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