1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * ARM System Control and Management Interface (ARM SCMI) reset driver |
4 | * |
5 | * Copyright (C) 2019-2021 ARM Ltd. |
6 | */ |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/of.h> |
10 | #include <linux/device.h> |
11 | #include <linux/reset-controller.h> |
12 | #include <linux/scmi_protocol.h> |
13 | |
14 | static const struct scmi_reset_proto_ops *reset_ops; |
15 | |
16 | /** |
17 | * struct scmi_reset_data - reset controller information structure |
18 | * @rcdev: reset controller entity |
19 | * @ph: ARM SCMI protocol handle used for communication with system controller |
20 | */ |
21 | struct scmi_reset_data { |
22 | struct reset_controller_dev rcdev; |
23 | const struct scmi_protocol_handle *ph; |
24 | }; |
25 | |
26 | #define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev) |
27 | #define to_scmi_handle(p) (to_scmi_reset_data(p)->ph) |
28 | |
29 | /** |
30 | * scmi_reset_assert() - assert device reset |
31 | * @rcdev: reset controller entity |
32 | * @id: ID of the reset to be asserted |
33 | * |
34 | * This function implements the reset driver op to assert a device's reset |
35 | * using the ARM SCMI protocol. |
36 | * |
37 | * Return: 0 for successful request, else a corresponding error value |
38 | */ |
39 | static int |
40 | scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) |
41 | { |
42 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); |
43 | |
44 | return reset_ops->assert(ph, id); |
45 | } |
46 | |
47 | /** |
48 | * scmi_reset_deassert() - deassert device reset |
49 | * @rcdev: reset controller entity |
50 | * @id: ID of the reset to be deasserted |
51 | * |
52 | * This function implements the reset driver op to deassert a device's reset |
53 | * using the ARM SCMI protocol. |
54 | * |
55 | * Return: 0 for successful request, else a corresponding error value |
56 | */ |
57 | static int |
58 | scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) |
59 | { |
60 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); |
61 | |
62 | return reset_ops->deassert(ph, id); |
63 | } |
64 | |
65 | /** |
66 | * scmi_reset_reset() - reset the device |
67 | * @rcdev: reset controller entity |
68 | * @id: ID of the reset signal to be reset(assert + deassert) |
69 | * |
70 | * This function implements the reset driver op to trigger a device's |
71 | * reset signal using the ARM SCMI protocol. |
72 | * |
73 | * Return: 0 for successful request, else a corresponding error value |
74 | */ |
75 | static int |
76 | scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id) |
77 | { |
78 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); |
79 | |
80 | return reset_ops->reset(ph, id); |
81 | } |
82 | |
83 | static const struct reset_control_ops scmi_reset_ops = { |
84 | .assert = scmi_reset_assert, |
85 | .deassert = scmi_reset_deassert, |
86 | .reset = scmi_reset_reset, |
87 | }; |
88 | |
89 | static int scmi_reset_probe(struct scmi_device *sdev) |
90 | { |
91 | struct scmi_reset_data *data; |
92 | struct device *dev = &sdev->dev; |
93 | struct device_node *np = dev->of_node; |
94 | const struct scmi_handle *handle = sdev->handle; |
95 | struct scmi_protocol_handle *ph; |
96 | |
97 | if (!handle) |
98 | return -ENODEV; |
99 | |
100 | reset_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_RESET, &ph); |
101 | if (IS_ERR(ptr: reset_ops)) |
102 | return PTR_ERR(ptr: reset_ops); |
103 | |
104 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
105 | if (!data) |
106 | return -ENOMEM; |
107 | |
108 | data->rcdev.ops = &scmi_reset_ops; |
109 | data->rcdev.owner = THIS_MODULE; |
110 | data->rcdev.of_node = np; |
111 | data->rcdev.nr_resets = reset_ops->num_domains_get(ph); |
112 | data->ph = ph; |
113 | |
114 | return devm_reset_controller_register(dev, rcdev: &data->rcdev); |
115 | } |
116 | |
117 | static const struct scmi_device_id scmi_id_table[] = { |
118 | { SCMI_PROTOCOL_RESET, "reset" }, |
119 | { }, |
120 | }; |
121 | MODULE_DEVICE_TABLE(scmi, scmi_id_table); |
122 | |
123 | static struct scmi_driver scmi_reset_driver = { |
124 | .name = "scmi-reset" , |
125 | .probe = scmi_reset_probe, |
126 | .id_table = scmi_id_table, |
127 | }; |
128 | module_scmi_driver(scmi_reset_driver); |
129 | |
130 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>" ); |
131 | MODULE_DESCRIPTION("ARM SCMI reset controller driver" ); |
132 | MODULE_LICENSE("GPL v2" ); |
133 | |