sysfs-devices-soc 3.6 KB

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  1. What: /sys/devices/socX
  2. Date: January 2012
  3. contact: Lee Jones <lee.jones@linaro.org>
  4. Description:
  5. The /sys/devices/ directory contains a sub-directory for each
  6. System-on-Chip (SoC) device on a running platform. Information
  7. regarding each SoC can be obtained by reading sysfs files. This
  8. functionality is only available if implemented by the platform.
  9. The directory created for each SoC will also house information
  10. about devices which are commonly contained in /sys/devices/platform.
  11. It has been agreed that if an SoC device exists, its supported
  12. devices would be better suited to appear as children of that SoC.
  13. What: /sys/devices/socX/machine
  14. Date: January 2012
  15. contact: Lee Jones <lee.jones@linaro.org>
  16. Description:
  17. Read-only attribute common to all SoCs. Contains the SoC machine
  18. name (e.g. Ux500).
  19. What: /sys/devices/socX/family
  20. Date: January 2012
  21. contact: Lee Jones <lee.jones@linaro.org>
  22. Description:
  23. Read-only attribute common to all SoCs. Contains SoC family name
  24. (e.g. DB8500).
  25. On many of ARM based silicon with SMCCC v1.2+ compliant firmware
  26. this will contain the JEDEC JEP106 manufacturer’s identification
  27. code. The format is "jep106:XXYY" where XX is identity code and
  28. YY is continuation code.
  29. This manufacturer’s identification code is defined by one
  30. or more eight (8) bit fields, each consisting of seven (7)
  31. data bits plus one (1) odd parity bit. It is a single field,
  32. limiting the possible number of vendors to 126. To expand
  33. the maximum number of identification codes, a continuation
  34. scheme has been defined.
  35. The specified mechanism is that an identity code of 0x7F
  36. represents the "continuation code" and implies the presence
  37. of an additional identity code field, and this mechanism
  38. may be extended to multiple continuation codes followed
  39. by the manufacturer's identity code.
  40. For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,
  41. which is code 0x3B on the fifth 'page'. This is shortened
  42. as JEP106 identity code of 0x3B and a continuation code of
  43. 0x4 to represent the four continuation codes preceding the
  44. identity code.
  45. What: /sys/devices/socX/serial_number
  46. Date: January 2019
  47. contact: Bjorn Andersson <bjorn.andersson@linaro.org>
  48. Description:
  49. Read-only attribute supported by most SoCs. Contains the SoC's
  50. serial number, if available.
  51. What: /sys/devices/socX/soc_id
  52. Date: January 2012
  53. contact: Lee Jones <lee.jones@linaro.org>
  54. Description:
  55. Read-only attribute supported by most SoCs. In the case of
  56. ST-Ericsson's chips this contains the SoC serial number.
  57. On many of ARM based silicon with SMCCC v1.2+ compliant firmware
  58. this will contain the SOC ID appended to the family attribute
  59. to ensure there is no conflict in this namespace across various
  60. vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity
  61. code, YY is continuation code and ZZZZ is the SOC ID.
  62. What: /sys/devices/socX/revision
  63. Date: January 2012
  64. contact: Lee Jones <lee.jones@linaro.org>
  65. Description:
  66. Read-only attribute supported by most SoCs. Contains the SoC's
  67. manufacturing revision number.
  68. What: /sys/devices/socX/process
  69. Date: January 2012
  70. contact: Lee Jones <lee.jones@linaro.org>
  71. Description:
  72. Read-only attribute supported ST-Ericsson's silicon. Contains the
  73. the process by which the silicon chip was manufactured.
  74. What: /sys/bus/soc
  75. Date: January 2012
  76. contact: Lee Jones <lee.jones@linaro.org>
  77. Description:
  78. The /sys/bus/soc/ directory contains the usual sub-folders
  79. expected under most buses. /sys/bus/soc/devices is of particular
  80. interest, as it contains a symlink for each SoC device found on
  81. the system. Each symlink points back into the aforementioned
  82. /sys/devices/socX devices.