1 What: /sys/devices/socX 1 What: /sys/devices/socX
2 Date: January 2012 2 Date: January 2012
3 contact: Lee Jones <lee@kernel.org> 3 contact: Lee Jones <lee@kernel.org>
4 Description: 4 Description:
5 The /sys/devices/ directory co 5 The /sys/devices/ directory contains a sub-directory for each
6 System-on-Chip (SoC) device on 6 System-on-Chip (SoC) device on a running platform. Information
7 regarding each SoC can be obta 7 regarding each SoC can be obtained by reading sysfs files. This
8 functionality is only availabl 8 functionality is only available if implemented by the platform.
9 9
10 The directory created for each 10 The directory created for each SoC will also house information
11 about devices which are common 11 about devices which are commonly contained in /sys/devices/platform.
12 It has been agreed that if an 12 It has been agreed that if an SoC device exists, its supported
13 devices would be better suited 13 devices would be better suited to appear as children of that SoC.
14 14
15 What: /sys/devices/socX/machine 15 What: /sys/devices/socX/machine
16 Date: January 2012 16 Date: January 2012
17 contact: Lee Jones <lee@kernel.org> 17 contact: Lee Jones <lee@kernel.org>
18 Description: 18 Description:
19 Read-only attribute common to 19 Read-only attribute common to all SoCs. Contains the SoC machine
20 name (e.g. Ux500). 20 name (e.g. Ux500).
21 21
22 What: /sys/devices/socX/family 22 What: /sys/devices/socX/family
23 Date: January 2012 23 Date: January 2012
24 contact: Lee Jones <lee@kernel.org> 24 contact: Lee Jones <lee@kernel.org>
25 Description: 25 Description:
26 Read-only attribute common to 26 Read-only attribute common to all SoCs. Contains SoC family name
27 (e.g. DB8500). 27 (e.g. DB8500).
28 28
29 On many of ARM based silicon w 29 On many of ARM based silicon with SMCCC v1.2+ compliant firmware
30 this will contain the JEDEC JE 30 this will contain the JEDEC JEP106 manufacturer’s identification
31 code. The format is "jep106:XX 31 code. The format is "jep106:XXYY" where XX is identity code and
32 YY is continuation code. 32 YY is continuation code.
33 33
34 This manufacturer’s identifi 34 This manufacturer’s identification code is defined by one
35 or more eight (8) bit fields, 35 or more eight (8) bit fields, each consisting of seven (7)
36 data bits plus one (1) odd par 36 data bits plus one (1) odd parity bit. It is a single field,
37 limiting the possible number o 37 limiting the possible number of vendors to 126. To expand
38 the maximum number of identifi 38 the maximum number of identification codes, a continuation
39 scheme has been defined. 39 scheme has been defined.
40 40
41 The specified mechanism is tha 41 The specified mechanism is that an identity code of 0x7F
42 represents the "continuation c 42 represents the "continuation code" and implies the presence
43 of an additional identity code 43 of an additional identity code field, and this mechanism
44 may be extended to multiple co 44 may be extended to multiple continuation codes followed
45 by the manufacturer's identity 45 by the manufacturer's identity code.
46 46
47 For example, ARM has identity 47 For example, ARM has identity code 0x7F 0x7F 0x7F 0x7F 0x3B,
48 which is code 0x3B on the fift 48 which is code 0x3B on the fifth 'page'. This is shortened
49 as JEP106 identity code of 0x3 49 as JEP106 identity code of 0x3B and a continuation code of
50 0x4 to represent the four cont 50 0x4 to represent the four continuation codes preceding the
51 identity code. 51 identity code.
52 52
53 What: /sys/devices/socX/serial_numbe 53 What: /sys/devices/socX/serial_number
54 Date: January 2019 54 Date: January 2019
55 contact: Bjorn Andersson <bjorn.andersso 55 contact: Bjorn Andersson <bjorn.andersson@linaro.org>
56 Description: 56 Description:
57 Read-only attribute supported 57 Read-only attribute supported by most SoCs. Contains the SoC's
58 serial number, if available. 58 serial number, if available.
59 59
60 What: /sys/devices/socX/soc_id 60 What: /sys/devices/socX/soc_id
61 Date: January 2012 61 Date: January 2012
62 contact: Lee Jones <lee@kernel.org> 62 contact: Lee Jones <lee@kernel.org>
63 Description: 63 Description:
64 Read-only attribute supported 64 Read-only attribute supported by most SoCs. In the case of
65 ST-Ericsson's chips this conta 65 ST-Ericsson's chips this contains the SoC serial number.
66 66
67 On many of ARM based silicon w 67 On many of ARM based silicon with SMCCC v1.2+ compliant firmware
68 this will contain the SOC ID a 68 this will contain the SOC ID appended to the family attribute
69 to ensure there is no conflict 69 to ensure there is no conflict in this namespace across various
70 vendors. The format is "jep106 70 vendors. The format is "jep106:XXYY:ZZZZ" where XX is identity
71 code, YY is continuation code 71 code, YY is continuation code and ZZZZ is the SOC ID.
72 72
73 What: /sys/devices/socX/revision 73 What: /sys/devices/socX/revision
74 Date: January 2012 74 Date: January 2012
75 contact: Lee Jones <lee@kernel.org> 75 contact: Lee Jones <lee@kernel.org>
76 Description: 76 Description:
77 Read-only attribute supported 77 Read-only attribute supported by most SoCs. Contains the SoC's
78 manufacturing revision number. 78 manufacturing revision number.
79 79
80 What: /sys/devices/socX/process 80 What: /sys/devices/socX/process
81 Date: January 2012 81 Date: January 2012
82 contact: Lee Jones <lee@kernel.org> 82 contact: Lee Jones <lee@kernel.org>
83 Description: 83 Description:
84 Read-only attribute supported 84 Read-only attribute supported ST-Ericsson's silicon. Contains the
85 the process by which the silic 85 the process by which the silicon chip was manufactured.
86 86
87 What: /sys/bus/soc 87 What: /sys/bus/soc
88 Date: January 2012 88 Date: January 2012
89 contact: Lee Jones <lee@kernel.org> 89 contact: Lee Jones <lee@kernel.org>
90 Description: 90 Description:
91 The /sys/bus/soc/ directory co 91 The /sys/bus/soc/ directory contains the usual sub-folders
92 expected under most buses. /sy 92 expected under most buses. /sys/bus/soc/devices is of particular
93 interest, as it contains a sym 93 interest, as it contains a symlink for each SoC device found on
94 the system. Each symlink point 94 the system. Each symlink points back into the aforementioned
95 /sys/devices/socX devices. 95 /sys/devices/socX devices.
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