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
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
9 #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>
16 #define container_obj(layr) ((struct cfserl *) layr)
18 #define CFSERL_STX 0x02
19 #define SERIAL_MINIUM_PACKET_SIZE 4
20 #define SERIAL_MAX_FRAMESIZE 4096
23 struct cfpkt *incomplete_frm;
24 /* Protects parallel processing of incoming packets */
29 static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt);
30 static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
31 static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
34 struct cflayer *cfserl_create(int type, int instance, bool use_stx)
36 struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC);
39 caif_assert(offsetof(struct cfserl, layer) == 0);
40 this->layer.receive = cfserl_receive;
41 this->layer.transmit = cfserl_transmit;
42 this->layer.ctrlcmd = cfserl_ctrlcmd;
43 this->layer.type = type;
44 this->usestx = use_stx;
45 spin_lock_init(&this->sync);
46 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
50 static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
52 struct cfserl *layr = container_obj(l);
54 struct cfpkt *pkt = NULL;
55 struct cfpkt *tail_pkt = NULL;
62 caif_assert(newpkt != NULL);
63 spin_lock(&layr->sync);
65 if (layr->incomplete_frm != NULL) {
66 layr->incomplete_frm =
67 cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
68 pkt = layr->incomplete_frm;
70 spin_unlock(&layr->sync);
76 layr->incomplete_frm = NULL;
79 /* Search for STX at start of pkt if STX is used */
81 cfpkt_extr_head(pkt, &tmp8, 1);
82 if (tmp8 != CFSERL_STX) {
83 while (cfpkt_more(pkt)
84 && tmp8 != CFSERL_STX) {
85 cfpkt_extr_head(pkt, &tmp8, 1);
87 if (!cfpkt_more(pkt)) {
89 layr->incomplete_frm = NULL;
90 spin_unlock(&layr->sync);
96 pkt_len = cfpkt_getlen(pkt);
99 * pkt_len is the accumulated length of the packet data
100 * we have received so far.
101 * Exit if frame doesn't hold length.
106 cfpkt_add_head(pkt, &stx, 1);
107 layr->incomplete_frm = pkt;
108 spin_unlock(&layr->sync);
113 * Find length of frame.
114 * expectlen is the length we need for a full frame.
116 cfpkt_peek_head(pkt, &tmp, 2);
117 expectlen = le16_to_cpu(tmp) + 2;
119 * Frame error handling
121 if (expectlen < SERIAL_MINIUM_PACKET_SIZE
122 || expectlen > SERIAL_MAX_FRAMESIZE) {
126 layr->incomplete_frm = NULL;
128 spin_unlock(&layr->sync);
134 if (pkt_len < expectlen) {
135 /* Too little received data */
137 cfpkt_add_head(pkt, &stx, 1);
138 layr->incomplete_frm = pkt;
139 spin_unlock(&layr->sync);
144 * Enough data for at least one frame.
145 * Split the frame, if too long
147 if (pkt_len > expectlen)
148 tail_pkt = cfpkt_split(pkt, expectlen);
152 /* Send the first part of packet upwards.*/
153 spin_unlock(&layr->sync);
154 ret = layr->layer.up->receive(layr->layer.up, pkt);
155 spin_lock(&layr->sync);
156 if (ret == -EILSEQ) {
158 if (tail_pkt != NULL)
159 pkt = cfpkt_append(pkt, tail_pkt, 0);
160 /* Start search for next STX if frame failed */
170 } while (pkt != NULL);
172 spin_unlock(&layr->sync);
176 static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
178 struct cfserl *layr = container_obj(layer);
179 u8 tmp8 = CFSERL_STX;
181 cfpkt_add_head(newpkt, &tmp8, 1);
182 return layer->dn->transmit(layer->dn, newpkt);
185 static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
188 layr->up->ctrlcmd(layr->up, ctrl, phyid);