NFC: add nfc subsystem core

The NFC subsystem core is responsible for providing the device driver
interface. It is also responsible for providing an interface to the control
operations and data exchange.

Signed-off-by: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Signed-off-by: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 466 insertions, 0 deletions

diff --git a/net/nfc/Kconfig b/net/nfc/Kconfig
new file mode 100644
index 000000000000..33e095b124b3
--- /dev/null
+++ b/net/nfc/Kconfig
@@ -0,0 +1,16 @@
+#
+# NFC sybsystem configuration
+#
+
+menuconfig NFC
+	depends on NET && EXPERIMENTAL
+	tristate "NFC subsystem support (EXPERIMENTAL)"
+	default n
+	help
+	  Say Y here if you want to build support for NFC (Near field
+	  communication) devices.
+
+	  To compile this support as a module, choose M here: the module will
+	  be called nfc.
+
+source "drivers/nfc/Kconfig"
diff --git a/net/nfc/Makefile b/net/nfc/Makefile
new file mode 100644
index 000000000000..28bee5958687
--- /dev/null
+++ b/net/nfc/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the Linux NFC subsystem.
+#
+
+obj-$(CONFIG_NFC) += nfc.o
+
+nfc-objs := core.o
diff --git a/net/nfc/core.c b/net/nfc/core.c
new file mode 100644
index 000000000000..19f8035a1ba9
--- /dev/null
+++ b/net/nfc/core.c
@@ -0,0 +1,365 @@
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "nfc.h"
+
+#define VERSION "0.1"
+
+int nfc_devlist_generation;
+DEFINE_MUTEX(nfc_devlist_mutex);
+
+int nfc_printk(const char *level, const char *format, ...)
+{
+	struct va_format vaf;
+	va_list args;
+	int r;
+
+	va_start(args, format);
+
+	vaf.fmt = format;
+	vaf.va = &args;
+
+	r = printk("%sNFC: %pV\n", level, &vaf);
+
+	va_end(args);
+
+	return r;
+}
+EXPORT_SYMBOL(nfc_printk);
+
+/**
+ * nfc_start_poll - start polling for nfc targets
+ *
+ * @dev: The nfc device that must start polling
+ * @protocols: bitset of nfc protocols that must be used for polling
+ *
+ * The device remains polling for targets until a target is found or
+ * the nfc_stop_poll function is called.
+ */
+int nfc_start_poll(struct nfc_dev *dev, u32 protocols)
+{
+	int rc;
+
+	nfc_dbg("dev_name=%s protocols=0x%x", dev_name(&dev->dev), protocols);
+
+	if (!protocols)
+		return -EINVAL;
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	if (dev->polling) {
+		rc = -EBUSY;
+		goto error;
+	}
+
+	rc = dev->ops->start_poll(dev, protocols);
+	if (!rc)
+		dev->polling = true;
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+/**
+ * nfc_stop_poll - stop polling for nfc targets
+ *
+ * @dev: The nfc device that must stop polling
+ */
+int nfc_stop_poll(struct nfc_dev *dev)
+{
+	int rc = 0;
+
+	nfc_dbg("dev_name=%s", dev_name(&dev->dev));
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	if (!dev->polling) {
+		rc = -EINVAL;
+		goto error;
+	}
+
+	dev->ops->stop_poll(dev);
+	dev->polling = false;
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+/**
+ * nfc_activate_target - prepare the target for data exchange
+ *
+ * @dev: The nfc device that found the target
+ * @target_idx: index of the target that must be activated
+ * @protocol: nfc protocol that will be used for data exchange
+ */
+int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
+{
+	int rc;
+
+	nfc_dbg("dev_name=%s target_idx=%u protocol=%u", dev_name(&dev->dev),
+							target_idx, protocol);
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	rc = dev->ops->activate_target(dev, target_idx, protocol);
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+/**
+ * nfc_deactivate_target - deactivate a nfc target
+ *
+ * @dev: The nfc device that found the target
+ * @target_idx: index of the target that must be deactivated
+ */
+int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
+{
+	int rc = 0;
+
+	nfc_dbg("dev_name=%s target_idx=%u", dev_name(&dev->dev), target_idx);
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	dev->ops->deactivate_target(dev, target_idx);
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+/**
+ * nfc_data_exchange - transceive data
+ *
+ * @dev: The nfc device that found the target
+ * @target_idx: index of the target
+ * @skb: data to be sent
+ * @cb: callback called when the response is received
+ * @cb_context: parameter for the callback function
+ *
+ * The user must wait for the callback before calling this function again.
+ */
+int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx,
+					struct sk_buff *skb,
+					data_exchange_cb_t cb,
+					void *cb_context)
+{
+	int rc;
+
+	nfc_dbg("dev_name=%s target_idx=%u skb->len=%u", dev_name(&dev->dev),
+							target_idx, skb->len);
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		kfree_skb(skb);
+		goto error;
+	}
+
+	rc = dev->ops->data_exchange(dev, target_idx, skb, cb, cb_context);
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+/**
