1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Greybus operations
4  *
5  * Copyright 2014 Google Inc.
6  * Copyright 2014 Linaro Ltd.
7  */
8 
9 #ifndef __OPERATION_H
10 #define __OPERATION_H
11 
12 #include <linux/completion.h>
13 #include <linux/kref.h>
14 #include <linux/timer.h>
15 #include <linux/types.h>
16 #include <linux/workqueue.h>
17 
18 struct gb_host_device;
19 struct gb_operation;
20 
21 /* The default amount of time a request is given to complete */
22 #define GB_OPERATION_TIMEOUT_DEFAULT	1000	/* milliseconds */
23 
24 /*
25  * The top bit of the type in an operation message header indicates
26  * whether the message is a request (bit clear) or response (bit set)
27  */
28 #define GB_MESSAGE_TYPE_RESPONSE	((u8)0x80)
29 
30 enum gb_operation_result {
31 	GB_OP_SUCCESS		= 0x00,
32 	GB_OP_INTERRUPTED	= 0x01,
33 	GB_OP_TIMEOUT		= 0x02,
34 	GB_OP_NO_MEMORY		= 0x03,
35 	GB_OP_PROTOCOL_BAD	= 0x04,
36 	GB_OP_OVERFLOW		= 0x05,
37 	GB_OP_INVALID		= 0x06,
38 	GB_OP_RETRY		= 0x07,
39 	GB_OP_NONEXISTENT	= 0x08,
40 	GB_OP_UNKNOWN_ERROR	= 0xfe,
41 	GB_OP_MALFUNCTION	= 0xff,
42 };
43 
44 #define GB_OPERATION_MESSAGE_SIZE_MIN	sizeof(struct gb_operation_msg_hdr)
45 #define GB_OPERATION_MESSAGE_SIZE_MAX	U16_MAX
46 
47 /*
48  * Protocol code should only examine the payload and payload_size fields, and
49  * host-controller drivers may use the hcpriv field. All other fields are
50  * intended to be private to the operations core code.
51  */
52 struct gb_message {
53 	struct gb_operation		*operation;
54 	struct gb_operation_msg_hdr	*header;
55 
56 	void				*payload;
57 	size_t				payload_size;
58 
59 	void				*buffer;
60 
61 	void				*hcpriv;
62 };
63 
64 #define GB_OPERATION_FLAG_INCOMING		BIT(0)
65 #define GB_OPERATION_FLAG_UNIDIRECTIONAL	BIT(1)
66 #define GB_OPERATION_FLAG_SHORT_RESPONSE	BIT(2)
67 #define GB_OPERATION_FLAG_CORE			BIT(3)
68 
69 #define GB_OPERATION_FLAG_USER_MASK	(GB_OPERATION_FLAG_SHORT_RESPONSE | \
70 					 GB_OPERATION_FLAG_UNIDIRECTIONAL)
71 
72 /*
73  * A Greybus operation is a remote procedure call performed over a
74  * connection between two UniPro interfaces.
75  *
76  * Every operation consists of a request message sent to the other
77  * end of the connection coupled with a reply message returned to
78  * the sender.  Every operation has a type, whose interpretation is
79  * dependent on the protocol associated with the connection.
80  *
81  * Only four things in an operation structure are intended to be
82  * directly usable by protocol handlers:  the operation's connection
83  * pointer; the operation type; the request message payload (and
84  * size); and the response message payload (and size).  Note that a
85  * message with a 0-byte payload has a null message payload pointer.
86  *
87  * In addition, every operation has a result, which is an errno
88  * value.  Protocol handlers access the operation result using
89  * gb_operation_result().
