blob: 8303fe3ebf891e820439c8359518022fe8c29a54 [file] [log] [blame]
Sjur Braendelandb482cd22010-03-30 13:56:23 +00001/*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author: Sjur Brendeland/sjur.brandeland@stericsson.com
4 * License terms: GNU General Public License (GPL) version 2
5 */
6
Joe Perchesb31fa5b2010-09-05 21:31:11 +00007#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
Sjur Braendelandb482cd22010-03-30 13:56:23 +00009#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/cfpkt.h>
14#include <net/caif/cfserl.h>
15
16#define container_obj(layr) ((struct cfserl *) layr)
17
18#define CFSERL_STX 0x02
Sjur Braendeland2aa40ae2010-06-17 06:55:40 +000019#define SERIAL_MINIUM_PACKET_SIZE 4
20#define SERIAL_MAX_FRAMESIZE 4096
Sjur Braendelandb482cd22010-03-30 13:56:23 +000021struct cfserl {
22 struct cflayer layer;
23 struct cfpkt *incomplete_frm;
24 /* Protects parallel processing of incoming packets */
25 spinlock_t sync;
26 bool usestx;
27};
Sjur Braendelandb482cd22010-03-30 13:56:23 +000028
29static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt);
30static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
31static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
32 int phyid);
33
34struct cflayer *cfserl_create(int type, int instance, bool use_stx)
35{
36 struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
37 if (!this) {
Joe Perchesb31fa5b2010-09-05 21:31:11 +000038 pr_warn("Out of memory\n");
Sjur Braendelandb482cd22010-03-30 13:56:23 +000039 return NULL;
40 }
41 caif_assert(offsetof(struct cfserl, layer) == 0);
42 memset(this, 0, sizeof(struct cfserl));
43 this->layer.receive = cfserl_receive;
44 this->layer.transmit = cfserl_transmit;
45 this->layer.ctrlcmd = cfserl_ctrlcmd;
46 this->layer.type = type;
47 this->usestx = use_stx;
48 spin_lock_init(&this->sync);
49 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
50 return &this->layer;
51}
52
53static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
54{
55 struct cfserl *layr = container_obj(l);
56 u16 pkt_len;
57 struct cfpkt *pkt = NULL;
58 struct cfpkt *tail_pkt = NULL;
59 u8 tmp8;
60 u16 tmp;
61 u8 stx = CFSERL_STX;
62 int ret;
63 u16 expectlen = 0;
Dan Carpenter97dc8752010-05-26 05:16:48 +000064
Sjur Braendelandb482cd22010-03-30 13:56:23 +000065 caif_assert(newpkt != NULL);
66 spin_lock(&layr->sync);
67
68 if (layr->incomplete_frm != NULL) {
Sjur Braendelandb482cd22010-03-30 13:56:23 +000069 layr->incomplete_frm =
70 cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
71 pkt = layr->incomplete_frm;
Dan Carpenter97dc8752010-05-26 05:16:48 +000072 if (pkt == NULL) {
73 spin_unlock(&layr->sync);
Sjur Braendeland638e6282010-05-21 02:16:09 +000074 return -ENOMEM;
Dan Carpenter97dc8752010-05-26 05:16:48 +000075 }
Sjur Braendelandb482cd22010-03-30 13:56:23 +000076 } else {
77 pkt = newpkt;
78 }
79 layr->incomplete_frm = NULL;
80
81 do {
82 /* Search for STX at start of pkt if STX is used */
83 if (layr->usestx) {
84 cfpkt_extr_head(pkt, &tmp8, 1);
85 if (tmp8 != CFSERL_STX) {
86 while (cfpkt_more(pkt)
87 && tmp8 != CFSERL_STX) {
88 cfpkt_extr_head(pkt, &tmp8, 1);
89 }
90 if (!cfpkt_more(pkt)) {
91 cfpkt_destroy(pkt);
92 layr->incomplete_frm = NULL;
93 spin_unlock(&layr->sync);
94 return -EPROTO;
95 }
96 }
97 }
98
99 pkt_len = cfpkt_getlen(pkt);
100
101 /*
102 * pkt_len is the accumulated length of the packet data
103 * we have received so far.
104 * Exit if frame doesn't hold length.
105 */
106
107 if (pkt_len < 2) {
108 if (layr->usestx)
109 cfpkt_add_head(pkt, &stx, 1);
110 layr->incomplete_frm = pkt;
111 spin_unlock(&layr->sync);
112 return 0;
113 }
114
115 /*
116 * Find length of frame.
117 * expectlen is the length we need for a full frame.
118 */
119 cfpkt_peek_head(pkt, &tmp, 2);
120 expectlen = le16_to_cpu(tmp) + 2;
121 /*
122 * Frame error handling
123 */
Sjur Braendeland2aa40ae2010-06-17 06:55:40 +0000124 if (expectlen < SERIAL_MINIUM_PACKET_SIZE
125 || expectlen > SERIAL_MAX_FRAMESIZE) {
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000126 if (!layr->usestx) {
127 if (pkt != NULL)
128 cfpkt_destroy(pkt);
129 layr->incomplete_frm = NULL;
130 expectlen = 0;
131 spin_unlock(&layr->sync);
132 return -EPROTO;
133 }
134 continue;
135 }
136
137 if (pkt_len < expectlen) {
138 /* Too little received data */
139 if (layr->usestx)
140 cfpkt_add_head(pkt, &stx, 1);
141 layr->incomplete_frm = pkt;
142 spin_unlock(&layr->sync);
143 return 0;
144 }
145
146 /*
147 * Enough data for at least one frame.
148 * Split the frame, if too long
149 */
150 if (pkt_len > expectlen)
151 tail_pkt = cfpkt_split(pkt, expectlen);
152 else
153 tail_pkt = NULL;
154
155 /* Send the first part of packet upwards.*/
156 spin_unlock(&layr->sync);
157 ret = layr->layer.up->receive(layr->layer.up, pkt);
158 spin_lock(&layr->sync);
159 if (ret == -EILSEQ) {
160 if (layr->usestx) {
161 if (tail_pkt != NULL)
162 pkt = cfpkt_append(pkt, tail_pkt, 0);
Sjur Braendelandb482cd22010-03-30 13:56:23 +0000163 /* Start search for next STX if frame failed */
164 continue;
165 } else {
166 cfpkt_destroy(pkt);
167 pkt = NULL;
168 }
169 }
170
171 pkt = tail_pkt;
172
173 } while (pkt != NULL);
174
175 spin_unlock(&layr->sync);
176 return 0;
177}
178
179static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
180{
181 struct cfserl *layr = container_obj(layer);
182 int ret;
183 u8 tmp8 = CFSERL_STX;
184 if (layr->usestx)
185 cfpkt_add_head(newpkt, &tmp8, 1);
186 ret = layer->dn->transmit(layer->dn, newpkt);
187 if (ret < 0)
188 cfpkt_extr_head(newpkt, &tmp8, 1);
189
190 return ret;
191}
192
193static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
194 int phyid)
195{
196 layr->up->ctrlcmd(layr->up, ctrl, phyid);
197}