1*04a1c1a1SRobert Mustacchi.\" 2*04a1c1a1SRobert Mustacchi.\" This file and its contents are supplied under the terms of the 3*04a1c1a1SRobert Mustacchi.\" Common Development and Distribution License ("CDDL"), version 1.0. 4*04a1c1a1SRobert Mustacchi.\" You may only use this file in accordance with the terms of version 5*04a1c1a1SRobert Mustacchi.\" 1.0 of the CDDL. 6*04a1c1a1SRobert Mustacchi.\" 7*04a1c1a1SRobert Mustacchi.\" A full copy of the text of the CDDL should have accompanied this 8*04a1c1a1SRobert Mustacchi.\" source. A copy of the CDDL is also available via the Internet at 9*04a1c1a1SRobert Mustacchi.\" http://www.illumos.org/license/CDDL. 10*04a1c1a1SRobert Mustacchi.\" 11*04a1c1a1SRobert Mustacchi.\" 12*04a1c1a1SRobert Mustacchi.\" Copyright 2025 Oxide Computer Company 13*04a1c1a1SRobert Mustacchi.\" 14*04a1c1a1SRobert Mustacchi.Dd September 21, 2025 15*04a1c1a1SRobert Mustacchi.Dt SPD511X 4D 16*04a1c1a1SRobert Mustacchi.Os 17*04a1c1a1SRobert Mustacchi.Sh NAME 18*04a1c1a1SRobert Mustacchi.Nm spd511x 19*04a1c1a1SRobert Mustacchi.Nd DDR5 hub and serial presence detect driver 20*04a1c1a1SRobert Mustacchi.Sh SYNOPSIS 21*04a1c1a1SRobert Mustacchi.Pa /dev/eeprom/spd511x/*/eeprom 22*04a1c1a1SRobert Mustacchi.Pp 23*04a1c1a1SRobert Mustacchi.Pa /dev/sensors/temperature/i2c/spd511x* 24*04a1c1a1SRobert Mustacchi.Sh DESCRIPTION 25*04a1c1a1SRobert MustacchiThe 26*04a1c1a1SRobert Mustacchi.Nm 27*04a1c1a1SRobert Mustacchidriver supports I2C devices compliant with JEDEC Standard JESD300-5 28*04a1c1a1SRobert Mustacchiwhich covers the hub and serial presence detect data found on DDR5 29*04a1c1a1SRobert MustacchiDIMMs. 30*04a1c1a1SRobert MustacchiThe driver provides access to the hub's built-in temperature sensor 31*04a1c1a1SRobert Mustacchithrough the 32*04a1c1a1SRobert Mustacchi.Xr ksensor 4D 33*04a1c1a1SRobert Mustacchidriver and provides read-only access to the SPD 34*04a1c1a1SRobert Mustacchi.Pq serial presence detect 35*04a1c1a1SRobert MustacchiEEPROM through a character device powered by the 36*04a1c1a1SRobert Mustacchi.Xr eedev 4D 37*04a1c1a1SRobert Mustacchidriver. 38*04a1c1a1SRobert MustacchiThese devices are generally found at 7-bit addresses between 0x50 and 39*04a1c1a1SRobert Mustacchi0x57. 40*04a1c1a1SRobert MustacchiThe lower three bits of the address are used to indicate which DIMM the 41*04a1c1a1SRobert Mustacchidevice is found on 42*04a1c1a1SRobert Mustacchi.Pq ranging from 0 to 7 . 43*04a1c1a1SRobert Mustacchi.Pp 44*04a1c1a1SRobert MustacchiThe SPD device contains 1024 bytes of memory that are organized into 16 45*04a1c1a1SRobert Mustacchiblocks of 64 bytes each. 46*04a1c1a1SRobert MustacchiA paging mechanism provides access to 128 bytes at a time. 47*04a1c1a1SRobert MustacchiDevices can be found under 48*04a1c1a1SRobert Mustacchi.Pa /dev/eeprom/spd511x . 49*04a1c1a1SRobert MustacchiContents of the SPD data can be decoded with 50*04a1c1a1SRobert Mustacchi.Xr libjedec 3LIB . 51*04a1c1a1SRobert Mustacchi.Pp 52*04a1c1a1SRobert MustacchiThe temperature sensor measures in units of 0.25 degrees Celsius and its 53*04a1c1a1SRobert Mustacchiaccuracy varies depending on the current temperature range. 54*04a1c1a1SRobert MustacchiTemperature information is available to the system through the fault 55*04a1c1a1SRobert Mustacchima management architecture 56*04a1c1a1SRobert Mustacchi.Pq FMA . 57*04a1c1a1SRobert MustacchiThe file system location and programming interface to the 58*04a1c1a1SRobert Mustacchi.Nm 59*04a1c1a1SRobert Mustacchitemperature sensors are considered 60*04a1c1a1SRobert Mustacchi.Sy volatile . 61*04a1c1a1SRobert Mustacchi.Sh FILES 62*04a1c1a1SRobert Mustacchi.Bl -tag -width Pa 63*04a1c1a1SRobert Mustacchi.It Pa /dev/eeprom/spd511x/*/eeprom 64*04a1c1a1SRobert MustacchiEEPROM character device file. 65*04a1c1a1SRobert Mustacchi.It Pa /dev/sensors/temperature/i2c/spd511x* 66*04a1c1a1SRobert MustacchiHub temperature sensor. 67*04a1c1a1SRobert Mustacchi.It Pa /kernel/drv/amd64/spd511x 68*04a1c1a1SRobert MustacchiDevice driver (x86) 69*04a1c1a1SRobert Mustacchi.El 70*04a1c1a1SRobert Mustacchi.Sh SEE ALSO 71*04a1c1a1SRobert Mustacchi.Xr libjedec 3LIB , 72*04a1c1a1SRobert Mustacchi.Xr ee100x 4D , 73*04a1c1a1SRobert Mustacchi.Xr eedev 4D , 74*04a1c1a1SRobert Mustacchi.Xr ts511x 4D , 75*04a1c1a1SRobert Mustacchi.Xr i2cadm 8 76*04a1c1a1SRobert Mustacchi.Rs 77*04a1c1a1SRobert Mustacchi.%Q JEDEC Solid State Technology Association 78*04a1c1a1SRobert Mustacchi.%T SPD5118 Hub and Serial Presence Detect Device Standard 79*04a1c1a1SRobert Mustacchi.%N JESD300-5B.01 Version 1.5.1 80*04a1c1a1SRobert Mustacchi.%D May 2024 81*04a1c1a1SRobert Mustacchi.Re 82