iio: Move generic buffer implementations to sub-directory

For generic IIO trigger implementations we already have a sub-directory,
but the generic buffer implementations currently reside in the IIO
top-level directory. The main reason is that things have historically grown
into this form.

With more generic buffer implementations on its way now is the perfect time
to clean this up and introduce a sub-directory for generic buffer
implementations to avoid too much clutter in the top-level directory.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

5 files changed, 494 insertions, 0 deletions

diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig
new file mode 100644
index 000000000000..0a7b2fd3699b
--- /dev/null
+++ b/drivers/iio/buffer/Kconfig
@@ -0,0 +1,24 @@
+#
+# Industrial I/O generic buffer implementations
+#
+# When adding new entries keep the list in alphabetical order
+
+config IIO_BUFFER_CB
+	tristate "IIO callback buffer used for push in-kernel interfaces"
+	help
+	  Should be selected by any drivers that do in-kernel push
+	  usage.  That is, those where the data is pushed to the consumer.
+
+config IIO_KFIFO_BUF
+	tristate "Industrial I/O buffering based on kfifo"
+	help
+	  A simple fifo based on kfifo.  Note that this currently provides
+	  no buffer events so it is up to userspace to work out how
+	  often to read from the buffer.
+
+config IIO_TRIGGERED_BUFFER
+	tristate
+	select IIO_TRIGGER
+	select IIO_KFIFO_BUF
+	help
+	  Provides helper functions for setting up triggered buffers.
diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile
new file mode 100644
index 000000000000..4d193b9a9123
--- /dev/null
+++ b/drivers/iio/buffer/Makefile
@@ -0,0 +1,8 @@
+#
+# Makefile for the industrial I/O buffer implementations
+#
+
+# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o
+obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
+obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
diff --git a/drivers/iio/buffer/industrialio-buffer-cb.c b/drivers/iio/buffer/industrialio-buffer-cb.c
new file mode 100644
index 000000000000..323079c3ccce
--- /dev/null
+++ b/drivers/iio/buffer/industrialio-buffer-cb.c
@@ -0,0 +1,138 @@
+/* The industrial I/O callback buffer
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/consumer.h>
+
+struct iio_cb_buffer {
+	struct iio_buffer buffer;
+	int (*cb)(const void *data, void *private);
+	void *private;
+	struct iio_channel *channels;
+};
+
+static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer)
+{
+	return container_of(buffer, struct iio_cb_buffer, buffer);
+}
+
+static int iio_buffer_cb_store_to(struct iio_buffer *buffer, const void *data)
+{
+	struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
+	return cb_buff->cb(data, cb_buff->private);
+}
+
+static void iio_buffer_cb_release(struct iio_buffer *buffer)
+{
+	struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
+	kfree(cb_buff->buffer.scan_mask);
+	kfree(cb_buff);
+}
+
+static const struct iio_buffer_access_funcs iio_cb_access = {
+	.store_to = &iio_buffer_cb_store_to,
+	.release = &iio_buffer_cb_release,
+
+	.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
+};
+
+struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
+					     int (*cb)(const void *data,
+						       void *private),
+					     void *private)
+{
+	int ret;
+	struct iio_cb_buffer *cb_buff;
+	struct iio_dev *indio_dev;
+	struct iio_channel *chan;
+
+	cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
+	if (cb_buff == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	iio_buffer_init(&cb_buff->buffer);
+
+	cb_buff->private = private;
+	cb_buff->cb = cb;
+	cb_buff->buffer.access = &iio_cb_access;
+	INIT_LIST_HEAD(&cb_buff->buffer.demux_list);
+
+	cb_buff->channels = iio_channel_get_all(dev);
+	if (IS_ERR(cb_buff->channels)) {
+		ret = PTR_ERR(cb_buff->channels);
+		goto error_free_cb_buff;
+	}
+
+	indio_dev = cb_buff->channels[0].indio_dev;
+	cb_buff->buffer.scan_mask
+		= kcalloc(BITS_TO_LONGS(indio_dev->masklength), sizeof(long),
+			  GFP_KERNEL);
+	if (cb_buff->buffer.scan_mask == NULL) {
+		ret = -ENOMEM;
+		goto error_release_channels;
+	}
+	chan = &cb_buff->channels[0];
+	while (chan->indio_dev) {
+		if (chan->indio_dev != indio_dev) {
+			ret = -EINVAL;
+			goto error_free_scan_mask;
+		}
+		set_bit(chan->channel->scan_index,
+			cb_buff->buffer.scan_mask);
+		chan++;
+	}
+
+	return cb_buff;
+
+error_free_scan_mask:
+	kfree(cb_buff->buffer.scan_mask);
+error_release_channels:
+	iio_channel_release_all(cb_buff->channels);
+error_free_cb_buff:
+	kfree(cb_buff);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
+
+int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	return iio_update_buffers(cb_buff->channels[0].indio_dev,
+				  &cb_buff->buffer,
+				  NULL);
+}
+EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
+
+void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	iio_update_buffers(cb_buff->channels[0].indio_dev,
+			   NULL,
+			   &cb_buff->buffer);
+}
+EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
+
+void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	iio_channel_release_all(cb_buff->channels);
+	iio_buffer_put(&cb_buff->buffer);
+}
+EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
+
+struct iio_channel
+*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
+{
+	return cb_buffer->channels;
+}
+EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("Industrial I/O callback buffer");
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/buffer/industrialio-triggered-buffer.c b/drivers/iio/buffer/industrialio-triggered-buffer.c
new file mode 100644
index 000000000000..4b2858ba1fd6
--- /dev/null
+++ b/drivers/iio/buffer/industrialio-triggered-buffer.c
@@ -0,0 +1,103 @@
+ /*
+ * Copyright (c) 2012 Analog Devices, Inc.
