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(size: sizeof(struct cfsrvl), GFP_ATOMIC); |
30 | if (!dgm) |
31 | return NULL; |
32 | caif_assert(offsetof(struct cfsrvl, layer) == 0); |
33 | cfsrvl_init(service: dgm, channel_id, dev_info, supports_flowctrl: true); |
34 | dgm->layer.receive = cfdgml_receive; |
35 | dgm->layer.transmit = cfdgml_transmit; |
36 | snprintf(buf: dgm->layer.name, CAIF_LAYER_NAME_SZ, fmt: "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, data: &cmd, len: 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, data: &dgmhdr, len: 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, err: &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, data: &zero, len: 3); |
101 | packet_type = 0x08; /* B9 set - UNCLASSIFIED */ |
102 | cfpkt_add_head(pkt, data: &packet_type, len: 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 | |