This patch set extends the size of QSFP EEPROM for the cable types
SSF-8436 and SFF-8636 from 256 bytes to 640 bytes. This allows ethtool
to show correct information for these cable types (more details below).
Patch #1 adds a macro that computes the EEPROM page number from the
provided offset specified in the request.
Patch #2 teaches the driver to access the information stored in the
upper pages of the QSFP memory map.
Details and examples:
SFF-8436 specification defines pages 0, 1, 2 and 3. Page 0 contains
lower memory page offsets (from 0x00 to 0x7f) and upper page offsets
(from 0x80 to 0xfe). Upper pages 1, 2 and 3 are optional and can be
empty.
Page 1 is provided if upper page 0 byte 0xc3 bit 6 is set.
Page 2 is provided if upper page 0 byte 0xc3 bit 7 is set.
Page 3 is provided if lower page 0 byte 0x02 bit 2 is cleared.
Offset 0xc3 for the upper page is provided as 0x43 = 0xc3 - 0x80.
As a result of exposing 256 bytes only, ethtool shows wrong information
for pages 1, 2 and 3. In the below hex dump from ethtool for a cable
compliant to SFF-8636 specification, it can be seen that EEPROM of this
device contains optical diagnostic page (lower page 0 byte 0x02 bit 2 is
cleared), but it is not exposed, as the length defined for this type is
256 bytes.
After changing the length returned by get_module_info() callback from
256 bytes to 640 bytes, the upper pages 1, 2 and 3 are exposed by
ethtool. In the below hex dump from the same cable it can be seen that
the optical diagnostic page (page 3, from offset 0x0200) has non-zero
data.
And 'ethtool -m sfp42' shows the real values for the below fields, while
before it exposed zeros for these fields:
Laser bias current high alarm threshold : 8.500 mA
Laser bias current low alarm threshold : 5.492 mA
Laser bias current high warning threshold : 8.000 mA
Laser bias current low warning threshold : 6.000 mA
Laser output power high alarm threshold : 3.4673 mW / 5.40 dBm
Laser output power low alarm threshold : 0.0724 mW / -11.40 dBm
Laser output power high warning threshold : 1.7378 mW / 2.40 dBm
Laser output power low warning threshold : 0.1445 mW / -8.40 dBm
Module temperature high alarm threshold : 80.00 degrees C / 176.00 F
Module temperature low alarm threshold : -10.00 degrees C / 14.00 F
Module temperature high warning threshold : 70.00 degrees C / 158.00 F
Module temperature low warning threshold : 0.00 degrees C / 32.00 F
Module voltage high alarm threshold : 3.5000 V
Module voltage low alarm threshold : 3.1000 V
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Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>