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 #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/caif_layer.h>
  13 #include <net/caif/cfsrvl.h>
  14 #include <net/caif/cfpkt.h>
  15
  16 #define container_obj(layr) ((struct cfsrvl *) layr)
  17
  18 #define DGM_CMD_BIT  0x80
  19 #define DGM_FLOW_OFF 0x81
  20 #define DGM_FLOW_ON  0x80
  21 #define DGM_CTRL_PKT_SIZE 1
  22 #define DGM_MTU 1500
  23
  24 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
  25 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  26
  27 struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
  28 {
  29         struct cfsrvl *dgm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
  30         if (!dgm) {
  31                 pr_warn("Out of memory\n");
  32                 return NULL;
  33         }
  34         caif_assert(offsetof(struct cfsrvl, layer) == 0);
  35         memset(dgm, 0, sizeof(struct cfsrvl));
  36         cfsrvl_init(dgm, channel_id, dev_info, true);
  37         dgm->layer.receive = cfdgml_receive;
  38         dgm->layer.transmit = cfdgml_transmit;
  39         snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ - 1, "dgm%d", channel_id);
  40         dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
  41         return &dgm->layer;
  42 }
  43
  44 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
  45 {
  46         u8 cmd = -1;
  47         u8 dgmhdr[3];
  48         int ret;
  49         caif_assert(layr->up != NULL);
  50         caif_assert(layr->receive != NULL);
  51         caif_assert(layr->ctrlcmd != NULL);
  52
  53         if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
  54                 pr_err("Packet is erroneous!\n");
  55                 cfpkt_destroy(pkt);
  56                 return -EPROTO;
  57         }
  58
  59         if ((cmd & DGM_CMD_BIT) == 0) {
  60                 if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
  61                         pr_err("Packet is erroneous!\n");
  62                         cfpkt_destroy(pkt);
  63                         return -EPROTO;
  64                 }
  65                 ret = layr->up->receive(layr->up, pkt);
  66                 return ret;
  67         }
  68
  69         switch (cmd) {
  70         case DGM_FLOW_OFF:      /* FLOW OFF */
  71                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
  72                 cfpkt_destroy(pkt);
  73                 return 0;
  74         case DGM_FLOW_ON:       /* FLOW ON */
  75                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
  76                 cfpkt_destroy(pkt);
  77                 return 0;
  78         default:
  79                 cfpkt_destroy(pkt);
  80                 pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
  81                 return -EPROTO;
  82         }
  83 }
  84
  85 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
  86 {
  87         u32 zero = 0;
  88         struct caif_payload_info *info;
  89         struct cfsrvl *service = container_obj(layr);
  90         int ret;
  91         if (!cfsrvl_ready(service, &ret))
  92                 return ret;
  93
  94         /* STE Modem cannot handle more than 1500 bytes datagrams */
  95         if (cfpkt_getlen(pkt) > DGM_MTU)
  96                 return -EMSGSIZE;
  97
  98         cfpkt_add_head(pkt, &zero, 4);
  99
 100         /* Add info for MUX-layer to route the packet out. */
 101         info = cfpkt_info(pkt);
 102         info->channel_id = service->layer.id;
 103         /* To optimize alignment, we add up the size of CAIF header
 104          * before payload.
 105          */
 106         info->hdr_len = 4;
 107         info->dev_info = &service->dev_info;
 108         ret = layr->dn->transmit(layr->dn, pkt);
 109         if (ret < 0) {
 110                 u32 tmp32;
 111                 cfpkt_extr_head(pkt, &tmp32, 4);
 112         }
 113         return ret;
 114 }