LXR linux/net/caif/cfdgml.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) ST-Ericsson AB 2010
   4 * Author:      Sjur Brendeland
   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, "dgm%d", channel_id);
  37        return &dgm->layer;
  38}
  39
  40static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
  41{
  42        u8 cmd = -1;
  43        u8 dgmhdr[3];
  44        int ret;
  45        caif_assert(layr->up != NULL);
  46        caif_assert(layr->receive != NULL);
  47        caif_assert(layr->ctrlcmd != NULL);
  48
  49        if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
  50                pr_err("Packet is erroneous!\n");
  51                cfpkt_destroy(pkt);
  52                return -EPROTO;
  53        }
  54
  55        if ((cmd & DGM_CMD_BIT) == 0) {
  56                if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
  57                        pr_err("Packet is erroneous!\n");
  58                        cfpkt_destroy(pkt);
  59                        return -EPROTO;
  60                }
  61                ret = layr->up->receive(layr->up, pkt);
  62                return ret;
  63        }
  64
  65        switch (cmd) {
  66        case DGM_FLOW_OFF:      /* FLOW OFF */
  67                layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
  68                cfpkt_destroy(pkt);
  69                return 0;
  70        case DGM_FLOW_ON:       /* FLOW ON */
  71                layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
  72                cfpkt_destroy(pkt);
  73                return 0;
  74        default:
  75                cfpkt_destroy(pkt);
  76                pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
  77                return -EPROTO;
  78        }
  79}
  80
  81static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
  82{
  83        u8 packet_type;
  84        u32 zero = 0;
  85        struct caif_payload_info *info;
  86        struct cfsrvl *service = container_obj(layr);
  87        int ret;
  88
  89        if (!cfsrvl_ready(service, &ret)) {
  90                cfpkt_destroy(pkt);
  91                return ret;
  92        }
  93
  94        /* STE Modem cannot handle more than 1500 bytes datagrams */
  95        if (cfpkt_getlen(pkt) > DGM_MTU) {
  96                cfpkt_destroy(pkt);
  97                return -EMSGSIZE;
  98        }
  99
 100        cfpkt_add_head(pkt, &zero, 3);
 101        packet_type = 0x08; /* B9 set - UNCLASSIFIED */
 102        cfpkt_add_head(pkt, &packet_type, 1);
 103
 104        /* Add info for MUX-layer to route the packet out. */
 105        info = cfpkt_info(pkt);
 106        info->channel_id = service->layer.id;
 107        /* To optimize alignment, we add up the size of CAIF header
 108         * before payload.
 109         */
 110        info->hdr_len = 4;
 111        info->dev_info = &service->dev_info;
 112        return layr->dn->transmit(layr->dn, pkt);
 113}
 114