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b482cd20 SB |
1 | /* |
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 | ||
7 | #include <linux/stddef.h> | |
8 | #include <linux/spinlock.h> | |
9 | #include <linux/slab.h> | |
10 | #include <net/caif/caif_layer.h> | |
11 | #include <net/caif/cfpkt.h> | |
12 | #include <net/caif/cfserl.h> | |
13 | ||
14 | #define container_obj(layr) ((struct cfserl *) layr) | |
15 | ||
16 | #define CFSERL_STX 0x02 | |
17 | #define CAIF_MINIUM_PACKET_SIZE 4 | |
18 | struct cfserl { | |
19 | struct cflayer layer; | |
20 | struct cfpkt *incomplete_frm; | |
21 | /* Protects parallel processing of incoming packets */ | |
22 | spinlock_t sync; | |
23 | bool usestx; | |
24 | }; | |
25 | #define STXLEN(layr) (layr->usestx ? 1 : 0) | |
26 | ||
27 | static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt); | |
28 | static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt); | |
29 | static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, | |
30 | int phyid); | |
31 | ||
32 | struct cflayer *cfserl_create(int type, int instance, bool use_stx) | |
33 | { | |
34 | struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC); | |
35 | if (!this) { | |
36 | pr_warning("CAIF: %s(): Out of memory\n", __func__); | |
37 | return NULL; | |
38 | } | |
39 | caif_assert(offsetof(struct cfserl, layer) == 0); | |
40 | memset(this, 0, sizeof(struct cfserl)); | |
41 | this->layer.receive = cfserl_receive; | |
42 | this->layer.transmit = cfserl_transmit; | |
43 | this->layer.ctrlcmd = cfserl_ctrlcmd; | |
44 | this->layer.type = type; | |
45 | this->usestx = use_stx; | |
46 | spin_lock_init(&this->sync); | |
47 | snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1"); | |
48 | return &this->layer; | |
49 | } | |
50 | ||
51 | static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt) | |
52 | { | |
53 | struct cfserl *layr = container_obj(l); | |
54 | u16 pkt_len; | |
55 | struct cfpkt *pkt = NULL; | |
56 | struct cfpkt *tail_pkt = NULL; | |
57 | u8 tmp8; | |
58 | u16 tmp; | |
59 | u8 stx = CFSERL_STX; | |
60 | int ret; | |
61 | u16 expectlen = 0; | |
97dc875f | 62 | |
b482cd20 SB |
63 | caif_assert(newpkt != NULL); |
64 | spin_lock(&layr->sync); | |
65 | ||
66 | if (layr->incomplete_frm != NULL) { | |
b482cd20 SB |
67 | layr->incomplete_frm = |
68 | cfpkt_append(layr->incomplete_frm, newpkt, expectlen); | |
69 | pkt = layr->incomplete_frm; | |
97dc875f DC |
70 | if (pkt == NULL) { |
71 | spin_unlock(&layr->sync); | |
638e628a | 72 | return -ENOMEM; |
97dc875f | 73 | } |
b482cd20 SB |
74 | } else { |
75 | pkt = newpkt; | |
76 | } | |
77 | layr->incomplete_frm = NULL; | |
78 | ||
79 | do { | |
80 | /* Search for STX at start of pkt if STX is used */ | |
81 | if (layr->usestx) { | |
82 | cfpkt_extr_head(pkt, &tmp8, 1); | |
83 | if (tmp8 != CFSERL_STX) { | |
84 | while (cfpkt_more(pkt) | |
85 | && tmp8 != CFSERL_STX) { | |
86 | cfpkt_extr_head(pkt, &tmp8, 1); | |
87 | } | |
88 | if (!cfpkt_more(pkt)) { | |
89 | cfpkt_destroy(pkt); | |
