[PATCH v6 01/13] iio: Add hardware consumer buffer support

Arnaud Pouliquen
2017-12-01T17:40:08Z

From: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>

Hardware consumer interface can be used when one IIO device has
a direct connection to another device in hardware.

Signed-off-by: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>
---
drivers/iio/buffer/Kconfig | 10 ++
drivers/iio/buffer/Makefile | 1 +
drivers/iio/buffer/industrialio-hw-consumer.c | 182 ++++++++++++++++++++++++++
include/linux/iio/hw-consumer.h | 20 +++
4 files changed, 213 insertions(+)
create mode 100644 drivers/iio/buffer/industrialio-hw-consumer.c
create mode 100644 include/linux/iio/hw-consumer.h

diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig
index 4ffd3db..338774c 100644
--- a/drivers/iio/buffer/Kconfig
+++ b/drivers/iio/buffer/Kconfig
@@ -29,6 +29,16 @@ config IIO_BUFFER_DMAENGINE

Should be selected by drivers that want to use this functionality.

+config IIO_BUFFER_HW_CONSUMER
+ tristate "Industrial I/O HW buffering"
+ help
+ Provides a way to bonding when an IIO device has a direct connection
+ to another device in hardware. In this case buffers for data transfers
+ are handled by hardware.
+
+ Should be selected by drivers that want to use the generic Hw consumer
+ interface.
+
config IIO_KFIFO_BUF
tristate "Industrial I/O buffering based on kfifo"
help
diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile
index 85beaae..324a36b 100644
--- a/drivers/iio/buffer/Makefile
+++ b/drivers/iio/buffer/Makefile
@@ -6,5 +6,6 @@
obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o
obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o
obj-$(CONFIG_IIO_BUFFER_DMAENGINE) += industrialio-buffer-dmaengine.o
+obj-$(CONFIG_IIO_BUFFER_HW_CONSUMER) += industrialio-hw-consumer.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-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c
new file mode 100644
index 0000000..0253be1
--- /dev/null
+++ b/drivers/iio/buffer/industrialio-hw-consumer.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright 2017 Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/hw-consumer.h>
+#include <linux/iio/buffer_impl.h>
+
+/**
+ * struct iio_hw_consumer - IIO hw consumer block
+ * @buffers: hardware buffers list head.
+ * @channels: IIO provider channels.
+ */
+struct iio_hw_consumer {
+ struct list_head buffers;
+ struct iio_channel *channels;
+};
+
+struct hw_consumer_buffer {
+ struct list_head head;
+ struct iio_dev *indio_dev;
+ struct iio_buffer buffer;
+ long scan_mask[];
+};
+
+static struct hw_consumer_buffer *iio_buffer_to_hw_consumer_buffer(
+ struct iio_buffer *buffer)
+{
+ return container_of(buffer, struct hw_consumer_buffer, buffer);
+}
+
+static void iio_hw_buf_release(struct iio_buffer *buffer)
+{
+ struct hw_consumer_buffer *hw_buf =
+ iio_buffer_to_hw_consumer_buffer(buffer);
+ kfree(hw_buf);
+}
+
+static const struct iio_buffer_access_funcs iio_hw_buf_access = {
+ .release = &iio_hw_buf_release,
+ .modes = INDIO_BUFFER_HARDWARE,
+};
+
+static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(
+ struct iio_hw_consumer *hwc, struct iio_dev *indio_dev)
+{
+ size_t mask_size = BITS_TO_LONGS(indio_dev->masklength) * sizeof(long);
+ struct hw_consumer_buffer *buf;
+
+ list_for_each_entry(buf, &hwc->buffers, head) {
+ if (buf->indio_dev == indio_dev)
+ return buf;
+ }
+
+ buf = kzalloc(sizeof(*buf) + mask_size, GFP_KERNEL);
+ if (!buf)
+ return NULL;
+
+ buf->buffer.access = &iio_hw_buf_access;
