tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1Qualcomm Always-On Subsystem side channel binding
2
3This binding describes the hardware component responsible for side channel
4requests to the always-on subsystem (AOSS), used for certain power management
5requests that is not handled by the standard RPMh interface. Each client in the
6SoC has it's own block of message RAM and IRQ for communication with the AOSS.
7The protocol used to communicate in the message RAM is known as Qualcomm
8Messaging Protocol (QMP)
9
10The AOSS side channel exposes control over a set of resources, used to control
11a set of debug related clocks and to affect the low power state of resources
12related to the secondary subsystems. These resources are exposed as a set of
13power-domains.
14
15- compatible:
16 Usage: required
17 Value type: <string>
18 Definition: must be one of:
19 "qcom,sc7180-aoss-qmp"
20 "qcom,sdm845-aoss-qmp"
21 "qcom,sm8150-aoss-qmp"
22 "qcom,sm8250-aoss-qmp"
23
24- reg:
25 Usage: required
26 Value type: <prop-encoded-array>
27 Definition: the base address and size of the message RAM for this
28 client's communication with the AOSS
29
30- interrupts:
31 Usage: required
32 Value type: <prop-encoded-array>
33 Definition: should specify the AOSS message IRQ for this client
34
35- mboxes:
36 Usage: required
37 Value type: <prop-encoded-array>
38 Definition: reference to the mailbox representing the outgoing doorbell
39 in APCS for this client, as described in mailbox/mailbox.txt
40
41- #clock-cells:
42 Usage: optional
43 Value type: <u32>
44 Definition: must be 0
45 The single clock represents the QDSS clock.
46
47- #power-domain-cells:
48 Usage: optional
49 Value type: <u32>
50 Definition: must be 1
51 The provided power-domains are:
52 CDSP state (0), LPASS state (1), modem state (2), SLPI
53 state (3), SPSS state (4) and Venus state (5).
54
55= SUBNODES
56The AOSS side channel also provides the controls for three cooling devices,
57these are expressed as subnodes of the QMP node. The name of the node is used
58to identify the resource and must therefor be "cx", "mx" or "ebi".
59
60- #cooling-cells:
61 Usage: optional
62 Value type: <u32>
63 Definition: must be 2
64
65= EXAMPLE
66
67The following example represents the AOSS side-channel message RAM and the
68mechanism exposing the power-domains, as found in SDM845.
69
70 aoss_qmp: qmp@c300000 {
71 compatible = "qcom,sdm845-aoss-qmp";
72 reg = <0x0c300000 0x100000>;
73 interrupts = <GIC_SPI 389 IRQ_TYPE_EDGE_RISING>;
74 mboxes = <&apss_shared 0>;
75
76 #power-domain-cells = <1>;
77
78 cx_cdev: cx {
79 #cooling-cells = <2>;
80 };
81
82 mx_cdev: mx {
83 #cooling-cells = <2>;
84 };
85 };