1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
5 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
9 #include <linux/stddef.h>
10 #include <linux/spinlock.h>
11 #include <linux/slab.h>
12 #include <linux/rculist.h>
13 #include <net/caif/cfpkt.h>
14 #include <net/caif/cfmuxl.h>
15 #include <net/caif/cfsrvl.h>
16 #include <net/caif/cffrml.h>
17
18 #define container_obj(layr) container_of(layr, struct cfmuxl, layer)
19
20 #define CAIF_CTRL_CHANNEL 0
21 #define UP_CACHE_SIZE 8
22 #define DN_CACHE_SIZE 8
23
24 struct cfmuxl {
25 struct cflayer layer;
26 struct list_head srvl_list;
27 struct list_head frml_list;
28 struct cflayer *up_cache[UP_CACHE_SIZE];
29 struct cflayer *dn_cache[DN_CACHE_SIZE];
30 /*
31 * Set when inserting or removing downwards layers.
32 */
33 spinlock_t transmit_lock;
34
35 /*
36 * Set when inserting or removing upwards layers.
37 */
38 spinlock_t receive_lock;
39
40 };
41
42 static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt);
43 static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt);
44 static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
45 int phyid);
46 static struct cflayer *get_up(struct cfmuxl *muxl, u16 id);
47
48 struct cflayer *cfmuxl_create(void)
49 {
50 struct cfmuxl *this = kzalloc(sizeof(struct cfmuxl), GFP_ATOMIC);
51
52 if (!this)
53 return NULL;
54 this->layer.receive = cfmuxl_receive;
55 this->layer.transmit = cfmuxl_transmit;
56 this->layer.ctrlcmd = cfmuxl_ctrlcmd;
57 INIT_LIST_HEAD(&this->srvl_list);
58 INIT_LIST_HEAD(&this->frml_list);
59 spin_lock_init(&this->transmit_lock);
60 spin_lock_init(&this->receive_lock);
61 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "mux");
62 return &this->layer;
63 }
64
65 int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
66 {
67 struct cfmuxl *muxl = (struct cfmuxl *) layr;
68
69 spin_lock_bh(&muxl->transmit_lock);
70 list_add_rcu(&dn->node, &muxl->frml_list);
71 spin_unlock_bh(&muxl->transmit_lock);
72 return 0;
73 }
74
75 static struct cflayer *get_from_id(struct list_head *list, u16 id)
76 {
77 struct cflayer *lyr;
78 list_for_each_entry_rcu(lyr, list, node) {
79 if (lyr->id == id)
80 return lyr;
81 }
82
83 return NULL;
84 }
85
86 int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
87 {
88 struct cfmuxl *muxl = container_obj(layr);
89 struct cflayer *old;
90
91 spin_lock_bh(&muxl->receive_lock);
92
93 /* Two entries with same id is wrong, so remove old layer from mux */
94 old = get_from_id(&muxl->srvl_list, linkid);
95 if (old != NULL)
96 list_del_rcu(&old->node);
97
98 list_add_rcu(&up->node, &muxl->srvl_list);
99 spin_unlock_bh(&muxl->receive_lock);
100
101 return 0;
102 }
103
104 struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
105 {
106 struct cfmuxl *muxl = container_obj(layr);
107 struct cflayer *dn;
108 int idx = phyid % DN_CACHE_SIZE;
109
110 spin_lock_bh(&muxl->transmit_lock);
111 RCU_INIT_POINTER(muxl->dn_cache[idx], NULL);
112 dn = get_from_id(&muxl->frml_list, phyid);
113 if (dn == NULL)
114 goto out;
115
116 list_del_rcu(&dn->node);
117 caif_assert(dn != NULL);
118 out:
119 spin_unlock_bh(&muxl->transmit_lock);
120 return dn;
121 }
122
123 static struct cflayer *get_up(struct cfmuxl *muxl, u16 id)
124 {
125 struct cflayer *up;
126 int idx = id % UP_CACHE_SIZE;
127 up = rcu_dereference(muxl->up_cache[idx]);
128 if (up == NULL || up->id != id) {
129 spin_lock_bh(&muxl->receive_lock);
130 up = get_from_id(&muxl->srvl_list, id);
131 rcu_assign_pointer(muxl->up_cache[idx], up);
