1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 ===================== 3 =====================
4 Intel North Mux-Agent 4 Intel North Mux-Agent
5 ===================== 5 =====================
6 6
7 Introduction 7 Introduction
8 ============ 8 ============
9 9
10 North Mux-Agent is a function of the Intel PMC 10 North Mux-Agent is a function of the Intel PMC firmware that is supported on
11 most Intel based platforms that have the PMC m 11 most Intel based platforms that have the PMC microcontroller. It's used for
12 configuring the various USB Multiplexer/DeMult 12 configuring the various USB Multiplexer/DeMultiplexers on the system. The
13 platforms that allow the mux-agent to be confi 13 platforms that allow the mux-agent to be configured from the operating system
14 have an ACPI device object (node) with HID "IN 14 have an ACPI device object (node) with HID "INTC105C" that represents it.
15 15
16 The North Mux-Agent (aka. Intel PMC Mux Contro 16 The North Mux-Agent (aka. Intel PMC Mux Control, or just mux-agent) driver
17 communicates with the PMC microcontroller by u 17 communicates with the PMC microcontroller by using the PMC IPC method
18 (drivers/platform/x86/intel_scu_ipc.c). The dr 18 (drivers/platform/x86/intel_scu_ipc.c). The driver registers with the USB Type-C
19 Mux Class which allows the USB Type-C Controll 19 Mux Class which allows the USB Type-C Controller and Interface drivers to
20 configure the cable plug orientation and mode 20 configure the cable plug orientation and mode (with Alternate Modes). The driver
21 also registers with the USB Role Class in orde 21 also registers with the USB Role Class in order to support both USB Host and
22 Device modes. The driver is located here: driv 22 Device modes. The driver is located here: drivers/usb/typec/mux/intel_pmc_mux.c.
23 23
24 Port nodes 24 Port nodes
25 ========== 25 ==========
26 26
27 General 27 General
28 ------- 28 -------
29 29
30 For every USB Type-C connector under the mux-a 30 For every USB Type-C connector under the mux-agent control on the system, there
31 is a separate child node under the PMC mux-age 31 is a separate child node under the PMC mux-agent device node. Those nodes do not
32 represent the actual connectors, but instead t 32 represent the actual connectors, but instead the "channels" in the mux-agent
33 that are associated with the connectors:: 33 that are associated with the connectors::
34 34
35 Scope (_SB.PCI0.PMC.MUX) 35 Scope (_SB.PCI0.PMC.MUX)
36 { 36 {
37 Device (CH0) 37 Device (CH0)
38 { 38 {
39 Name (_ADR, 0) 39 Name (_ADR, 0)
40 } 40 }
41 41
42 Device (CH1) 42 Device (CH1)
43 { 43 {
44 Name (_ADR, 1) 44 Name (_ADR, 1)
45 } 45 }
46 } 46 }
47 47
48 _PLD (Physical Location of Device) 48 _PLD (Physical Location of Device)
49 ---------------------------------- 49 ----------------------------------
50 50
51 The optional _PLD object can be used with the 51 The optional _PLD object can be used with the port (the channel) nodes. If _PLD
52 is supplied, it should match the connector nod 52 is supplied, it should match the connector node _PLD::
53 53
54 Scope (_SB.PCI0.PMC.MUX) 54 Scope (_SB.PCI0.PMC.MUX)
55 { 55 {
56 Device (CH0) 56 Device (CH0)
57 { 57 {
58 Name (_ADR, 0) 58 Name (_ADR, 0)
59 Method (_PLD, 0, NotSerialized 59 Method (_PLD, 0, NotSerialized)
60 { 60 {
61 /* Consider this as pseudo 61 /* Consider this as pseudocode. */
62 Return (\_SB.USBC.CON0._PL 62 Return (\_SB.USBC.CON0._PLD())
63 } 63 }
64 } 64 }
65 } 65 }
66 66
67 Mux-agent specific _DSD Device Properties 67 Mux-agent specific _DSD Device Properties
68 ----------------------------------------- 68 -----------------------------------------
69 69
70 Port Numbers 70 Port Numbers
71 ~~~~~~~~~~~~ 71 ~~~~~~~~~~~~
72 72
73 In order to configure the muxes behind a USB T 73 In order to configure the muxes behind a USB Type-C connector, the PMC firmware
74 needs to know the USB2 port and the USB3 port 74 needs to know the USB2 port and the USB3 port that is associated with the
75 connector. The driver extracts the correct por 75 connector. The driver extracts the correct port numbers by reading specific _DSD
