NFC: Add an LLC Core layer to HCI

The LLC layer manages modules that control the link layer protocol (such
as shdlc) between HCI and an HCI driver. The driver must simply specify
the required llc when it registers with HCI.
Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/net/nfc/llc.h

+/*
+ * Link Layer Control manager public interface
+ *
+ * Copyright (C) 2012  Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __NFC_LLC_H_
+#define __NFC_LLC_H_
+
+#include <net/nfc/hci.h>
+#include <linux/skbuff.h>
+
+typedef void (*rcv_to_hci_t) (struct nfc_hci_dev *hdev, struct sk_buff *skb);
+typedef int (*xmit_to_drv_t) (struct nfc_hci_dev *hdev, struct sk_buff *skb);
+typedef void (*llc_failure_t) (struct nfc_hci_dev *hdev, int err);
+
+struct nfc_llc;
+
+struct nfc_llc *nfc_llc_allocate(const char *name, struct nfc_hci_dev *hdev,
+				 xmit_to_drv_t xmit_to_drv,
+				 rcv_to_hci_t rcv_to_hci, int tx_headroom,
+				 int tx_tailroom, llc_failure_t llc_failure);
+void nfc_llc_free(struct nfc_llc *llc);
+
+void nfc_llc_get_rx_head_tail_room(struct nfc_llc *llc, int *rx_headroom,
+				   int *rx_tailroom);
+
+
+int nfc_llc_start(struct nfc_llc *llc);
+int nfc_llc_stop(struct nfc_llc *llc);
+void nfc_llc_rcv_from_drv(struct nfc_llc *llc, struct sk_buff *skb);
+int nfc_llc_xmit_from_hci(struct nfc_llc *llc, struct sk_buff *skb);
+
+int nfc_llc_init(void);
+void nfc_llc_exit(void);
+
+#endif /* __NFC_LLC_H_ */

net/nfc/hci/Makefile

@@ -4,5 +4,5 @@
 
 obj-$(CONFIG_NFC_HCI) += hci.o
 
-hci-y			:= core.o hcp.o command.o
+hci-y			:= core.o hcp.o command.o llc.o
 hci-$(CONFIG_NFC_SHDLC)	+= shdlc.o

net/nfc/hci/core.c

@@ -26,6 +26,7 @@
 
 #include <net/nfc/nfc.h>
 #include <net/nfc/hci.h>
+#include <net/nfc/llc.h>
 
 #include "hci.h"
 
@@ -821,4 +822,17 @@ void nfc_hci_recv_frame(struct nfc_hci_dev *hdev, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(nfc_hci_recv_frame);
 
+static int __init nfc_hci_init(void)
+{
+	return nfc_llc_init();
+}
+
+static void __exit nfc_hci_exit(void)
+{
+	nfc_llc_exit();
+}
+
+module_init(nfc_hci_init);
+module_exit(nfc_hci_exit);
+
 MODULE_LICENSE("GPL");

