net/caif/cfutill.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/kernel.h>
   8 #include <linux/types.h>
   9 #include <linux/slab.h>
  10 #include <linux/errno.h>
  11 #include <net/caif/caif_layer.h>
  12 #include <net/caif/cfsrvl.h>
  13 #include <net/caif/cfpkt.h>
  14
  15 #define container_obj(layr) ((struct cfsrvl *) layr)
  16 #define UTIL_PAYLOAD  0x00
  17 #define UTIL_CMD_BIT  0x80
  18 #define UTIL_REMOTE_SHUTDOWN 0x82
  19 #define UTIL_FLOW_OFF 0x81
  20 #define UTIL_FLOW_ON  0x80
  21 #define UTIL_CTRL_PKT_SIZE 1
  22 static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt);
  23 static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt);
  24
  25 struct cflayer *cfutill_create(u8 channel_id, struct dev_info *dev_info)
  26 {
  27         struct cfsrvl *util = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
  28         if (!util) {
  29                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
  30                 return NULL;
  31         }
  32         caif_assert(offsetof(struct cfsrvl, layer) == 0);
  33         memset(util, 0, sizeof(struct cfsrvl));
  34         cfsrvl_init(util, channel_id, dev_info);
  35         util->layer.receive = cfutill_receive;
  36         util->layer.transmit = cfutill_transmit;
  37         snprintf(util->layer.name, CAIF_LAYER_NAME_SZ - 1, "util1");
  38         return &util->layer;
  39 }
  40
  41 static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt)
  42 {
  43         u8 cmd = -1;
  44         struct cfsrvl *service = container_obj(layr);
  45         caif_assert(layr != NULL);
  46         caif_assert(layr->up != NULL);
  47         caif_assert(layr->up->receive != NULL);
  48         caif_assert(layr->up->ctrlcmd != NULL);
  49         if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
  50                 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
  51                 cfpkt_destroy(pkt);
  52                 return -EPROTO;
  53         }
  54
  55         switch (cmd) {
  56         case UTIL_PAYLOAD:
  57                 return layr->up->receive(layr->up, pkt);
  58         case UTIL_FLOW_OFF:
  59                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
  60                 cfpkt_destroy(pkt);
  61                 return 0;
  62         case UTIL_FLOW_ON:
  63                 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
  64                 cfpkt_destroy(pkt);
  65                 return 0;
  66         case UTIL_REMOTE_SHUTDOWN:      /* Remote Shutdown Request */
  67                 pr_err("CAIF: %s(): REMOTE SHUTDOWN REQUEST RECEIVED\n",
  68                         __func__);
  69                 layr->ctrlcmd(layr, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND, 0);
  70                 service->open = false;
  71                 cfpkt_destroy(pkt);
  72                 return 0;
  73         default:
  74                 cfpkt_destroy(pkt);
  75                 pr_warning("CAIF: %s(): Unknown service control %d (0x%x)\n",
  76                            __func__, cmd, cmd);
  77                 return -EPROTO;
  78         }
  79 }
  80
  81 static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt)
  82 {
  83         u8 zero = 0;
  84         struct caif_payload_info *info;
  85         int ret;
  86         struct cfsrvl *service = container_obj(layr);
  87         caif_assert(layr != NULL);
  88         caif_assert(layr->dn != NULL);
  89         caif_assert(layr->dn->transmit != NULL);
  90         if (!cfsrvl_ready(service, &ret))
  91                 return ret;
  92
  93         if (cfpkt_getlen(pkt) > CAIF_MAX_PAYLOAD_SIZE) {
  94                 pr_err("CAIF: %s(): packet too large size=%d\n",
  95                         __func__, cfpkt_getlen(pkt));
  96                 return -EOVERFLOW;
  97         }
  98
  99         cfpkt_add_head(pkt, &zero, 1);
 100         /* Add info for MUX-layer to route the packet out. */
 101         info = cfpkt_info(pkt);
 102         info->channel_id = service->layer.id;
 103         /*
 104          * To optimize alignment, we add up the size of CAIF header before
 105          * payload.
 106          */
 107         info->hdr_len = 1;
 108         info->dev_info = &service->dev_info;
 109         ret = layr->dn->transmit(layr->dn, pkt);
 110         if (ret < 0) {
 111                 u32 tmp32;
 112                 cfpkt_extr_head(pkt, &tmp32, 4);
 113         }
 114         return ret;
 115 }