1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * CAIF Framing Layer. 4 * 5 * Copyright (C) ST-Ericsson AB 2010 6 * Author: Sjur Brendeland 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 int 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 if (len < 2) { 97 ++cffrml_rcv_error; 98 pr_err("Invalid frame length (%d)\n", len); 99 cfpkt_destroy(pkt); 100 return -EPROTO; 101 } 102 len -= 2; 103 } 104 105 if (cfpkt_setlen(pkt, len) < 0) { 106 ++cffrml_rcv_error; 107 pr_err("Framing length error (%d)\n", len); 108 cfpkt_destroy(pkt); 109 return -EPROTO; 110 } 111 /* 112 * Don't do extract if FCS is false, rather do setlen - then we don't 113 * get a cache-miss. 114 */ 115 if (this->dofcs) { 116 cfpkt_extr_trail(pkt, &tmp, 2); 117 hdrchks = le16_to_cpu(tmp); 118 pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 119 if (pktchks != hdrchks) { 120 cfpkt_add_trail(pkt, &tmp, 2); 121 ++cffrml_rcv_error; 122 ++cffrml_rcv_checsum_error; 123 pr_info("Frame checksum error (0x%x != 0x%x)\n", 124 hdrchks, pktchks); 125 return -EILSEQ; 126 } 127 } 128 if (cfpkt_erroneous(pkt)) { 129 ++cffrml_rcv_error; 130 pr_err("Packet is erroneous!\n"); 131 cfpkt_destroy(pkt); 132 return -EPROTO; 133 } 134 135 if (layr->up == NULL) { 136 pr_err("Layr up is missing!\n"); 137 cfpkt_destroy(pkt); 138 return -EINVAL; 139 } 140 141 return layr->up->receive(layr->up, pkt); 142 } 143 144 static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) 145 { 146 u16 chks; 147 u16 len; 148 __le16 data; 149 150 struct cffrml *this = container_obj(layr); 151 if (this->dofcs) { 152 chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); 153 data = cpu_to_le16(chks); 154 cfpkt_add_trail(pkt, &data, 2); 155 } else { 156 cfpkt_pad_trail(pkt, 2); 157 } 158 len = cfpkt_getlen(pkt); 159 data = cpu_to_le16(len); 160 cfpkt_add_head(pkt, &data, 2); 161 cfpkt_info(pkt)->hdr_len += 2; 162 if (cfpkt_erroneous(pkt)) { 163 pr_err("Packet is erroneous!\n"); 164 cfpkt_destroy(pkt); 165 return -EPROTO; 166 } 167 168 if (layr->dn == NULL) { 169 cfpkt_destroy(pkt); 170 return -ENODEV; 171 172 } 173 return layr->dn->transmit(layr->dn, pkt); 174 } 175 176 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, 177 int phyid) 178 { 179 if (layr->up && layr->up->ctrlcmd) 180 layr->up->ctrlcmd(layr->up, ctrl, layr->id); 181 } 182 183 void cffrml_put(struct cflayer *layr) 184 { 185 struct cffrml *this = container_obj(layr); 186 if (layr != NULL && this->pcpu_refcnt != NULL) 187 this_cpu_dec(*this->pcpu_refcnt); 188 } 189 190 void cffrml_hold(struct cflayer *layr) 191 { 192 struct cffrml *this = container_obj(layr); 193 if (layr != NULL && this->pcpu_refcnt != NULL) 194 this_cpu_inc(*this->pcpu_refcnt); 195 } 196 197 int cffrml_refcnt_read(struct cflayer *layr) 198 { 199 int i, refcnt = 0; 200 struct cffrml *this = container_obj(layr); 201 for_each_possible_cpu(i) 202 refcnt += *per_cpu_ptr(this->pcpu_refcnt, i); 203 return refcnt; 204 } 205