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/*
* 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
*/
#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 <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_warn("Out of memory\n");
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("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;
}
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("Packet is erroneous!\n");
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);
}
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