1 /* 2 * CAIF Framing Layer. 3 * 4 * Copyright (C) ST-Ericsson AB 2010 5 * Author: Sjur Brendeland/sjur.brandeland@stericsson.com 6 * License terms: GNU General Public License (GPL) version 2 7 */ 8 9 #include <linux/stddef.h> 10 #include <linux/spinlock.h> 11 #include <linux/slab.h> 12 #include <linux/crc-ccitt.h> 13 #include <net/caif/caif_layer.h> 14 #include <net/caif/cfpkt.h> 15 #include <net/caif/cffrml.h> 16 17 #define container_obj(layr) container_of(layr, struct cffrml, layer) 18 19 struct cffrml { 20 struct cflayer layer; 21 bool dofcs; /* !< FCS active */ 22 }; 23 24 static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); 25 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); 26 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 27 int phyid); 28 29 static u32 cffrml_rcv_error; 30 static u32 cffrml_rcv_checsum_error; 31 struct cflayer *cffrml_create(u16 phyid, bool use_fcs) 32 { 33 struct cffrml *this = kmalloc(sizeof(struct cffrml), GFP_ATOMIC); 34 if (!this) { 35 pr_warning("CAIF: %s(): Out of memory\n", __func__); 36 return NULL; 37 } 38 caif_assert(offsetof(struct cffrml, layer) == 0); 39 40 memset(this, 0, sizeof(struct cflayer)); 41 this->layer.receive = cffrml_receive; 42 this->layer.transmit = cffrml_transmit; 43 this->layer.ctrlcmd = cffrml_ctrlcmd; 44 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid); 45 this->dofcs = use_fcs; 46 this->layer.id = phyid; 47 return (struct cflayer *) this; 48 } 49 50 void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) 51 { 52 this->up = up; 53 } 54 55 void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) 56 { 57 this->dn = dn; 58 } 59 60 static u16 cffrml_checksum(u16 chks, void *buf, u16 len) 61 { 62 /* FIXME: FCS should be moved to glue in order to use OS-Specific 63 * solutions 64 */ 65 return crc_ccitt(chks, buf, len); 66 } 67 68 static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) 69 { 70 u16 tmp; 71 u16 len; 72 u16 hdrchks; 73 u16 pktchks; 74 struct cffrml *this; 75 this = container_obj(layr); 76 77 cfpkt_extr_head(pkt, &tmp, 2); 78 len = le16_to_cpu(tmp); 79 80 /* Subtract for FCS on length if FCS is not used. */ 81 if (!this->dofcs) 82 len -= 2; 83 84 if (cfpkt_setlen(pkt, len) < 0) { 85 ++cffrml_rcv_error; 86 pr_err("CAIF: %s():Framing length error (%d)\n", __func__, len); 87 cfpkt_destroy(pkt); 88 return -EPROTO; 89 } 90 /* 91 * Don't do extract if FCS is false, rather do setlen - then we don't 92 * get a cache-miss. 93 */ 94 if (this->dofcs) { 95 cfpkt_extr_trail(pkt, &tmp, 2); 96 hdrchks = le16_to_cpu(tmp); 97 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 98 if (pktchks != hdrchks) { 99 cfpkt_add_trail(pkt, &tmp, 2); 100 ++cffrml_rcv_error; 101 ++cffrml_rcv_checsum_error; 102 pr_info("CAIF: %s(): Frame checksum error " 103 "(0x%x != 0x%x)\n", __func__, hdrchks, pktchks); 104 return -EILSEQ; 105 } 106 } 107 if (cfpkt_erroneous(pkt)) { 108 ++cffrml_rcv_error; 109 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); 110 cfpkt_destroy(pkt); 111 return -EPROTO; 112 } 113 return layr->up->receive(layr->up, pkt); 114 } 115 116 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) 117 { 118 int tmp; 119 u16 chks; 120 u16 len; 121 int ret; 122 struct cffrml *this = container_obj(layr); 123 if (this->dofcs) { 124 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 125 tmp = cpu_to_le16(chks); 126 cfpkt_add_trail(pkt, &tmp, 2); 127 } else { 128 cfpkt_pad_trail(pkt, 2); 129 } 130 len = cfpkt_getlen(pkt); 131 tmp = cpu_to_le16(len); 132 cfpkt_add_head(pkt, &tmp, 2); 133 cfpkt_info(pkt)->hdr_len += 2; 134 if (cfpkt_erroneous(pkt)) { 135 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); 136 return -EPROTO; 137 } 138 ret = layr->dn->transmit(layr->dn, pkt); 139 if (ret < 0) { 140 /* Remove header on faulty packet. */ 141 cfpkt_extr_head(pkt, &tmp, 2); 142 } 143 return ret; 144 } 145 146 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 147 int phyid) 148 { 149 if (layr->up->ctrlcmd) 150 layr->up->ctrlcmd(layr->up, ctrl, layr->id); 151 } 152