1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) ST-Ericsson AB 2010
4  * Author:	Sjur Brendeland
5  */
6 
7 #ifndef CAIF_LAYER_H_
8 #define CAIF_LAYER_H_
9 
10 #include <linux/list.h>
11 
12 struct cflayer;
13 struct cfpkt;
14 struct cfpktq;
15 struct caif_payload_info;
16 struct caif_packet_funcs;
17 
18 #define CAIF_LAYER_NAME_SZ 16
19 
20 /**
21  * caif_assert() - Assert function for CAIF.
22  * @assert: expression to evaluate.
23  *
24  * This function will print a error message and a do WARN_ON if the
25  * assertion failes. Normally this will do a stack up at the current location.
26  */
27 #define caif_assert(assert)					\
28 do {								\
29 	if (!(assert)) {					\
30 		pr_err("caif:Assert detected:'%s'\n", #assert); \
31 		WARN_ON(!(assert));				\
32 	}							\
33 } while (0)
34 
35 /**
36  * enum caif_ctrlcmd - CAIF Stack Control Signaling sent in layer.ctrlcmd().
37  *
38  * @CAIF_CTRLCMD_FLOW_OFF_IND:		Flow Control is OFF, transmit function
39  *					should stop sending data
40  *
41  * @CAIF_CTRLCMD_FLOW_ON_IND:		Flow Control is ON, transmit function
42  *					can start sending data
43  *
44  * @CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:	Remote end modem has decided to close
45  *					down channel
46  *
47  * @CAIF_CTRLCMD_INIT_RSP:		Called initially when the layer below
48  *					has finished initialization
49  *
50  * @CAIF_CTRLCMD_DEINIT_RSP:		Called when de-initialization is
51  *					complete
52  *
53  * @CAIF_CTRLCMD_INIT_FAIL_RSP:		Called if initialization fails
54  *
55  * @_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:	CAIF Link layer temporarily cannot
56  *					send more packets.
57  * @_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND:	Called if CAIF Link layer is able
58  *					to send packets again.
59  * @_CAIF_CTRLCMD_PHYIF_DOWN_IND:	Called if CAIF Link layer is going
60  *					down.
61  *
62  * These commands are sent upwards in the CAIF stack to the CAIF Client.
63  * They are used for signaling originating from the modem or CAIF Link Layer.
64  * These are either responses (*_RSP) or events (*_IND).
65  */
66 enum caif_ctrlcmd {
67 	CAIF_CTRLCMD_FLOW_OFF_IND,
68 	CAIF_CTRLCMD_FLOW_ON_IND,
69 	CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
70 	CAIF_CTRLCMD_INIT_RSP,
71 	CAIF_CTRLCMD_DEINIT_RSP,
72 	CAIF_CTRLCMD_INIT_FAIL_RSP,
73 	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
74 	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
75 	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
76 };
77 
78 /**
79  * enum caif_modemcmd -	 Modem Control Signaling, sent from CAIF Client
80  *			 to the CAIF Link Layer or modem.
81  *
82  * @CAIF_MODEMCMD_FLOW_ON_REQ:		Flow Control is ON, transmit function
83  *					can start sending data.
84  *
85  * @CAIF_MODEMCMD_FLOW_OFF_REQ:		Flow Control is OFF, transmit function
86  *					should stop sending data.
87  *
88  * @_CAIF_MODEMCMD_PHYIF_USEFULL:	Notify physical layer that it is in use
89  *
90  * @_CAIF_MODEMCMD_PHYIF_USELESS:	Notify physical layer that it is
91  *					no longer in use.
92  *
93  * These are requests sent 'downwards' in the stack.
94  * Flow ON, OFF can be indicated to the modem.
95  */
96 enum caif_modemcmd {
97 	CAIF_MODEMCMD_FLOW_ON_REQ = 0,
98 	CAIF_MODEMCMD_FLOW_OFF_REQ = 1,
99 	_CAIF_MODEMCMD_PHYIF_USEFULL = 3,
100 	_CAIF_MODEMCMD_PHYIF_USELESS = 4
101 };
102 
103 /**
104  * enum caif_direction - CAIF Packet Direction.
105  * Indicate if a packet is to be sent out or to be received in.
106  * @CAIF_DIR_IN:		Incoming packet received.
107  * @CAIF_DIR_OUT:		Outgoing packet to be transmitted.
108  */
109 enum caif_direction {
110 	CAIF_DIR_IN = 0,
111 	CAIF_DIR_OUT = 1
112 };
113 
114 /**
115  * struct cflayer - CAIF Stack layer.
116  * Defines the framework for the CAIF Core Stack.
117  * @up:		Pointer up to the layer above.
118  * @dn:		Pointer down to the layer below.
119  * @node:	List node used when layer participate in a list.
120  * @receive:	Packet receive function.
121  * @transmit:	Packet transmit funciton.
122  * @ctrlcmd:	Used for control signalling upwards in the stack.
123  * @modemcmd:	Used for control signaling downwards in the stack.
124  * @id:		The identity of this layer
125  * @name:	Name of the layer.
126  *
127  *  This structure defines the layered structure in CAIF.
128  *
129  *  It defines CAIF layering structure, used by all CAIF Layers and the
130  *  layers interfacing CAIF.
131  *
132  *  In order to integrate with CAIF an adaptation layer on top of the CAIF stack
133  *  and PHY layer below the CAIF stack
134  *  must be implemented. These layer must follow the design principles below.
135  *
136  *  Principles for layering of protocol layers:
137  *    - All layers must use this structure. If embedding it, then place this
138  *	structure first in the layer specific structure.
139  *
140  *    - Each layer should not depend on any others layer's private data.
