| Message ID | 20210916182914.1810-2-mihail.chindris@analog.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | iio: Add output buffer support | expand |
On Thu, 16 Sep 2021 18:29:09 +0000 Mihail Chindris <mihail.chindris@analog.com> wrote: > Currently IIO only supports buffer mode for capture devices like ADCs. Add > support for buffered mode for output devices like DACs. > > The output buffer implementation is analogous to the input buffer > implementation. Instead of using read() to get data from the buffer write() > is used to copy data into the buffer. > > poll() with POLLOUT will wakeup if there is space available. > > Drivers can remove data from a buffer using iio_pop_from_buffer(), the > function can e.g. called from a trigger handler to write the data to > hardware. > > A buffer can only be either a output buffer or an input, but not both. So, > for a device that has an ADC and DAC path, this will mean 2 IIO buffers > (one for each direction). > > The direction of the buffer is decided by the new direction field of the > iio_buffer struct and should be set after allocating and before registering > it. > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com> > Signed-off-by: Mihail Chindris <mihail.chindris@analog.com> A few minor things inline. I would have expected the missing check on insert_buffer to have resulted in a nasty deference of a null pointer though which does make me nervous about whether we have tested this series enough. Jonathan > --- > drivers/iio/iio_core.h | 4 + > drivers/iio/industrialio-buffer.c | 120 +++++++++++++++++++++++++++++- > drivers/iio/industrialio-core.c | 1 + > include/linux/iio/buffer.h | 7 ++ > include/linux/iio/buffer_impl.h | 11 +++ > 5 files changed, 141 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h > index 8f4a9b264962..61e318431de9 100644 > --- a/drivers/iio/iio_core.h > +++ b/drivers/iio/iio_core.h > @@ -68,12 +68,15 @@ __poll_t iio_buffer_poll_wrapper(struct file *filp, > struct poll_table_struct *wait); > ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, > size_t n, loff_t *f_ps); > +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf, > + size_t n, loff_t *f_ps); > > int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev); > void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev); > > #define iio_buffer_poll_addr (&iio_buffer_poll_wrapper) > #define iio_buffer_read_outer_addr (&iio_buffer_read_wrapper) > +#define iio_buffer_write_outer_addr (&iio_buffer_write_wrapper) > > void iio_disable_all_buffers(struct iio_dev *indio_dev); > void iio_buffer_wakeup_poll(struct iio_dev *indio_dev); > @@ -83,6 +86,7 @@ void iio_device_detach_buffers(struct iio_dev *indio_dev); > > #define iio_buffer_poll_addr NULL > #define iio_buffer_read_outer_addr NULL > +#define iio_buffer_write_outer_addr NULL > > static inline int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev) > { > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c > index a95cc2da56be..a2a34c5652a7 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -161,6 +161,62 @@ static ssize_t iio_buffer_read(struct file *filp, char __user *buf, > return ret; > } > > +static size_t iio_buffer_space_available(struct iio_buffer *buf) > +{ > + if (buf->access->space_available) > + return buf->access->space_available(buf); > + > + return SIZE_MAX; > +} > + > +static ssize_t iio_buffer_write(struct file *filp, const char __user *buf, > + size_t n, loff_t *f_ps) > +{ > + struct iio_dev_buffer_pair *ib = filp->private_data; > + struct iio_buffer *rb = ib->buffer; > + struct iio_dev *indio_dev = ib->indio_dev; > + DEFINE_WAIT_FUNC(wait, woken_wake_function); > + int ret; > + size_t written; > + > + if (!indio_dev->info) > + return -ENODEV; > + > + if (!rb || !rb->access->write) > + return -EINVAL; > + > + written = 0; > + add_wait_queue(&rb->pollq, &wait); > + do { > + if (indio_dev->info == NULL) > + return -ENODEV; > + > + if (!iio_buffer_space_available(rb)) { > + if (signal_pending(current)) { > + ret = -ERESTARTSYS; > + break; > + } > + > + wait_woken(&wait, TASK_INTERRUPTIBLE, > + MAX_SCHEDULE_TIMEOUT); > + continue; > + } > + > + ret = rb->access->write(rb, n - written, buf + written); > + if (ret == 0 && (filp->f_flags & O_NONBLOCK)) > + ret = -EAGAIN; > + > + if (ret > 0) { > + written += ret; > + if (written != n && !