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Tom Rini83d290c2018-05-06 17:58:06 -04001/* SPDX-License-Identifier: GPL-2.0 */
Stephen Warren89c1e2d2016-06-17 09:43:58 -06002/*
3 * Copyright (c) 2016, NVIDIA CORPORATION.
Stephen Warren89c1e2d2016-06-17 09:43:58 -06004 */
5
6#ifndef _RESET_H
7#define _RESET_H
8
Jagan Tekiea9dc352019-02-28 00:26:55 +05309#include <dm/ofnode.h>
Masahiro Yamada4815db82016-09-21 11:29:01 +090010#include <linux/errno.h>
11
Stephen Warren89c1e2d2016-06-17 09:43:58 -060012/**
13 * A reset is a hardware signal indicating that a HW module (or IP block, or
14 * sometimes an entire off-CPU chip) reset all of its internal state to some
15 * known-good initial state. Drivers will often reset HW modules when they
16 * begin execution to ensure that hardware correctly responds to all requests,
17 * or in response to some error condition. Reset signals are often controlled
18 * externally to the HW module being reset, by an entity this API calls a reset
19 * controller. This API provides a standard means for drivers to request that
20 * reset controllers set or clear reset signals.
21 *
22 * A driver that implements UCLASS_RESET is a reset controller or provider. A
23 * controller will often implement multiple separate reset signals, since the
24 * hardware it manages often has this capability. reset-uclass.h describes the
25 * interface which reset controllers must implement.
26 *
27 * Reset consumers/clients are the HW modules affected by reset signals. This
28 * header file describes the API used by drivers for those HW modules.
29 */
30
31struct udevice;
32
33/**
34 * struct reset_ctl - A handle to (allowing control of) a single reset signal.
35 *
36 * Clients provide storage for reset control handles. The content of the
37 * structure is managed solely by the reset API and reset drivers. A reset
38 * control struct is initialized by "get"ing the reset control struct. The
39 * reset control struct is passed to all other reset APIs to identify which
40 * reset signal to operate upon.
41 *
42 * @dev: The device which implements the reset signal.
43 * @id: The reset signal ID within the provider.
Andreas Dannenbergc72f9b72018-08-27 15:57:40 +053044 * @data: An optional data field for scenarios where a single integer ID is not
45 * sufficient. If used, it can be populated through an .of_xlate op and
46 * processed during the various reset ops.
Shawn Guof5ed7482019-03-20 15:32:38 +080047 * @polarity: An optional polarity field for drivers that support
48 * different reset polarities.
Stephen Warren89c1e2d2016-06-17 09:43:58 -060049 *
Andreas Dannenbergc72f9b72018-08-27 15:57:40 +053050 * Should additional information to identify and configure any reset signal
51 * for any provider be required in the future, the struct could be expanded to
Stephen Warren89c1e2d2016-06-17 09:43:58 -060052 * either (a) add more fields to allow reset providers to store additional
53 * information, or (b) replace the id field with an opaque pointer, which the
54 * provider would dynamically allocated during its .of_xlate op, and process
55 * during is .request op. This may require the addition of an extra op to clean
56 * up the allocation.
57 */
58struct reset_ctl {
59 struct udevice *dev;
60 /*
Andreas Dannenbergc72f9b72018-08-27 15:57:40 +053061 * Written by of_xlate. In the future, we might add more fields here.
Stephen Warren89c1e2d2016-06-17 09:43:58 -060062 */
63 unsigned long id;
Andreas Dannenbergc72f9b72018-08-27 15:57:40 +053064 unsigned long data;
Shawn Guof5ed7482019-03-20 15:32:38 +080065 unsigned long polarity;
Stephen Warren89c1e2d2016-06-17 09:43:58 -060066};
67
Neil Armstrong0c282332018-04-03 11:40:50 +020068/**
69 * struct reset_ctl_bulk - A handle to (allowing control of) a bulk of reset
70 * signals.
71 *
72 * Clients provide storage for the reset control bulk. The content of the
73 * structure is managed solely by the reset API. A reset control bulk struct is
74 * initialized by "get"ing the reset control bulk struct.
75 * The reset control bulk struct is passed to all other bulk reset APIs to apply
76 * the API to all the reset signals in the bulk struct.
77 *
78 * @resets: An array of reset signal handles handles.
79 * @count: The number of reset signal handles in the reset array.
80 */
81struct reset_ctl_bulk {
82 struct reset_ctl *resets;
83 unsigned int count;
84};
85
Ley Foon Tand99894d2018-06-14 18:45:20 +080086#if CONFIG_IS_ENABLED(DM_RESET)
Stephen Warren89c1e2d2016-06-17 09:43:58 -060087/**
88 * reset_get_by_index - Get/request a reset signal by integer index.
89 *
90 * This looks up and requests a reset signal. The index is relative to the
91 * client device; each device is assumed to have n reset signals associated
92 * with it somehow, and this function finds and requests one of them. The
93 * mapping of client device reset signal indices to provider reset signals may
94 * be via device-tree properties, board-provided mapping tables, or some other
95 * mechanism.
