Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CAIF Framing Layer.
4 *
5 * Copyright (C) ST-Ericsson AB 2010
6 * Author: Sjur Brendeland
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
10
11#include <linux/stddef.h>
12#include <linux/spinlock.h>
13#include <linux/slab.h>
14#include <linux/crc-ccitt.h>
15#include <linux/netdevice.h>
16#include <net/caif/caif_layer.h>
17#include <net/caif/cfpkt.h>
18#include <net/caif/cffrml.h>
19
20#define container_obj(layr) container_of(layr, struct cffrml, layer)
21
22struct cffrml {
23 struct cflayer layer;
24 bool dofcs; /* !< FCS active */
25 int __percpu *pcpu_refcnt;
26};
27
28static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt);
29static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt);
30static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
31 int phyid);
32
33static u32 cffrml_rcv_error;
34static u32 cffrml_rcv_checsum_error;
35struct cflayer *cffrml_create(u16 phyid, bool use_fcs)
36{
37 struct cffrml *this = kzalloc(sizeof(struct cffrml), GFP_ATOMIC);
38 if (!this)
39 return NULL;
40 this->pcpu_refcnt = alloc_percpu(int);
41 if (this->pcpu_refcnt == NULL) {
42 kfree(this);
43 return NULL;
44 }
45
46 caif_assert(offsetof(struct cffrml, layer) == 0);
47
48 this->layer.receive = cffrml_receive;
49 this->layer.transmit = cffrml_transmit;
50 this->layer.ctrlcmd = cffrml_ctrlcmd;
51 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid);
52 this->dofcs = use_fcs;
53 this->layer.id = phyid;
54 return (struct cflayer *) this;
55}
56
57void cffrml_free(struct cflayer *layer)
58{
59 struct cffrml *this = container_obj(layer);
60 free_percpu(this->pcpu_refcnt);
61 kfree(layer);
62}
63
64void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
65{
66 this->up = up;
67}
68
69void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn)
70{
71 this->dn = dn;
72}
73
74static u16 cffrml_checksum(u16 chks, void *buf, u16 len)
75{
76 /* FIXME: FCS should be moved to glue in order to use OS-Specific
77 * solutions
78 */
79 return crc_ccitt(chks, buf, len);
80}
81
82static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt)
83{
84 u16 tmp;
85 u16 len;
86 u16 hdrchks;
87 int pktchks;
88 struct cffrml *this;
89 this = container_obj(layr);
90
91 cfpkt_extr_head(pkt, &tmp, 2);
92 len = le16_to_cpu(tmp);
93
94 /* Subtract for FCS on length if FCS is not used. */
95 if (!this->dofcs) {
96 if (len < 2) {
97 ++cffrml_rcv_error;
98 pr_err("Invalid frame length (%d)\n", len);
99 cfpkt_destroy(pkt);
100 return -EPROTO;
101 }
102 len -= 2;
103 }
104
105 if (cfpkt_setlen(pkt, len) < 0) {
106 ++cffrml_rcv_error;
107 pr_err("Framing length error (%d)\n", len);
108 cfpkt_destroy(pkt);
109 return -EPROTO;
110 }
111 /*
112 * Don't do extract if FCS is false, rather do setlen - then we don't
113 * get a cache-miss.
114 */
115 if (this->dofcs) {
116 cfpkt_extr_trail(pkt, &tmp, 2);
117 hdrchks = le16_to_cpu(tmp);
118 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
119 if (pktchks != hdrchks) {
120 cfpkt_add_trail(pkt, &tmp, 2);
121 ++cffrml_rcv_error;
122 ++cffrml_rcv_checsum_error;
123 pr_info("Frame checksum error (0x%x != 0x%x)\n",
124 hdrchks, pktchks);
125 return -EILSEQ;
126 }
127 }
128 if (cfpkt_erroneous(pkt)) {
129 ++cffrml_rcv_error;
130 pr_err("Packet is erroneous!\n");
131 cfpkt_destroy(pkt);
132 return -EPROTO;
133 }
134
135 if (layr->up == NULL) {
136 pr_err("Layr up is missing!\n");
137 cfpkt_destroy(pkt);
138 return -EINVAL;
139 }
140
141 return layr->up->receive(layr->up, pkt);
142}
143
144static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
145{
146 u16 chks;
147 u16 len;
148 __le16 data;
149
150 struct cffrml *this = container_obj(layr);
151 if (this->dofcs) {
152 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
153 data = cpu_to_le16(chks);
154 cfpkt_add_trail(pkt, &data, 2);
155 } else {
156 cfpkt_pad_trail(pkt, 2);
157 }
158 len = cfpkt_getlen(pkt);
159 data = cpu_to_le16(len);
160 cfpkt_add_head(pkt, &data, 2);
161 cfpkt_info(pkt)->hdr_len += 2;
162 if (cfpkt_erroneous(pkt)) {
163 pr_err("Packet is erroneous!\n");
164 cfpkt_destroy(pkt);
165 return -EPROTO;
166 }
167
168 if (layr->dn == NULL) {
169 cfpkt_destroy(pkt);
170 return -ENODEV;
171
172 }
173 return layr->dn->transmit(layr->dn, pkt);
174}
175
176static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
177 int phyid)
178{
179 if (layr->up && layr->up->ctrlcmd)
180 layr->up->ctrlcmd(layr->up, ctrl, layr->id);
181}
182
183void cffrml_put(struct cflayer *layr)
184{
185 struct cffrml *this = container_obj(layr);
186 if (layr != NULL && this->pcpu_refcnt != NULL)
187 this_cpu_dec(*this->pcpu_refcnt);
188}
189
190void cffrml_hold(struct cflayer *layr)
191{
192 struct cffrml *this = container_obj(layr);
193 if (layr != NULL && this->pcpu_refcnt != NULL)
194 this_cpu_inc(*this->pcpu_refcnt);
195}
196
197int cffrml_refcnt_read(struct cflayer *layr)
198{
199 int i, refcnt = 0;
200 struct cffrml *this = container_obj(layr);
201 for_each_possible_cpu(i)
202 refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
203 return refcnt;
204}