summaryrefslogtreecommitdiff
path: root/drivers/reset/reset-ti-sci.c
blob: d8510a4abb27291f8c5089aabd0953dfc9e6517b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
// SPDX-License-Identifier: GPL-2.0+
/*
 * Texas Instruments System Control Interface (TI SCI) reset driver
 *
 * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
 *	Andreas Dannenberg <dannenberg@ti.com>
 *
 * Loosely based on Linux kernel reset-ti-sci.c...
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <reset-uclass.h>
#include <dm/device_compat.h>
#include <linux/err.h>
#include <linux/soc/ti/ti_sci_protocol.h>

/**
 * struct ti_sci_reset_data - reset controller information structure
 * @sci: TI SCI handle used for communication with system controller
 */
struct ti_sci_reset_data {
	const struct ti_sci_handle *sci;
};

static int ti_sci_reset_probe(struct udevice *dev)
{
	struct ti_sci_reset_data *data = dev_get_priv(dev);

	debug("%s(dev=%p)\n", __func__, dev);

	if (!data)
		return -ENOMEM;

	/* Store handle for communication with the system controller */
	data->sci = ti_sci_get_handle(dev);
	if (IS_ERR(data->sci))
		return PTR_ERR(data->sci);

	return 0;
}

static int ti_sci_reset_of_xlate(struct reset_ctl *rst,
				 struct ofnode_phandle_args *args)
{
	debug("%s(rst=%p, args_count=%d)\n", __func__, rst, args->args_count);

	if (args->args_count != 2) {
		debug("Invalid args_count: %d\n", args->args_count);
		return -EINVAL;
	}

	/*
	 * On TI SCI-based devices, the reset provider id field is used as a
	 * device ID, and the data field is used as the associated reset mask.
	 */
	rst->id = args->args[0];
	rst->data = args->args[1];

	return 0;
}

static int ti_sci_reset_request(struct reset_ctl *rst)
{
	debug("%s(rst=%p)\n", __func__, rst);
	return 0;
}

static int ti_sci_reset_free(struct reset_ctl *rst)
{
	debug("%s(rst=%p)\n", __func__, rst);
	return 0;
}

/**
 * ti_sci_reset_set() - program a device's reset
 * @rst: Handle to a single reset signal
 * @assert: boolean flag to indicate assert or deassert
 *
 * This is a common internal function used to assert or deassert a device's
 * reset using the TI SCI protocol. The device's reset is asserted if the
 * @assert argument is true, or deasserted if @assert argument is false.
 * The mechanism itself is a read-modify-write procedure, the current device
 * reset register is read using a TI SCI device operation, the new value is
 * set or un-set using the reset's mask, and the new reset value written by
 * using another TI SCI device operation.
 *
 * Return: 0 for successful request, else a corresponding error value
 */
static int ti_sci_reset_set(struct reset_ctl *rst, bool assert)
{
	struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
	const struct ti_sci_handle *sci = data->sci;
	const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
	u32 reset_state;
	int ret;

	ret = dops->get_device_resets(sci, rst->id, &reset_state);
	if (ret) {
		dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
			__func__, ret);
		return ret;
	}

	if (assert)
		reset_state |= rst->data;
	else
		reset_state &= ~rst->data;

	ret = dops->set_device_resets(sci, rst->id, reset_state);
	if (ret) {
		dev_err(rst->dev, "%s: set_device_resets failed (%d)\n",
			__func__, ret);
		return ret;
	}

	return 0;
}

/**
 * ti_sci_reset_assert() - assert device reset
 * @rst: Handle to a single reset signal
 *
 * This function implements the reset driver op to assert a device's reset
 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
 * with the corresponding parameters as passed in, but with the @assert
 * argument set to true for asserting the reset.
 *
 * Return: 0 for successful request, else a corresponding error value
 */
static int ti_sci_reset_assert(struct reset_ctl *rst)
{
	debug("%s(rst=%p)\n", __func__, rst);
	return ti_sci_reset_set(rst, true);
}

/**
 * ti_sci_reset_deassert() - deassert device reset
 * @rst: Handle to a single reset signal
 *
 * This function implements the reset driver op to deassert a device's reset
 * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
 * with the corresponding parameters as passed in, but with the @assert
 * argument set to false for deasserting the reset.
 *
 * Return: 0 for successful request, else a corresponding error value
 */
static int ti_sci_reset_deassert(struct reset_ctl *rst)
{
	debug("%s(rst=%p)\n", __func__, rst);
	return ti_sci_reset_set(rst, false);
}

/**
 * ti_sci_reset_status() - check device reset status
 * @rst: Handle to a single reset signal
 *
 * This function implements the reset driver op to return the status of a
 * device's reset using the TI SCI protocol. The reset register value is read
 * by invoking the TI SCI device operation .get_device_resets(), and the
 * status of the specific reset is extracted and returned using this reset's
 * reset mask.
 *
 * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
 */
static int ti_sci_reset_status(struct reset_ctl *rst)
{
	struct ti_sci_reset_data *data = dev_get_priv(rst->dev);
	const struct ti_sci_handle *sci = data->sci;
	const struct ti_sci_dev_ops *dops = &sci->ops.dev_ops;
	u32 reset_state;
	int ret;

	debug("%s(rst=%p)\n", __func__, rst);

	ret = dops->get_device_resets(sci, rst->id, &reset_state);
	if (ret) {
		dev_err(rst->dev, "%s: get_device_resets failed (%d)\n",
			__func__, ret);
		return ret;
	}

	return reset_state & rst->data;
}

static const struct udevice_id ti_sci_reset_of_match[] = {
	{ .compatible = "ti,sci-reset", },
	{ /* sentinel */ },
};

static struct reset_ops ti_sci_reset_ops = {
	.of_xlate = ti_sci_reset_of_xlate,
	.request = ti_sci_reset_request,
	.rfree = ti_sci_reset_free,
	.rst_assert = ti_sci_reset_assert,
	.rst_deassert = ti_sci_reset_deassert,
	.rst_status = ti_sci_reset_status,
};

U_BOOT_DRIVER(ti_sci_reset) = {
	.name = "ti-sci-reset",
	.id = UCLASS_RESET,
	.of_match = ti_sci_reset_of_match,
	.probe = ti_sci_reset_probe,
	.priv_auto	= sizeof(struct ti_sci_reset_data),
	.ops = &ti_sci_reset_ops,
};