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 creating the magic value manually with the correct size.
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.
This fix will cause a warning message to be emitted by probe() for at24mac402 chips but theys should be initialized correctly anyway.
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 | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index e0b4b36ef010..72adf34627f5 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -141,8 +141,17 @@ static const struct i2c_device_id at24_ids[] = { { "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) }, { "24cs02", AT24_DEVICE_MAGIC(16, AT24_FLAG_SERIAL | AT24_FLAG_READONLY) }, - { "24mac402", AT24_DEVICE_MAGIC(48 / 8, - AT24_FLAG_MAC | AT24_FLAG_READONLY) }, + /* + * 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. We + * might want to eventually remove it altogether or maybe even convert + * the magic values to real structs. + * + * For now just create the magic value manually with the right size. + */ + { "24mac402", ((1 << AT24_SIZE_FLAGS | + (AT24_FLAG_MAC | AT24_FLAG_READONLY)) + << AT24_SIZE_BYTELEN | (48 / 8)) }, { "24mac602", AT24_DEVICE_MAGIC(64 / 8, AT24_FLAG_MAC | AT24_FLAG_READONLY) }, /* spd is a 24c02 in memory DIMMs */
Am 27.11.2017 um 13:28 schrieb Bartosz Golaszewski:
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 creating the magic value manually with the correct size.
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.
This fix will cause a warning message to be emitted by probe() for at24mac402 chips but theys should be initialized correctly anyway.
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 | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index e0b4b36ef010..72adf34627f5 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -141,8 +141,17 @@ static const struct i2c_device_id at24_ids[] = { { "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) }, { "24cs02", AT24_DEVICE_MAGIC(16, AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
- { "24mac402", AT24_DEVICE_MAGIC(48 / 8,
AT24_FLAG_MAC | AT24_FLAG_READONLY) },
- /*
* 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. We* might want to eventually remove it altogether or maybe even convert* the magic values to real structs.** For now just create the magic value manually with the right size.*/- { "24mac402", ((1 << AT24_SIZE_FLAGS |
(AT24_FLAG_MAC | AT24_FLAG_READONLY))<< AT24_SIZE_BYTELEN | (48 / 8)) },
I'm afraid this won't work. byte_len = BIT(least 5 bits of magic value) Means byte_len for 24mac402 would be BIT(6) = 64 with your patch.
What we could do, although it seems to be quite ugly: round up the ilog2 value. Instead of ilog2(_len) we could use ilog2((_len) * 2 - 1)
Rgds, Heiner
2017-11-27 20:15 GMT+01:00 Heiner Kallweit hkallweit1@gmail.com:
Am 27.11.2017 um 13:28 schrieb Bartosz Golaszewski:
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 creating the magic value manually with the correct size.
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.
This fix will cause a warning message to be emitted by probe() for at24mac402 chips but theys should be initialized correctly anyway.
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 | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index e0b4b36ef010..72adf34627f5 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -141,8 +141,17 @@ static const struct i2c_device_id at24_ids[] = { { "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) }, { "24cs02", AT24_DEVICE_MAGIC(16, AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
{ "24mac402", AT24_DEVICE_MAGIC(48 / 8,AT24_FLAG_MAC | AT24_FLAG_READONLY) },
/** 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. We* might want to eventually remove it altogether or maybe even convert* the magic values to real structs.** For now just create the magic value manually with the right size.*/{ "24mac402", ((1 << AT24_SIZE_FLAGS |(AT24_FLAG_MAC | AT24_FLAG_READONLY))<< AT24_SIZE_BYTELEN | (48 / 8)) }, { "24mac602", AT24_DEVICE_MAGIC(64 / 8, AT24_FLAG_MAC | AT24_FLAG_READONLY) }, /* spd is a 24c02 in memory DIMMs */I'm afraid this won't work. byte_len = BIT(least 5 bits of magic value) Means byte_len for 24mac402 would be BIT(6) = 64 with your patch.
What we could do, although it seems to be quite ugly: round up the ilog2 value. Instead of ilog2(_len) we could use ilog2((_len) * 2 - 1)
Rgds, Heiner
This is exactly why we should get rid of these magic values. ;) Thanks for spotting that.
Another (slightly cleaner) solution that comes to mind is checking the eeprom type in probe and adjusting byte_len manually.
Thanks, Bartosz
linux-stable-mirror@lists.linaro.org
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Bartosz Golaszewski -
Heiner Kallweit