+ buf->indio_dev = indio_dev;
+ buf->buffer.scan_mask = buf->scan_mask;
+
+ iio_buffer_init(&buf->buffer);
+ list_add_tail(&buf->head, &hwc->buffers);
+
+ return buf;
+}
+
+/**
+ * iio_hw_consumer_alloc() - Allocate IIO hardware consumer
+ * @dev: Pointer to consumer device.
+ *
+ * Returns a valid iio_hw_consumer on success or a ERR_PTR() on failure.
+ */
+struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev)
+{
+ struct hw_consumer_buffer *buf;
+ struct iio_hw_consumer *hwc;
+ struct iio_channel *chan;
+ int ret;
+
+ hwc = kzalloc(sizeof(*hwc), GFP_KERNEL);
+ if (!hwc)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&hwc->buffers);
+
+ hwc->channels = iio_channel_get_all(dev);
+ if (IS_ERR(hwc->channels)) {
+ ret = PTR_ERR(hwc->channels);
+ goto err_free_hwc;
+ }
+
+ chan = &hwc->channels[0];
+ while (chan->indio_dev) {
+ buf = iio_hw_consumer_get_buffer(hwc, chan->indio_dev);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto err_put_buffers;
+ }
+ set_bit(chan->channel->scan_index, buf->buffer.scan_mask);
+ chan++;
+ }
+
+ return hwc;
+
+err_put_buffers:
+ list_for_each_entry(buf, &hwc->buffers, head)
+ iio_buffer_put(&buf->buffer);
+ iio_channel_release_all(hwc->channels);
+err_free_hwc:
+ kfree(hwc);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iio_hw_consumer_alloc);
+
+/**
+ * iio_hw_consumer_free() - Free IIO hardware consumer
+ * @hwc: hw consumer to free.
+ */
+void iio_hw_consumer_free(struct iio_hw_consumer *hwc)
+{
+ struct hw_consumer_buffer *buf, *n;
+
+ iio_channel_release_all(hwc->channels);
+ list_for_each_entry_safe(buf, n, &hwc->buffers, head)
+ iio_buffer_put(&buf->buffer);
+ kfree(hwc);
+}
+EXPORT_SYMBOL_GPL(iio_hw_consumer_free);
+
+/**
+ * iio_hw_consumer_enable() - Enable IIO hardware consumer
+ * @hwc: iio_hw_consumer to enable.
+ *
+ * Returns 0 on success.
+ */
+int iio_hw_consumer_enable(struct iio_hw_consumer *hwc)
+{
+ struct hw_consumer_buffer *buf;
+ int ret;
+
+ list_for_each_entry(buf, &hwc->buffers, head) {
+ ret = iio_update_buffers(buf->indio_dev, &buf->buffer, NULL);
+ if (ret)
+ goto err_disable_buffers;
+ }
+
+ return 0;
+
+err_disable_buffers:
+ list_for_each_entry_continue_reverse(buf, &hwc->buffers, head)
+ iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_hw_consumer_enable);
+
+/**
+ * iio_hw_consumer_disable() - Disable IIO hardware consumer
+ * @hwc: iio_hw_consumer to disable.
+ */
+void iio_hw_consumer_disable(struct iio_hw_consumer *hwc)
+{
+ struct hw_consumer_buffer *buf;
+
+ list_for_each_entry(buf, &hwc->buffers, head)
+ iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
+}
+EXPORT_SYMBOL_GPL(iio_hw_consumer_disable);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>");
+MODULE_DESCRIPTION("Hardware consumer buffer the IIO framework");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/iio/hw-consumer.h b/include/linux/iio/hw-consumer.h
new file mode 100644
index 0000000..f16791b
--- /dev/null
+++ b/include/linux/iio/hw-consumer.h
@@ -0,0 +1,20 @@
+/*
+ * Industrial I/O in kernel hardware consumer interface
+ *
+ * Copyright 2017 Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef LINUX_IIO_HW_CONSUMER_H
+#define LINUX_IIO_HW_CONSUMER_H
+
+struct iio_hw_consumer;
+
+struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev);
+void iio_hw_consumer_free(struct iio_hw_consumer *hwc);
+int iio_hw_consumer_enable(struct iio_hw_consumer *hwc);
+void iio_hw_consumer_disable(struct iio_hw_consumer *hwc);
+
+#endif
--
2.7.4

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