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1What: /sys/devices/socX2Date: January 20123contact: Lee Jones <lee@kernel.org>4Description:5 The /sys/devices/ directory contains a sub-directory for each6 System-on-Chip (SoC) device on a running platform. Information7 regarding each SoC can be obtained by reading sysfs files. This8 functionality is only available if implemented by the platform.9 10 The directory created for each SoC will also house information11 about devices which are commonly contained in /sys/devices/platform.12 It has been agreed that if an SoC device exists, its supported13 devices would be better suited to appear as children of that SoC.14 15What: /sys/devices/socX/machine16Date: January 201217contact: Lee Jones <lee@kernel.org>18Description:19 Read-only attribute common to all SoCs. Contains the SoC machine20 name (e.g. Ux500).21 22What: /sys/devices/socX/family23Date: January 201224contact: Lee Jones <lee@kernel.org>25Description:26 Read-only attribute common to all SoCs. Contains SoC family name27 (e.g. DB8500).28 29 On many of ARM based silicon with SMCCC v1.2+ compliant firmware30 this will contain the JEDEC JEP106 manufacturer’s identification31 code. The format is "jep106:XXYY" where XX is identity code and32 YY is continuation code.33 34 This manufacturer’s identification code is defined by one35 or more eight (8) bit fields, each consisting of seven (7)36 data bits plus one (1) odd parity bit. It is a single field,37 limiting the possible number of vendors to 126. To expand38 the maximum number of identification codes, a continuation39 scheme has been defined.40 41 The specified mechanism is that an identity code of 0x7F42 represents the "continuation code" and implies the presence43 of an additional identity code field, and this mechanism44 may be extended to multiple continuation codes followed45 by the manufacturer's identity code.46 47 For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,48 which is code 0x3B on the fifth 'page'. This is shortened49 as JEP106 identity code of 0x3B and a continuation code of50 0x4 to represent the four continuation codes preceding the51 identity code.52 53What: /sys/devices/socX/serial_number54Date: January 201955contact: Bjorn Andersson <bjorn.andersson@linaro.org>56Description:57 Read-only attribute supported by most SoCs. Contains the SoC's58 serial number, if available.59 60What: /sys/devices/socX/soc_id61Date: January 201262contact: Lee Jones <lee@kernel.org>63Description:64 Read-only attribute supported by most SoCs. In the case of65 ST-Ericsson's chips this contains the SoC serial number.66 67 On many of ARM based silicon with SMCCC v1.2+ compliant firmware68 this will contain the SOC ID appended to the family attribute69 to ensure there is no conflict in this namespace across various70 vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity71 code, YY is continuation code and ZZZZ is the SOC ID.72 73What: /sys/devices/socX/revision74Date: January 201275contact: Lee Jones <lee@kernel.org>76Description:77 Read-only attribute supported by most SoCs. Contains the SoC's78 manufacturing revision number.79 80What: /sys/devices/socX/process81Date: January 201282contact: Lee Jones <lee@kernel.org>83Description:84 Read-only attribute supported ST-Ericsson's silicon. Contains the85 the process by which the silicon chip was manufactured.86 87What: /sys/bus/soc88Date: January 201289contact: Lee Jones <lee@kernel.org>90Description:91 The /sys/bus/soc/ directory contains the usual sub-folders92 expected under most buses. /sys/bus/soc/devices is of particular93 interest, as it contains a symlink for each SoC device found on94 the system. Each symlink points back into the aforementioned95 /sys/devices/socX devices.96