1 .. SPDX-License-Identifier: GPL-2.0
2
3
4 AMD Sensor Fusion Hub
5 =====================
6 AMD Sensor Fusion Hub (SFH) is part of an SOC
7 The solution is working well on several OEM pr
8 In terms of architecture it resembles ISH, how
9 the HID reports are generated as part of the k
10
11 Block Diagram
12 -------------
13
14 ::
15
16 ---------------------------------
17 | HID User Space Applications |
18 - -------------------------------
19
20 ------------------------------------------
21 ---------------------------------
22 | HID Core |
23 ---------------------------------
24
25 ---------------------------------
26 | AMD HID Transport |
27 ---------------------------------
28
29 --------------------------------
30 | AMD HID Client |
31 | with HID Report Generator|
32 --------------------------------
33
34 --------------------------------
35 | AMD MP2 PCIe Driver |
36 --------------------------------
37 OS
38 ------------------------------------------
39 Hardware + Firmware
40 --------------------------------
41 | SFH MP2 Processor |
42 --------------------------------
43
44
45 AMD HID Transport Layer
46 -----------------------
47 AMD SFH transport is also implemented as a bus
48 registered as a device on this bus. Here, MP2
49 sensor data. The layer, which binds each devic
50 registers with the HID core. Transport layer a
51 each device. Once a device is registered with
52 used by HID core to communicate with the devic
53
54 AMD HID Client Layer
55 --------------------
56 This layer is responsible to implement HID req
57 client layer fills the HID request structure a
58 interface between MP2 PCIe layer and HID. HID
59 the instance of MP2 layer. It identifies the n
60 on that allocates the DRAM address for each an
61 enumeration of each sensor, client layer fills
62 structure. HID Feature report structure is opt
63 sensor to sensor.
64
65 AMD MP2 PCIe layer
66 ------------------
67 MP2 PCIe Layer is responsible for making all t
68 The connection establishment between firmware
69
70 The communication between X86 and MP2 is split
71 1. Command transfer via the C2P mailbox regist
72 2. Data transfer via DRAM.
73 3. Supported sensor info via P2C registers.
74
75 Commands are sent to MP2 using C2P Mailbox reg
76 interrupt to MP2. The client layer allocates t
77 the PCI layer. MP2 firmware writes the command
78 layer has allocated. Firmware always writes mi
79 shall allocate minimum of 32 bytes DRAM space.
80
81 Enumeration and Probing flow
82 ----------------------------
83 ::
84
85 HID AMD AMD
86 Core Transport Client laye
87 | | |
88 | | |
89 | | |
90 | | |
91 | | |
92 | | |---Get
93 | | |
94 | | |
95 | | |
96 | | | Loop(
97 | | |------
98 | | | Creat
99 | | | Creat
100 | | | Desc
101 | | | the
102 | | | HID
103 | | | Alloc
104 | | |
105 | | |------
106 | | HID transport|
107 | |<--Probe------|
108 | | Create the |
109 | | HID device |
110 | | (MFD) |
111 | | by Populating|
112 | | the HID |
113 | | ll_driver |
114 | HID | |
115 | add | |
116 |Device | |
117 |<------------- | |
118
119
120 Data Flow from Application to the AMD SFH Driv
121 ----------------------------------------------
122
123 ::
124
125 | |
126 | |
127 | |
128 | |
129 | |
130 |HID_req |
131 |get_report |
132 |------------->|
133 | | HID_get_input
134 | | report
135 | |------------->
136 | |
137 | |
138 | |
139 | |
140 | |
141 | |Data received
142 | | in HID report
143 To |<-------------|<-------------
144 Applications| |
145 <-------| |
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