xref: /openbmc/linux/net/caif/cfdgml.c (revision af873fce)
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 
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, "dgm%d", channel_id);
37 	return &dgm->layer;
38 }
39 
cfdgml_receive(struct cflayer * layr,struct cfpkt * pkt)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 
cfdgml_transmit(struct cflayer * layr,struct cfpkt * pkt)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