Sjur Braendeland | b482cd2 | 2010-03-30 13:56:23 +0000 | [diff] [blame] | 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; |
| 62 | caif_assert(newpkt != NULL); |
| 63 | spin_lock(&layr->sync); |
| 64 | |
| 65 | if (layr->incomplete_frm != NULL) { |
| 66 | |
| 67 | layr->incomplete_frm = |
| 68 | cfpkt_append(layr->incomplete_frm, newpkt, expectlen); |
| 69 | pkt = layr->incomplete_frm; |
Sjur Braendeland | 638e628 | 2010-05-21 02:16:09 +0000 | [diff] [blame^] | 70 | if (pkt == NULL) |
| 71 | return -ENOMEM; |
Sjur Braendeland | b482cd2 | 2010-03-30 13:56:23 +0000 | [diff] [blame] | 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 | */ |
| 120 | if (expectlen < CAIF_MINIUM_PACKET_SIZE |
| 121 | || expectlen > CAIF_MAX_FRAMESIZE) { |
| 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); |
Sjur Braendeland | b482cd2 | 2010-03-30 13:56:23 +0000 | [diff] [blame] | 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); |
| 178 | int ret; |
| 179 | u8 tmp8 = CFSERL_STX; |
| 180 | if (layr->usestx) |
| 181 | cfpkt_add_head(newpkt, &tmp8, 1); |
| 182 | ret = layer->dn->transmit(layer->dn, newpkt); |
| 183 | if (ret < 0) |
| 184 | cfpkt_extr_head(newpkt, &tmp8, 1); |
| 185 | |
| 186 | return ret; |
| 187 | } |
| 188 | |
| 189 | static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, |
| 190 | int phyid) |
| 191 | { |
| 192 | layr->up->ctrlcmd(layr->up, ctrl, phyid); |
| 193 | } |