1 files changed, 302 insertions, 0 deletions
diff --git a/net/caif/cfrfml.c b/net/caif/cfrfml.c
new file mode 100644
index 00000000..2b563ad0
--- /dev/null
+++ b/net/caif/cfrfml.c
@@ -0,0 +1,302 @@
+/*
+ * 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 <asm/unaligned.h>
+#include <net/caif/caif_layer.h>
+#include <net/caif/cfsrvl.h>
+#include <net/caif/cfpkt.h>
+
+#define container_obj(layr) container_of(layr, struct cfrfml, serv.layer)
+#define RFM_SEGMENTATION_BIT 0x01
+#define RFM_HEAD_SIZE 7
+
+static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt);
+static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt);
+
+struct cfrfml {
+	struct cfsrvl serv;
+	struct cfpkt *incomplete_frm;
+	int fragment_size;
+	u8  seghead[6];
+	u16 pdu_size;
+	/* Protects serialized processing of packets */
+	spinlock_t sync;
+};
+
+static void cfrfml_release(struct cflayer *layer)
+{
+	struct cfsrvl *srvl = container_of(layer, struct cfsrvl, layer);
+	struct cfrfml *rfml = container_obj(&srvl->layer);
+
+	if (rfml->incomplete_frm)
+		cfpkt_destroy(rfml->incomplete_frm);
+
+	kfree(srvl);
+}
+
+struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info,
+					int mtu_size)
+{
+	int tmp;
+	struct cfrfml *this = kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);
+
+	if (!this)
+		return NULL;
+
+	cfsrvl_init(&this->serv, channel_id, dev_info, false);
+	this->serv.release = cfrfml_release;
+	this->serv.layer.receive = cfrfml_receive;
+	this->serv.layer.transmit = cfrfml_transmit;
+
+	/* Round down to closest multiple of 16 */
+	tmp = (mtu_size - RFM_HEAD_SIZE - 6) / 16;
+	tmp *= 16;
+
+	this->fragment_size = tmp;
+	spin_lock_init(&this->sync);
+	snprintf(this->serv.layer.name, CAIF_LAYER_NAME_SZ,
+		"rfm%d", channel_id);
+
+	return &this->serv.layer;
+}
+
+static struct cfpkt *rfm_append(struct cfrfml *rfml, char *seghead,
+			struct cfpkt *pkt, int *err)
+{
+	struct cfpkt *tmppkt;
+	*err = -EPROTO;
+	/* n-th but not last segment */
+
+	if (cfpkt_extr_head(pkt, seghead, 6) < 0)
+		return NULL;
+
+	/* Verify correct header */
+	if (memcmp(seghead, rfml->seghead, 6) != 0)
+		return NULL;
+
+	tmppkt = cfpkt_append(rfml->incomplete_frm, pkt,
+			rfml->pdu_size + RFM_HEAD_SIZE);
+
+	/* If cfpkt_append failes input pkts are not freed */
+	*err = -ENOMEM;
+	if (tmppkt == NULL)
+		return NULL;
+
+	*err = 0;
+	return tmppkt;
+}
+
+static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
+{
+	u8 tmp;
+	bool segmented;
+	int err;
+	u8 seghead[6];
+	struct cfrfml *rfml;
+	struct cfpkt *tmppkt = NULL;
+
+	caif_assert(layr->up != NULL);
+	caif_assert(layr->receive != NULL);
+	rfml = container_obj(layr);
+	spin_lock(&rfml->sync);
+
+	err = -EPROTO;
+	if (cfpkt_extr_head(pkt, &tmp, 1) < 0)
+		goto out;
+	segmented = tmp & RFM_SEGMENTATION_BIT;
+
+	if (segmented) {
+		if (rfml->incomplete_frm == NULL) {
+			/* Initial Segment */
+			if (cfpkt_peek_head(pkt, rfml->seghead, 6) < 0)
+				goto out;
+
+			rfml->pdu_size = get_unaligned_le16(rfml->seghead+4);
+
+			if (cfpkt_erroneous(pkt))
+				goto out;
+			rfml->incomplete_frm = pkt;
+			pkt = NULL;
+		} else {
+
+			tmppkt = rfm_append(rfml, seghead, pkt, &err);
+			if (tmppkt == NULL)
+				goto out;
+
+			if (cfpkt_erroneous(tmppkt))
+				goto out;
+
+			rfml->incomplete_frm = tmppkt;
+
+
+			if (cfpkt_erroneous(tmppkt))
+				goto out;
+		}
+		err = 0;
+		goto out;
+	}
+
