1 .. SPDX-License-Identifier: GPL-2.0
2
3 ============
4 MHI Topology
5 ============
6
7 This document provides information about the M
8 representation in the kernel.
9
10 MHI Controller
11 --------------
12
13 MHI controller driver manages the interaction
14 such as the external modems and WiFi chipsets.
15 which is in charge of managing the physical li
16 It is however not involved in the actual data
17 is taken care by the physical bus such as PCIe
18 channels and events based on the client device
19
20 Below are the roles of the MHI controller driv
21
22 * Turns on the physical bus and establishes th
23 * Configures IRQs, IOMMU, and IOMEM
24 * Allocates struct mhi_controller and register
25 with channel and event configurations using
26 * Initiates power on and shutdown sequence
27 * Initiates suspend and resume power managemen
28
29 MHI Device
30 ----------
31
32 MHI device is the logical device which binds t
33 for bi-directional communication. Once MHI is
34 core will create MHI devices based on the chan
35 by the controller. There can be a single MHI d
36 couple of channels.
37
38 Each supported device is enumerated in::
39
40 /sys/bus/mhi/devices/
41
42 MHI Driver
43 ----------
44
45 MHI driver is the client driver which binds to
46 driver sends and receives the upper-layer prot
47 modem control messages, and diagnostics messag
48 bind the MHI devices to the MHI driver.
49
50 Each supported driver is enumerated in::
51
52 /sys/bus/mhi/drivers/
53
54 Below are the roles of the MHI driver:
55
56 * Registers the driver with the MHI bus framew
57 * Prepares the device for transfer by calling
58 * Initiates data transfer by calling mhi_queue
59 * Once the data transfer is finished, calls mh
60 end data transfer.
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