summaryrefslogtreecommitdiff
path: root/net/caif/cffrml.c
blob: 434ba8557826ddf160fafd08a04949d546201692 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
/*
 * CAIF Framing Layer.
 *
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/crc-ccitt.h>
#include <linux/netdevice.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cffrml.h>

#define container_obj(layr) container_of(layr, struct cffrml, layer)

struct cffrml {
	struct cflayer layer;
	bool dofcs;		/* !< FCS active */
	int __percpu		*pcpu_refcnt;
};

static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt);
static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
			   int phyid);

static u32 cffrml_rcv_error;
static u32 cffrml_rcv_checsum_error;
struct cflayer *cffrml_create(u16 phyid, bool use_fcs)
{
	struct cffrml *this = kzalloc(sizeof(struct cffrml), GFP_ATOMIC);
	if (!this)
		return NULL;
	this->pcpu_refcnt = alloc_percpu(int);
	if (this->pcpu_refcnt == NULL) {
		kfree(this);
		return NULL;
	}

	caif_assert(offsetof(struct cffrml, layer) == 0);

	this->layer.receive = cffrml_receive;
	this->layer.transmit = cffrml_transmit;
	this->layer.ctrlcmd = cffrml_ctrlcmd;
	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid);
	this->dofcs = use_fcs;
	this->layer.id = phyid;
	return (struct cflayer *) this;
}

void cffrml_free(struct cflayer *layer)
{
	struct cffrml *this = container_obj(layer);
	free_percpu(this->pcpu_refcnt);
	kfree(layer);
}

void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
{
	this->up = up;
}

void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn)
{
	this->dn = dn;
}

static u16 cffrml_checksum(u16 chks, void *buf, u16 len)
{
	/* FIXME: FCS should be moved to glue in order to use OS-Specific
	 * solutions
	 */
	return crc_ccitt(chks, buf, len);
}

static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt)
{
	u16 tmp;
	u16 len;
	u16 hdrchks;
	int pktchks;
	struct cffrml *this;
	this = container_obj(layr);

	cfpkt_extr_head(pkt, &tmp, 2);
	len = le16_to_cpu(tmp);

	/* Subtract for FCS on length if FCS is not used. */
	if (!this->dofcs)
		len -= 2;

	if (cfpkt_setlen(pkt, len) < 0) {
		++cffrml_rcv_error;
		pr_err("Framing length error (%d)\n", len);
		cfpkt_destroy(pkt);
		return -EPROTO;
	}
	/*
	 * Don't do extract if FCS is false, rather do setlen - then we don't
	 * get a cache-miss.
	 */
	if (this->dofcs) {
		cfpkt_extr_trail(pkt, &tmp, 2);
		hdrchks = le16_to_cpu(tmp);
		pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
		if (pktchks != hdrchks) {
			cfpkt_add_trail(pkt, &tmp, 2);
			++cffrml_rcv_error;
			++cffrml_rcv_checsum_error;
			pr_info("Frame checksum error (0x%x != 0x%x)\n",
				hdrchks, pktchks);
			return -EILSEQ;
		}
	}
	if (cfpkt_erroneous(pkt)) {
		++cffrml_rcv_error;
		pr_err("Packet is erroneous!\n");
		cfpkt_destroy(pkt);
		return -EPROTO;
	}

	if (layr->up == NULL) {
		pr_err("Layr up is missing!\n");
		cfpkt_destroy(pkt);
		return -EINVAL;
	}

	return layr->up->receive(layr->up, pkt);
}

static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
	u16 chks;
	u16 len;
	__le16 data;

	struct cffrml *this = container_obj(layr);
	if (this->dofcs) {
		chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
		data = cpu_to_le16(chks);
		cfpkt_add_trail(pkt, &data, 2);
	} else {
		cfpkt_pad_trail(pkt, 2);
	}
	len = cfpkt_getlen(pkt);
	data = cpu_to_le16(len);
	cfpkt_add_head(pkt, &data, 2);
	cfpkt_info(pkt)->hdr_len += 2;
	if (cfpkt_erroneous(pkt)) {
		pr_err("Packet is erroneous!\n");
		cfpkt_destroy(pkt);
		return -EPROTO;
	}

	if (layr->dn == NULL) {
		cfpkt_destroy(pkt);
		return -ENODEV;

	}
	return layr->dn->transmit(layr->dn, pkt);
}

static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
			   int phyid)
{
	if (layr->up && layr->up->ctrlcmd)
		layr->up->ctrlcmd(layr->up, ctrl, layr->id);
}

void cffrml_put(struct cflayer *layr)
{
	struct cffrml *this = container_obj(layr);
	if (layr != NULL && this->pcpu_refcnt != NULL)
		this_cpu_dec(*this->pcpu_refcnt);
}

void cffrml_hold(struct cflayer *layr)
{
	struct cffrml *this = container_obj(layr);
	if (layr != NULL && this->pcpu_refcnt != NULL)
		this_cpu_inc(*this->pcpu_refcnt);
}

int cffrml_refcnt_read(struct cflayer *layr)
{
	int i, refcnt = 0;
	struct cffrml *this = container_obj(layr);
	for_each_possible_cpu(i)
		refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
	return refcnt;
}