")
>> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
>> ---
>> 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(&client->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
>>
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-12-04 12:36 UTC | newest]
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2017-11-27 21:06 [PATCH] eeprom: at24: correctly set the size for at24mac402 Bartosz Golaszewski
2017-11-28 10:25 ` Andy Shevchenko
2017-11-28 10:44 ` Bartosz Golaszewski
2017-12-04 12:36 ` Claudiu Beznea
2017-11-28 12:09 ` Andy Shevchenko
2017-11-28 19:39 ` Heiner Kallweit
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