net/caif/cfdgml.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 #include <linux/stddef.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/slab.h>
  10 #include <net/caif/caif_layer.h>
  11 #include <net/caif/cfsrvl.h>
  12 #include <net/caif/cfpkt.h>
  13
  14 #define container_obj(layr) ((struct cfsrvl *) layr)
  15
  16 #define DGM_CMD_BIT  0x80
  17 #define DGM_FLOW_OFF 0x81
  18 #define DGM_FLOW_ON  0x80
  19 #define DGM_CTRL_PKT_SIZE 1
  20
  21 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
  22 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  23
  24 struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
  25 {
  26         struct cfsrvl *dgm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
  27         if (!dgm) {
  28                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
  29                 return NULL;
  30         }
  31         caif_assert(offsetof(struct cfsrvl, layer) == 0);
  32         memset(dgm, 0, sizeof(struct cfsrvl));
  33         cfsrvl_init(dgm, channel_id, dev_info);
  34         dgm->layer.receive = cfdgml_receive;
  35         dgm->layer.transmit = cfdgml_transmit;
  36         snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ - 1, "dgm%d", channel_id);
  37         dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
  38         return &dgm->layer;
  39 }
  40
  41 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
  42 {
  43         u8 cmd = -1;
  44         u8 dgmhdr[3];
  45         int ret;
  46         caif_assert(layr->up != NULL);
  47         caif_assert(layr->receive != NULL);
  48         caif_assert(layr->ctrlcmd != NULL);
  49
  50         if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
  51                 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
  52                 cfpkt_destroy(pkt);
  53                 return -EPROTO;
  54         }
  55
  56         if ((cmd & DGM_CMD_BIT) == 0) {
  57                 if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
  58                         pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
  59                         cfpkt_destroy(pkt);
  60                         return -EPROTO;
  61                 }
  62                 ret = layr->up->receive(layr->up, pkt);
  63                 return ret;
  64         }
  65
  66         switch (cmd) {
  67         case DGM_FLOW_OFF:      /* FLOW OFF */
  68                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
  69                 cfpkt_destroy(pkt);
  70                 return 0;
  71         case DGM_FLOW_ON:       /* FLOW ON */
  72                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
  73                 cfpkt_destroy(pkt);
  74                 return 0;
  75         default:
  76                 cfpkt_destroy(pkt);
  77                 pr_info("CAIF: %s(): Unknown datagram control %d (0x%x)\n",
  78                         __func__, cmd, cmd);
  79                 return -EPROTO;
  80         }
  81 }
  82
  83 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
  84 {
  85         u32 zero = 0;
  86         struct caif_payload_info *info;
  87         struct cfsrvl *service = container_obj(layr);
  88         int ret;
  89         if (!cfsrvl_ready(service, &ret))
  90                 return ret;
  91
  92         cfpkt_add_head(pkt, &zero, 4);
  93
  94         /* Add info for MUX-layer to route the packet out. */
  95         info = cfpkt_info(pkt);
  96         info->channel_id = service->layer.id;
  97         /* To optimize alignment, we add up the size of CAIF header
  98          * before payload.
  99          */
 100         info->hdr_len = 4;
 101         info->dev_info = &service->dev_info;
 102         ret = layr->dn->transmit(layr->dn, pkt);
 103         if (ret < 0) {
 104                 u32 tmp32;
 105                 cfpkt_extr_head(pkt, &tmp32, 4);
 106         }
 107         return ret;
 108 }