(filp->f_flags & O_NONBLOCK)) > + continue; > + } > + } while (ret == 0); > + remove_wait_queue(&rb->pollq, &wait); > + > + return ret < 0 ? ret : n; > +} > + > /** > * iio_buffer_poll() - poll the buffer to find out if it has data > * @filp: File structure pointer for device access > @@ -181,8 +237,18 @@ static __poll_t iio_buffer_poll(struct file *filp, > return 0; > > poll_wait(filp, &rb->pollq, wait); > - if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0)) > - return EPOLLIN | EPOLLRDNORM; > + > + switch (rb->direction) { > + case IIO_BUFFER_DIRECTION_IN: > + if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0)) > + return EPOLLIN | EPOLLRDNORM; > + break; > + case IIO_BUFFER_DIRECTION_OUT: > + if (iio_buffer_space_available(rb)) > + return EPOLLOUT | EPOLLWRNORM; > + break; > + } > + > return 0; > } > > @@ -199,6 +265,19 @@ ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, > return iio_buffer_read(filp, buf, n, f_ps); > } > > +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf, > + size_t n, loff_t *f_ps) > +{ > + struct iio_dev_buffer_pair *ib = filp->private_data; > + struct iio_buffer *rb = ib->buffer; > + > + /* check if buffer was opened through new API */ > + if (test_bit(IIO_BUSY_BIT_POS, &rb->flags)) > + return -EBUSY; > + > + return iio_buffer_write(filp, buf, n, f_ps); > +} > + > __poll_t iio_buffer_poll_wrapper(struct file *filp, > struct poll_table_struct *wait) > { > @@ -231,6 +310,15 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev) > } > } > > +int iio_pop_from_buffer(struct iio_buffer *buffer, void *data) > +{ > + if (!buffer || !buffer->access || !buffer->access->remove_from) > + return -EINVAL; > + > + return buffer->access->remove_from(buffer, data); > +} > +EXPORT_SYMBOL_GPL(iio_pop_from_buffer); > + > void iio_buffer_init(struct iio_buffer *buffer) > { > INIT_LIST_HEAD(&buffer->demux_list); > @@ -1156,6 +1244,9 @@ int iio_update_buffers(struct iio_dev *indio_dev, > if (insert_buffer == remove_buffer) > return 0; > > + if (insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT) > + ret = -EINVAL; > + This block is unusual enough that it needs a comment to explain what the intent is. You are poking in an error code, but then continuing... I'm fairly sure you need to check if (insert_buffer && (insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT)) The lack of that test makes me thing this will blow up when called to remove an output buffer. > mutex_lock(&iio_dev_opaque->info_exist_lock); > mutex_lock(&indio_dev->mlock); > > @@ -1277,6 +1368,22 @@ static ssize_t iio_dma_show_data_available(struct device *dev, > return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer)); > } > > +static ssize_t direction_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > + > + switch (buffer->direction) { > + case IIO_BUFFER_DIRECTION_IN: > + return sprintf(buf, "in\n"); > + case IIO_BUFFER_DIRECTION_OUT: > + return sprintf(buf, "out\n"); > + default: > + return -EINVAL; > + } > +} > + > static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length, > iio_buffer_write_length); > static struct device_attribute dev_attr_length_ro = __ATTR(length, > @@ -1289,12 +1396,20 @@ static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark, > S_IRUGO, iio_buffer_show_watermark, NULL); > static DEVICE_ATTR(data_available, S_IRUGO, > iio_dma_show_data_available, NULL); > +static DEVICE_ATTR_RO(direction); > > +/* > + * When adding new attributes here, put the at the end, at least until > + * the code that handles the lengh/length_ro & watermark/watermark_ro length/length_ro > + * assignments gets cleaned up. Otherwise