90 | layr->incomplete_frm = NULL; | |
91 | spin_unlock(&layr->sync); | |
92 | return -EPROTO; | |
93 | } | |
94 | } | |
95 | } | |
96 | ||
97 | pkt_len = cfpkt_getlen(pkt); | |
98 | ||
99 | /* | |
100 | * pkt_len is the accumulated length of the packet data | |
101 | * we have received so far. | |
102 | * Exit if frame doesn't hold length. | |
103 | */ | |
104 | ||
105 | if (pkt_len < 2) { | |
106 | if (layr->usestx) | |
107 | cfpkt_add_head(pkt, &stx, 1); | |
108 | layr->incomplete_frm = pkt; | |
109 | spin_unlock(&layr->sync); | |
110 | return 0; | |
111 | } | |
112 | ||
113 | /* | |
114 | * Find length of frame. | |
115 | * expectlen is the length we need for a full frame. | |
116 | */ | |
117 | cfpkt_peek_head(pkt, &tmp, 2); | |
118 | expectlen = le16_to_cpu(tmp) + 2; | |
119 | /* | |
120 | * Frame error handling | |
121 | */ | |
122 | if (expectlen < CAIF_MINIUM_PACKET_SIZE | |
123 | || expectlen > CAIF_MAX_FRAMESIZE) { | |
124 | if (!layr->usestx) { | |
125 | if (pkt != NULL) | |
126 | cfpkt_destroy(pkt); | |
127 | layr->incomplete_frm = NULL; | |
128 | expectlen = 0; | |
129 | spin_unlock(&layr->sync); | |
130 | return -EPROTO; | |
131 | } | |
132 | continue; | |
133 | } | |
134 | ||
135 | if (pkt_len < expectlen) { | |
136 | /* Too little received data */ | |
137 | if (layr->usestx) | |
138 | cfpkt_add_head(pkt, &stx, 1); | |
139 | layr->incomplete_frm = pkt; | |
140 | spin_unlock(&layr->sync); | |
141 | return 0; | |
142 | } | |
143 | ||
144 | /* | |
145 | * Enough data for at least one frame. | |
146 | * Split the frame, if too long | |
147 | */ | |
148 | if (pkt_len > expectlen) | |
149 | tail_pkt = cfpkt_split(pkt, expectlen); | |
150 | else | |
151 | tail_pkt = NULL; | |
152 | ||
153 | /* Send the first part of packet upwards.*/ | |
154 | spin_unlock(&layr->sync); | |
155 | ret = layr->layer.up->receive(layr->layer.up, pkt); | |
156 | spin_lock(&layr->sync); | |
157 | if (ret == -EILSEQ) { | |
158 | if (layr->usestx) { | |
159 | if (tail_pkt != NULL) | |
160 | pkt = cfpkt_append(pkt, tail_pkt, 0); | |
b482cd20 SB |
161 | /* Start search for next STX if frame failed */ |
162 | continue; | |
163 | } else { | |
164 | cfpkt_destroy(pkt); | |
165 | pkt = NULL; | |
166 | } | |
167 | } | |
168 | ||
169 | pkt = tail_pkt; | |
170 | ||
171 | } while (pkt != NULL); | |
172 | ||
173 | spin_unlock(&layr->sync); | |
174 | return 0; | |
175 | } | |
176 | ||
177 | static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt) | |
178 | { | |
179 | struct cfserl *layr = container_obj(layer); | |
180 | int ret; | |
181 | u8 tmp8 = CFSERL_STX; | |
182 | if (layr->usestx) | |
183 | cfpkt_add_head(newpkt, &tmp8, 1); | |
184 | ret = layer->dn->transmit(layer->dn, newpkt); | |
185 | if (ret < 0) | |
186 | cfpkt_extr_head(newpkt, &tmp8, 1); | |
187 | ||
188 | return ret; | |
189 | } | |
190 | ||
191 | static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, | |
192 | int phyid) | |
193 | { | |
194 | layr->up->ctrlcmd(layr->up, ctrl, phyid); | |
195 | } |