1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
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
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, "dgm%d", channel_id);
37 return &dgm->layer;
38 }
39
40 static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
41 {
42 u8 cmd = -1;
43 u8 dgmhdr[3];
44 int ret;
45 caif_assert(layr->up != NULL);
46 caif_assert(layr->receive != NULL);
47 caif_assert(layr->ctrlcmd != NULL);
48
49 if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
50 pr_err("Packet is erroneous!\n");
51 cfpkt_destroy(pkt);
52 return -EPROTO;
53 }
54
55 if ((cmd & DGM_CMD_BIT) == 0) {
56 if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
57 pr_err("Packet is erroneous!\n");
58 cfpkt_destroy(pkt);
59 return -EPROTO;
60 }
61 ret = layr->up->receive(layr->up, pkt);
62 return ret;
63 }
64
65 switch (cmd) {
66 case DGM_FLOW_OFF: /* FLOW OFF */
67 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
68 cfpkt_destroy(pkt);
69 return 0;
70 case DGM_FLOW_ON: /* FLOW ON */
71 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
72 cfpkt_destroy(pkt);
73 return 0;
74 default:
75 cfpkt_destroy(pkt);
76 pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
77 return -EPROTO;
78 }
79 }
80
81 static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
82 {
83 u8 packet_type;
84 u32 zero = 0;
85 struct caif_payload_info *info;
86 struct cfsrvl *service = container_obj(layr);
87 int ret;
88
89 if (!cfsrvl_ready(service, &ret)) {
90 cfpkt_destroy(pkt);
91 return ret;
92 }
93
94 /* STE Modem cannot handle more than 1500 bytes datagrams */
95 if (cfpkt_getlen(pkt) > DGM_MTU) {
96 cfpkt_destroy(pkt);
97 return -EMSGSIZE;
98 }
99
100 cfpkt_add_head(pkt, &zero, 3);
101 packet_type = 0x08; /* B9 set - UNCLASSIFIED */
102 cfpkt_add_head(pkt, &packet_type, 1);
103
104 /* Add info for MUX-layer to route the packet out. */
105 info = cfpkt_info(pkt);
106 info->channel_id = service->layer.id;
107 /* To optimize alignment, we add up the size of CAIF header
108 * before payload.
109 */
110 info->hdr_len = 4;
111 info->dev_info = &service->dev_info;
112 return layr->dn->transmit(layr->dn, pkt);
113 }
114
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