diff options
Diffstat (limited to 'net/caif/cffrml.c')
| -rw-r--r-- | net/caif/cffrml.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/net/caif/cffrml.c b/net/caif/cffrml.c new file mode 100644 index 000000000000..e86a4ca3b217 --- /dev/null +++ b/net/caif/cffrml.c @@ -0,0 +1,151 @@ +/* + * CAIF Framing Layer. + * + * Copyright (C) ST-Ericsson AB 2010 + * Author: Sjur Brendeland/sjur.brandeland@stericsson.com + * License terms: GNU General Public License (GPL) version 2 + */ + +#include <linux/stddef.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/crc-ccitt.h> +#include <net/caif/caif_layer.h> +#include <net/caif/cfpkt.h> +#include <net/caif/cffrml.h> + +#define container_obj(layr) container_of(layr, struct cffrml, layer) + +struct cffrml { + struct cflayer layer; + bool dofcs; /* !< FCS active */ +}; + +static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); +static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); +static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, + int phyid); + +static u32 cffrml_rcv_error; +static u32 cffrml_rcv_checsum_error; +struct cflayer *cffrml_create(u16 phyid, bool use_fcs) +{ + struct cffrml *this = kmalloc(sizeof(struct cffrml), GFP_ATOMIC); + if (!this) { + pr_warning("CAIF: %s(): Out of memory\n", __func__); + return NULL; + } + caif_assert(offsetof(struct cffrml, layer) == 0); + + memset(this, 0, sizeof(struct cflayer)); + this->layer.receive = cffrml_receive; + this->layer.transmit = cffrml_transmit; + this->layer.ctrlcmd = cffrml_ctrlcmd; + snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid); + this->dofcs = use_fcs; + this->layer.id = phyid; + return (struct cflayer *) this; +} + +void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) +{ + this->up = up; +} + +void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) +{ + this->dn = dn; +} + +static u16 cffrml_checksum(u16 chks, void *buf, u16 len) +{ + /* FIXME: FCS should be moved to glue in order to use OS-Specific + * solutions + */ + return crc_ccitt(chks, buf, len); +} + +static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) +{ + u16 tmp; + u16 len; + u16 hdrchks; + u16 pktchks; + struct cffrml *this; + this = container_obj(layr); + + cfpkt_extr_head(pkt, &tmp, 2); + len = le16_to_cpu(tmp); + + /* Subtract for FCS on length if FCS is not used. */ + if (!this->dofcs) + len -= 2; + + if (cfpkt_setlen(pkt, len) < 0) { + ++cffrml_rcv_error; + pr_err("CAIF: %s():Framing length error (%d)\n", __func__, len); + cfpkt_destroy(pkt); + return -EPROTO; + } + /* + * Don't do extract if FCS is false, rather do setlen - then we don't + * get a cache-miss. + */ + if (this->dofcs) { + cfpkt_extr_trail(pkt, &tmp, 2); + hdrchks = le16_to_cpu(tmp); + pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); + if (pktchks != hdrchks) { + cfpkt_add_trail(pkt, &tmp, 2); + ++cffrml_rcv_error; + ++cffrml_rcv_checsum_error; + pr_info("CAIF: %s(): Frame checksum error " + "(0x%x != 0x%x)\n", __func__, hdrchks, pktchks); + return -EILSEQ; + } + } + if (cfpkt_erroneous(pkt)) { + ++cffrml_rcv_error; + pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); + cfpkt_destroy(pkt); + return -EPROTO; + } + return layr->up->receive(layr->up, pkt); +} + +static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) +{ + int tmp; + u16 chks; + u16 len; + int ret; + struct cffrml *this = container_obj(layr); + if (this->dofcs) { + chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); + tmp = cpu_to_le16(chks); + cfpkt_add_trail(pkt, &tmp, 2); + } else { + cfpkt_pad_trail(pkt, 2); + } + len = cfpkt_getlen(pkt); + tmp = cpu_to_le16(len); + cfpkt_add_head(pkt, &tmp, 2); + cfpkt_info(pkt)->hdr_len += 2; + if (cfpkt_erroneous(pkt)) { + pr_err("CAIF: %s(): Packet is erroneous!\n", __func__); + return -EPROTO; + } + ret = layr->dn->transmit(layr->dn, pkt); + if (ret < 0) { + /* Remove header on faulty packet. */ + cfpkt_extr_head(pkt, &tmp, 2); + } + return ret; +} + +static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, + int phyid) +{ + if (layr->up->ctrlcmd) + layr->up->ctrlcmd(layr->up, ctrl, layr->id); +} |