+ *  Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
+	.postenable = &iio_triggered_buffer_postenable,
+	.predisable = &iio_triggered_buffer_predisable,
+};
+
+/**
+ * iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
+ * @indio_dev:		IIO device structure
+ * @h:			Function which will be used as pollfunc top half
+ * @thread:		Function which will be used as pollfunc bottom half
+ * @setup_ops:		Buffer setup functions to use for this device.
+ *			If NULL the default setup functions for triggered
+ *			buffers will be used.
+ *
+ * This function combines some common tasks which will normally be performed
+ * when setting up a triggered buffer. It will allocate the buffer and the
+ * pollfunc.
+ *
+ * Before calling this function the indio_dev structure should already be
+ * completely initialized, but not yet registered. In practice this means that
+ * this function should be called right before iio_device_register().
+ *
+ * To free the resources allocated by this function call
+ * iio_triggered_buffer_cleanup().
+ */
+int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
+	irqreturn_t (*h)(int irq, void *p),
+	irqreturn_t (*thread)(int irq, void *p),
+	const struct iio_buffer_setup_ops *setup_ops)
+{
+	struct iio_buffer *buffer;
+	int ret;
+
+	buffer = iio_kfifo_allocate();
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	iio_device_attach_buffer(indio_dev, buffer);
+
+	indio_dev->pollfunc = iio_alloc_pollfunc(h,
+						 thread,
+						 IRQF_ONESHOT,
+						 indio_dev,
+						 "%s_consumer%d",
+						 indio_dev->name,
+						 indio_dev->id);
+	if (indio_dev->pollfunc == NULL) {
+		ret = -ENOMEM;
+		goto error_kfifo_free;
+	}
+
+	/* Ring buffer functions - here trigger setup related */
+	if (setup_ops)
+		indio_dev->setup_ops = setup_ops;
+	else
+		indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
+
+	/* Flag that polled ring buffering is possible */
+	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
+
+	return 0;
+
+error_kfifo_free:
+	iio_kfifo_free(indio_dev->buffer);
+error_ret:
+	return ret;
+}
+EXPORT_SYMBOL(iio_triggered_buffer_setup);
+
+/**
+ * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
+ * @indio_dev: IIO device structure
+ */
+void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
+{
+	iio_dealloc_pollfunc(indio_dev->pollfunc);
+	iio_kfifo_free(indio_dev->buffer);
+}
+EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
+MODULE_LICENSE("GPL");
diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c
new file mode 100644
index 000000000000..c5b999f0c519
--- /dev/null
+++ b/drivers/iio/buffer/kfifo_buf.c
@@ -0,0 +1,221 @@
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/workqueue.h>
+#include <linux/kfifo.h>
+#include <linux/mutex.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
+
+struct iio_kfifo {
+	struct iio_buffer buffer;
+	struct kfifo kf;
+	struct mutex user_lock;
+	int update_needed;
+};
+
+#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
+
+static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
+				int bytes_per_datum, int length)
+{
+	if ((length == 0) || (bytes_per_datum == 0))
+		return -EINVAL;
+
+	return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
+			     bytes_per_datum, GFP_KERNEL);
+}
+
+static int iio_request_update_kfifo(struct iio_buffer *r)
+{
+	int ret = 0;
+	struct iio_kfifo *buf = iio_to_kfifo(r);
+
+	mutex_lock(&buf->user_lock);
+	if (buf->update_needed) {
+		kfifo_free(&buf->kf);
+		ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
+				   buf->buffer.length);
+		if (ret >= 0)
+			buf->update_needed = false;
+	} else {
+		kfifo_reset_out(&buf->kf);
+	}
+	mutex_unlock(&buf->user_lock);
+
+	return ret;