141  *
142  *    - In order to send data upwards do
143  *	layer->up->receive(layer->up, packet);
144  *
145  *    - In order to send data downwards do
146  *	layer->dn->transmit(layer->dn, info, packet);
147  */
148 struct cflayer {
149 	struct cflayer *up;
150 	struct cflayer *dn;
151 	struct list_head node;
152 
153 	/*
154 	 *  receive() - Receive Function (non-blocking).
155 	 *  Contract: Each layer must implement a receive function passing the
156 	 *  CAIF packets upwards in the stack.
157 	 *	Packet handling rules:
158 	 *	      - The CAIF packet (cfpkt) ownership is passed to the
159 	 *		called receive function. This means that the
160 	 *		packet cannot be accessed after passing it to the
161 	 *		above layer using up->receive().
162 	 *
163 	 *	      - If parsing of the packet fails, the packet must be
164 	 *		destroyed and negative error code returned
165 	 *		from the function.
166 	 *		EXCEPTION: If the framing layer (cffrml) returns
167 	 *			-EILSEQ, the packet is not freed.
168 	 *
169 	 *	      - If parsing succeeds (and above layers return OK) then
170 	 *		      the function must return a value >= 0.
171 	 *
172 	 *  Returns result < 0 indicates an error, 0 or positive value
173 	 *	     indicates success.
174 	 *
175 	 *  @layr: Pointer to the current layer the receive function is
176 	 *		implemented for (this pointer).
177 	 *  @cfpkt: Pointer to CaifPacket to be handled.
178 	 */
179 	int (*receive)(struct cflayer *layr, struct cfpkt *cfpkt);
180 
181 	/*
182 	 *  transmit() - Transmit Function (non-blocking).
183 	 *  Contract: Each layer must implement a transmit function passing the
184 	 *	CAIF packet downwards in the stack.
185 	 *	Packet handling rules:
186 	 *	      - The CAIF packet (cfpkt) ownership is passed to the
187 	 *		transmit function. This means that the packet
188 	 *		cannot be accessed after passing it to the below
189 	 *		layer using dn->transmit().
190 	 *
191 	 *	      - Upon error the packet ownership is still passed on,
192 	 *		so the packet shall be freed where error is detected.
193 	 *		Callers of the transmit function shall not free packets,
194 	 *		but errors shall be returned.
195 	 *
196 	 *	      - Return value less than zero means error, zero or
197 	 *		greater than zero means OK.
198 	 *
199 	 *  Returns result < 0 indicates an error, 0 or positive value
200 	 *		indicates success.
201 	 *
202 	 *  @layr:	Pointer to the current layer the receive function
203 	 *		isimplemented for (this pointer).
204 	 *  @cfpkt:	 Pointer to CaifPacket to be handled.
205 	 */
206 	int (*transmit) (struct cflayer *layr, struct cfpkt *cfpkt);
207 
208 	/*
209 	 *  cttrlcmd() - Control Function upwards in CAIF Stack  (non-blocking).
210 	 *  Used for signaling responses (CAIF_CTRLCMD_*_RSP)
211 	 *  and asynchronous events from the modem  (CAIF_CTRLCMD_*_IND)
212 	 *
213 	 *  @layr:	Pointer to the current layer the receive function
214 	 *		is implemented for (this pointer).
215 	 *  @ctrl:	Control Command.
216 	 */
217 	void (*ctrlcmd) (struct cflayer *layr, enum caif_ctrlcmd ctrl,
218 			 int phyid);
219 
220 	/*
221 	 *  modemctrl() - Control Function used for controlling the modem.
222 	 *  Used to signal down-wards in the CAIF stack.
223 	 *  Returns 0 on success, < 0 upon failure.
224 	 *
225 	 *  @layr:	Pointer to the current layer the receive function
226 	 *		is implemented for (this pointer).
227 	 *  @ctrl:  Control Command.
228 	 */
229 	int (*modemcmd) (struct cflayer *layr, enum caif_modemcmd ctrl);
230 
231 	unsigned int id;
232 	char name[CAIF_LAYER_NAME_SZ];
233 };
234 
235 /**
236  * layer_set_up() - Set the up pointer for a specified layer.
237  *  @layr: Layer where up pointer shall be set.
238  *  @above: Layer above.
239  */
240 #define layer_set_up(layr, above) ((layr)->up = (struct cflayer *)(above))
241 
242 /**
243  *  layer_set_dn() - Set the down pointer for a specified layer.
244  *  @layr:  Layer where down pointer shall be set.
245  *  @below: Layer below.
246  */
247 #define layer_set_dn(layr, below) ((layr)->dn = (struct cflayer *)(below))
248 
249 /**
250  * struct dev_info - Physical Device info information about physical layer.
251  * @dev:	Pointer to native physical device.
252  * @id:		Physical ID of the physical connection used by the
253  *		logical CAIF connection. Used by service layers to
254  *		identify their physical id to Caif MUX (CFMUXL)so
255  *		that the MUX can add the correct physical ID to the
256  *		packet.
257  */
258 struct dev_info {
259 	void *dev;
260 	unsigned int id;
261 };
262 
263 /**
264  * struct caif_payload_info - Payload information embedded in packet (sk_buff).
265  *
266  * @dev_info:	Information about the receiving device.
267  *
268  * @hdr_len:	Header length, used to align pay load on 32bit boundary.
269  *
270  * @channel_id: Channel ID of the logical CAIF connection.
271  *		Used by mux to insert channel id into the caif packet.
272  */
273 struct caif_payload_info {
274 	struct dev_info *dev_info;
275 	unsigned short hdr_len;
276 	unsigned short channel_id;
277 };
278 
279 #endif	/* CAIF_LAYER_H_ */
280