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1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Texas Instruments System Control Interface (TI SCI) reset driver | |
4 | * | |
a94a4071 | 5 | * Copyright (C) 2018 Texas Instruments Incorporated - https://www.ti.com/ |
65c8a798 AD |
6 | * Andreas Dannenberg <dannenberg@ti.com> |
7 | * | |
8 | * Loosely based on Linux kernel reset-ti-sci.c... | |
9 | */ | |
10 | ||
11 | #include <common.h> | |
12 | #include <dm.h> | |
13 | #include <errno.h> | |
f7ae49fc | 14 | #include <log.h> |
336d4615 | 15 | #include <malloc.h> |
65c8a798 | 16 | #include <reset-uclass.h> |
336d4615 | 17 | #include <dm/device_compat.h> |
61b29b82 | 18 | #include <linux/err.h> |
65c8a798 AD |
19 | #include <linux/soc/ti/ti_sci_protocol.h> |
20 | ||
21 | /** | |
22 | * struct ti_sci_reset_data - reset controller information structure | |
23 | * @sci: TI SCI handle used for communication with system controller | |
24 | */ | |
25 | struct ti_sci_reset_data { | |
26 | const struct ti_sci_handle *sci; | |
27 | }; | |
28 | ||
29 | static int ti_sci_reset_probe(struct udevice *dev) | |
30 | { | |
31 | struct ti_sci_reset_data *data = dev_get_priv(dev); | |
32 | ||
33 | debug("%s(dev=%p)\n", __func__, dev); | |
34 | ||
35 | if (!data) | |
36 | return -ENOMEM; | |
37 | ||
38 | /* Store handle for communication with the system controller */ | |
39 | data->sci = ti_sci_get_handle(dev); | |
40 | if (IS_ERR(data->sci)) | |
41 | return PTR_ERR(data->sci); | |
42 | ||
43 | return 0; | |
44 | } | |
45 | ||
46 | static int ti_sci_reset_of_xlate(struct reset_ctl *rst, | |
47 | struct ofnode_phandle_args *args) | |
48 | { | |
49 | debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count); | |
50 | ||
51 | if (args->args_count != 2) { | |
52 | debug("Invalid args_count: %d\n", args->args_count); | |
53 | return -EINVAL; | |
54 | } | |
55 | ||
56 | /* | |
57 | * On TI SCI-based devices, the reset provider id field is used as a | |
58 | * device ID, and the data field is used as the associated reset mask. | |
59 | */ | |
60 | rst->id = args->args[0]; | |
61 | rst->data = args->args[1]; | |
62 | ||
63 | return 0; | |
64 | } | |
65 | ||
65c8a798 AD |
66 | /** |
67 | * ti_sci_reset_set() - program a device's reset | |
68 | * @rst: Handle to a single reset signal | |
69 | * @assert: boolean flag to indicate assert or deassert | |
70 | * | |
71 | * This is a common internal function used to assert or deassert a device's | |
72 | * reset using the TI SCI protocol. The device's reset is asserted if the | |
73 | * @assert argument is true, or deasserted if @assert argument is false. | |
74 | * The mechanism itself is a read-modify-write procedure, the current device | |
75 | * reset register is read using a TI SCI device operation, the new value is | |
76 | * set or un-set using the reset's mask, and the new reset value written by | |
77 | * using another TI SCI device operation. | |
78 | * | |
79 | * Return: 0 for successful request, else a corresponding error value | |
80 | */ | |
81 | static int ti_sci_reset_set(struct reset_ctl *rst, bool assert) | |
82 | { | |
83 | struct ti_sci_reset_data *data = dev_get_priv(rst->dev); | |
84 | const struct ti_sci_handle *sci = data->sci; | |
85 | const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops; | |
86 | u32 reset_state; | |
87 | int ret; | |
88 | ||
89 | ret = dops->get_device_resets(sci, rst->id, &reset_state); | |
90 | if (ret) { | |
91 | dev_err(rst->dev, "%s: get_device_resets failed (%d)\n", | |
92 | __func__, ret); | |
93 | return ret; | |
94 | } | |
95 | ||
96 | if (assert) | |
97 | reset_state |= rst->data; | |
98 | else | |
99 | reset_state &= ~rst->data; | |
100 | ||
