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
12struct cflayer;
13struct cfpkt;
14struct cfpktq;
15struct caif_payload_info;
16struct 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)					\
28do {								\
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 */
66enum 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 */
96enum 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 */
109enum 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 */
148struct 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 */
258struct 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 */
273struct 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