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
22 struct cffrml {
23 struct cflayer layer;
24 bool dofcs; /* !< FCS active */
25 int __percpu *pcpu_refcnt;
26 };
27
28 static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt);
29 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt);
30 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
31 int phyid);
32
33 static u32 cffrml_rcv_error;
34 static u32 cffrml_rcv_checsum_error;
cffrml_create(u16 phyid,bool use_fcs)35 struct 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
cffrml_free(struct cflayer * layer)57 void cffrml_free(struct cflayer *layer)
58 {
59 struct cffrml *this = container_obj(layer);
60 free_percpu(this->pcpu_refcnt);
61 kfree(layer);
62 }
63
cffrml_set_uplayer(struct cflayer * this,struct cflayer * up)64 void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
65 {
66 this->up = up;
67 }
68
cffrml_set_dnlayer(struct cflayer * this,struct cflayer * dn)69 void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn)
70 {
71 this->dn = dn;
72 }
73
cffrml_checksum(u16 chks,void * buf,u16 len)74 static 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
cffrml_receive(struct cflayer * layr,struct cfpkt * pkt)82 static 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 len -= 2;
97
98 if (cfpkt_setlen(pkt, len) < 0) {
99 ++cffrml_rcv_error;
100 pr_err("Framing length error (%d)\n", len);
101 cfpkt_destroy(pkt);
102 return -EPROTO;
103 }
104 /*
105 * Don't do extract if FCS is false, rather do setlen - then we don't
106 * get a cache-miss.
107 */
108 if (this->dofcs) {
109 cfpkt_extr_trail(pkt, &tmp, 2);
110 hdrchks = le16_to_cpu(tmp);
111 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
112 if (pktchks != hdrchks) {
113 cfpkt_add_trail(pkt, &tmp, 2);
114 ++cffrml_rcv_error;
115 ++cffrml_rcv_checsum_error;
116 pr_info("Frame checksum error (0x%x != 0x%x)\n",
117 hdrchks, pktchks);
118 return -EILSEQ;
119 }
120 }
121 if (cfpkt_erroneous(pkt)) {
122 ++cffrml_rcv_error;
123 pr_err("Packet is erroneous!\n");
124 cfpkt_destroy(pkt);
125 return -EPROTO;
126 }
127
128 if (layr->up == NULL) {
129 pr_err("Layr up is missing!\n");
130 cfpkt_destroy(pkt);
131 return -EINVAL;
132 }
133
134 return layr->up->receive(layr->up, pkt);
135 }
136
cffrml_transmit(struct cflayer * layr,struct cfpkt * pkt)137 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
138 {
139 u16 chks;
140 u16 len;
141 __le16 data;
142
143 struct cffrml *this = container_obj(layr);
144 if (this->dofcs) {
145 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
146 data = cpu_to_le16(chks);
147 cfpkt_add_trail(pkt, &data, 2);
148 } else {
149 cfpkt_pad_trail(pkt, 2);
150 }
151 len = cfpkt_getlen(pkt);
152 data = cpu_to_le16(len);
153 cfpkt_add_head(pkt, &data, 2);
154 cfpkt_info(pkt)->hdr_len += 2;
155 if (cfpkt_erroneous(pkt)) {
156 pr_err("Packet is erroneous!\n");
157 cfpkt_destroy(pkt);
158 return -EPROTO;
159 }
160
161 if (layr->dn == NULL) {
162 cfpkt_destroy(pkt);
163 return -ENODEV;
164
165 }
166 return layr->dn->transmit(layr->dn, pkt);
167 }
168
cffrml_ctrlcmd(struct cflayer * layr,enum caif_ctrlcmd ctrl,int phyid)169 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
170 int phyid)
171 {
172 if (layr->up && layr->up->ctrlcmd)
173 layr->up->ctrlcmd(layr->up, ctrl, layr->id);
174 }
175
cffrml_put(struct cflayer * layr)176 void cffrml_put(struct cflayer *layr)
177 {
178 struct cffrml *this = container_obj(layr);
179 if (layr != NULL && this->pcpu_refcnt != NULL)
180 this_cpu_dec(*this->pcpu_refcnt);
181 }
182
cffrml_hold(struct cflayer * layr)183 void cffrml_hold(struct cflayer *layr)
184 {
185 struct cffrml *this = container_obj(layr);
186 if (layr != NULL && this->pcpu_refcnt != NULL)
187 this_cpu_inc(*this->pcpu_refcnt);
188 }
189
cffrml_refcnt_read(struct cflayer * layr)190 int cffrml_refcnt_read(struct cflayer *layr)
191 {
192 int i, refcnt = 0;
193 struct cffrml *this = container_obj(layr);
194 for_each_possible_cpu(i)
195 refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
196 return refcnt;
197 }
198