xref: /openbmc/linux/net/caif/cfdgml.c (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
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