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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 | ||
b31fa5ba JP |
7 | #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ |
8 | ||
b482cd20 SB |
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> | |
15 | ||
16 | #define container_obj(layr) ((struct cfserl *) layr) | |
17 | ||
18 | #define CFSERL_STX 0x02 | |
2aa40aef SB |
19 | #define SERIAL_MINIUM_PACKET_SIZE 4 |
20 | #define SERIAL_MAX_FRAMESIZE 4096 | |
b482cd20 SB |
21 | struct 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 | }; | |
b482cd20 SB |
28 | |
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, | |
32 | int phyid); | |
33 | ||
e977b4cf | 34 | struct cflayer *cfserl_create(int instance, bool use_stx) |
b482cd20 | 35 | { |
7ac2ed0c JP |
36 | struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC); |
37 | if (!this) | |
b482cd20 | 38 | return NULL; |
b482cd20 | 39 | caif_assert(offsetof(struct cfserl, layer) == 0); |
b482cd20 SB |
40 | this->layer.receive = cfserl_receive; |
41 | this->layer.transmit = cfserl_transmit; | |
42 | this->layer.ctrlcmd = cfserl_ctrlcmd; | |
b482cd20 SB |
43 | this->usestx = use_stx; |
44 | spin_lock_init(&this->sync); | |
45 | snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1"); | |
46 | return &this->layer; | |
47 | } | |
48 | ||
49 | static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt) | |
50 | { | |
51 | struct cfserl *layr = container_obj(l); | |
52 | u16 pkt_len; | |
53 | struct cfpkt *pkt = NULL; | |
54 | struct cfpkt *tail_pkt = NULL; | |
55 | u8 tmp8; | |
56 | u16 tmp; | |
57 | u8 stx = CFSERL_STX; | |
58 | int ret; | |
59 | u16 expectlen = 0; | |
97dc875f | 60 | |
b482cd20 SB |
61 | caif_assert(newpkt != NULL); |
62 | spin_lock(&layr->sync); | |
63 | ||
64 | if (layr->incomplete_frm != NULL) { | |
b482cd20 SB |
65 | layr->incomplete_frm = |
66 | cfpkt_append(layr->incomplete_frm, newpkt, expectlen); | |
67 | pkt = layr->incomplete_frm; | |
97dc875f DC |
68 | if (pkt == NULL) { |
69 | spin_unlock(&layr->sync); | |
638e628a | 70 | return -ENOMEM; |
97dc875f | 71 | } |
b482cd20 SB |
72 | } else { |
73 | pkt = newpkt; | |
74 | } | |
75 | layr->incomplete_frm = NULL; | |
76 | ||
77 | do { | |
78 | /* Search for STX at start of pkt if STX is used */ | |
79 | if (layr->usestx) { | |
80 | cfpkt_extr_head(pkt, &tmp8, 1); | |
81 | if (tmp8 != CFSERL_STX) { | |
82 | while (cfpkt_more(pkt) | |
83 | && tmp8 != CFSERL_STX) { | |
84 | cfpkt_extr_head(pkt, &tmp8, 1); | |
85 | } | |
86 | if (!cfpkt_more(pkt)) { | |
87 | cfpkt_destroy(pkt); | |
88 | layr->incomplete_frm = NULL; | |
89 | spin_unlock(&layr->sync); | |
90 | return -EPROTO; | |
91 | } | |
92 | } | |
93 | } | |
94 | ||
95 | pkt_len = cfpkt_getlen(pkt); | |
96 | ||
97 | /* | |
98 | * pkt_len is the accumulated length of the packet data | |
99 | * we have received so far. | |
100 | * Exit if frame doesn't hold length. | |
101 | */ | |
102 | ||
103 | if (pkt_len < 2) { | |
104 | if (layr->usestx) | |
105 | cfpkt_add_head(pkt, &stx, 1); | |
106 | layr->incomplete_frm = pkt; | |
107 | spin_unlock(&layr->sync); | |
108 | return 0; | |
109 | } | |
110 | ||
111 | /* | |
112 | * Find length of frame. | |
113 | * expectlen is the length we need for a full frame. | |
114 | */ | |
115 | cfpkt_peek_head(pkt, &tmp, 2); | |
116 | expectlen = le16_to_cpu(tmp) + 2; | |
117 | /* | |
118 | * Frame error handling | |
119 | */ | |
2aa40aef SB |
120 | if (expectlen < SERIAL_MINIUM_PACKET_SIZE |
121 | || expectlen > SERIAL_MAX_FRAMESIZE) { | |
b482cd20 SB |
122 | if (!layr->usestx) { |
123 | if (pkt != NULL) | |
124 | cfpkt_destroy(pkt); | |
125 | layr->incomplete_frm = NULL; | |
126 | expectlen = 0; | |
127 | spin_unlock(&layr->sync); | |
128 | return -EPROTO; | |
129 | } | |
130 | continue; | |
131 | } | |
132 | ||
133 | if (pkt_len < expectlen) { | |
134 | /* Too little received data */ | |
135 | if (layr->usestx) | |
136 | cfpkt_add_head(pkt, &stx, 1); | |
137 | layr->incomplete_frm = pkt; | |
138 | spin_unlock(&layr->sync); | |
139 | return 0; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Enough data for at least one frame. | |
144 | * Split the frame, if too long | |
145 | */ | |
146 | if (pkt_len > expectlen) | |
147 | tail_pkt = cfpkt_split(pkt, expectlen); | |
148 | else | |
149 | tail_pkt = NULL; | |
150 | ||
151 | /* Send the first part of packet upwards.*/ | |
152 | spin_unlock(&layr->sync); | |
153 | ret = layr->layer.up->receive(layr->layer.up, pkt); | |
154 | spin_lock(&layr->sync); | |
155 | if (ret == -EILSEQ) { | |
156 | if (layr->usestx) { | |
157 | if (tail_pkt != NULL) | |
158 | pkt = cfpkt_append(pkt, tail_pkt, 0); | |
b482cd20 SB |
159 | /* Start search for next STX if frame failed */ |
160 | continue; | |
161 | } else { | |
162 | cfpkt_destroy(pkt); | |
163 | pkt = NULL; | |
164 | } | |
165 | } | |
166 | ||
167 | pkt = tail_pkt; | |
168 | ||
169 | } while (pkt != NULL); | |
170 | ||
171 | spin_unlock(&layr->sync); | |
172 | return 0; | |
173 | } | |
174 | ||
175 | static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt) | |
176 | { | |
177 | struct cfserl *layr = container_obj(layer); | |
b482cd20 SB |
178 | u8 tmp8 = CFSERL_STX; |
179 | if (layr->usestx) | |
180 | cfpkt_add_head(newpkt, &tmp8, 1); | |
4dd820c0 | 181 | return layer->dn->transmit(layer->dn, newpkt); |
b482cd20 SB |
182 | } |
183 | ||
184 | static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, | |
185 | int phyid) | |
186 | { | |
187 | layr->up->ctrlcmd(layr->up, ctrl, phyid); | |
188 | } |