96 *
97 * @dev: The client device.
98 * @index: The index of the reset signal to request, within the client's
99 * list of reset signals.
100 * @reset_ctl A pointer to a reset control struct to initialize.
101 * @return 0 if OK, or a negative error code.
102 */
103int reset_get_by_index(struct udevice *dev, int index,
104 struct reset_ctl *reset_ctl);
105
106/**
Jagan Tekiea9dc352019-02-28 00:26:55 +0530107 * reset_get_by_index_nodev - Get/request a reset signal by integer index
108 * without a device.
109 *
110 * This is a version of reset_get_by_index() that does not use a device.
111 *
112 * @node: The client ofnode.
113 * @index: The index of the reset signal to request, within the client's
114 * list of reset signals.
115 * @reset_ctl A pointer to a reset control struct to initialize.
116 * @return 0 if OK, or a negative error code.
117 */
118int reset_get_by_index_nodev(ofnode node, int index,
119 struct reset_ctl *reset_ctl);
120
121/**
Neil Armstrong0c282332018-04-03 11:40:50 +0200122 * reset_get_bulk - Get/request all reset signals of a device.
123 *
124 * This looks up and requests all reset signals of the client device; each
125 * device is assumed to have n reset signals associated with it somehow,
126 * and this function finds and requests all of them in a separate structure.
127 * The mapping of client device reset signals indices to provider reset signals
128 * may be via device-tree properties, board-provided mapping tables, or some
129 * other mechanism.
130 *
131 * @dev: The client device.
132 * @bulk A pointer to a reset control bulk struct to initialize.
133 * @return 0 if OK, or a negative error code.
134 */
135int reset_get_bulk(struct udevice *dev, struct reset_ctl_bulk *bulk);
136
137/**
Stephen Warren89c1e2d2016-06-17 09:43:58 -0600138 * reset_get_by_name - Get/request a reset signal by name.
139 *
140 * This looks up and requests a reset signal. The name is relative to the
141 * client device; each device is assumed to have n reset signals associated
142 * with it somehow, and this function finds and requests one of them. The
143 * mapping of client device reset signal names to provider reset signal may be
144 * via device-tree properties, board-provided mapping tables, or some other
145 * mechanism.
146 *
147 * @dev: The client device.
148 * @name: The name of the reset signal to request, within the client's
149 * list of reset signals.
150 * @reset_ctl: A pointer to a reset control struct to initialize.
151 * @return 0 if OK, or a negative error code.
152 */
153int reset_get_by_name(struct udevice *dev, const char *name,
154 struct reset_ctl *reset_ctl);
155
156/**
Patrice Chotard9bd5cdf2017-07-18 11:57:05 +0200157 * reset_request - Request a reset signal.
158 *
159 * @reset_ctl: A reset control struct.
160 *
161 * @return 0 if OK, or a negative error code.
162 */
163int reset_request(struct reset_ctl *reset_ctl);
164
165/**
Stephen Warren89c1e2d2016-06-17 09:43:58 -0600166 * reset_free - Free a previously requested reset signal.
167 *
168 * @reset_ctl: A reset control struct that was previously successfully
169 * requested by reset_get_by_*().
170 * @return 0 if OK, or a negative error code.
171 */
172int reset_free(struct reset_ctl *reset_ctl);
173
174/**
175 * reset_assert - Assert a reset signal.
176 *
177 * This function will assert the specified reset signal, thus resetting the
178 * affected HW module(s). Depending on the reset controller hardware, the reset
179 * signal will either stay asserted until reset_deassert() is called, or the
180 * hardware may autonomously clear the reset signal itself.
181 *
182 * @reset_ctl: A reset control struct that was previously successfully
183 * requested by reset_get_by_*().
184 * @return 0 if OK, or a negative error code.
185 */
186int reset_assert(struct reset_ctl *reset_ctl);
187
188/**
Neil Armstrong0c282332018-04-03 11:40:50 +0200189 * reset_assert_bulk - Assert all reset signals in a reset control bulk struct.
190 *
191 * This function will assert the specified reset signals in a reset control
192 * bulk struct, thus resetting the affected HW module(s). Depending on the
193 * reset controller hardware, the reset signals will either stay asserted
194 * until reset_deassert_bulk() is called, or the hardware may autonomously
195 * clear the reset signals itself.
196 *
197 * @bulk: A reset control bulk struct that was previously successfully
198 * requested by reset_get_bulk().
199 * @return 0 if OK, or a negative error code.
200 */
201int reset_assert_bulk(struct reset_ctl_bulk *bulk);
202
203/**
Stephen Warren89c1e2d2016-06-17 09:43:58 -0600204 * reset_deassert - Deassert a reset signal.
205 *
206 * This function will deassert the specified reset signal, thus releasing the
207 * affected HW modules() from reset, and allowing them to continue normal
208 * operation.
209 *
210 * @reset_ctl: A reset control struct that was previously successfully
211 * requested by reset_get_by_*().
