linux/net/caif/cfdgml.c
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   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
  21static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
  22static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  23
  24struct 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
  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("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
  83static 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}
 109