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Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-soc')
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diff --git a/Documentation/ABI/testing/sysfs-devices-soc b/Documentation/ABI/testing/sysfs-devices-soc new file mode 100644 index 0000000000..5269808ec3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-soc @@ -0,0 +1,95 @@ +What: /sys/devices/socX +Date: January 2012 +contact: Lee Jones <lee@kernel.org> +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 <lee@kernel.org> +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 <lee@kernel.org> +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 <bjorn.andersson@linaro.org> +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 <lee@kernel.org> +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 <lee@kernel.org> +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 <lee@kernel.org> +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 <lee@kernel.org> +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. |