net/nfc/hci/llc.c

+/*
+ * Link Layer Control manager
+ *
+ * Copyright (C) 2012  Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/export.h>
+#include <net/nfc/llc.h>
+#include "llc.h"
+
+static struct list_head llc_engines;
+
+int nfc_llc_init(void)
+{
+	INIT_LIST_HEAD(&llc_engines);
+
+	return 0;
+}
+EXPORT_SYMBOL(nfc_llc_init);
+
+void nfc_llc_exit(void)
+{
+	struct nfc_llc_engine *llc_engine, *n;
+
+	list_for_each_entry_safe(llc_engine, n, &llc_engines, entry) {
+		list_del(&llc_engine->entry);
+		kfree(llc_engine->name);
+		kfree(llc_engine);
+	}
+}
+EXPORT_SYMBOL(nfc_llc_exit);
+
+int nfc_llc_register(const char *name, struct nfc_llc_ops *ops)
+{
+	struct nfc_llc_engine *llc_engine;
+
+	llc_engine = kzalloc(sizeof(struct nfc_llc_engine), GFP_KERNEL);
+	if (llc_engine == NULL)
+		return -ENOMEM;
+
+	llc_engine->name = kstrdup(name, GFP_KERNEL);
+	if (llc_engine->name == NULL) {
+		kfree(llc_engine);
+		return -ENOMEM;
+	}
+	llc_engine->ops = ops;
+
+	INIT_LIST_HEAD(&llc_engine->entry);
+	list_add_tail (&llc_engine->entry, &llc_engines);
+
+	return 0;
+}
+EXPORT_SYMBOL(nfc_llc_register);
+
+static struct nfc_llc_engine *nfc_llc_name_to_engine(const char *name)
+{
+	struct nfc_llc_engine *llc_engine;
+
+	list_for_each_entry(llc_engine, &llc_engines, entry) {
+		if (strcmp(llc_engine->name, name) == 0)
+			return llc_engine;
+	}
+
+	return NULL;
+}
+
+void nfc_llc_unregister(const char *name)
+{
+	struct nfc_llc_engine *llc_engine;
+
+	llc_engine = nfc_llc_name_to_engine(name);
+	if (llc_engine == NULL)
+		return;
+
+	list_del(&llc_engine->entry);
+	kfree(llc_engine->name);
+	kfree(llc_engine);
+}
+EXPORT_SYMBOL(nfc_llc_unregister);
+
+struct nfc_llc *nfc_llc_allocate(const char *name, struct nfc_hci_dev *hdev,
+				 xmit_to_drv_t xmit_to_drv,
+				 rcv_to_hci_t rcv_to_hci, int tx_headroom,
+				 int tx_tailroom, llc_failure_t llc_failure)
+{
+	struct nfc_llc_engine *llc_engine;
+	struct nfc_llc *llc;
+
+	llc_engine = nfc_llc_name_to_engine(name);
+	if (llc_engine == NULL)
+		return NULL;
+
+	llc = kzalloc(sizeof(struct nfc_llc), GFP_KERNEL);
+	if (llc == NULL)
+		return NULL;
+
+	llc->data = llc_engine->ops->init(hdev, xmit_to_drv, rcv_to_hci,
+					  tx_headroom, tx_tailroom,
+					  &llc->rx_headroom, &llc->rx_tailroom,
+					  llc_failure);
+	if (llc->data == NULL) {
+		kfree(llc);
+		return NULL;
+	}
+	llc->ops = llc_engine->ops;
+
+	return llc;
+}
+EXPORT_SYMBOL(nfc_llc_allocate);
+
+void nfc_llc_free(struct nfc_llc *llc)
+{
+	llc->ops->deinit(llc);
+	kfree(llc);
+}
+EXPORT_SYMBOL(nfc_llc_free);
+
+inline void nfc_llc_get_rx_head_tail_room(struct nfc_llc *llc, int *rx_headroom,
+					  int *rx_tailroom)
+{
+	*rx_headroom = llc->rx_headroom;
+	*rx_tailroom = llc->rx_tailroom;
+}
+EXPORT_SYMBOL(nfc_llc_get_rx_head_tail_room);
+
+inline int nfc_llc_start(struct nfc_llc *llc)
+{
+	return llc->ops->start(llc);
+}
+EXPORT_SYMBOL(nfc_llc_start);
+
+inline int nfc_llc_stop(struct nfc_llc *llc)
+{
+	return llc->ops->stop(llc);
+}
+EXPORT_SYMBOL(nfc_llc_stop);
+
+inline void nfc_llc_rcv_from_drv(struct nfc_llc *llc, struct sk_buff *skb)
+{
+	llc->ops->rcv_from_drv(llc, skb);
+}
+EXPORT_SYMBOL(nfc_llc_rcv_from_drv);
+
+inline int nfc_llc_xmit_from_hci(struct nfc_llc *llc, struct sk_buff *skb)
+{
+	return llc->ops->xmit_from_hci(llc, skb);
+}
+EXPORT_SYMBOL(nfc_llc_xmit_from_hci);
+
+inline void *nfc_llc_get_data(struct nfc_llc *llc)
+{
+	return llc->data;
+}
+EXPORT_SYMBOL(nfc_llc_get_data);

net/nfc/hci/llc.h

+/*
+ * Link Layer Control manager
+ *
+ * Copyright (C) 2012  Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __LOCAL_LLC_H_
+#define __LOCAL_LLC_H_
+
+#include <net/nfc/hci.h>
+#include <net/nfc/llc.h>
+#include <linux/skbuff.h>
+
+struct nfc_llc_ops {
+	void *(*init) (struct nfc_hci_dev *hdev, xmit_to_drv_t xmit_to_drv,
+		       rcv_to_hci_t rcv_to_hci, int tx_headroom,
+		       int tx_tailroom, int *rx_headroom, int *rx_tailroom,
+		       llc_failure_t llc_failure);
+	void (*deinit) (struct nfc_llc *llc);
+	int (*start) (struct nfc_llc *llc);
+	int (*stop) (struct nfc_llc *llc);
+	void (*rcv_from_drv) (struct nfc_llc *llc, struct sk_buff *skb);
+	int (*xmit_from_hci) (struct nfc_llc *llc, struct sk_buff *skb);
+};
+
+struct nfc_llc_engine {
+	const char *name;
+	struct nfc_llc_ops *ops;
+	struct list_head entry;
+};
+
+struct nfc_llc {
+	void *data;
+	struct nfc_llc_ops *ops;
+	int rx_headroom;
+	int rx_tailroom;
+};
+
+void *nfc_llc_get_data(struct nfc_llc *llc);
+
+int nfc_llc_register(const char *name, struct nfc_llc_ops *ops);
+void nfc_llc_unregister(const char *name);
+
+#endif /* __LOCAL_LLC_H_ */