76 device properties named "usb2-port-number" and 76 device properties named "usb2-port-number" and "usb3-port-number". These
77 properties have integer value that means the p 77 properties have integer value that means the port index. The port index number
78 is 1's based, and value 0 is illegal. The driv 78 is 1's based, and value 0 is illegal. The driver uses the numbers extracted from
79 these device properties as-is when sending the 79 these device properties as-is when sending the mux-agent specific messages to
80 the PMC:: 80 the PMC::
81 81
82 Name (_DSD, Package () { 82 Name (_DSD, Package () {
83 ToUUID("daffd814-6eba-4d8c-8a91-bc 83 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
84 Package() { 84 Package() {
85 Package () {"usb2-port-number" 85 Package () {"usb2-port-number", 6},
86 Package () {"usb3-port-number" 86 Package () {"usb3-port-number", 3},
87 }, 87 },
88 }) 88 })
89 89
90 Orientation 90 Orientation
91 ~~~~~~~~~~~ 91 ~~~~~~~~~~~
92 92
93 Depending on the platform, the data and SBU li 93 Depending on the platform, the data and SBU lines coming from the connector may
94 be "fixed" from the mux-agent's point of view, 94 be "fixed" from the mux-agent's point of view, which means the mux-agent driver
95 should not configure them according to the cab 95 should not configure them according to the cable plug orientation. This can
96 happen for example if a retimer on the platfor 96 happen for example if a retimer on the platform handles the cable plug
97 orientation. The driver uses a specific device 97 orientation. The driver uses a specific device properties "sbu-orientation"
98 (SBU) and "hsl-orientation" (data) to know if 98 (SBU) and "hsl-orientation" (data) to know if those lines are "fixed", and to
99 which orientation. The value that these proper 99 which orientation. The value that these properties have is a string value, and
100 it can be one that is defined for the USB Type 100 it can be one that is defined for the USB Type-C connector orientation: "normal"
101 or "reversed":: 101 or "reversed"::
102 102
103 Name (_DSD, Package () { 103 Name (_DSD, Package () {
104 ToUUID("daffd814-6eba-4d8c-8a91-bc 104 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
105 Package() { 105 Package() {
106 Package () {"sbu-orientation", 106 Package () {"sbu-orientation", "normal"},
107 Package () {"hsl-orientation", 107 Package () {"hsl-orientation", "normal"},
108 }, 108 },
109 }) 109 })
110 110
111 Example ASL 111 Example ASL
112 =========== 112 ===========
113 113
114 The following ASL is an example that shows the 114 The following ASL is an example that shows the mux-agent node, and two
115 connectors under its control:: 115 connectors under its control::
116 116
117 Scope (_SB.PCI0.PMC) 117 Scope (_SB.PCI0.PMC)
118 { 118 {
119 Device (MUX) 119 Device (MUX)
120 { 120 {
121 Name (_HID, "INTC105C") 121 Name (_HID, "INTC105C")
122 122
123 Device (CH0) 123 Device (CH0)
124 { 124 {
125 Name (_ADR, 0) 125 Name (_ADR, 0)
126 126
127 Name (_DSD, Package () { 127 Name (_DSD, Package () {
128 ToUUID("daffd814-6eba- 128 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
129 Package() { 129 Package() {
130 Package () {"usb2- 130 Package () {"usb2-port-number", 6},
131 Package () {"usb3- 131 Package () {"usb3-port-number", 3},
132 Package () {"sbu-o 132 Package () {"sbu-orientation", "normal"},
133 Package () {"hsl-o 133 Package () {"hsl-orientation", "normal"},
134 }, 134 },
135 }) 135 })
136 } 136 }
137 137
138 Device (CH1) 138 Device (CH1)
139 { 139 {
140 Name (_ADR, 1) 140 Name (_ADR, 1)
141 141
142 Name (_DSD, Package () { 142 Name (_DSD, Package () {
143 ToUUID("daffd814-6eba- 143 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
144 Package() { 144 Package() {
145 Package () {"usb2- 145 Package () {"usb2-port-number", 5},
146 Package () {"usb3- 146 Package () {"usb3-port-number", 2},
147 Package () {"sbu-o 147 Package () {"sbu-orientation", "normal"},
148 Package () {"hsl-o 148 Package () {"hsl-orientation", "normal"},
149 }, 149 },
150 }) 150 })
151 } 151 }
152 } 152 }
153 } 153 }
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