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Sjur Braendelandb482cd22010-03-30 13:56:23 +00001/*
2 * CAIF Framing Layer.
3 *
4 * Copyright (C) ST-Ericsson AB 2010
5 * Author: Sjur Brendeland/sjur.brandeland@stericsson.com
6 * License terms: GNU General Public License (GPL) version 2
7 */
8
Joe Perchesb31fa5b2010-09-05 21:31:11 +00009#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
10
Sjur Braendelandb482cd22010-03-30 13:56:23 +000011#include <linux/stddef.h>
12#include <linux/spinlock.h>
13#include <linux/slab.h>
14#include <linux/crc-ccitt.h>
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +000015#include <linux/netdevice.h>
Sjur Braendelandb482cd22010-03-30 13:56:23 +000016#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 */
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +000025 int __percpu *pcpu_refcnt;
Sjur Braendelandb482cd22010-03-30 13:56:23 +000026};
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 = kmalloc(sizeof(struct cffrml), GFP_ATOMIC);
38 if (!this) {
Joe Perchesb31fa5b2010-09-05 21:31:11 +000039 pr_warn("Out of memory\n");
Sjur Braendelandb482cd22010-03-30 13:56:23 +000040 return NULL;
41 }
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +000042 this->pcpu_refcnt = alloc_percpu(int);
43 if (this->pcpu_refcnt == NULL) {
44 kfree(this);
45 return NULL;
46 }
47
Sjur Braendelandb482cd22010-03-30 13:56:23 +000048 caif_assert(offsetof(struct cffrml, layer) == 0);
49
50 memset(this, 0, sizeof(struct cflayer));
51 this->layer.receive = cffrml_receive;
52 this->layer.transmit = cffrml_transmit;
53 this->layer.ctrlcmd = cffrml_ctrlcmd;
54 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid);
55 this->dofcs = use_fcs;
56 this->layer.id = phyid;
57 return (struct cflayer *) this;
58}
59
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +000060void cffrml_free(struct cflayer *layer)
61{
62 struct cffrml *this = container_obj(layer);
63 free_percpu(this->pcpu_refcnt);
64 kfree(layer);
65}
66
Sjur Braendelandb482cd22010-03-30 13:56:23 +000067void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
68{
69 this->up = up;
70}
71
72void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn)
73{
74 this->dn = dn;
75}
76
77static u16 cffrml_checksum(u16 chks, void *buf, u16 len)
78{
79 /* FIXME: FCS should be moved to glue in order to use OS-Specific
80 * solutions
81 */
82 return crc_ccitt(chks, buf, len);
83}
84
85static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt)
86{
87 u16 tmp;
88 u16 len;
89 u16 hdrchks;
90 u16 pktchks;
91 struct cffrml *this;
92 this = container_obj(layr);
93
94 cfpkt_extr_head(pkt, &tmp, 2);
95 len = le16_to_cpu(tmp);
96
97 /* Subtract for FCS on length if FCS is not used. */
98 if (!this->dofcs)
99 len -= 2;
100
101 if (cfpkt_setlen(pkt, len) < 0) {
102 ++cffrml_rcv_error;
Joe Perchesb31fa5b2010-09-05 21:31:11 +0000103 pr_err("Framing length error (%d)\n", len);
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000104 cfpkt_destroy(pkt);
105 return -EPROTO;
106 }
107 /*
108 * Don't do extract if FCS is false, rather do setlen - then we don't
109 * get a cache-miss.
110 */
111 if (this->dofcs) {
112 cfpkt_extr_trail(pkt, &tmp, 2);
113 hdrchks = le16_to_cpu(tmp);
114 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
115 if (pktchks != hdrchks) {
116 cfpkt_add_trail(pkt, &tmp, 2);
117 ++cffrml_rcv_error;
118 ++cffrml_rcv_checsum_error;
Joe Perchesb31fa5b2010-09-05 21:31:11 +0000119 pr_info("Frame checksum error (0x%x != 0x%x)\n",
120 hdrchks, pktchks);
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000121 return -EILSEQ;
122 }
123 }
124 if (cfpkt_erroneous(pkt)) {
125 ++cffrml_rcv_error;
Joe Perchesb31fa5b2010-09-05 21:31:11 +0000126 pr_err("Packet is erroneous!\n");
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000127 cfpkt_destroy(pkt);
128 return -EPROTO;
129 }
sjur.brandeland@stericsson.comc85c2952011-05-13 02:44:06 +0000130
131 if (layr->up == NULL) {
132 pr_err("Layr up is missing!\n");
133 cfpkt_destroy(pkt);
134 return -EINVAL;
135 }
136
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000137 return layr->up->receive(layr->up, pkt);
138}
139
140static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
141{
142 int tmp;
143 u16 chks;
144 u16 len;
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000145 struct cffrml *this = container_obj(layr);
146 if (this->dofcs) {
147 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
148 tmp = cpu_to_le16(chks);
149 cfpkt_add_trail(pkt, &tmp, 2);
150 } else {
151 cfpkt_pad_trail(pkt, 2);
152 }
153 len = cfpkt_getlen(pkt);
154 tmp = cpu_to_le16(len);
155 cfpkt_add_head(pkt, &tmp, 2);
156 cfpkt_info(pkt)->hdr_len += 2;
157 if (cfpkt_erroneous(pkt)) {
Joe Perchesb31fa5b2010-09-05 21:31:11 +0000158 pr_err("Packet is erroneous!\n");
sjur.brandeland@stericsson.comc85c2952011-05-13 02:44:06 +0000159 cfpkt_destroy(pkt);
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000160 return -EPROTO;
161 }
sjur.brandeland@stericsson.comc85c2952011-05-13 02:44:06 +0000162
163 if (layr->dn == NULL) {
164 cfpkt_destroy(pkt);
165 return -ENODEV;
166
167 }
Sjur Brændeland4dd820c2011-04-11 10:43:51 +0000168 return layr->dn->transmit(layr->dn, pkt);
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000169}
170
171static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
172 int phyid)
173{
sjur.brandeland@stericsson.comc85c2952011-05-13 02:44:06 +0000174 if (layr->up && layr->up->ctrlcmd)
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000175 layr->up->ctrlcmd(layr->up, ctrl, layr->id);
176}
sjur.brandeland@stericsson.com0b1e9732011-05-13 02:43:59 +0000177
178void cffrml_put(struct cflayer *layr)
179{
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +0000180 struct cffrml *this = container_obj(layr);
181 if (layr != NULL && this->pcpu_refcnt != NULL)
182 irqsafe_cpu_dec(*this->pcpu_refcnt);
sjur.brandeland@stericsson.com0b1e9732011-05-13 02:43:59 +0000183}
184
185void cffrml_hold(struct cflayer *layr)
186{
sjur.brandeland@stericsson.comcb3cb422011-05-13 02:44:02 +0000187 struct cffrml *this = container_obj(layr);
188 if (layr != NULL && this->pcpu_refcnt != NULL)
189 irqsafe_cpu_inc(*this->pcpu_refcnt);
190}
191
192int cffrml_refcnt_read(struct cflayer *layr)
193{
194 int i, refcnt = 0;
195 struct cffrml *this = container_obj(layr);
196 for_each_possible_cpu(i)
197 refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
198 return refcnt;
sjur.brandeland@stericsson.com0b1e9732011-05-13 02:43:59 +0000199}