blob: f5d82b56810b22f985d976f3b46278df948eb206 [file] [log] [blame]
Andreas Dannenberg65c8a792018-08-27 15:57:41 +05301// 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>
Simon Glass336d4612020-02-03 07:36:16 -070014#include <malloc.h>
Andreas Dannenberg65c8a792018-08-27 15:57:41 +053015#include <reset-uclass.h>
Simon Glass336d4612020-02-03 07:36:16 -070016#include <dm/device_compat.h>
Simon Glass61b29b82020-02-03 07:36:15 -070017#include <linux/err.h>
Andreas Dannenberg65c8a792018-08-27 15:57:41 +053018#include <linux/soc/ti/ti_sci_protocol.h>
19
20/**
21 * struct ti_sci_reset_data - reset controller information structure
22 * @sci: TI SCI handle used for communication with system controller
23 */
24struct ti_sci_reset_data {
25 const struct ti_sci_handle *sci;
26};
27
28static int ti_sci_reset_probe(struct udevice *dev)
29{
30 struct ti_sci_reset_data *data = dev_get_priv(dev);
31
32 debug("%s(dev=%p)\n", __func__, dev);
33
34 if (!data)
35 return -ENOMEM;
36
37 /* Store handle for communication with the system controller */
38 data->sci = ti_sci_get_handle(dev);
39 if (IS_ERR(data->sci))
40 return PTR_ERR(data->sci);
41
42 return 0;
43}
44
45static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
46 struct ofnode_phandle_args *args)
47{
48 debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);
49
50 if (args->args_count != 2) {
51 debug("Invalid args_count: %d\n", args->args_count);
52 return -EINVAL;
53 }
54
55 /*
56 * On TI SCI-based devices, the reset provider id field is used as a
57 * device ID, and the data field is used as the associated reset mask.
58 */
59 rst->id = args->args[0];
60 rst->data = args->args[1];
61
62 return 0;
63}
64
65static int ti_sci_reset_request(struct reset_ctl *rst)
66{
67 debug("%s(rst=%p)\n", __func__, rst);
68 return 0;
69}
70
71static int ti_sci_reset_free(struct reset_ctl *rst)
72{
73 debug("%s(rst=%p)\n", __func__, rst);
74 return 0;
75}
76
77/**
78 * ti_sci_reset_set() - program a device's reset
79 * @rst: Handle to a single reset signal
80 * @assert: boolean flag to indicate assert or deassert
81 *
82 * This is a common internal function used to assert or deassert a device's
83 * reset using the TI SCI protocol. The device's reset is asserted if the
84 * @assert argument is true, or deasserted if @assert argument is false.
85 * The mechanism itself is a read-modify-write procedure, the current device
86 * reset register is read using a TI SCI device operation, the new value is
87 * set or un-set using the reset's mask, and the new reset value written by
88 * using another TI SCI device operation.
89 *
90 * Return: 0 for successful request, else a corresponding error value
91 */
92static int ti_sci_reset_set(struct reset_ctl *rst, bool assert)
93{
94 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
95 const struct ti_sci_handle *sci = data->sci;
96 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
97 u32 reset_state;
98 int ret;
99
100 ret = dops->get_device_resets(sci, rst->id, &reset_state);
101 if (ret) {
102 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
103 __func__, ret);
104 return ret;
105 }
106
107 if (assert)
108 reset_state |= rst->data;
109 else
110 reset_state &= ~rst->data;
111
112 ret = dops->set_device_resets(sci, rst->id, reset_state);
113 if (ret) {
114 dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
115 __func__, ret);
116 return ret;
117 }
118
119 return 0;
120}
121
122/**
123 * ti_sci_reset_assert() - assert device reset
124 * @rst: Handle to a single reset signal
125 *
126 * This function implements the reset driver op to assert a device's reset
127 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
128 * with the corresponding parameters as passed in, but with the @assert
129 * argument set to true for asserting the reset.
130 *
131 * Return: 0 for successful request, else a corresponding error value
132 */
133static int ti_sci_reset_assert(struct reset_ctl *rst)
134{
135 debug("%s(rst=%p)\n", __func__, rst);
136 return ti_sci_reset_set(rst, true);
137}
138
139/**
140 * ti_sci_reset_deassert() - deassert device reset
141 * @rst: Handle to a single reset signal
142 *
143 * This function implements the reset driver op to deassert a device's reset
144 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
145 * with the corresponding parameters as passed in, but with the @assert
146 * argument set to false for deasserting the reset.
147 *
148 * Return: 0 for successful request, else a corresponding error value
149 */
150static int ti_sci_reset_deassert(struct reset_ctl *rst)
151{
152 debug("%s(rst=%p)\n", __func__, rst);
153 return ti_sci_reset_set(rst, false);
154}
155
156/**
157 * ti_sci_reset_status() - check device reset status
158 * @rst: Handle to a single reset signal
159 *
160 * This function implements the reset driver op to return the status of a
161 * device's reset using the TI SCI protocol. The reset register value is read
162 * by invoking the TI SCI device operation .get_device_resets(), and the
163 * status of the specific reset is extracted and returned using this reset's
164 * reset mask.
165 *
166 * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
167 */
168static int ti_sci_reset_status(struct reset_ctl *rst)
169{
170 struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
171 const struct ti_sci_handle *sci = data->sci;
172 const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
173 u32 reset_state;
174 int ret;
175
176 debug("%s(rst=%p)\n", __func__, rst);
177
178 ret = dops->get_device_resets(sci, rst->id, &reset_state);
179 if (ret) {
180 dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
181 __func__, ret);
182 return ret;
183 }
184
185 return reset_state & rst->data;
186}
187
188static const struct udevice_id ti_sci_reset_of_match[] = {
189 { .compatible = "ti,sci-reset", },
190 { /* sentinel */ },
191};
192
193static struct reset_ops ti_sci_reset_ops = {
194 .of_xlate = ti_sci_reset_of_xlate,
195 .request = ti_sci_reset_request,
Simon Glass94474b22020-02-03 07:35:52 -0700196 .rfree = ti_sci_reset_free,
Andreas Dannenberg65c8a792018-08-27 15:57:41 +0530197 .rst_assert = ti_sci_reset_assert,
198 .rst_deassert = ti_sci_reset_deassert,
199 .rst_status = ti_sci_reset_status,
200};
201
202U_BOOT_DRIVER(ti_sci_reset) = {
203 .name = "ti-sci-reset",
204 .id = UCLASS_RESET,
205 .of_match = ti_sci_reset_of_match,
206 .probe = ti_sci_reset_probe,
207 .priv_auto_alloc_size = sizeof(struct ti_sci_reset_data),
208 .ops = &ti_sci_reset_ops,
209};