90  */
91 typedef void (*gb_operation_callback)(struct gb_operation *);
92 struct gb_operation {
93 	struct gb_connection	*connection;
94 	struct gb_message	*request;
95 	struct gb_message	*response;
96 
97 	unsigned long		flags;
98 	u8			type;
99 	u16			id;
100 	int			errno;		/* Operation result */
101 
102 	struct work_struct	work;
103 	gb_operation_callback	callback;
104 	struct completion	completion;
105 	struct timer_list	timer;
106 
107 	struct kref		kref;
108 	atomic_t		waiters;
109 
110 	int			active;
111 	struct list_head	links;		/* connection->operations */
112 
113 	void			*private;
114 };
115 
116 static inline bool
gb_operation_is_incoming(struct gb_operation * operation)117 gb_operation_is_incoming(struct gb_operation *operation)
118 {
119 	return operation->flags & GB_OPERATION_FLAG_INCOMING;
120 }
121 
122 static inline bool
gb_operation_is_unidirectional(struct gb_operation * operation)123 gb_operation_is_unidirectional(struct gb_operation *operation)
124 {
125 	return operation->flags & GB_OPERATION_FLAG_UNIDIRECTIONAL;
126 }
127 
128 static inline bool
gb_operation_short_response_allowed(struct gb_operation * operation)129 gb_operation_short_response_allowed(struct gb_operation *operation)
130 {
131 	return operation->flags & GB_OPERATION_FLAG_SHORT_RESPONSE;
132 }
133 
gb_operation_is_core(struct gb_operation * operation)134 static inline bool gb_operation_is_core(struct gb_operation *operation)
135 {
136 	return operation->flags & GB_OPERATION_FLAG_CORE;
137 }
138 
139 void gb_connection_recv(struct gb_connection *connection,
140 					void *data, size_t size);
141 
142 int gb_operation_result(struct gb_operation *operation);
143 
144 size_t gb_operation_get_payload_size_max(struct gb_connection *connection);
145 struct gb_operation *
146 gb_operation_create_flags(struct gb_connection *connection,
147 				u8 type, size_t request_size,
148 				size_t response_size, unsigned long flags,
149 				gfp_t gfp);
150 
151 static inline struct gb_operation *
gb_operation_create(struct gb_connection * connection,u8 type,size_t request_size,size_t response_size,gfp_t gfp)152 gb_operation_create(struct gb_connection *connection,
153 				u8 type, size_t request_size,
154 				size_t response_size, gfp_t gfp)
155 {
156 	return gb_operation_create_flags(connection, type, request_size,
157 						response_size, 0, gfp);
158 }
159 
160 struct gb_operation *
161 gb_operation_create_core(struct gb_connection *connection,
162 				u8 type, size_t request_size,
163 				size_t response_size, unsigned long flags,
164 				gfp_t gfp);
165 
166 void gb_operation_get(struct gb_operation *operation);
167 void gb_operation_put(struct gb_operation *operation);
168 
169 bool gb_operation_response_alloc(struct gb_operation *operation,
170 					size_t response_size, gfp_t gfp);
171 
172 int gb_operation_request_send(struct gb_operation *operation,
173 				gb_operation_callback callback,
174 				unsigned int timeout,
175 				gfp_t gfp);
176 int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
177 						unsigned int timeout);
178 static inline int
gb_operation_request_send_sync(struct gb_operation * operation)179 gb_operation_request_send_sync(struct gb_operation *operation)
180 {
181 	return gb_operation_request_send_sync_timeout(operation,
182 			GB_OPERATION_TIMEOUT_DEFAULT);
183 }
184 
185 void gb_operation_cancel(struct gb_operation *operation, int errno);
186 void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);
187 
188 void greybus_message_sent(struct gb_host_device *hd,
189 				struct gb_message *message, int status);
190 
191 int gb_operation_sync_timeout(struct gb_connection *connection, int type,
192 				void *request, int request_size,
193 				void *response, int response_size,
194 				unsigned int timeout);
195 int gb_operation_unidirectional_timeout(struct gb_connection *connection,
196 				int type, void *request, int request_size,
197 				unsigned int timeout);
198 
gb_operation_sync(struct gb_connection * connection,int type,void * request,int request_size,void * response,int response_size)199 static inline int gb_operation_sync(struct gb_connection *connection, int type,
200 		      void *request, int request_size,
201 		      void *response, int response_size)
202 {
203 	return gb_operation_sync_timeout(connection, type,
204 			request, request_size, response, response_size,
205 			GB_OPERATION_TIMEOUT_DEFAULT);
206 }
207 
gb_operation_unidirectional(struct gb_connection * connection,int type,void * request,int request_size)208 static inline int gb_operation_unidirectional(struct gb_connection *connection,
209 				int type, void *request, int request_size)
210 {
211 	return gb_operation_unidirectional_timeout(connection, type,
212 			request, request_size, GB_OPERATION_TIMEOUT_DEFAULT);
213 }
214 
gb_operation_get_data(struct gb_operation * operation)215 static inline void *gb_operation_get_data(struct gb_operation *operation)
216 {
217 	return operation->private;
218 }
219 
gb_operation_set_data(struct gb_operation * operation,void * data)220 static inline void gb_operation_set_data(struct gb_operation *operation,
221 					 void *data)
222 {
223 	operation->private = data;
224 }
225 
226 int gb_operation_init(void);
227 void gb_operation_exit(void);
228 
229 #endif /* !__OPERATION_H */
230