101 | ret = dops->set_device_resets(sci, rst->id, reset_state); | |
102 | if (ret) { | |
103 | dev_err(rst->dev, "%s: set_device_resets failed (%d)\n", | |
104 | __func__, ret); | |
105 | return ret; | |
106 | } | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | /** | |
112 | * ti_sci_reset_assert() - assert device reset | |
113 | * @rst: Handle to a single reset signal | |
114 | * | |
115 | * This function implements the reset driver op to assert a device's reset | |
116 | * using the TI SCI protocol. This invokes the function ti_sci_reset_set() | |
117 | * with the corresponding parameters as passed in, but with the @assert | |
118 | * argument set to true for asserting the reset. | |
119 | * | |
120 | * Return: 0 for successful request, else a corresponding error value | |
121 | */ | |
122 | static int ti_sci_reset_assert(struct reset_ctl *rst) | |
123 | { | |
124 | debug("%s(rst=%p)\n", __func__, rst); | |
125 | return ti_sci_reset_set(rst, true); | |
126 | } | |
127 | ||
128 | /** | |
129 | * ti_sci_reset_deassert() - deassert device reset | |
130 | * @rst: Handle to a single reset signal | |
131 | * | |
132 | * This function implements the reset driver op to deassert a device's reset | |
133 | * using the TI SCI protocol. This invokes the function ti_sci_reset_set() | |
134 | * with the corresponding parameters as passed in, but with the @assert | |
135 | * argument set to false for deasserting the reset. | |
136 | * | |
137 | * Return: 0 for successful request, else a corresponding error value | |
138 | */ | |
139 | static int ti_sci_reset_deassert(struct reset_ctl *rst) | |
140 | { | |
141 | debug("%s(rst=%p)\n", __func__, rst); | |
142 | return ti_sci_reset_set(rst, false); | |
143 | } | |
144 | ||
145 | /** | |
146 | * ti_sci_reset_status() - check device reset status | |
147 | * @rst: Handle to a single reset signal | |
148 | * | |
149 | * This function implements the reset driver op to return the status of a | |
150 | * device's reset using the TI SCI protocol. The reset register value is read | |
151 | * by invoking the TI SCI device operation .get_device_resets(), and the | |
152 | * status of the specific reset is extracted and returned using this reset's | |
153 | * reset mask. | |
154 | * | |
155 | * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted | |
156 | */ | |
157 | static int ti_sci_reset_status(struct reset_ctl *rst) | |
158 | { | |
159 | struct ti_sci_reset_data *data = dev_get_priv(rst->dev); | |
160 | const struct ti_sci_handle *sci = data->sci; | |
161 | const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops; | |
162 | u32 reset_state; | |
163 | int ret; | |
164 | ||
165 | debug("%s(rst=%p)\n", __func__, rst); | |
166 | ||
167 | ret = dops->get_device_resets(sci, rst->id, &reset_state); | |
168 | if (ret) { | |
169 | dev_err(rst->dev, "%s: get_device_resets failed (%d)\n", | |
170 | __func__, ret); | |
171 | return ret; | |
172 | } | |
173 | ||
174 | return reset_state & rst->data; | |
175 | } | |
176 | ||
177 | static const struct udevice_id ti_sci_reset_of_match[] = { | |
178 | { .compatible = "ti,sci-reset", }, | |
179 | { /* sentinel */ }, | |
180 | }; | |
181 | ||
182 | static struct reset_ops ti_sci_reset_ops = { | |
183 | .of_xlate = ti_sci_reset_of_xlate, | |
65c8a798 AD |
184 | .rst_assert = ti_sci_reset_assert, |
185 | .rst_deassert = ti_sci_reset_deassert, | |
186 | .rst_status = ti_sci_reset_status, | |
187 | }; | |
188 | ||
189 | U_BOOT_DRIVER(ti_sci_reset) = { | |
190 | .name = "ti-sci-reset", | |
191 | .id = UCLASS_RESET, | |
192 | .of_match = ti_sci_reset_of_match, | |
193 | .probe = ti_sci_reset_probe, | |
41575d8e | 194 | .priv_auto = sizeof(struct ti_sci_reset_data), |
65c8a798 AD |
195 | .ops = &ti_sci_reset_ops, |
196 | }; |