|
| 1 | +/* |
| 2 | + * CAIF Framing Layer. |
| 3 | + * |
| 4 | + * Copyright (C) ST-Ericsson AB 2010 |
| 5 | + * Author: Sjur Brendeland/[email protected] |
| 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 | +} |
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