LXR linux/net/caif/cfdgml.c

   1/*
   2 * Copyright (C) ST-Ericsson AB 2010
   3 * Author:      Sjur Brendeland
   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
  17#define container_obj(layr) ((struct cfsrvl *) layr)
  18
  19#define DGM_CMD_BIT  0x80
  20#define DGM_FLOW_OFF 0x81
  21#define DGM_FLOW_ON  0x80
  22#define DGM_MTU 1500
  23
  24static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
  25static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  26
  27struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
  28{
  29        struct cfsrvl *dgm = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
  30        if (!dgm)
  31                return NULL;
  32        caif_assert(offsetof(struct cfsrvl, layer) == 0);
  33        cfsrvl_init(dgm, channel_id, dev_info, true);
  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
  41static 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("Packet is erroneous!\n");
  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("Packet is erroneous!\n");
  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("Unknown datagram control %d (0x%x)\n", cmd, cmd);
  78                return -EPROTO;
  79        }
  80}
  81
  82static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
  83{
  84        u8 packet_type;
  85        u32 zero = 0;
  86        struct caif_payload_info *info;
  87        struct cfsrvl *service = container_obj(layr);
  88        int ret;
  89
  90        if (!cfsrvl_ready(service, &ret)) {
  91                cfpkt_destroy(pkt);
  92                return ret;
  93        }
  94
  95        /* STE Modem cannot handle more than 1500 bytes datagrams */
  96        if (cfpkt_getlen(pkt) > DGM_MTU) {
  97                cfpkt_destroy(pkt);
  98                return -EMSGSIZE;
  99        }
 100
 101        cfpkt_add_head(pkt, &zero, 3);
 102        packet_type = 0x08; /* B9 set - UNCLASSIFIED */
 103        cfpkt_add_head(pkt, &packet_type, 1);
 104
 105        /* Add info for MUX-layer to route the packet out. */
 106        info = cfpkt_info(pkt);
 107        info->channel_id = service->layer.id;
 108        /* To optimize alignment, we add up the size of CAIF header
 109         * before payload.
 110         */
 111        info->hdr_len = 4;
 112        info->dev_info = &service->dev_info;
 113        return layr->dn->transmit(layr->dn, pkt);
 114}
 115