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