net/caif/cfmuxl.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland/sjur.brandeland@stericsson.com
   4  * License terms: GNU General Public License (GPL) version 2
   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 <net/caif/cfpkt.h>
  13 #include <net/caif/cfmuxl.h>
  14 #include <net/caif/cfsrvl.h>
  15 #include <net/caif/cffrml.h>
  16
  17 #define container_obj(layr) container_of(layr, struct cfmuxl, layer)
  18
  19 #define CAIF_CTRL_CHANNEL 0
  20 #define UP_CACHE_SIZE 8
  21 #define DN_CACHE_SIZE 8
  22
  23 struct cfmuxl {
  24         struct cflayer layer;
  25         struct list_head srvl_list;
  26         struct list_head frml_list;
  27         struct cflayer *up_cache[UP_CACHE_SIZE];
  28         struct cflayer *dn_cache[DN_CACHE_SIZE];
  29         /*
  30          * Set when inserting or removing downwards layers.
  31          */
  32         spinlock_t transmit_lock;
  33
  34         /*
  35          * Set when inserting or removing upwards layers.
  36          */
  37         spinlock_t receive_lock;
  38
  39 };
  40
  41 static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt);
  42 static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt);
  43 static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
  44                                 int phyid);
  45 static struct cflayer *get_up(struct cfmuxl *muxl, u16 id);
  46
  47 struct cflayer *cfmuxl_create(void)
  48 {
  49         struct cfmuxl *this = kmalloc(sizeof(struct cfmuxl), GFP_ATOMIC);
  50         if (!this)
  51                 return NULL;
  52         memset(this, 0, sizeof(*this));
  53         this->layer.receive = cfmuxl_receive;
  54         this->layer.transmit = cfmuxl_transmit;
  55         this->layer.ctrlcmd = cfmuxl_ctrlcmd;
  56         INIT_LIST_HEAD(&this->srvl_list);
  57         INIT_LIST_HEAD(&this->frml_list);
  58         spin_lock_init(&this->transmit_lock);
  59         spin_lock_init(&this->receive_lock);
  60         snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "mux");
  61         return &this->layer;
  62 }
  63
  64 int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
  65 {
  66         struct cfmuxl *muxl = container_obj(layr);
  67         spin_lock(&muxl->receive_lock);
  68         cfsrvl_get(up);
  69         list_add(&up->node, &muxl->srvl_list);
  70         spin_unlock(&muxl->receive_lock);
  71         return 0;
  72 }
  73
  74 int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
  75 {
  76         struct cfmuxl *muxl = (struct cfmuxl *) layr;
  77         spin_lock(&muxl->transmit_lock);
  78         list_add(&dn->node, &muxl->frml_list);
  79         spin_unlock(&muxl->transmit_lock);
  80         return 0;
  81 }
  82
  83 static struct cflayer *get_from_id(struct list_head *list, u16 id)
  84 {
  85         struct list_head *node;
  86         struct cflayer *layer;
  87         list_for_each(node, list) {
  88                 layer = list_entry(node, struct cflayer, node);
  89                 if (layer->id == id)
  90                         return layer;
  91         }
  92         return NULL;
  93 }
  94
  95 struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
  96 {
  97         struct cfmuxl *muxl = container_obj(layr);
  98         struct cflayer *dn;
  99         spin_lock(&muxl->transmit_lock);
 100         memset(muxl->dn_cache, 0, sizeof(muxl->dn_cache));
 101         dn = get_from_id(&muxl->frml_list, phyid);
 102         if (dn == NULL) {
 103                 spin_unlock(&muxl->transmit_lock);
 104                 return NULL;
 105         }
 106         list_del(&dn->node);
 107         caif_assert(dn != NULL);
 108         spin_unlock(&muxl->transmit_lock);
 109         return dn;
 110 }
 111
 112 /* Invariant: lock is taken */
