net-caif: add CAIF core protocol stack
CAIF generic protocol implementation. This layer is somewhat generic in order to be able to use and test it outside the Linux Kernel. cfctrl.c - CAIF control protocol layer cfdbgl.c - CAIF debug protocol layer cfdgml.c - CAIF datagram protocol layer cffrml.c - CAIF framing protocol layer cfmuxl.c - CAIF mux protocol layer cfrfml.c - CAIF remote file manager protocol layer cfserl.c - CAIF serial (fragmentation) protocol layer cfsrvl.c - CAIF generic service layer functions cfutill.c - CAIF utility protocol layer cfveil.c - CAIF AT protocol layer cfvidl.c - CAIF video protocol layer Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sjur Braendeland
committed by
David S. Miller
David S. Miller
parent
2721c5b9dd
commit
b482cd2053
192
net/caif/cfserl.c
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192
net/caif/cfserl.c
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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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#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 <net/caif/caif_layer.h>
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#include <net/caif/cfpkt.h>
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#include <net/caif/cfserl.h>
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#define container_obj(layr) ((struct cfserl *) layr)
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#define CFSERL_STX 0x02
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#define CAIF_MINIUM_PACKET_SIZE 4
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struct cfserl {
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struct cflayer layer;
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struct cfpkt *incomplete_frm;
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/* Protects parallel processing of incoming packets */
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spinlock_t sync;
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bool usestx;
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};
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#define STXLEN(layr) (layr->usestx ? 1 : 0)
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static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt);
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static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
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static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
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int phyid);
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struct cflayer *cfserl_create(int type, int instance, bool use_stx)
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{
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struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
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if (!this) {
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pr_warning("CAIF: %s(): Out of memory\n", __func__);
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return NULL;
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}
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caif_assert(offsetof(struct cfserl, layer) == 0);
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memset(this, 0, sizeof(struct cfserl));
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this->layer.receive = cfserl_receive;
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this->layer.transmit = cfserl_transmit;
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this->layer.ctrlcmd = cfserl_ctrlcmd;
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this->layer.type = type;
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this->usestx = use_stx;
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spin_lock_init(&this->sync);
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snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
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return &this->layer;
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}
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static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
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{
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struct cfserl *layr = container_obj(l);
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u16 pkt_len;
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struct cfpkt *pkt = NULL;
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struct cfpkt *tail_pkt = NULL;
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u8 tmp8;
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u16 tmp;
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u8 stx = CFSERL_STX;
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int ret;
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u16 expectlen = 0;
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caif_assert(newpkt != NULL);
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spin_lock(&layr->sync);
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if (layr->incomplete_frm != NULL) {
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layr->incomplete_frm =
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cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
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pkt = layr->incomplete_frm;
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} else {
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pkt = newpkt;
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}
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layr->incomplete_frm = NULL;
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do {
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/* Search for STX at start of pkt if STX is used */
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if (layr->usestx) {
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cfpkt_extr_head(pkt, &tmp8, 1);
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if (tmp8 != CFSERL_STX) {
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while (cfpkt_more(pkt)
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&& tmp8 != CFSERL_STX) {
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cfpkt_extr_head(pkt, &tmp8, 1);
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}
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if (!cfpkt_more(pkt)) {
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cfpkt_destroy(pkt);
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layr->incomplete_frm = NULL;
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spin_unlock(&layr->sync);
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return -EPROTO;
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}
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}
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}
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pkt_len = cfpkt_getlen(pkt);
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/*
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* pkt_len is the accumulated length of the packet data
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* we have received so far.
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* Exit if frame doesn't hold length.
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*/
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if (pkt_len < 2) {
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if (layr->usestx)
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cfpkt_add_head(pkt, &stx, 1);
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layr->incomplete_frm = pkt;
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spin_unlock(&layr->sync);
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return 0;
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}
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/*
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* Find length of frame.
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* expectlen is the length we need for a full frame.
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*/
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cfpkt_peek_head(pkt, &tmp, 2);
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expectlen = le16_to_cpu(tmp) + 2;
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/*
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* Frame error handling
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*/
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if (expectlen < CAIF_MINIUM_PACKET_SIZE
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|| expectlen > CAIF_MAX_FRAMESIZE) {
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if (!layr->usestx) {
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if (pkt != NULL)
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cfpkt_destroy(pkt);
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layr->incomplete_frm = NULL;
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expectlen = 0;
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spin_unlock(&layr->sync);
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return -EPROTO;
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}
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continue;
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}
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if (pkt_len < expectlen) {
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/* Too little received data */
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if (layr->usestx)
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cfpkt_add_head(pkt, &stx, 1);
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layr->incomplete_frm = pkt;
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spin_unlock(&layr->sync);
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return 0;
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}
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/*
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* Enough data for at least one frame.
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* Split the frame, if too long
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*/
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if (pkt_len > expectlen)
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tail_pkt = cfpkt_split(pkt, expectlen);
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else
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tail_pkt = NULL;
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/* Send the first part of packet upwards.*/
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spin_unlock(&layr->sync);
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ret = layr->layer.up->receive(layr->layer.up, pkt);
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spin_lock(&layr->sync);
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if (ret == -EILSEQ) {
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if (layr->usestx) {
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if (tail_pkt != NULL)
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pkt = cfpkt_append(pkt, tail_pkt, 0);
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/* Start search for next STX if frame failed */
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continue;
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} else {
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cfpkt_destroy(pkt);
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pkt = NULL;
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}
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}
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pkt = tail_pkt;
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} while (pkt != NULL);
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spin_unlock(&layr->sync);
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return 0;
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}
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static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
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{
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struct cfserl *layr = container_obj(layer);
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int ret;
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u8 tmp8 = CFSERL_STX;
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if (layr->usestx)
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cfpkt_add_head(newpkt, &tmp8, 1);
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ret = layer->dn->transmit(layer->dn, newpkt);
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if (ret < 0)
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cfpkt_extr_head(newpkt, &tmp8, 1);
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return ret;
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}
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static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
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int phyid)
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{
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layr->up->ctrlcmd(layr->up, ctrl, phyid);
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}
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