+}
+
+static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	kf->update_needed = true;
+	return 0;
+}
+
+static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
+{
+	if (r->bytes_per_datum != bpd) {
+		r->bytes_per_datum = bpd;
+		iio_mark_update_needed_kfifo(r);
+	}
+	return 0;
+}
+
+static int iio_set_length_kfifo(struct iio_buffer *r, int length)
+{
+	/* Avoid an invalid state */
+	if (length < 2)
+		length = 2;
+	if (r->length != length) {
+		r->length = length;
+		iio_mark_update_needed_kfifo(r);
+	}
+	return 0;
+}
+
+static int iio_store_to_kfifo(struct iio_buffer *r,
+			      const void *data)
+{
+	int ret;
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	ret = kfifo_in(&kf->kf, data, 1);
+	if (ret != 1)
+		return -EBUSY;
+	return 0;
+}
+
+static int iio_read_first_n_kfifo(struct iio_buffer *r,
+			   size_t n, char __user *buf)
+{
+	int ret, copied;
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+
+	if (mutex_lock_interruptible(&kf->user_lock))
+		return -ERESTARTSYS;
+
+	if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
+		ret = -EINVAL;
+	else
+		ret = kfifo_to_user(&kf->kf, buf, n, &copied);
+	mutex_unlock(&kf->user_lock);
+	if (ret < 0)
+		return ret;
+
+	return copied;
+}
+
+static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(r);
+	size_t samples;
+
+	mutex_lock(&kf->user_lock);
+	samples = kfifo_len(&kf->kf);
+	mutex_unlock(&kf->user_lock);
+
+	return samples;
+}
+
+static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
+{
+	struct iio_kfifo *kf = iio_to_kfifo(buffer);
+
+	mutex_destroy(&kf->user_lock);
+	kfifo_free(&kf->kf);
+	kfree(kf);
+}
+
+static const struct iio_buffer_access_funcs kfifo_access_funcs = {
+	.store_to = &iio_store_to_kfifo,
+	.read_first_n = &iio_read_first_n_kfifo,
+	.data_available = iio_kfifo_buf_data_available,
+	.request_update = &iio_request_update_kfifo,
+	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
+	.set_length = &iio_set_length_kfifo,
+	.release = &iio_kfifo_buffer_release,
+
+	.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
+};
+
+struct iio_buffer *iio_kfifo_allocate(void)
+{
+	struct iio_kfifo *kf;
+
+	kf = kzalloc(sizeof(*kf), GFP_KERNEL);
+	if (!kf)
+		return NULL;
+
+	kf->update_needed = true;
+	iio_buffer_init(&kf->buffer);
+	kf->buffer.access = &kfifo_access_funcs;
+	kf->buffer.length = 2;
+	mutex_init(&kf->user_lock);
+
+	return &kf->buffer;
+}
+EXPORT_SYMBOL(iio_kfifo_allocate);
+
+void iio_kfifo_free(struct iio_buffer *r)
+{
+	iio_buffer_put(r);
+}
+EXPORT_SYMBOL(iio_kfifo_free);
+
+static void devm_iio_kfifo_release(struct device *dev, void *res)
+{
+	iio_kfifo_free(*(struct iio_buffer **)res);
+}
+
+static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
+{
+	struct iio_buffer **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+/**
+ * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
+ * @dev:		Device to allocate kfifo buffer for
+ *
+ * RETURNS:
+ * Pointer to allocated iio_buffer on success, NULL on failure.
+ */
+struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
+{
+	struct iio_buffer **ptr, *r;
+
+	ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	r = iio_kfifo_allocate();
+	if (r) {
+		*ptr = r;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return r;
+}
+EXPORT_SYMBOL(devm_iio_kfifo_allocate);
+
+/**
+ * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
+ * @dev:		Device the buffer belongs to
+ * @r:			The buffer associated with the device
+ */
+void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
+{
+	WARN_ON(devres_release(dev, devm_iio_kfifo_release,
+			       devm_iio_kfifo_match, r));
+}
+EXPORT_SYMBOL(devm_iio_kfifo_free);
+
+MODULE_LICENSE("GPL");