+ * nfc_alloc_skb - allocate a skb for data exchange responses
+ *
+ * @size: size to allocate
+ * @gfp: gfp flags
+ */
+struct sk_buff *nfc_alloc_skb(unsigned int size, gfp_t gfp)
+{
+	struct sk_buff *skb;
+	unsigned int total_size;
+
+	total_size = size + 1;
+	skb = alloc_skb(total_size, gfp);
+
+	if (skb)
+		skb_reserve(skb, 1);
+
+	return skb;
+}
+EXPORT_SYMBOL(nfc_alloc_skb);
+
+static void nfc_release(struct device *d)
+{
+	struct nfc_dev *dev = to_nfc_dev(d);
+
+	nfc_dbg("dev_name=%s", dev_name(&dev->dev));
+
+	kfree(dev);
+}
+
+struct class nfc_class = {
+	.name = "nfc",
+	.dev_release = nfc_release,
+};
+EXPORT_SYMBOL(nfc_class);
+
+static int match_idx(struct device *d, void *data)
+{
+	struct nfc_dev *dev = to_nfc_dev(d);
+	unsigned *idx = data;
+
+	return dev->idx == *idx;
+}
+
+struct nfc_dev *nfc_get_device(unsigned idx)
+{
+	struct device *d;
+
+	d = class_find_device(&nfc_class, NULL, &idx, match_idx);
+	if (!d)
+		return NULL;
+
+	return to_nfc_dev(d);
+}
+
+/**
+ * nfc_allocate_device - allocate a new nfc device
+ *
+ * @ops: device operations
+ * @supported_protocols: NFC protocols supported by the device
+ */
+struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
+					u32 supported_protocols)
+{
+	static atomic_t dev_no = ATOMIC_INIT(0);
+	struct nfc_dev *dev;
+
+	if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
+		!ops->deactivate_target || !ops->data_exchange)
+		return NULL;
+
+	if (!supported_protocols)
+		return NULL;
+
+	dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+
+	dev->dev.class = &nfc_class;
+	dev->idx = atomic_inc_return(&dev_no) - 1;
+	dev_set_name(&dev->dev, "nfc%d", dev->idx);
+	device_initialize(&dev->dev);
+
+	dev->ops = ops;
+	dev->supported_protocols = supported_protocols;
+
+	return dev;
+}
+EXPORT_SYMBOL(nfc_allocate_device);
+
+/**
+ * nfc_register_device - register a nfc device in the nfc subsystem
+ *
+ * @dev: The nfc device to register
+ */
+int nfc_register_device(struct nfc_dev *dev)
+{
+	int rc;
+
+	nfc_dbg("dev_name=%s", dev_name(&dev->dev));
+
+	mutex_lock(&nfc_devlist_mutex);
+	nfc_devlist_generation++;
+	rc = device_add(&dev->dev);
+	mutex_unlock(&nfc_devlist_mutex);
+
+	return rc;
+}
+EXPORT_SYMBOL(nfc_register_device);
+
+/**
+ * nfc_unregister_device - unregister a nfc device in the nfc subsystem
+ *
+ * @dev: The nfc device to unregister
+ */
+void nfc_unregister_device(struct nfc_dev *dev)
+{
+	nfc_dbg("dev_name=%s", dev_name(&dev->dev));
+
+	mutex_lock(&nfc_devlist_mutex);
+	nfc_devlist_generation++;
+
+	/* lock to avoid unregistering a device while an operation
+	   is in progress */
+	device_lock(&dev->dev);
+	device_del(&dev->dev);
+	device_unlock(&dev->dev);
+
+	mutex_unlock(&nfc_devlist_mutex);
+}
+EXPORT_SYMBOL(nfc_unregister_device);
+
+static int __init nfc_init(void)
+{
+	nfc_info("NFC Core ver %s", VERSION);
+
+	return class_register(&nfc_class);
+}
+
+static void __exit nfc_exit(void)
+{
+	class_unregister(&nfc_class);
+}
+
+subsys_initcall(nfc_init);
+module_exit(nfc_exit);
+
+MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>");
+MODULE_DESCRIPTION("NFC Core ver " VERSION);
+MODULE_VERSION(VERSION);
+MODULE_LICENSE("GPL");
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
new file mode 100644
index 000000000000..55f83f86fe2c
--- /dev/null
+++ b/net/nfc/nfc.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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_NFC_H
+#define __LOCAL_NFC_H
+
+#include <net/nfc.h>
+
+__attribute__((format (printf, 2, 3)))
+int nfc_printk(const char *level, const char *fmt, ...);
+
+#define nfc_info(fmt, arg...) nfc_printk(KERN_INFO, fmt, ##arg)
+#define nfc_err(fmt, arg...) nfc_printk(KERN_ERR, fmt, ##arg)
+#define nfc_dbg(fmt, arg...) pr_debug(fmt "\n", ##arg)
+
+extern int nfc_devlist_generation;
+extern struct mutex nfc_devlist_mutex;
+
+struct nfc_dev *nfc_get_device(unsigned idx);
+
+static inline void nfc_put_device(struct nfc_dev *dev)
+{
+	put_device(&dev->dev);
+}
+
+static inline void nfc_device_iter_init(struct class_dev_iter *iter)
+{
+	class_dev_iter_init(iter, &nfc_class, NULL, NULL);
+}
+
+static inline struct nfc_dev *nfc_device_iter_next(struct class_dev_iter *iter)
+{
+	struct device *d = class_dev_iter_next(iter);
+	if (!d)
+		return NULL;
+
+	return to_nfc_dev(d);
+}
+
+static inline void nfc_device_iter_exit(struct class_dev_iter *iter)
+{
+	class_dev_iter_exit(iter);
+}
+
+int nfc_start_poll(struct nfc_dev *dev, u32 protocols);
+
+int nfc_stop_poll(struct nfc_dev *dev);
+
+int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol);
+
+int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx);
+
+int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx,
+					struct sk_buff *skb,
+					data_exchange_cb_t cb,
+					void *cb_context);
+
+#endif /* __LOCAL_NFC_H */