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>

1 files changed, 192 insertions, 0 deletions

diff --git a/net/caif/cfserl.c b/net/caif/cfserl.c
new file mode 100644
index 000000000000..06029ea2da2f
--- /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);
+}