UCSI Interface
EC must have the ability to interface with a discrete PD controller to negotiate power contracts/alt-modes with port partner
See the UCSI specification for commands that are required in all UCSI implementations.
USB-C Connector System Software Interface (UCSI) Driver - Windows drivers | Microsoft Learn
In addition to the commands marked as Required, Windows requires these commands:
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GET_ALTERNATE_MODES
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GET_CAM_SUPPORTED
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GET_PDOS
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SET_NOTIFICATION_ENABLE: The system or controller must support the following notifications within SET_NOTIFICATION_ENABLE:
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Supported Provider Capabilities Change
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Negotiated Power Level Change
-
-
GET_CONNECTOR_STATUS: The system or controller must support these connector status changes within GET_CONNECTOR_STATUS:
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Supported Provider Capabilities Change
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Negotiated Power Level Change
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UCSI ACPI Interface
Shared Mailbox Interface
The following table is the reserved memory structure that must be reserved and shared with the EC for communication. When using FF-A this memory region must be statically carved out and 4K aligned and directly accessible by secure world.
| Offset (Bytes) | Mnemonic | Description | Direction | Size (bits) |
|---|---|---|---|---|
| 0 | VERSION | UCSI Version Number | PPM->OPM | 16 |
| 2 | RESERVED | Reserved | N/A | 16 |
| 4 | CCI | USB Type-C Command Status and Connector Change Indication | PPM->OPM | 32 |
| 8 | CONTROL | USB Type-C Control | OPM->PPM | 64 |
| 16 | MESSAGE IN | USB Type-C Message In | PPM->OPM | 128 |
| 32 | MESSAGE OUT | USB Type-C Message Out | OPM->PPM | 128 |
ACPI Definitions
Device(USBC) {
Name(_HID,EISAID(“USBC000”))
Name(_CID,EISAID(“PNP0CA0”))
Name(_UID,1)
Name(_DDN, “USB Type-C”)
Name(_ADR,0x0)
OperationRegion(USBC, SystemMemory, 0xFFFF0000, 0x30)
Field(USBC,AnyAcc,Lock,Preserve)
{
// USB C Mailbox Interface
VERS,16, // PPM-\>OPM Version
RES, 16, // Reservied
CCI, 32, // PPM-\>OPM CCI Indicator
CTRL,64, // OPM-\>PPM Control Messages
MSGI,128, // OPM-\>PPM Message In
MSGO,128, // PPM-\>OPM Message Out
}
Method(_DSM,4,Serialized,0,UnknownObj, {BuffObj, IntObj,IntObj,PkgObj})
{
// Compare passed in UUID to Supported UUID
If(LEqual(Arg0,ToUUID(“6f8398c2-7ca4-11e4-ad36-631042b5008f”)))
{
// Use FFA to send Notification event down to copy data to EC
If(LEqual(\\_SB.FFA0.AVAL,One)) {
CreateQwordField(BUFF,0,STAT) // Out – Status
CreateField(BUFF,128,128,UUID) // UUID of service
CreateByteField(BUFF,32, CMDD) // In – First byte of command
CreateField(BUFF,288,384,FIFD) // Out – Msg data
// Create USCI Doorbell Event
Store(0x0, CMDD) // UCSI set doorbell
Store(ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), UUID) // UCSI
Store(USBC, FIFD) // Copy output data
Store(Store(BUFF, \_SB_.FFA0.FFAC), BUFF)
If(LEqual(STAT,0x0) ) // Check FF-A successful?
{
Return (FIFD)
}
} // End AVAL
Return(Zero)
} // End UUID
} // End DSM
}