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