these can create some weird > + * duplicate attributes errors under some setups. > + */ > static struct attribute *iio_buffer_attrs[] = { > &dev_attr_length.attr, > &dev_attr_enable.attr, > &dev_attr_watermark.attr, > &dev_attr_data_available.attr, > + &dev_attr_direction.attr, > }; > > #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) > @@ -1397,6 +1512,7 @@ static const struct file_operations iio_buffer_chrdev_fileops = { > .owner = THIS_MODULE, > .llseek = noop_llseek, > .read = iio_buffer_read, > + .write = iio_buffer_write, > .poll = iio_buffer_poll, > .release = iio_buffer_chrdev_release, > }; > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > index 2dbb37e09b8c..537a08549a69 100644 > --- a/drivers/iio/industrialio-core.c > +++ b/drivers/iio/industrialio-core.c > @@ -1822,6 +1822,7 @@ static const struct file_operations iio_buffer_fileops = { > .owner = THIS_MODULE, > .llseek = noop_llseek, > .read = iio_buffer_read_outer_addr, > + .write = iio_buffer_write_outer_addr, > .poll = iio_buffer_poll_addr, > .unlocked_ioctl = iio_ioctl, > .compat_ioctl = compat_ptr_ioctl, > diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h > index b6928ac5c63d..fe2e680d9b5e 100644 > --- a/include/linux/iio/buffer.h > +++ b/include/linux/iio/buffer.h > @@ -11,8 +11,15 @@ > > struct iio_buffer; > > +enum iio_buffer_direction { > + IIO_BUFFER_DIRECTION_IN, > + IIO_BUFFER_DIRECTION_OUT, > +}; > + > int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data); > > +int iio_pop_from_buffer(struct iio_buffer *buffer, void *data); > + > /** > * iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers > * @indio_dev: iio_dev structure for device. > diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h > index 245b32918ae1..e2ca8ea23e19 100644 > --- a/include/linux/iio/buffer_impl.h > +++ b/include/linux/iio/buffer_impl.h > @@ -7,6 +7,7 @@ > #ifdef CONFIG_IIO_BUFFER > > #include <uapi/linux/iio/buffer.h> > +#include <linux/iio/buffer.h> > > struct iio_dev; > struct iio_buffer; > @@ -23,6 +24,10 @@ struct iio_buffer; > * @read: try to get a specified number of bytes (must exist) > * @data_available: indicates how much data is available for reading from > * the buffer. > + * @remove_from: remove scan from buffer. Drivers should calls this to > + * remove a scan from a buffer. > + * @write: try to write a number of bytes > + * @space_available: returns the amount of bytes available in a buffer > * @request_update: if a parameter change has been marked, update underlying > * storage. > * @set_bytes_per_datum:set number of bytes per datum > @@ -49,6 +54,9 @@ struct iio_buffer_access_funcs { > int (*store_to)(struct iio_buffer *buffer, const void *data); > int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf); > size_t (*data_available)(struct iio_buffer *buffer); > + int (*remove_from)(struct iio_buffer *buffer, void *data); > + int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf); > + size_t (*space_available)(struct iio_buffer *buffer); > > int (*request_update)(struct iio_buffer *buffer); > > @@ -80,6 +88,9 @@ struct iio_buffer { > /** @bytes_per_datum: Size of individual datum including timestamp. */ > size_t bytes_per_datum; > > + /* @direction: Direction of the data stream (in/out). */ > + enum iio_buffer_direction direction; > + > /** > * @access: Buffer access functions associated with the > * implementation.
