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>
diff --git a/net/caif/cfserl.c b/net/caif/cfserl.c
new file mode 100644
index 0000000..06029ea
--- /dev/null
+++ b/net/caif/cfserl.c
@@ -0,0 +1,192 @@
+/*
+ * 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 <net/caif/caif_layer.h>
+#include <net/caif/cfpkt.h>
+#include <net/caif/cfserl.h>
+
+#define container_obj(layr) ((struct cfserl *) layr)
+
+#define CFSERL_STX 0x02
+#define CAIF_MINIUM_PACKET_SIZE 4
+struct cfserl {
+ struct cflayer layer;
+ struct cfpkt *incomplete_frm;
+ /* Protects parallel processing of incoming packets */
+ spinlock_t sync;
+ bool usestx;
+};
+#define STXLEN(layr) (layr->usestx ? 1 : 0)
+
+static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt);
+static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
+static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+ int phyid);
+
+struct cflayer *cfserl_create(int type, int instance, bool use_stx)
+{
+ struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
+ if (!this) {
+ pr_warning("CAIF: %s(): Out of memory\n", __func__);
+ return NULL;
+ }
+ caif_assert(offsetof(struct cfserl, layer) == 0);
+ memset(this, 0, sizeof(struct cfserl));
+ this->layer.receive = cfserl_receive;
+ this->layer.transmit = cfserl_transmit;
+ this->layer.ctrlcmd = cfserl_ctrlcmd;
+ this->layer.type = type;
+ this->usestx = use_stx;
+ spin_lock_init(&this->sync);
+ snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
+ return &this->layer;
+}
+
+static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
+{
+ struct cfserl *layr = container_obj(l);
+ u16 pkt_len;
+ struct cfpkt *pkt = NULL;
+ struct cfpkt *tail_pkt = NULL;
+ u8 tmp8;
+ u16 tmp;
+ u8 stx = CFSERL_STX;
+ int ret;
+ u16 expectlen = 0;
+ caif_assert(newpkt != NULL);
+ spin_lock(&layr->sync);
+
+ if (layr->incomplete_frm != NULL) {
+
+ layr->incomplete_frm =
+ cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
+ pkt = layr->incomplete_frm;
+ } else {
+ pkt = newpkt;
+ }
+ layr->incomplete_frm = NULL;
+
+ do {
+ /* Search for STX at start of pkt if STX is used */
+ if (layr->usestx) {
+ cfpkt_extr_head(pkt, &tmp8, 1);
+ if (tmp8 != CFSERL_STX) {
+ while (cfpkt_more(pkt)
+ && tmp8 != CFSERL_STX) {
+ cfpkt_extr_head(pkt, &tmp8, 1);
+ }
+ if (!cfpkt_more(pkt)) {
+ cfpkt_destroy(pkt);
+ layr->incomplete_frm = NULL;
+ spin_unlock(&layr->sync);
+ return -EPROTO;
+ }
+ }
+ }
+
+ pkt_len = cfpkt_getlen(pkt);
+
+ /*
+ * pkt_len is the accumulated length of the packet data
+ * we have received so far.
+ * Exit if frame doesn't hold length.
+ */
+
+ if (pkt_len < 2) {
+ if (layr->usestx)
+ cfpkt_add_head(pkt, &stx, 1);
+ layr->incomplete_frm = pkt;
+ spin_unlock(&layr->sync);
+ return 0;
+ }
+
+ /*
+ * Find length of frame.
+ * expectlen is the length we need for a full frame.
+ */
+ cfpkt_peek_head(pkt, &tmp, 2);
+ expectlen = le16_to_cpu(tmp) + 2;
+ /*
+ * Frame error handling
+ */
+ if (expectlen < CAIF_MINIUM_PACKET_SIZE
+ || expectlen > CAIF_MAX_FRAMESIZE) {
+ if (!layr->usestx) {
+ if (pkt != NULL)
+ cfpkt_destroy(pkt);
+ layr->incomplete_frm = NULL;
+ expectlen = 0;
+ spin_unlock(&layr->sync);
+ return -EPROTO;
+ }
+ continue;
+ }
+
+ if (pkt_len < expectlen) {
+ /* Too little received data */
+ if (layr->usestx)
+ cfpkt_add_head(pkt, &stx, 1);
+ layr->incomplete_frm = pkt;
+ spin_unlock(&layr->sync);
+ return 0;
+ }
+
+ /*
+ * Enough data for at least one frame.
+ * Split the frame, if too long
+ */
+ if (pkt_len > expectlen)
+ tail_pkt = cfpkt_split(pkt, expectlen);
+ else
+ tail_pkt = NULL;
+
+ /* Send the first part of packet upwards.*/
+ spin_unlock(&layr->sync);
+ ret = layr->layer.up->receive(layr->layer.up, pkt);
+ spin_lock(&layr->sync);
+ if (ret == -EILSEQ) {
+ if (layr->usestx) {
+ if (tail_pkt != NULL)
+ pkt = cfpkt_append(pkt, tail_pkt, 0);
+
+ /* Start search for next STX if frame failed */
+ continue;
+ } else {
+ cfpkt_destroy(pkt);
+ pkt = NULL;
+ }
+ }
+
+ pkt = tail_pkt;
+
+ } while (pkt != NULL);
+
+ spin_unlock(&layr->sync);
+ return 0;
+}
+
+static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
+{
+ struct cfserl *layr = container_obj(layer);
+ int ret;
+ u8 tmp8 = CFSERL_STX;
+ if (layr->usestx)
+ cfpkt_add_head(newpkt, &tmp8, 1);
+ ret = layer->dn->transmit(layer->dn, newpkt);
+ if (ret < 0)
+ cfpkt_extr_head(newpkt, &tmp8, 1);
+
+ return ret;
+}
+
+static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+ int phyid)
+{
+ layr->up->ctrlcmd(layr->up, ctrl, phyid);
+}