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; 70 } else { 71 pkt = newpkt; 72 } 73 layr->incomplete_frm = NULL; 74 75 do { 76 /* Search for STX at start of pkt if STX is used */ 77 if (layr->usestx) { 78 cfpkt_extr_head(pkt, &tmp8, 1); 79 if (tmp8 != CFSERL_STX) { 80 while (cfpkt_more(pkt) 81 && tmp8 != CFSERL_STX) { 82 cfpkt_extr_head(pkt, &tmp8, 1); 83 } 84 if (!cfpkt_more(pkt)) { 85 cfpkt_destroy(pkt); 86 layr->incomplete_frm = NULL; 87 spin_unlock(&layr->sync); 88 return -EPROTO; 89 } 90 } 91 } 92 93 pkt_len = cfpkt_getlen(pkt); 94 95 /* 96 * pkt_len is the accumulated length of the packet data 97 * we have received so far. 98 * Exit if frame doesn't hold length. 99 */ 100 101 if (pkt_len < 2) { 102 if (layr->usestx) 103 cfpkt_add_head(pkt, &stx, 1); 104 layr->incomplete_frm = pkt; 105 spin_unlock(&layr->sync); 106 return 0; 107 } 108 109 /* 110 * Find length of frame. 111 * expectlen is the length we need for a full frame. 112 */ 113 cfpkt_peek_head(pkt, &tmp, 2); 114 expectlen = le16_to_cpu(tmp) + 2; 115 /* 116 * Frame error handling 117 */ 118 if (expectlen < CAIF_MINIUM_PACKET_SIZE 119 || expectlen > CAIF_MAX_FRAMESIZE) { 120 if (!layr->usestx) { 121 if (pkt != NULL) 122 cfpkt_destroy(pkt); 123 layr->incomplete_frm = NULL; 124 expectlen = 0; 125 spin_unlock(&layr->sync); 126 return -EPROTO; 127 } 128 continue; 129 } 130 131 if (pkt_len < expectlen) { 132 /* Too little received data */ 133 if (layr->usestx) 134 cfpkt_add_head(pkt, &stx, 1); 135 layr->incomplete_frm = pkt; 136 spin_unlock(&layr->sync); 137 return 0; 138 } 139 140 /* 141 * Enough data for at least one frame. 142 * Split the frame, if too long 143 */ 144 if (pkt_len > expectlen) 145 tail_pkt = cfpkt_split(pkt, expectlen); 146 else 147 tail_pkt = NULL; 148 149 /* Send the first part of packet upwards.*/ 150 spin_unlock(&layr->sync); 151 ret = layr->layer.up->receive(layr->layer.up, pkt); 152 spin_lock(&layr->sync); 153 if (ret == -EILSEQ) { 154 if (layr->usestx) { 155 if (tail_pkt != NULL) 156 pkt = cfpkt_append(pkt, tail_pkt, 0); 157 158 /* Start search for next STX if frame failed */ 159 continue; 160 } else { 161 cfpkt_destroy(pkt); 162 pkt = NULL; 163 } 164 } 165 166 pkt = tail_pkt; 167 168 } while (pkt != NULL); 169 170 spin_unlock(&layr->sync); 171 return 0; 172 } 173 174 static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt) 175 { 176 struct cfserl *layr = container_obj(layer); 177 int ret; 178 u8 tmp8 = CFSERL_STX; 179 if (layr->usestx) 180 cfpkt_add_head(newpkt, &tmp8, 1); 181 ret = layer->dn->transmit(layer->dn, newpkt); 182 if (ret < 0) 183 cfpkt_extr_head(newpkt, &tmp8, 1); 184 185 return ret; 186 } 187 188 static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 189 int phyid) 190 { 191 layr->up->ctrlcmd(layr->up, ctrl, phyid); 192 } 193