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Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-soc')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-soc | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-soc b/Documentation/ABI/testing/sysfs-devices-soc index ba3a3fac0ee1..ea999e292f11 100644 --- a/Documentation/ABI/testing/sysfs-devices-soc +++ b/Documentation/ABI/testing/sysfs-devices-soc @@ -26,6 +26,30 @@ 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> @@ -40,6 +64,12 @@ 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.jones@linaro.org> |