> From: Jonathan Cameron <jic23@kernel.org> > Sent: Sunday, September 19, 2021 7:03 PM > To: Chindris, Mihail <Mihail.Chindris@analog.com> > Cc: linux-kernel@vger.kernel.org; linux-iio@vger.kernel.org; > lars@metafoo.de; Hennerich, Michael > <Michael.Hennerich@analog.com>; Sa, Nuno > <Nuno.Sa@analog.com>; Bogdan, Dragos > <Dragos.Bogdan@analog.com>; alexandru.ardelean@analog.com > Subject: Re: [PATCH v5 1/6] iio: Add output buffer support > > On Thu, 16 Sep 2021 18:29:09 +0000 > Mihail Chindris <mihail.chindris@analog.com> wrote: > > > Currently IIO only supports buffer mode for capture devices like > ADCs. Add > > support for buffered mode for output devices like DACs. > > > > The output buffer implementation is analogous to the input buffer > > implementation. Instead of using read() to get data from the buffer > write() > > is used to copy data into the buffer. > > > > poll() with POLLOUT will wakeup if there is space available. > > > > Drivers can remove data from a buffer using iio_pop_from_buffer(), > the > > function can e.g. called from a trigger handler to write the data to > > hardware. > > > > A buffer can only be either a output buffer or an input, but not both. > So, > > for a device that has an ADC and DAC path, this will mean 2 IIO > buffers > > (one for each direction). > > > > The direction of the buffer is decided by the new direction field of > the > > iio_buffer struct and should be set after allocating and before > registering > > it. > > > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> > > Signed-off-by: Alexandru Ardelean > <alexandru.ardelean@analog.com> > > Signed-off-by: Mihail Chindris <mihail.chindris@analog.com> > > A few minor things inline. I would have expected the missing check > on insert_buffer to have resulted in a nasty deference of a null pointer > though which does make me nervous about whether we have tested > this > series enough. > > Jonathan > > > --- > > drivers/iio/iio_core.h | 4 + > > drivers/iio/industrialio-buffer.c | 120 > +++++++++++++++++++++++++++++- > > drivers/iio/industrialio-core.c | 1 + > > include/linux/iio/buffer.h | 7 ++ > > include/linux/iio/buffer_impl.h | 11 +++ > > 5 files changed, 141 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h > > index 8f4a9b264962..61e318431de9 100644 > > --- a/drivers/iio/iio_core.h > > +++ b/drivers/iio/iio_core.h > > @@ -68,12 +68,15 @@ __poll_t iio_buffer_poll_wrapper(struct file > *filp, > > struct poll_table_struct *wait); > > ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, > > size_t n, loff_t *f_ps); > > +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user > *buf, > > + size_t n, loff_t *f_ps); > > > > int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev); > > void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev); > > > > #define iio_buffer_poll_addr (&iio_buffer_poll_wrapper) > > #define iio_buffer_read_outer_addr (&iio_buffer_read_wrapper) > > +#define iio_buffer_write_outer_addr > (&iio_buffer_write_wrapper) > > > > void iio_disable_all_buffers(struct iio_dev *indio_dev); > > void iio_buffer_wakeup_poll(struct iio_dev *indio_dev); > > @@ -83,6 +86,7 @@ void iio_device_detach_buffers(struct iio_dev > *indio_dev); > > > > #define iio_buffer_poll_addr NULL > > #define iio_buffer_read_outer_addr NULL > > +#define iio_buffer_write_outer_addr NULL > > > > static inline int iio_buffers_alloc_sysfs_and_mask(struct iio_dev > *indio_dev) > > { > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio- > buffer.c > > index a95cc2da56be..a2a34c5652a7 100644 > > --- a/drivers/iio/industrialio-buffer.c > > +++ b/drivers/iio/industrialio-buffer.c > > @@ -161,6 +161,62 @@ static ssize_t iio_buffer_read(struct file *filp, > char __user *buf, > > return ret; > > } > > > > +static size_t iio_buffer_space_available(struct iio_buffer *buf) > > +{ > > + if (buf->access->space_available) > > + return buf->access->space_available(buf); > > + > > + return SIZE_MAX; > > +} > > + > > +static ssize_t iio_buffer_write(struct file *filp, const char __user > *buf, > > + size_t n, loff_t *f_ps) > > +{ > > + struct iio_dev_buffer_pair *ib = filp->private_data; > > + struct iio_buffer *rb = ib->buffer; > > + struct iio_dev *indio_dev = ib->indio_dev; > > + DEFINE_WAIT_FUNC(wait, woken_wake_function); > > + int ret; > > + size_t written; > > + > > + if (!indio_dev->info) > > + return -ENODEV; > > + > > + if (!rb || !rb->access->write) > > + return -EINVAL; > > + As the buffer implementation can support both 'read()' and 'write()', the following check might make sense: if (rb->direction != IIO_BUFFER_DIRECTION_OUT) return -EPERM; If going with this, we should add an extra patch to do a similar thing on the read side... - Nuno Sá
