1# OpenBMC MRW Requirements 2 3This document describes the data requirements that OpenBMC has on the machine 4readable workbook XML generated by [Serverwiz2](https://www.github.com/open-power/serverwiz). 5The requirements in this document are broken up by the OpenBMC functions that 6use them. 7 8If a particular OpenBMC implementation doesn't use a certain function, 9then that MRW data isn't required. 10 11## System Inventory 12 13The system inventory can be generated from the MRW XML. The inventory 14typically contains all FRUs (field replaceable units), along with a few 15non-FRU entities, like the BMC chip and processor cores. 16 17To specify a target in the MRW should be in the inventory: 18 19* Set the FRU\_NAME attribute of that target. 20 21**Note**: The BMC and cores will be automatically added without the need to 22set FRU\_NAME. 23 24 25## BMC Device Tree 26 27The BMC device tree can be generated from the MRW XML. For the full device 28tree to be generated, all of the corresponding devices and connections must 29be modeled in the MRW XML. For a system built with parts that already have 30existing XML representations, there are only a few attributes that need to 31be set. If a new part is being modeled, initial values for some attributes 32may need to be determined, depending on the part. 33 34The following sections list the system dependent information that the device 35tree generator requires. The majority of the information it requires is 36static data that is either already built into the XML representations of 37the existing parts or pulled in from an include file. 38 39 40### System Level Attributes 41 42##### SYSTEM\_NAME 43The name of the system as the firmware would know it. 44 45##### MANUFACTURER 46The system manufacturer. 47 48 49### BMC Chip 50All of the BMC chip attributes that are needed for the device tree are 51pre-built into the XML representation and don't need to be updated when 52the device is placed into a system in Serverwiz. 53 54> Note: The AST2500 is currently the only BMC XML model that contains all 55of the necessary device tree attributes. 56 57 58### SPI Flashes 59> Coming soon after new device driver released. 60 61 62### Ethernet MAC Units 63To enable a BMC MAC module, its ethernet master unit in the MRW must be 64connected to an ethernet slave unit. Additionally, the following 65attributes may need to be set. 66 67##### NCSI\_MODE 68This attribute in the ethernet master unit can be set to 1 if the link uses 69NCSI. The default is 0. 70 71##### USE\_HW\_CHECKSUM 72This attribute in the ethernet master unit can be set to 1 if the MAC has 73hardware checksum enabled, or 0 if not enabled. The default is 1. 74 75 76### UARTS 77UARTs are enabled by connecting the appropriate UART master units in the 78BMC part to their corresponding uart slave units. No additional attributes 79are required. 80 81 82### LEDs 83LEDS will be listed in the device tree when LED parts in the MRW are wired to 84their GPIO master endpoints. The instance name in the MRW is the name of 85its node in the device tree. 86 87##### ON\_STATE 88Set to the logic value required to activate the LED - either 0 or 1. The 89default is 0. 90 91 92### I2C 93I2C devices are enabled by connecting the I2C master units in the BMC to 94the I2C slave units on the devices. 95 96##### I2C\_ADDRESS 97The 8 bit hexadecimal I2C address should be set in the slave unit of the 98end device. 99 100##### BMC\_DT\_COMPATIBLE 101When creating a new XML device model, this attribute should be used to 102specify which device driver the kernel will use to access the device. 103For example, `ti,423` or `bosch,bmp280`. For existing parts, this should 104already be set. 105 106##### BMC\_DT\_ATTR\_NAMES 107This attribute is also only required when creating a new XML representation 108of an I2C device. It specifies which other attributes of the device should be 109listed as properties in the device tree, as required by the device driver 110for that device. It can contain up to 4 pairs of names, the first name in the 111pair is the attribute name in the XML to read, and the second name in the 112pair is the name of the property to call it in the device tree. For example, 113`ATTR_WRITE_PAGE_SIZE, pagesize` indicates that the value of the 114`ATTR_WRITE_PAGE_SIZE` attribute should be stored in a property called 115`pagesize` in the device tree. 116 117