Saurin Shah, senior software engineer at Microsoft Corporation, and Rob Gough, platform software architect at Intel Corporation, discuss how the DisCo creation tool simplifies the development process by using device templates created from MIPI DisCo specifications to generate ASL files.

1. Saurin Shah Rob Gough
Microsoft Corporation Intel Corporation
MIPI Discovery and
Configuration (DisCoSM)
Creation Tool

2. © 2019 MIPI Alliance, Inc. 2
Agenda
• DisCo Background
• DisCo Creation Tool
• Demo
Microsoft Corporation & Intel Corporation

3. © 2019 MIPI Alliance, Inc. 3
What is DisCo (Discovery and Configuration)?
• ACPI based specifications that describe hardware
– Defines properties that are device-specific: MIPI I3C HCISM, MIPI Soundwire Master, etc.
• MIPI currently defines 4 DisCo specifications (software.mipi.org) - more on the
way
• Information is encoded in ACPI Objects like _DSD (Device-Specific Data)
properties and includes:
– Platform-specific information
– Component-specific information
• DisCo properties are published by platform firmware into system memory, and
consumed by software drivers in the operating system
Microsoft Corporation & Intel Corporation

4. © 2019 MIPI Alliance, Inc. 4
DisCo Properties
Microsoft Corporation & Intel Corporation
• Properties are often hierarchical, many layers
of sub properties
• Properties are written in Advanced
Configuration and Power Interface Source
Language (ASL)
Property String Data Type Description
“mipi-sdw-sw-interface-
revision”
Integer This is a 32-bit value where the upper word
contains the major version number of this
Specification, and the lower word contains the
minor version number.
“mipi-sdw-max-clock-
frequency”
Integer This value provides the maximum Bus clock in Hz
for this master. This is the maximum usable Bus
clock frequency for this platform.
“mipi-sdw-clock-
frequencies-supported”
Package A package containing one integer entry for each
clock frequency supported. Frequencies are
represented in Hz.
“mipi-sdw-supported-
clock-gears”
Package A package containing one integer entry for each
supported gear, e.g. {1, 2, 3, 4, , 16}. Some
Masters may only support a single gear, or
powers of two.
Property, Value
Property, Value
Property, Value
Link Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
Slave Device
Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
DP0 Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
DPn Audio Port
Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
DP1 Audio Port
Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
Audio Mode m
Properties
Property, Value
Property, Value
Property, Value
Property, Reference
Property, Reference
Property, Reference
Audio Mode 1
Properties
Soundwire Slave Device DisCo Properties
Property, Value
Property, Value
Property, Value
BRA Mode
Properties

5. © 2019 MIPI Alliance, Inc. 5
Challenges with DisCo Properties
• Properties are written “by hand” (with a text editor)
– DisCo Property sets are documented in multiple specs
– Vendor-specific property definitions also exist
– Development process is prone to error
• Property values must be provided by a component vendor,
or discerned by the firmware developer from a datasheet
– Hand-coding complex hierarchies is easy to get wrong
– Current compilers do not check _DSD syntax or data types
Microsoft Corporation & Intel Corporation

6. © 2019 MIPI Alliance, Inc. 6
DisCo Creation Tool
• Allows component vendors to select the properties that apply to their
components, select/enter the value(s) that apply to those properties, and
ensures that the input values and format conform to DisCo specifications
• Allows vendors to extend with vendor-specific properties as needed
• Provides open-source access to device property templates via repository
• Makes DisCo properties easy to manage and use
• Reduces amount of effort required to develop platform firmware images
• Reduces effort needed for platform firmware/software debug
Microsoft Corporation & Intel Corporation

7. © 2019 MIPI Alliance, Inc. 7
Demo
Microsoft Corporation & Intel Corporation

8. © 2019 MIPI Alliance, Inc. 8
Typical Workflow
DisCo
Creation
Tool
MIPI
Template
Repository
Private
Template
Repository
Component Vendors
Use MIPI
provided Device
Templates
Create Device
Configuration
Template for
their Device
MIPI Alliance
Define New
Specification
Build DisCo Tool
Template for
New
Specification
Maintain DisCo Tool
System Integrators
Obtain Device
Templates from
Repository
Generate Final
ASL
Microsoft Corporation & Intel Corporation

9. © 2019 MIPI Alliance, Inc. 9
Current status
• Initial code contributed by Microsoft
• New features are constantly getting added
• Tentative Public Availability: June 2020
Microsoft Corporation & Intel Corporation

10. © 2019 MIPI Alliance, Inc. 10
• DisCo Specifications: software.mipi.org
ADDITIONAL RESOURCES
Microsoft Corporation & Intel Corporation