1 /*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author: Sjur Brendeland
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/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
24 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
25 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
26
cfdgml_create(u8 channel_id,struct dev_info * dev_info)27 struct 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 - 1, "dgm%d", channel_id);
37 dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
38 return &dgm->layer;
39 }
40
cfdgml_receive(struct cflayer * layr,struct cfpkt * pkt)41 static 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("Packet is erroneous!\n");
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("Packet is erroneous!\n");
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("Unknown datagram control %d (0x%x)\n", cmd, cmd);
78 return -EPROTO;
79 }
80 }
81
cfdgml_transmit(struct cflayer * layr,struct cfpkt * pkt)82 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
83 {
84 u8 packet_type;
85 u32 zero = 0;
86 struct caif_payload_info *info;
87 struct cfsrvl *service = container_obj(layr);
88 int ret;
89
90 if (!cfsrvl_ready(service, &ret)) {
91 cfpkt_destroy(pkt);
92 return ret;
93 }
94
95 /* STE Modem cannot handle more than 1500 bytes datagrams */
96 if (cfpkt_getlen(pkt) > DGM_MTU) {
97 cfpkt_destroy(pkt);
98 return -EMSGSIZE;
99 }
100
101 cfpkt_add_head(pkt, &zero, 3);
102 packet_type = 0x08; /* B9 set - UNCLASSIFIED */
103 cfpkt_add_head(pkt, &packet_type, 1);
104
105 /* Add info for MUX-layer to route the packet out. */
106 info = cfpkt_info(pkt);
107 info->channel_id = service->layer.id;
108 /* To optimize alignment, we add up the size of CAIF header
109 * before payload.
110 */
111 info->hdr_len = 4;
112 info->dev_info = &service->dev_info;
113 return layr->dn->transmit(layr->dn, pkt);
114 }
115