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)
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;
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
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
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
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
linux-stable-mirror@lists.linaro.org
-
Andy Shevchenko -
Bartosz Golaszewski -
Claudiu Beznea -
Heiner Kallweit