1 /* SPDX-License-Identifier: BSD-2-Clause */
2 /*
3  * Copyright (c) 2021, Linaro Limited
4  */
5 
6 #ifndef __DRIVERS_RSTCTRL_H
7 #define __DRIVERS_RSTCTRL_H
8 
9 #include <kernel/dt.h>
10 #include <kernel/dt_driver.h>
11 #include <stdint.h>
12 #include <tee_api_types.h>
13 
14 struct rstctrl;
15 
16 struct rstctrl_ops {
17 	/*
18 	 * Operators on reset control(s) exposed by a reset controller
19 	 *
20 	 * @assert_level: Assert reset level on control with a timeout hint
21 	 * @deassert_level: Deassert reset level on control with a timeout hint
22 	 * @get_name: Get a string name for the controller, or NULL is none
23 	 *
24 	 * Operator functions @assert_level and @deassert_level use arguments:
25 	 * @rstctrl: Reset controller
26 	 * @id: Identifier for the reset level control in the reset controller
27 	 * @to_ms: Timeout in microseconds or RSTCTRL_NO_TIMEOUT, may be ignored
28 	 * by reset controller.
29 	 * Return a TEE_Result compliant code.
30 	 */
31 	TEE_Result (*assert_level)(struct rstctrl *rstctrl, unsigned int to_us);
32 	TEE_Result (*deassert_level)(struct rstctrl *rstctrl,
33 				     unsigned int to_us);
34 	const char *(*get_name)(struct rstctrl *rstctrl);
35 };
36 
37 /*
38  * struct rstctrl - Instance of a control exposed by a reset controller
39  * @ops: Operators of the reset controller
40  * @exclusive: Set when a consumer has exclusive control on the reset level
41  */
42 struct rstctrl {
43 	const struct rstctrl_ops *ops;
44 	bool exclusive;
45 };
46 
47 /**
48  * RSTCTRL_DECLARE - Declare a reset controller driver with a single
49  * device tree compatible string.
50  *
51  * @__name: Reset controller driver name
52  * @__compat: Compatible string
53  * @__probe: Reset controller probe function
54  */
55 #define RSTCTRL_DT_DECLARE(__name, __compat, __probe) \
56 	static const struct dt_device_match __name ## _match_table[] = { \
57 		{ .compatible = __compat }, \
58 		{ } \
59 	}; \
60 	DEFINE_DT_DRIVER(__name ## _dt_driver) = { \
61 		.name = # __name, \
62 		.type = DT_DRIVER_RSTCTRL, \
63 		.match_table = __name ## _match_table, \
64 		.probe = __probe, \
65 	}
66 
67 /*
68  * Platform driver may ignore the timeout hint according to their
69  * capabilities. RSTCTRL_NO_TIMEOUT specifies no timeout hint.
70  */
71 #define RSTCTRL_NO_TIMEOUT	0
72 
73 /*
74  * rstctrl_assert_to - Assert reset control possibly with timeout
75  * rstctrl_assert - Assert reset control
76  * rstctrl_deassert_to - Deassert reset control possibly with timeout
77  * rstctrl_deassert - Deassert reset control
78  *
79  * @rstctrl: Reset controller
80  * @to_us: Timeout in microseconds
81  * Return a TEE_Result compliant code
82  */
rstctrl_assert_to(struct rstctrl * rstctrl,unsigned int to_us)83 static inline TEE_Result rstctrl_assert_to(struct rstctrl *rstctrl,
84 					   unsigned int to_us)
85 {
86 	return rstctrl->ops->assert_level(rstctrl, to_us);
87 }
88 
rstctrl_assert(struct rstctrl * rstctrl)89 static inline TEE_Result rstctrl_assert(struct rstctrl *rstctrl)
90 {
91 	return rstctrl_assert_to(rstctrl, RSTCTRL_NO_TIMEOUT);
92 }
93 
rstctrl_deassert_to(struct rstctrl * rstctrl,unsigned int to_us)94 static inline TEE_Result rstctrl_deassert_to(struct rstctrl *rstctrl,
95 					     unsigned int to_us)
96 {
97 	return rstctrl->ops->deassert_level(rstctrl, to_us);
98 }
99 
rstctrl_deassert(struct rstctrl * rstctrl)100 static inline TEE_Result rstctrl_deassert(struct rstctrl *rstctrl)
101 {
102 	return rstctrl_deassert_to(rstctrl, RSTCTRL_NO_TIMEOUT);
103 }
104 
105 /*
106  * rstctrl_name - Get a name for the reset level control or NULL
107  *
108  * @rstctrl: Reset controller
109  * Return a pointer to controller name or NULL
110  */
rstctrl_name(struct rstctrl * rstctrl)111 static inline const char *rstctrl_name(struct rstctrl *rstctrl)
112 {
113 	if (rstctrl->ops->get_name)
114 		return rstctrl->ops->get_name(rstctrl);
115 
116 	return NULL;
117 }
118 
119 /**
120  * rstctrl_dt_get_exclusive - Get exclusive access to reset controller
121  *
122  * @rstctrl: Reset controller
123  * Return a TEE_Result compliant value
124  */
125 TEE_Result rstctrl_get_exclusive(struct rstctrl *rstctrl);
126 
127 /**
128  * rstctrl_put_exclusive - Release exclusive access to target
