diff options
Diffstat (limited to 'net/caif/cffrml.c')
| -rw-r--r-- | net/caif/cffrml.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/net/caif/cffrml.c b/net/caif/cffrml.c new file mode 100644 index 000000000..434ba8557 --- /dev/null +++ b/net/caif/cffrml.c @@ -0,0 +1,197 @@ +/* + * CAIF Framing Layer. + * + * Copyright (C) ST-Ericsson AB 2010 + * Author: Sjur Brendeland + * License terms: GNU General Public License (GPL) version 2 + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ + +#include <linux/stddef.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/crc-ccitt.h> +#include <linux/netdevice.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 */ + int __percpu *pcpu_refcnt; +}; + +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 = kzalloc(sizeof(struct cffrml), GFP_ATOMIC); + if (!this) + return NULL; + this->pcpu_refcnt = alloc_percpu(int); + if (this->pcpu_refcnt == NULL) { + kfree(this); + return NULL; + } + + caif_assert(offsetof(struct cffrml, layer) == 0); + + 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_free(struct cflayer *layer) +{ + struct cffrml *this = container_obj(layer); + free_percpu(this->pcpu_refcnt); + kfree(layer); +} + +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; + int 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("Framing length error (%d)\n", 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("Frame checksum error (0x%x != 0x%x)\n", + hdrchks, pktchks); + return -EILSEQ; + } + } + if (cfpkt_erroneous(pkt)) { + ++cffrml_rcv_error; + pr_err("Packet is erroneous!\n"); + cfpkt_destroy(pkt); + return -EPROTO; + } + + if (layr->up == NULL) { + pr_err("Layr up is missing!\n"); + cfpkt_destroy(pkt); + return -EINVAL; + } + + return layr->up->receive(layr->up, pkt); +} + +static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) +{ + u16 chks; + u16 len; + __le16 data; + + struct cffrml *this = container_obj(layr); + if (this->dofcs) { + chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); + data = cpu_to_le16(chks); + cfpkt_add_trail(pkt, &data, 2); + } else { + cfpkt_pad_trail(pkt, 2); + } + len = cfpkt_getlen(pkt); + data = cpu_to_le16(len); + cfpkt_add_head(pkt, &data, 2); + cfpkt_info(pkt)->hdr_len += 2; + if (cfpkt_erroneous(pkt)) { + pr_err("Packet is erroneous!\n"); + cfpkt_destroy(pkt); + return -EPROTO; + } + + if (layr->dn == NULL) { + cfpkt_destroy(pkt); + return -ENODEV; + + } + return layr->dn->transmit(layr->dn, pkt); +} + +static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, + int phyid) +{ + if (layr->up && layr->up->ctrlcmd) + layr->up->ctrlcmd(layr->up, ctrl, layr->id); +} + +void cffrml_put(struct cflayer *layr) +{ + struct cffrml *this = container_obj(layr); + if (layr != NULL && this->pcpu_refcnt != NULL) + this_cpu_dec(*this->pcpu_refcnt); +} + +void cffrml_hold(struct cflayer *layr) +{ + struct cffrml *this = container_obj(layr); + if (layr != NULL && this->pcpu_refcnt != NULL) + this_cpu_inc(*this->pcpu_refcnt); +} + +int cffrml_refcnt_read(struct cflayer *layr) +{ + int i, refcnt = 0; + struct cffrml *this = container_obj(layr); + for_each_possible_cpu(i) + refcnt += *per_cpu_ptr(this->pcpu_refcnt, i); + return refcnt; +} |