 113 static struct cflayer *get_up(struct cfmuxl *muxl, u16 id)
 114 {
 115         struct cflayer *up;
 116         int idx = id % UP_CACHE_SIZE;
 117         up = muxl->up_cache[idx];
 118         if (up == NULL || up->id != id) {
 119                 up = get_from_id(&muxl->srvl_list, id);
 120                 muxl->up_cache[idx] = up;
 121         }
 122         return up;
 123 }
 124
 125 /* Invariant: lock is taken */
 126 static struct cflayer *get_dn(struct cfmuxl *muxl, struct dev_info *dev_info)
 127 {
 128         struct cflayer *dn;
 129         int idx = dev_info->id % DN_CACHE_SIZE;
 130         dn = muxl->dn_cache[idx];
 131         if (dn == NULL || dn->id != dev_info->id) {
 132                 dn = get_from_id(&muxl->frml_list, dev_info->id);
 133                 muxl->dn_cache[idx] = dn;
 134         }
 135         return dn;
 136 }
 137
 138 struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
 139 {
 140         struct cflayer *up;
 141         struct cfmuxl *muxl = container_obj(layr);
 142         spin_lock(&muxl->receive_lock);
 143         up = get_up(muxl, id);
 144         if (up == NULL)
 145                 goto out;
 146         memset(muxl->up_cache, 0, sizeof(muxl->up_cache));
 147         list_del(&up->node);
 148         cfsrvl_put(up);
 149 out:
 150         spin_unlock(&muxl->receive_lock);
 151         return up;
 152 }
 153
 154 static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
 155 {
 156         int ret;
 157         struct cfmuxl *muxl = container_obj(layr);
 158         u8 id;
 159         struct cflayer *up;
 160         if (cfpkt_extr_head(pkt, &id, 1) < 0) {
 161                 pr_err("erroneous Caif Packet\n");
 162                 cfpkt_destroy(pkt);
 163                 return -EPROTO;
 164         }
 165
 166         spin_lock(&muxl->receive_lock);
 167         up = get_up(muxl, id);
 168         spin_unlock(&muxl->receive_lock);
 169         if (up == NULL) {
 170                 pr_info("Received data on unknown link ID = %d (0x%x) up == NULL",
 171                         id, id);
 172                 cfpkt_destroy(pkt);
 173                 /*
 174                  * Don't return ERROR, since modem misbehaves and sends out
 175                  * flow on before linksetup response.
 176                  */
 177                 return /* CFGLU_EPROT; */ 0;
 178         }
 179         cfsrvl_get(up);
 180         ret = up->receive(up, pkt);
 181         cfsrvl_put(up);
 182         return ret;
 183 }
 184
 185 static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
 186 {
 187         struct cfmuxl *muxl = container_obj(layr);
 188         u8 linkid;
 189         struct cflayer *dn;
 190         struct caif_payload_info *info = cfpkt_info(pkt);
 191         BUG_ON(!info);
 192         dn = get_dn(muxl, info->dev_info);
 193         if (dn == NULL) {
 194                 pr_warn("Send data on unknown phy ID = %d (0x%x)\n",
 195                         info->dev_info->id, info->dev_info->id);
 196                 return -ENOTCONN;
 197         }
 198         info->hdr_len += 1;
 199         linkid = info->channel_id;
 200         cfpkt_add_head(pkt, &linkid, 1);
 201         return dn->transmit(dn, pkt);
 202 }
 203
 204 static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 205                                 int phyid)
 206 {
 207         struct cfmuxl *muxl = container_obj(layr);
 208         struct list_head *node, *next;
 209         struct cflayer *layer;
 210         list_for_each_safe(node, next, &muxl->srvl_list) {
 211                 layer = list_entry(node, struct cflayer, node);
 212                 if (cfsrvl_phyid_match(layer, phyid))
 213                         layer->ctrlcmd(layer, ctrl, phyid);
 214         }
 215 }