129  *
130  * @rstctrl: Reset controller
131  */
132 void rstctrl_put_exclusive(struct rstctrl *rstctrl);
133 
134 /**
135  * rstctrl_ops_is_valid - Check reset controller ops is valid
136  *
137  * @ops: Reference to reset controller operator instance
138  */
rstctrl_ops_is_valid(const struct rstctrl_ops * ops)139 static inline bool rstctrl_ops_is_valid(const struct rstctrl_ops *ops)
140 {
141 	return ops && ops->assert_level && ops->deassert_level;
142 }
143 
144 #ifdef CFG_DT
145 /**
146  * rstctrl_dt_get_by_index - Get a reset controller at a specific index in
147  * 'resets' property
148  *
149  * @fdt: Device tree to work on
150  * @nodeoffset: Node offset of the subnode containing a 'resets' property
151  * @index: Reset controller index in 'resets' property
152  * @rstctrl: Output reset controller reference upon success
153  *
154  * Return TEE_SUCCESS in case of success
155  * Return TEE_ERROR_DEFER_DRIVER_INIT if reset controller is not initialized
156  * Return a TEE_Result compliant code in case of error
157  */
rstctrl_dt_get_by_index(const void * fdt,int nodeoffset,unsigned int index,struct rstctrl ** rstctrl)158 static inline TEE_Result rstctrl_dt_get_by_index(const void *fdt,
159 						 int nodeoffset,
160 						 unsigned int index,
161 						 struct rstctrl **rstctrl)
162 {
163 	TEE_Result res = TEE_ERROR_GENERIC;
164 
165 	*rstctrl = dt_driver_device_from_node_idx_prop("resets", fdt,
166 						       nodeoffset, index,
167 						       DT_DRIVER_RSTCTRL, &res);
168 	return res;
169 }
170 #else
rstctrl_dt_get_by_index(const void * fdt __unused,int nodeoffset __unused,unsigned int index __unused,struct rstctrl ** rstctrl)171 static inline TEE_Result rstctrl_dt_get_by_index(const void *fdt __unused,
172 						 int nodeoffset __unused,
173 						 unsigned int index __unused,
174 						 struct rstctrl **rstctrl)
175 {
176 	*rstctrl = NULL;
177 	return TEE_ERROR_NOT_SUPPORTED;
178 }
179 #endif /*CFG_DT*/
180 
181 /**
182  * rstctrl_dt_get_by_name - Get a reset controller matching a name in the
183  * 'reset-names' property
184  *
185  * @fdt: Device tree to work on
186  * @nodeoffset: Node offset of the subnode containing a 'resets' property
187  * @name: Reset controller name to get
188  * @rstctrl: Output reset controller reference upon success
189  *
190  * Return TEE_SUCCESS in case of success
191  * Return TEE_ERROR_DEFER_DRIVER_INIT if reset controller is not initialized
192  * Return a TEE_Result compliant code in case of error
193  */
194 TEE_Result rstctrl_dt_get_by_name(const void *fdt, int nodeoffset,
195 				  const char *name, struct rstctrl **rstctrl);
196 
197 /**
198  * rstctrl_dt_get_func - Typedef of function to get reset controller from
199  * devicetree properties
200  *
201  * @a: Pointer to devicetree description of the reset controller to parse
202  * @data: Pointer to data given at rstctrl_dt_register_provider() call
203  * @res: Output result code of the operation:
204  *	TEE_SUCCESS in case of success
205  *	TEE_ERROR_DEFER_DRIVER_INIT if reset controller is not initialized
206  *	Any TEE_Result compliant code in case of error.
207  *
208  * Returns a struct rstctrl pointer pointing to a reset controller matching
209  * the devicetree description or NULL if invalid description in which case
210  * @res provides the error code.
211  */
212 typedef struct rstctrl *(*rstctrl_dt_get_func)(struct dt_driver_phandle_args *a,
213 					       void *data, TEE_Result *res);
214 
215 /**
216  * rstctrl_dt_register_provider - Register a reset controller provider
217  *
218  * @fdt: Device tree to work on
219  * @nodeoffset: Node offset of the reset controller
220  * @get_dt_rstctrl: Callback to match the reset controller with a struct rstctrl
221  * @data: Data which will be passed to the get_dt_rstctrl callback
222  * Returns TEE_Result value
223  */
224 static inline
225 TEE_Result rstctrl_register_provider(const void *fdt, int nodeoffset,
226 				     rstctrl_dt_get_func get_dt_rstctrl,
227 				     void *data)
228 {
229 	return dt_driver_register_provider(fdt, nodeoffset,
230 					   (get_of_device_func)get_dt_rstctrl,
231 					   data, DT_DRIVER_RSTCTRL);
232 }
233 #endif /* __DRIVERS_RSTCTRL_H */
234 
235