1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) ST-Ericsson AB 2010
4*4882a593Smuzhiyun * Author: Sjur Brendeland
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/stddef.h>
10*4882a593Smuzhiyun #include <linux/spinlock.h>
11*4882a593Smuzhiyun #include <linux/slab.h>
12*4882a593Smuzhiyun #include <net/caif/caif_layer.h>
13*4882a593Smuzhiyun #include <net/caif/cfsrvl.h>
14*4882a593Smuzhiyun #include <net/caif/cfpkt.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #define container_obj(layr) ((struct cfsrvl *) layr)
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #define DGM_CMD_BIT 0x80
20*4882a593Smuzhiyun #define DGM_FLOW_OFF 0x81
21*4882a593Smuzhiyun #define DGM_FLOW_ON 0x80
22*4882a593Smuzhiyun #define DGM_MTU 1500
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
25*4882a593Smuzhiyun static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
26*4882a593Smuzhiyun
cfdgml_create(u8 channel_id,struct dev_info * dev_info)27*4882a593Smuzhiyun struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun struct cfsrvl *dgm = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
30*4882a593Smuzhiyun if (!dgm)
31*4882a593Smuzhiyun return NULL;
32*4882a593Smuzhiyun caif_assert(offsetof(struct cfsrvl, layer) == 0);
33*4882a593Smuzhiyun cfsrvl_init(dgm, channel_id, dev_info, true);
34*4882a593Smuzhiyun dgm->layer.receive = cfdgml_receive;
35*4882a593Smuzhiyun dgm->layer.transmit = cfdgml_transmit;
36*4882a593Smuzhiyun snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ, "dgm%d", channel_id);
37*4882a593Smuzhiyun return &dgm->layer;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
cfdgml_receive(struct cflayer * layr,struct cfpkt * pkt)40*4882a593Smuzhiyun static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun u8 cmd = -1;
43*4882a593Smuzhiyun u8 dgmhdr[3];
44*4882a593Smuzhiyun int ret;
45*4882a593Smuzhiyun caif_assert(layr->up != NULL);
46*4882a593Smuzhiyun caif_assert(layr->receive != NULL);
47*4882a593Smuzhiyun caif_assert(layr->ctrlcmd != NULL);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
50*4882a593Smuzhiyun pr_err("Packet is erroneous!\n");
51*4882a593Smuzhiyun cfpkt_destroy(pkt);
52*4882a593Smuzhiyun return -EPROTO;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun if ((cmd & DGM_CMD_BIT) == 0) {
56*4882a593Smuzhiyun if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
57*4882a593Smuzhiyun pr_err("Packet is erroneous!\n");
58*4882a593Smuzhiyun cfpkt_destroy(pkt);
59*4882a593Smuzhiyun return -EPROTO;
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun ret = layr->up->receive(layr->up, pkt);
62*4882a593Smuzhiyun return ret;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun switch (cmd) {
66*4882a593Smuzhiyun case DGM_FLOW_OFF: /* FLOW OFF */
67*4882a593Smuzhiyun layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
68*4882a593Smuzhiyun cfpkt_destroy(pkt);
69*4882a593Smuzhiyun return 0;
70*4882a593Smuzhiyun case DGM_FLOW_ON: /* FLOW ON */
71*4882a593Smuzhiyun layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
72*4882a593Smuzhiyun cfpkt_destroy(pkt);
73*4882a593Smuzhiyun return 0;
74*4882a593Smuzhiyun default:
75*4882a593Smuzhiyun cfpkt_destroy(pkt);
76*4882a593Smuzhiyun pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
77*4882a593Smuzhiyun return -EPROTO;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
cfdgml_transmit(struct cflayer * layr,struct cfpkt * pkt)81*4882a593Smuzhiyun static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun u8 packet_type;
84*4882a593Smuzhiyun u32 zero = 0;
85*4882a593Smuzhiyun struct caif_payload_info *info;
86*4882a593Smuzhiyun struct cfsrvl *service = container_obj(layr);
87*4882a593Smuzhiyun int ret;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun if (!cfsrvl_ready(service, &ret)) {
90*4882a593Smuzhiyun cfpkt_destroy(pkt);
91*4882a593Smuzhiyun return ret;
92*4882a593Smuzhiyun }
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun /* STE Modem cannot handle more than 1500 bytes datagrams */
95*4882a593Smuzhiyun if (cfpkt_getlen(pkt) > DGM_MTU) {
96*4882a593Smuzhiyun cfpkt_destroy(pkt);
97*4882a593Smuzhiyun return -EMSGSIZE;
98*4882a593Smuzhiyun }
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun cfpkt_add_head(pkt, &zero, 3);
101*4882a593Smuzhiyun packet_type = 0x08; /* B9 set - UNCLASSIFIED */
102*4882a593Smuzhiyun cfpkt_add_head(pkt, &packet_type, 1);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun /* Add info for MUX-layer to route the packet out. */
105*4882a593Smuzhiyun info = cfpkt_info(pkt);
106*4882a593Smuzhiyun info->channel_id = service->layer.id;
107*4882a593Smuzhiyun /* To optimize alignment, we add up the size of CAIF header
108*4882a593Smuzhiyun * before payload.
109*4882a593Smuzhiyun */
110*4882a593Smuzhiyun info->hdr_len = 4;
111*4882a593Smuzhiyun info->dev_info = &service->dev_info;
112*4882a593Smuzhiyun return layr->dn->transmit(layr->dn, pkt);
113*4882a593Smuzhiyun }
114