[PATCH v4 01/12] iio: Add hardware consumer buffer support
Jonathan Cameron
jic23 at kernel.org
Sun Nov 19 04:32:07 PST 2017
On Thu, 9 Nov 2017 11:12:23 +0100
Arnaud Pouliquen <arnaud.pouliquen at st.com> wrote:
> From: Lars-Peter Clausen <lars at metafoo.de>
>
> 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 at metafoo.de>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
I think this is fine though it is something we will have to
keep an eye on to make sure it is appropriately used...
Jonathan
> ---
> 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..7d4d800
> --- /dev/null
> +++ b/drivers/iio/buffer/industrialio-hw-consumer.c
> @@ -0,0 +1,182 @@
> +/*
> + * Copyright 2017 Analog Devices Inc.
> + * Author: Lars-Peter Clausen <lars at metafoo.de>
> + *
> + * 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;
> +
> + iio_channel_release_all(hwc->channels);
> + list_for_each_entry(buf, &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 at metafoo.de>");
> +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 at metafoo.de>
> + *
> + * 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
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