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 19struct cffrml { 20 struct cflayer layer; 21 bool dofcs; /* !< FCS active */ 22}; 23 24static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); 25static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); 26static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 27 int phyid); 28 29static u32 cffrml_rcv_error; 30static u32 cffrml_rcv_checsum_error; 31struct 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 50void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) 51{ 52 this->up = up; 53} 54 55void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) 56{ 57 this->dn = dn; 58} 59 60static u16 cffrml_checksum(u16 chks, void *buf, u16 len) 61{ 62 return crc_ccitt(chks, buf, len); 63} 64 65static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) 66{ 67 u16 tmp; 68 u16 len; 69 u16 hdrchks; 70 u16 pktchks; 71 struct cffrml *this; 72 this = container_obj(layr); 73 74 cfpkt_extr_head(pkt, &tmp, 2); 75 len = le16_to_cpu(tmp); 76 77 /* Subtract for FCS on length if FCS is not used. */ 78 if (!this->dofcs) 79 len -= 2; 80 81 if (cfpkt_setlen(pkt, len) < 0) { 82 ++cffrml_rcv_error; 83 pr_err("CAIF: %s():Framing length error (%d)\n", __func__, len); 84 cfpkt_destroy(pkt); 85 return -EPROTO; 86 } 87 /* 88 * Don't do extract if FCS is false, rather do setlen - then we don't 89 * get a cache-miss. 90 */ 91 if (this->dofcs) { 92 cfpkt_extr_trail(pkt, &tmp, 2); 93 hdrchks = le16_to_cpu(tmp); 94 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 95 if (pktchks != hdrchks) { 96 cfpkt_add_trail(pkt, &tmp, 2); 97 ++cffrml_rcv_error; 98 ++cffrml_rcv_checsum_error; 99 pr_info("CAIF: %s(): Frame checksum error " 100 "(0x%x != 0x%x)\n", __func__, hdrchks, pktchks); 101 return -EILSEQ; 102 } 103 } 104 if (cfpkt_erroneous(pkt)) { 105 ++cffrml_rcv_error; 106 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); 107 cfpkt_destroy(pkt); 108 return -EPROTO; 109 } 110 return layr->up->receive(layr->up, pkt); 111} 112 113static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) 114{ 115 int tmp; 116 u16 chks; 117 u16 len; 118 int ret; 119 struct cffrml *this = container_obj(layr); 120 if (this->dofcs) { 121 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 122 tmp = cpu_to_le16(chks); 123 cfpkt_add_trail(pkt, &tmp, 2); 124 } else { 125 cfpkt_pad_trail(pkt, 2); 126 } 127 len = cfpkt_getlen(pkt); 128 tmp = cpu_to_le16(len); 129 cfpkt_add_head(pkt, &tmp, 2); 130 cfpkt_info(pkt)->hdr_len += 2; 131 if (cfpkt_erroneous(pkt)) { 132 pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); 133 return -EPROTO; 134 } 135 ret = layr->dn->transmit(layr->dn, pkt); 136 if (ret < 0) { 137 /* Remove header on faulty packet. */ 138 cfpkt_extr_head(pkt, &tmp, 2); 139 } 140 return ret; 141} 142 143static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 144 int phyid) 145{ 146 if (layr->up->ctrlcmd) 147 layr->up->ctrlcmd(layr->up, ctrl, layr->id); 148} 149