+	if (rfml->incomplete_frm) {
+
+		/* Last Segment */
+		tmppkt = rfm_append(rfml, seghead, pkt, &err);
+		if (tmppkt == NULL)
+			goto out;
+
+		if (cfpkt_erroneous(tmppkt))
+			goto out;
+
+		rfml->incomplete_frm = NULL;
+		pkt = tmppkt;
+		tmppkt = NULL;
+
+		/* Verify that length is correct */
+		err = EPROTO;
+		if (rfml->pdu_size != cfpkt_getlen(pkt) - RFM_HEAD_SIZE + 1)
+			goto out;
+	}
+
+	err = rfml->serv.layer.up->receive(rfml->serv.layer.up, pkt);
+
+out:
+
+	if (err != 0) {
+		if (tmppkt)
+			cfpkt_destroy(tmppkt);
+		if (pkt)
+			cfpkt_destroy(pkt);
+		if (rfml->incomplete_frm)
+			cfpkt_destroy(rfml->incomplete_frm);
+		rfml->incomplete_frm = NULL;
+
+		pr_info("Connection error %d triggered on RFM link\n", err);
+
+		/* Trigger connection error upon failure.*/
+		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
+					rfml->serv.dev_info.id);
+	}
+	spin_unlock(&rfml->sync);
+
+	if (unlikely(err == -EAGAIN))
+		/* It is not possible to recover after drop of a fragment */
+		err = -EIO;
+
+	return err;
+}
+
+
+static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
+{
+	caif_assert(cfpkt_getlen(pkt) < rfml->fragment_size + RFM_HEAD_SIZE);
+
+	/* Add info for MUX-layer to route the packet out. */
+	cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;
+
+	/*
+	 * To optimize alignment, we add up the size of CAIF header before
+	 * payload.
+	 */
+	cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
+	cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;
+
+	return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
+}
+
+static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
+{
+	int err;
+	u8 seg;
+	u8 head[6];
+	struct cfpkt *rearpkt = NULL;
+	struct cfpkt *frontpkt = pkt;
+	struct cfrfml *rfml = container_obj(layr);
+
+	caif_assert(layr->dn != NULL);
+	caif_assert(layr->dn->transmit != NULL);
+
+	if (!cfsrvl_ready(&rfml->serv, &err))
+		goto out;
+
+	err = -EPROTO;
+	if (cfpkt_getlen(pkt) <= RFM_HEAD_SIZE-1)
+		goto out;
+
+	err = 0;
+	if (cfpkt_getlen(pkt) > rfml->fragment_size + RFM_HEAD_SIZE)
+		err = cfpkt_peek_head(pkt, head, 6);
+
+	if (err < 0)
+		goto out;
+
+	while (cfpkt_getlen(frontpkt) > rfml->fragment_size + RFM_HEAD_SIZE) {
+
+		seg = 1;
+		err = -EPROTO;
+
+		if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
+			goto out;
+		/*
+		 * On OOM error cfpkt_split returns NULL.
+		 *
+		 * NOTE: Segmented pdu is not correctly aligned.
+		 * This has negative performance impact.
+		 */
+
+		rearpkt = cfpkt_split(frontpkt, rfml->fragment_size);
+		if (rearpkt == NULL)
+			goto out;
+
+		err = cfrfml_transmit_segment(rfml, frontpkt);
+
+		if (err != 0) {
+			frontpkt = NULL;
+			goto out;
+		}
+
+		frontpkt = rearpkt;
+		rearpkt = NULL;
+
+		err = -ENOMEM;
+		if (frontpkt == NULL)
+			goto out;
+		err = -EPROTO;
+		if (cfpkt_add_head(frontpkt, head, 6) < 0)
+			goto out;
+
+	}
+
+	seg = 0;
+	err = -EPROTO;
+
+	if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
+		goto out;
+
+	err = cfrfml_transmit_segment(rfml, frontpkt);
+
+	frontpkt = NULL;
+out:
+
+	if (err != 0) {
+		pr_info("Connection error %d triggered on RFM link\n", err);
+		/* Trigger connection error upon failure.*/
+
+		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
+					rfml->serv.dev_info.id);
+
+		if (rearpkt)
+			cfpkt_destroy(rearpkt);
+
+		if (frontpkt)
+			cfpkt_destroy(frontpkt);
+	}
+
+	return err;
+}