What: /sys/devices/socX
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
The /sys/devices/ directory contains a sub-directory for each
System-on-Chip (SoC) device on a running platform. Information
regarding each SoC can be obtained by reading sysfs files. This
functionality is only available if implemented by the platform.
The directory created for each SoC will also house information
about devices which are commonly contained in /sys/devices/platform.
It has been agreed that if an SoC device exists, its supported
devices would be better suited to appear as children of that SoC.
What: /sys/devices/socX/machine
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
Read-only attribute common to all SoCs. Contains the SoC machine
name (e.g. Ux500).
What: /sys/devices/socX/family
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
Read-only attribute common to all SoCs. Contains SoC family name
(e.g. DB8500).
On many of ARM based silicon with SMCCC v1.2+ compliant firmware
this will contain the JEDEC JEP106 manufacturer’s identification
code. The format is "jep106:XXYY" where XX is identity code and
YY is continuation code.
This manufacturer’s identification code is defined by one
or more eight (8) bit fields, each consisting of seven (7)
data bits plus one (1) odd parity bit. It is a single field,
limiting the possible number of vendors to 126. To expand
the maximum number of identification codes, a continuation
scheme has been defined.
The specified mechanism is that an identity code of 0x7F
represents the "continuation code" and implies the presence
of an additional identity code field, and this mechanism
may be extended to multiple continuation codes followed
by the manufacturer's identity code.
For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,
which is code 0x3B on the fifth 'page'. This is shortened
as JEP106 identity code of 0x3B and a continuation code of
0x4 to represent the four continuation codes preceding the
identity code.
What: /sys/devices/socX/serial_number
Date: January 2019
contact: Bjorn Andersson <[email protected]>
Description:
Read-only attribute supported by most SoCs. Contains the SoC's
serial number, if available.
What: /sys/devices/socX/soc_id
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
Read-only attribute supported by most SoCs. In the case of
ST-Ericsson's chips this contains the SoC serial number.
On many of ARM based silicon with SMCCC v1.2+ compliant firmware
this will contain the SOC ID appended to the family attribute
to ensure there is no conflict in this namespace across various
vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity
code, YY is continuation code and ZZZZ is the SOC ID.
What: /sys/devices/socX/revision
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
Read-only attribute supported by most SoCs. Contains the SoC's
manufacturing revision number.
What: /sys/devices/socX/process
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
Read-only attribute supported ST-Ericsson's silicon. Contains the
the process by which the silicon chip was manufactured.
What: /sys/bus/soc
Date: January 2012
contact: Lee Jones <[email protected]>
Description:
The /sys/bus/soc/ directory contains the usual sub-folders
expected under most buses. /sys/bus/soc/devices is of particular
interest, as it contains a symlink for each SoC device found on
the system. Each symlink points back into the aforementioned
/sys/devices/socX devices.
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