132 spin_unlock_bh(&muxl->receive_lock);
133 }
134 return up;
135 }
136
137 static struct cflayer *get_dn(struct cfmuxl *muxl, struct dev_info *dev_info)
138 {
139 struct cflayer *dn;
140 int idx = dev_info->id % DN_CACHE_SIZE;
141 dn = rcu_dereference(muxl->dn_cache[idx]);
142 if (dn == NULL || dn->id != dev_info->id) {
143 spin_lock_bh(&muxl->transmit_lock);
144 dn = get_from_id(&muxl->frml_list, dev_info->id);
145 rcu_assign_pointer(muxl->dn_cache[idx], dn);
146 spin_unlock_bh(&muxl->transmit_lock);
147 }
148 return dn;
149 }
150
151 struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
152 {
153 struct cflayer *up;
154 struct cfmuxl *muxl = container_obj(layr);
155 int idx = id % UP_CACHE_SIZE;
156
157 if (id == 0) {
158 pr_warn("Trying to remove control layer\n");
159 return NULL;
160 }
161
162 spin_lock_bh(&muxl->receive_lock);
163 up = get_from_id(&muxl->srvl_list, id);
164 if (up == NULL)
165 goto out;
166
167 RCU_INIT_POINTER(muxl->up_cache[idx], NULL);
168 list_del_rcu(&up->node);
169 out:
170 spin_unlock_bh(&muxl->receive_lock);
171 return up;
172 }
173
174 static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
175 {
176 int ret;
177 struct cfmuxl *muxl = container_obj(layr);
178 u8 id;
179 struct cflayer *up;
180 if (cfpkt_extr_head(pkt, &id, 1) < 0) {
181 pr_err("erroneous Caif Packet\n");
182 cfpkt_destroy(pkt);
183 return -EPROTO;
184 }
185 rcu_read_lock();
186 up = get_up(muxl, id);
187
188 if (up == NULL) {
189 pr_debug("Received data on unknown link ID = %d (0x%x)"
190 " up == NULL", id, id);
191 cfpkt_destroy(pkt);
192 /*
193 * Don't return ERROR, since modem misbehaves and sends out
194 * flow on before linksetup response.
195 */
196
197 rcu_read_unlock();
198 return /* CFGLU_EPROT; */ 0;
199 }
200
201 /* We can't hold rcu_lock during receive, so take a ref count instead */
202 cfsrvl_get(up);
203 rcu_read_unlock();
204
205 ret = up->receive(up, pkt);
206
207 cfsrvl_put(up);
208 return ret;
209 }
210
211 static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
212 {
213 struct cfmuxl *muxl = container_obj(layr);
214 int err;
215 u8 linkid;
216 struct cflayer *dn;
217 struct caif_payload_info *info = cfpkt_info(pkt);
218 BUG_ON(!info);
219
220 rcu_read_lock();
221
222 dn = get_dn(muxl, info->dev_info);
223 if (dn == NULL) {
224 pr_debug("Send data on unknown phy ID = %d (0x%x)\n",
225 info->dev_info->id, info->dev_info->id);
226 rcu_read_unlock();
227 cfpkt_destroy(pkt);
228 return -ENOTCONN;
229 }
230
231 info->hdr_len += 1;
232 linkid = info->channel_id;
233 cfpkt_add_head(pkt, &linkid, 1);
234
235 /* We can't hold rcu_lock during receive, so take a ref count instead */
236 cffrml_hold(dn);
237
238 rcu_read_unlock();
239
240 err = dn->transmit(dn, pkt);
241
242 cffrml_put(dn);
243 return err;
244 }
245
246 static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
247 int phyid)
248 {
249 struct cfmuxl *muxl = container_obj(layr);
250 struct cflayer *layer;
251
252 rcu_read_lock();
253 list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
254
255 if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd) {
256
257 if ((ctrl == _CAIF_CTRLCMD_PHYIF_DOWN_IND ||
258 ctrl == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND) &&
259 layer->id != 0)
260 cfmuxl_remove_uplayer(layr, layer->id);
261
262 /* NOTE: ctrlcmd is not allowed to block */
263 layer->ctrlcmd(layer, ctrl, phyid);
264 }
265 }
266 rcu_read_unlock();
267 }
268
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.