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
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 - 1, "dgm%d", channel_id);
37	dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
38	return &dgm->layer;
39}
40
41static 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
82static 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