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1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Texas Instruments System Control Interface (TI SCI) reset driver | |
4 | * | |
5 | * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/ | |
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 | ||
66 | static int ti_sci_reset_request(struct reset_ctl *rst) | |
67 | { | |
68 | debug("%s(rst=%p)\n", __func__, rst); | |
69 | return 0; | |
70 | } | |
71 | ||
72 | static int ti_sci_reset_free(struct reset_ctl *rst) | |
73 | { | |
74 | debug("%s(rst=%p)\n", __func__, rst); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | /** | |
79 | * ti_sci_reset_set() - program a device's reset | |
80 | * @rst: Handle to a single reset signal | |
81 | * @assert: boolean flag to indicate assert or deassert | |
82 | * | |
83 | * This is a common internal function used to assert or deassert a device's | |
84 | * reset using the TI SCI protocol. The device's reset is asserted if the | |
85 | * @assert argument is true, or deasserted if @assert argument is false. | |
86 | * The mechanism itself is a read-modify-write procedure, the current device | |
87 | * reset register is read using a TI SCI device operation, the new value is | |
88 | * set or un-set using the reset's mask, and the new reset value written by | |
89 | * using another TI SCI device operation. | |
90 | * | |
91 | * Return: 0 for successful request, else a corresponding error value | |
92 | */ | |
93 | static int ti_sci_reset_set(struct reset_ctl *rst, bool assert) | |
94 | { | |
95 | struct ti_sci_reset_data *data = dev_get_priv(rst->dev); | |
96 | const struct ti_sci_handle *sci = data->sci; | |
97 | const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops; | |
98 | u32 reset_state; | |
99 | int ret; | |
100 | ||
101 | ret = dops->get_device_resets(sci, rst->id, &reset_state); | |
102 | if (ret) { | |
103 | dev_err(rst->dev, "%s: get_device_resets failed (%d)\n", | |
104 | __func__, ret); | |
105 | return ret; | |
106 | } | |
107 | ||
108 | if (assert) | |
109 | reset_state |= rst->data; | |
110 | else | |
111 | reset_state &= ~rst->data; | |
112 | ||
113 | ret = dops->set_device_resets(sci, rst->id, reset_state); | |
114 | if (ret) { | |
115 | dev_err(rst->dev, "%s: set_device_resets failed (%d)\n", | |
116 | __func__, ret); | |
117 | return ret; | |
118 | } | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
123 | /** | |
124 | * ti_sci_reset_assert() - assert device reset | |
125 | * @rst: Handle to a single reset signal | |
126 | * | |
127 | * This function implements the reset driver op to assert a device's reset | |
128 | * using the TI SCI protocol. This invokes the function ti_sci_reset_set() | |
129 | * with the corresponding parameters as passed in, but with the @assert | |
130 | * argument set to true for asserting the reset. | |
131 | * | |
132 | * Return: 0 for successful request, else a corresponding error value | |
133 | */ | |
134 | static int ti_sci_reset_assert(struct reset_ctl *rst) | |
135 | { | |
136 | debug("%s(rst=%p)\n", __func__, rst); | |
137 | return ti_sci_reset_set(rst, true); | |
138 | } | |
139 | ||
140 | /** | |
141 | * ti_sci_reset_deassert() - deassert device reset | |
142 | * @rst: Handle to a single reset signal | |
143 | * | |
144 | * This function implements the reset driver op to deassert a device's reset | |
145 | * using the TI SCI protocol. This invokes the function ti_sci_reset_set() | |
146 | * with the corresponding parameters as passed in, but with the @assert | |
147 | * argument set to false for deasserting the reset. | |
148 | * | |
149 | * Return: 0 for successful request, else a corresponding error value | |
150 | */ | |
151 | static int ti_sci_reset_deassert(struct reset_ctl *rst) | |
152 | { | |
153 | debug("%s(rst=%p)\n", __func__, rst); | |
154 | return ti_sci_reset_set(rst, false); | |
155 | } | |
156 | ||
157 | /** | |
158 | * ti_sci_reset_status() - check device reset status | |
159 | * @rst: Handle to a single reset signal | |
160 | * | |
161 | * This function implements the reset driver op to return the status of a | |
162 | * device's reset using the TI SCI protocol. The reset register value is read | |
163 | * by invoking the TI SCI device operation .get_device_resets(), and the | |
164 | * status of the specific reset is extracted and returned using this reset's | |
165 | * reset mask. | |
166 | * | |
167 | * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted | |
168 | */ | |
169 | static int ti_sci_reset_status(struct reset_ctl *rst) | |
170 | { | |
171 | struct ti_sci_reset_data *data = dev_get_priv(rst->dev); | |
172 | const struct ti_sci_handle *sci = data->sci; | |
173 | const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops; | |
174 | u32 reset_state; | |
175 | int ret; | |
176 | ||
177 | debug("%s(rst=%p)\n", __func__, rst); | |
178 | ||
179 | ret = dops->get_device_resets(sci, rst->id, &reset_state); | |
180 | if (ret) { | |
181 | dev_err(rst->dev, "%s: get_device_resets failed (%d)\n", | |
182 | __func__, ret); | |
183 | return ret; | |
184 | } | |
185 | ||
186 | return reset_state & rst->data; | |
187 | } | |
188 | ||
189 | static const struct udevice_id ti_sci_reset_of_match[] = { | |
190 | { .compatible = "ti,sci-reset", }, | |
191 | { /* sentinel */ }, | |
192 | }; | |
193 | ||
194 | static struct reset_ops ti_sci_reset_ops = { | |
195 | .of_xlate = ti_sci_reset_of_xlate, | |
196 | .request = ti_sci_reset_request, | |
94474b25 | 197 | .rfree = ti_sci_reset_free, |
65c8a798 AD |
198 | .rst_assert = ti_sci_reset_assert, |
199 | .rst_deassert = ti_sci_reset_deassert, | |
200 | .rst_status = ti_sci_reset_status, | |
201 | }; | |
202 | ||
203 | U_BOOT_DRIVER(ti_sci_reset) = { | |
204 | .name = "ti-sci-reset", | |
205 | .id = UCLASS_RESET, | |
206 | .of_match = ti_sci_reset_of_match, | |
207 | .probe = ti_sci_reset_probe, | |
208 | .priv_auto_alloc_size = sizeof(struct ti_sci_reset_data), | |
209 | .ops = &ti_sci_reset_ops, | |
210 | }; |