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 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ 10 11 #include <linux/stddef.h> 12 #include <linux/spinlock.h> 13 #include <linux/slab.h> 14 #include <linux/crc-ccitt.h> 15 #include <linux/netdevice.h> 16 #include <net/caif/caif_layer.h> 17 #include <net/caif/cfpkt.h> 18 #include <net/caif/cffrml.h> 19 20 #define container_obj(layr) container_of(layr, struct cffrml, layer) 21 22 struct cffrml { 23 struct cflayer layer; 24 bool dofcs; /* !< FCS active */ 25 int __percpu *pcpu_refcnt; 26 }; 27 28 static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); 29 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); 30 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 31 int phyid); 32 33 static u32 cffrml_rcv_error; 34 static u32 cffrml_rcv_checsum_error; 35 struct cflayer *cffrml_create(u16 phyid, bool use_fcs) 36 { 37 struct cffrml *this = kzalloc(sizeof(struct cffrml), GFP_ATOMIC); 38 if (!this) 39 return NULL; 40 this->pcpu_refcnt = alloc_percpu(int); 41 if (this->pcpu_refcnt == NULL) { 42 kfree(this); 43 return NULL; 44 } 45 46 caif_assert(offsetof(struct cffrml, layer) == 0); 47 48 this->layer.receive = cffrml_receive; 49 this->layer.transmit = cffrml_transmit; 50 this->layer.ctrlcmd = cffrml_ctrlcmd; 51 snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid); 52 this->dofcs = use_fcs; 53 this->layer.id = phyid; 54 return (struct cflayer *) this; 55 } 56 57 void cffrml_free(struct cflayer *layer) 58 { 59 struct cffrml *this = container_obj(layer); 60 free_percpu(this->pcpu_refcnt); 61 kfree(layer); 62 } 63 64 void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) 65 { 66 this->up = up; 67 } 68 69 void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) 70 { 71 this->dn = dn; 72 } 73 74 static u16 cffrml_checksum(u16 chks, void *buf, u16 len) 75 { 76 /* FIXME: FCS should be moved to glue in order to use OS-Specific 77 * solutions 78 */ 79 return crc_ccitt(chks, buf, len); 80 } 81 82 static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) 83 { 84 u16 tmp; 85 u16 len; 86 u16 hdrchks; 87 u16 pktchks; 88 struct cffrml *this; 89 this = container_obj(layr); 90 91 cfpkt_extr_head(pkt, &tmp, 2); 92 len = le16_to_cpu(tmp); 93 94 /* Subtract for FCS on length if FCS is not used. */ 95 if (!this->dofcs) 96 len -= 2; 97 98 if (cfpkt_setlen(pkt, len) < 0) { 99 ++cffrml_rcv_error; 100 pr_err("Framing length error (%d)\n", len); 101 cfpkt_destroy(pkt); 102 return -EPROTO; 103 } 104 /* 105 * Don't do extract if FCS is false, rather do setlen - then we don't 106 * get a cache-miss. 107 */ 108 if (this->dofcs) { 109 cfpkt_extr_trail(pkt, &tmp, 2); 110 hdrchks = le16_to_cpu(tmp); 111 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 112 if (pktchks != hdrchks) { 113 cfpkt_add_trail(pkt, &tmp, 2); 114 ++cffrml_rcv_error; 115 ++cffrml_rcv_checsum_error; 116 pr_info("Frame checksum error (0x%x != 0x%x)\n", 117 hdrchks, pktchks); 118 return -EILSEQ; 119 } 120 } 121 if (cfpkt_erroneous(pkt)) { 122 ++cffrml_rcv_error; 123 pr_err("Packet is erroneous!\n"); 124 cfpkt_destroy(pkt); 125 return -EPROTO; 126 } 127 128 if (layr->up == NULL) { 129 pr_err("Layr up is missing!\n"); 130 cfpkt_destroy(pkt); 131 return -EINVAL; 132 } 133 134 return layr->up->receive(layr->up, pkt); 135 } 136 137 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) 138 { 139 int tmp; 140 u16 chks; 141 u16 len; 142 struct cffrml *this = container_obj(layr); 143 if (this->dofcs) { 144 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 145 tmp = cpu_to_le16(chks); 146 cfpkt_add_trail(pkt, &tmp, 2); 147 } else { 148 cfpkt_pad_trail(pkt, 2); 149 } 150 len = cfpkt_getlen(pkt); 151 tmp = cpu_to_le16(len); 152 cfpkt_add_head(pkt, &tmp, 2); 153 cfpkt_info(pkt)->hdr_len += 2; 154 if (cfpkt_erroneous(pkt)) { 155 pr_err("Packet is erroneous!\n"); 156 cfpkt_destroy(pkt); 157 return -EPROTO; 158 } 159 160 if (layr->dn == NULL) { 161 cfpkt_destroy(pkt); 162 return -ENODEV; 163 164 } 165 return layr->dn->transmit(layr->dn, pkt); 166 } 167 168 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 169 int phyid) 170 { 171 if (layr->up && layr->up->ctrlcmd) 172 layr->up->ctrlcmd(layr->up, ctrl, layr->id); 173 } 174 175 void cffrml_put(struct cflayer *layr) 176 { 177 struct cffrml *this = container_obj(layr); 178 if (layr != NULL && this->pcpu_refcnt != NULL) 179 irqsafe_cpu_dec(*this->pcpu_refcnt); 180 } 181 182 void cffrml_hold(struct cflayer *layr) 183 { 184 struct cffrml *this = container_obj(layr); 185 if (layr != NULL && this->pcpu_refcnt != NULL) 186 irqsafe_cpu_inc(*this->pcpu_refcnt); 187 } 188 189 int cffrml_refcnt_read(struct cflayer *layr) 190 { 191 int i, refcnt = 0; 192 struct cffrml *this = container_obj(layr); 193 for_each_possible_cpu(i) 194 refcnt += *per_cpu_ptr(this->pcpu_refcnt, i); 195 return refcnt; 196 } 197