On Mon, 20 Sep 2021 08:02:29 +0000 "Sa, Nuno" <Nuno.Sa@analog.com> wrote: > > From: Jonathan Cameron <jic23@kernel.org> > > Sent: Sunday, September 19, 2021 7:03 PM > > To: Chindris, Mihail <Mihail.Chindris@analog.com> > > Cc: linux-kernel@vger.kernel.org; linux-iio@vger.kernel.org; > > lars@metafoo.de; Hennerich, Michael > > <Michael.Hennerich@analog.com>; Sa, Nuno > > <Nuno.Sa@analog.com>; Bogdan, Dragos > > <Dragos.Bogdan@analog.com>; alexandru.ardelean@analog.com > > Subject: Re: [PATCH v5 1/6] iio: Add output buffer support > > > > On Thu, 16 Sep 2021 18:29:09 +0000 > > Mihail Chindris <mihail.chindris@analog.com> wrote: > > > > > Currently IIO only supports buffer mode for capture devices like > > ADCs. Add > > > support for buffered mode for output devices like DACs. > > > > > > The output buffer implementation is analogous to the input buffer > > > implementation. Instead of using read() to get data from the buffer > > write() > > > is used to copy data into the buffer. > > > > > > poll() with POLLOUT will wakeup if there is space available. > > > > > > Drivers can remove data from a buffer using iio_pop_from_buffer(), > > the > > > function can e.g. called from a trigger handler to write the data to > > > hardware. > > > > > > A buffer can only be either a output buffer or an input, but not both. > > So, > > > for a device that has an ADC and DAC path, this will mean 2 IIO > > buffers > > > (one for each direction). > > > > > > The direction of the buffer is decided by the new direction field of > > the > > > iio_buffer struct and should be set after allocating and before > > registering > > > it. > > > > > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> > > > Signed-off-by: Alexandru Ardelean > > <alexandru.ardelean@analog.com> > > > Signed-off-by: Mihail Chindris <mihail.chindris@analog.com> > > > > A few minor things inline. I would have expected the missing check > > on insert_buffer to have resulted in a nasty deference of a null pointer > > though which does make me nervous about whether we have tested > > this > > series enough. > > > > Jonathan > > > > > --- > > > drivers/iio/iio_core.h | 4 + > > > drivers/iio/industrialio-buffer.c | 120 > > +++++++++++++++++++++++++++++- > > > drivers/iio/industrialio-core.c | 1 + > > > include/linux/iio/buffer.h | 7 ++ > > > include/linux/iio/buffer_impl.h | 11 +++ > > > 5 files changed, 141 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h > > > index 8f4a9b264962..61e318431de9 100644 > > > --- a/drivers/iio/iio_core.h > > > +++ b/drivers/iio/iio_core.h > > > @@ -68,12 +68,15 @@ __poll_t iio_buffer_poll_wrapper(struct file > > *filp, > > > struct poll_table_struct *wait); > > > ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, > > > size_t n, loff_t *f_ps); > > > +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user > > *buf, > > > + size_t n, loff_t *f_ps); > > > > > > int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev); > > > void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev); > > > > > > #define iio_buffer_poll_addr (&iio_buffer_poll_wrapper) > > > #define iio_buffer_read_outer_addr (&iio_buffer_read_wrapper) > > > +#define iio_buffer_write_outer_addr > > (&iio_buffer_write_wrapper) > > > > > > void iio_disable_all_buffers(struct iio_dev *indio_dev); > > > void iio_buffer_wakeup_poll(struct iio_dev *indio_dev); > > > @@ -83,6 +86,7 @@ void iio_device_detach_buffers(struct iio_dev > > *indio_dev); > > > > > > #define iio_buffer_poll_addr NULL > > > #define iio_buffer_read_outer_addr NULL > > > +#define iio_buffer_write_outer_addr NULL > > > > > > static inline int iio_buffers_alloc_sysfs_and_mask(struct iio_dev > > *indio_dev) > > > { > > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio- > > buffer.c > > > index a95cc2da56be..a2a34c5652a7 100644 > > > --- a/drivers/iio/industrialio-buffer.c > > > +++ b/drivers/iio/industrialio-buffer.c > > > @@ -161,6 +161,62 @@ static ssize_t iio_buffer_read(struct file *filp, > > char __user *buf, > > > return ret; > > > } > > > > > > +static size_t iio_buffer_space_available(struct iio_buffer *buf) > > > +{ > > > + if (buf->access->space_available) > > > + return buf->access->space_available(buf); > > > + > > > + return SIZE_MAX; > > > +} > > > + > > > +static ssize_t iio_buffer_write(struct file *filp, const char __user > > *buf, > > > + size_t n, loff_t *f_ps) > > > +{ > > > + struct iio_dev_buffer_pair *ib = filp->private_data; > > > + struct iio_buffer *rb = ib->buffer; > > > + struct iio_dev *indio_dev = ib->indio_dev; > > > + DEFINE_WAIT_FUNC(wait, woken_wake_function); > > > + int ret; > > > + size_t written; > > > + > > > + if (!indio_dev->info) > > > + return -ENODEV; > > > + > > > + if (!rb || !rb->access->write) > > > + return -EINVAL; > > > + > > As the buffer implementation can support both 'read()' and 'write()', the following > check might make sense: > > if (rb->direction != IIO_BUFFER_DIRECTION_OUT) > return -EPERM; Makes sense. Whether EPERM is the right error code is a different question. Doesn't seem perfectly aligned with this case, but it's not too bad. Jonathan > > If going with this, we should add an extra patch to do a similar thing on the read side... > > - Nuno Sá >
diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h index 8f4a9b264962..61e318431de9 100644 --- a/drivers/iio/iio_core.h +++ b/drivers/iio/iio_core.h @@ -68,12 +68,15 @@ __poll_t iio_buffer_poll_wrapper(struct file *filp, struct poll_table_struct *wait); ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, size_t n, loff_t *f_ps); +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf, + size_t n, loff_t *f_ps); int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev); void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev); #define iio_buffer_poll_addr (&iio_buffer_poll_wrapper) #define iio_buffer_read_outer_addr (&iio_buffer_read_wrapper) +#define iio_buffer_write_outer_addr (&iio_buffer_write_wrapper) void iio_disable_all_buffers(struct iio_dev *indio_dev); void iio_buffer_wakeup_poll(struct iio_dev *indio_dev); @@ -83,6 +86,7 @@ void iio_device_detach_buffers(struct iio_dev *indio_dev); #define iio_buffer_poll_addr NULL #define iio_buffer_read_outer_addr NULL +#define iio_buffer_write_outer_addr NULL static inline int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev) { diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index a95cc2da56be..a2a34c5652a7 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -161,6 +161,62 @@ static ssize_t iio_buffer_read(struct file *filp, char __user *buf, return ret; } +static size_t iio_buffer_space_available(struct iio_buffer *buf) +{ + if (buf->access->space_available) + return buf->access->space_available(buf); + + return SIZE_MAX; +} + +static ssize_t iio_buffer_write(struct file *filp, const char __user *buf, + size_t n, loff_t *f_ps) +{ + struct iio_dev_buffer_pair *ib = filp->private_data; + struct iio_buffer *rb = ib->buffer; + struct iio_dev *indio_dev = ib->indio_dev; + DEFINE_WAIT_FUNC(wait, woken_wake_function); + int ret; + size_t written; + + if (!indio_dev->info) + return -ENODEV; + + if (!rb || !rb->access->write) + return -EINVAL; + + written = 0; + add_wait_queue(&rb->pollq, &wait); + do { + if (indio_dev->info == NULL) + return -ENODEV; + + if (!iio_buffer_space_available(rb)) { + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + wait_woken(&wait, TASK_INTERRUPTIBLE, + MAX_SCHEDULE_TIMEOUT); + continue; + } + + ret = rb->access->write(rb, n - written, buf + written); + if (ret == 0 && (filp->f_flags & O_NONBLOCK)) + ret = -EAGAIN; + + if (ret > 0) { + written += ret; + if (written != n && !