net/caif/cfrfml.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/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) container_of(layr, struct cfsrvl, layer)
  15
  16 #define RFM_SEGMENTATION_BIT 0x01
  17 #define RFM_PAYLOAD  0x00
  18 #define RFM_CMD_BIT  0x80
  19 #define RFM_FLOW_OFF 0x81
  20 #define RFM_FLOW_ON  0x80
  21 #define RFM_SET_PIN  0x82
  22 #define RFM_CTRL_PKT_SIZE 1
  23
  24 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt);
  25 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  26
  27 struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info)
  28 {
  29         struct cfsrvl *rfm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
  30
  31         if (!rfm) {
  32                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
  33                 return NULL;
  34         }
  35
  36         caif_assert(offsetof(struct cfsrvl, layer) == 0);
  37
  38         memset(rfm, 0, sizeof(struct cfsrvl));
  39         cfsrvl_init(rfm, channel_id, dev_info, false);
  40         rfm->layer.receive = cfrfml_receive;
  41         rfm->layer.transmit = cfrfml_transmit;
  42         snprintf(rfm->layer.name, CAIF_LAYER_NAME_SZ, "rfm%d", channel_id);
  43         return &rfm->layer;
  44 }
  45
  46 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
  47 {
  48         u8 tmp;
  49         bool segmented;
  50         int ret;
  51         caif_assert(layr->up != NULL);
  52         caif_assert(layr->receive != NULL);
  53
  54         /*
  55          * RFM is taking care of segmentation and stripping of
  56          * segmentation bit.
  57          */
  58         if (cfpkt_extr_head(pkt, &tmp, 1) < 0) {
  59                 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
  60                 cfpkt_destroy(pkt);
  61                 return -EPROTO;
  62         }
  63         segmented = tmp & RFM_SEGMENTATION_BIT;
  64         caif_assert(!segmented);
  65
  66         ret = layr->up->receive(layr->up, pkt);
  67         return ret;
  68 }
  69
  70 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
  71 {
  72         u8 tmp = 0;
  73         int ret;
  74         struct cfsrvl *service = container_obj(layr);
  75
  76         caif_assert(layr->dn != NULL);
  77         caif_assert(layr->dn->transmit != NULL);
  78
  79         if (!cfsrvl_ready(service, &ret))
  80                 return ret;
  81
  82         if (cfpkt_getlen(pkt) > CAIF_MAX_PAYLOAD_SIZE) {
  83                 pr_err("CAIF: %s():Packet too large - size=%d\n",
  84                         __func__, cfpkt_getlen(pkt));
  85                 return -EOVERFLOW;
  86         }
  87         if (cfpkt_add_head(pkt, &tmp, 1) < 0) {
  88                 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
  89                 return -EPROTO;
  90         }
  91
  92         /* Add info for MUX-layer to route the packet out. */
  93         cfpkt_info(pkt)->channel_id = service->layer.id;
  94         /*
  95          * To optimize alignment, we add up the size of CAIF header before
  96          * payload.
  97          */
  98         cfpkt_info(pkt)->hdr_len = 1;
  99         cfpkt_info(pkt)->dev_info = &service->dev_info;
 100         ret = layr->dn->transmit(layr->dn, pkt);
 101         if (ret < 0)
 102                 cfpkt_extr_head(pkt, &tmp, 1);
 103         return ret;
 104 }