212 * @return 0 if OK, or a negative error code.
213 */
214int reset_deassert(struct reset_ctl *reset_ctl);
215
Patrice Chotard3b9d1bd2017-07-18 11:57:06 +0200216/**
Neil Armstrong0c282332018-04-03 11:40:50 +0200217 * reset_deassert_bulk - Deassert all reset signals in a reset control bulk
218 * struct.
219 *
220 * This function will deassert the specified reset signals in a reset control
221 * bulk struct, thus releasing the affected HW modules() from reset, and
222 * allowing them to continue normal operation.
223 *
224 * @bulk: A reset control bulk struct that was previously successfully
225 * requested by reset_get_bulk().
226 * @return 0 if OK, or a negative error code.
227 */
228int reset_deassert_bulk(struct reset_ctl_bulk *bulk);
229
230/**
Andreas Dannenberge7012e62018-08-27 15:57:39 +0530231 * rst_status - Check reset signal status.
232 *
233 * @reset_ctl: The reset signal to check.
234 * @return 0 if deasserted, positive if asserted, or a negative
235 * error code.
236 */
237int reset_status(struct reset_ctl *reset_ctl);
238
239/**
Patrice Chotard3b9d1bd2017-07-18 11:57:06 +0200240 * reset_release_all - Assert/Free an array of previously requested resets.
241 *
242 * For each reset contained in the reset array, this function will check if
243 * reset has been previously requested and then will assert and free it.
244 *
245 * @reset_ctl: A reset struct array that was previously successfully
246 * requested by reset_get_by_*().
247 * @count Number of reset contained in the array
248 * @return 0 if OK, or a negative error code.
249 */
250int reset_release_all(struct reset_ctl *reset_ctl, int count);
Neil Armstrong0c282332018-04-03 11:40:50 +0200251
252/**
253 * reset_release_bulk - Assert/Free an array of previously requested reset
254 * signals in a reset control bulk struct.
255 *
256 * For each reset contained in the reset control bulk struct, this function
257 * will check if reset has been previously requested and then will assert
258 * and free it.
259 *
260 * @bulk: A reset control bulk struct that was previously successfully
261 * requested by reset_get_bulk().
262 * @return 0 if OK, or a negative error code.
263 */
264static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
265{
266 return reset_release_all(bulk->resets, bulk->count);
267}
Masahiro Yamada4815db82016-09-21 11:29:01 +0900268#else
269static inline int reset_get_by_index(struct udevice *dev, int index,
270 struct reset_ctl *reset_ctl)
271{
272 return -ENOTSUPP;
273}
274
Neil Armstrong1dd181f2018-04-12 10:03:19 +0200275static inline int reset_get_bulk(struct udevice *dev,
276 struct reset_ctl_bulk *bulk)
Neil Armstrong0c282332018-04-03 11:40:50 +0200277{
278 return -ENOTSUPP;
279}
280
Masahiro Yamada4815db82016-09-21 11:29:01 +0900281static inline int reset_get_by_name(struct udevice *dev, const char *name,
282 struct reset_ctl *reset_ctl)
283{
284 return -ENOTSUPP;
285}
286
287static inline int reset_free(struct reset_ctl *reset_ctl)
288{
289 return 0;
290}
291
292static inline int reset_assert(struct reset_ctl *reset_ctl)
293{
294 return 0;
295}
296
Neil Armstrong0c282332018-04-03 11:40:50 +0200297static inline int reset_assert_bulk(struct reset_ctl_bulk *bulk)
298{
299 return 0;
300}
301
Masahiro Yamada4815db82016-09-21 11:29:01 +0900302static inline int reset_deassert(struct reset_ctl *reset_ctl)
303{
304 return 0;
305}
Patrice Chotard3b9d1bd2017-07-18 11:57:06 +0200306
Neil Armstrong0c282332018-04-03 11:40:50 +0200307static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
308{
309 return 0;
310}
311
Andreas Dannenberge7012e62018-08-27 15:57:39 +0530312static inline int reset_status(struct reset_ctl *reset_ctl)
313{
314 return -ENOTSUPP;
315}
316
Patrice Chotard3b9d1bd2017-07-18 11:57:06 +0200317static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
318{
319 return 0;
320}
321
Neil Armstrong1dd181f2018-04-12 10:03:19 +0200322static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
Neil Armstrong0c282332018-04-03 11:40:50 +0200323{
324 return 0;
325}
Masahiro Yamada4815db82016-09-21 11:29:01 +0900326#endif
327
Jagan Teki652ee272018-08-06 18:55:06 +0530328/**
329 * reset_valid() - check if reset is valid
330 *
331 * @reset_ctl: the reset to check
332 * @return TRUE if valid, or FALSE
333 */
334static inline bool reset_valid(struct reset_ctl *reset_ctl)
335{
336 return !!reset_ctl->dev;
337}
338
Stephen Warren89c1e2d2016-06-17 09:43:58 -0600339#endif