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) ((struct cfsrvl *) layr)
15
16#define DGM_CMD_BIT  0x80
17#define DGM_FLOW_OFF 0x81
18#define DGM_FLOW_ON  0x80
19#define DGM_CTRL_PKT_SIZE 1
20#define DGM_MTU 1500
21
22static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
23static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
24
25struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
26{
27	struct cfsrvl *dgm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
28	if (!dgm) {
29		pr_warning("CAIF: %s(): Out of memory\n", __func__);
30		return NULL;
31	}
32	caif_assert(offsetof(struct cfsrvl, layer) == 0);
33	memset(dgm, 0, sizeof(struct cfsrvl));
34	cfsrvl_init(dgm, channel_id, dev_info, true);
35	dgm->layer.receive = cfdgml_receive;
36	dgm->layer.transmit = cfdgml_transmit;
37	snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ - 1, "dgm%d", channel_id);
38	dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
39	return &dgm->layer;
40}
41
42static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
43{
44	u8 cmd = -1;
45	u8 dgmhdr[3];
46	int ret;
47	caif_assert(layr->up != NULL);
48	caif_assert(layr->receive != NULL);
49	caif_assert(layr->ctrlcmd != NULL);
50
51	if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
52		pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
53		cfpkt_destroy(pkt);
54		return -EPROTO;
55	}
56
57	if ((cmd & DGM_CMD_BIT) == 0) {
58		if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
59			pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
60			cfpkt_destroy(pkt);
61			return -EPROTO;
62		}
63		ret = layr->up->receive(layr->up, pkt);
64		return ret;
65	}
66
67	switch (cmd) {
68	case DGM_FLOW_OFF:	/* FLOW OFF */
69		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
70		cfpkt_destroy(pkt);
71		return 0;
72	case DGM_FLOW_ON:	/* FLOW ON */
73		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
74		cfpkt_destroy(pkt);
75		return 0;
76	default:
77		cfpkt_destroy(pkt);
78		pr_info("CAIF: %s(): Unknown datagram control %d (0x%x)\n",
79			__func__, cmd, cmd);
80		return -EPROTO;
81	}
82}
83
84static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
85{
86	u32 zero = 0;
87	struct caif_payload_info *info;
88	struct cfsrvl *service = container_obj(layr);
89	int ret;
90	if (!cfsrvl_ready(service, &ret))
91		return ret;
92
93	/* STE Modem cannot handle more than 1500 bytes datagrams */
94	if (cfpkt_getlen(pkt) > DGM_MTU)
95		return -EMSGSIZE;
96
97	cfpkt_add_head(pkt, &zero, 4);
98
99	/* Add info for MUX-layer to route the packet out. */
100	info = cfpkt_info(pkt);
101	info->channel_id = service->layer.id;
102	/* To optimize alignment, we add up the size of CAIF header
103	 * before payload.
104	 */
105	info->hdr_len = 4;
106	info->dev_info = &service->dev_info;
107	ret = layr->dn->transmit(layr->dn, pkt);
108	if (ret < 0) {
109		u32 tmp32;
110		cfpkt_extr_head(pkt, &tmp32, 4);
111	}
112	return ret;
113}
114