(filp->f_flags & O_NONBLOCK)) + continue; + } + } while (ret == 0); + remove_wait_queue(&rb->pollq, &wait); + + return ret < 0 ? ret : n; +} + /** * iio_buffer_poll() - poll the buffer to find out if it has data * @filp: File structure pointer for device access @@ -181,8 +237,18 @@ static __poll_t iio_buffer_poll(struct file *filp, return 0; poll_wait(filp, &rb->pollq, wait); - if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0)) - return EPOLLIN | EPOLLRDNORM; + + switch (rb->direction) { + case IIO_BUFFER_DIRECTION_IN: + if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0)) + return EPOLLIN | EPOLLRDNORM; + break; + case IIO_BUFFER_DIRECTION_OUT: + if (iio_buffer_space_available(rb)) + return EPOLLOUT | EPOLLWRNORM; + break; + } + return 0; } @@ -199,6 +265,19 @@ ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf, return iio_buffer_read(filp, buf, n, f_ps); } +ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf, + size_t n, loff_t *f_ps) +{ + struct iio_dev_buffer_pair *ib = filp->private_data; + struct iio_buffer *rb = ib->buffer; + + /* check if buffer was opened through new API */ + if (test_bit(IIO_BUSY_BIT_POS, &rb->flags)) + return -EBUSY; + + return iio_buffer_write(filp, buf, n, f_ps); +} + __poll_t iio_buffer_poll_wrapper(struct file *filp, struct poll_table_struct *wait) { @@ -231,6 +310,15 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev) } } +int iio_pop_from_buffer(struct iio_buffer *buffer, void *data) +{ + if (!buffer || !buffer->access || !buffer->access->remove_from) + return -EINVAL; + + return buffer->access->remove_from(buffer, data); +} +EXPORT_SYMBOL_GPL(iio_pop_from_buffer); + void iio_buffer_init(struct iio_buffer *buffer) { INIT_LIST_HEAD(&buffer->demux_list); @@ -1156,6 +1244,9 @@ int iio_update_buffers(struct iio_dev *indio_dev, if (insert_buffer == remove_buffer) return 0; + if (insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT) + ret = -EINVAL; + mutex_lock(&iio_dev_opaque->info_exist_lock); mutex_lock(&indio_dev->mlock); @@ -1277,6 +1368,22 @@ static ssize_t iio_dma_show_data_available(struct device *dev, return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer)); } +static ssize_t direction_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; + + switch (buffer->direction) { + case IIO_BUFFER_DIRECTION_IN: + return sprintf(buf, "in\n"); + case IIO_BUFFER_DIRECTION_OUT: + return sprintf(buf, "out\n"); + default: + return -EINVAL; + } +} + static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length, iio_buffer_write_length); static struct device_attribute dev_attr_length_ro = __ATTR(length, @@ -1289,12 +1396,20 @@ static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark, S_IRUGO, iio_buffer_show_watermark, NULL); static DEVICE_ATTR(data_available, S_IRUGO, iio_dma_show_data_available, NULL); +static DEVICE_ATTR_RO(direction); +/* + * When adding new attributes here, put the at the end, at least until + * the code that handles the lengh/length_ro & watermark/watermark_ro + * assignments gets cleaned up. Otherwise these can create some weird + * duplicate attributes errors under some setups. + */ static struct attribute *iio_buffer_attrs[] = { &dev_attr_length.attr, &dev_attr_enable.attr, &dev_attr_watermark.attr, &dev_attr_data_available.attr, + &dev_attr_direction.attr, }; #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) @@ -1397,6 +1512,7 @@ static const struct file_operations iio_buffer_chrdev_fileops = { .owner = THIS_MODULE, .llseek = noop_llseek, .read = iio_buffer_read, + .write = iio_buffer_write, .poll = iio_buffer_poll, .release = iio_buffer_chrdev_release, }; diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 2dbb37e09b8c..537a08549a69 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -1822,6 +1822,7 @@ static const struct file_operations iio_buffer_fileops = { .owner = THIS_MODULE, .llseek = noop_llseek, .read = iio_buffer_read_outer_addr, + .write = iio_buffer_write_outer_addr, .poll = iio_buffer_poll_addr, .unlocked_ioctl = iio_ioctl, .compat_ioctl = compat_ptr_ioctl, diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h index b6928ac5c63d..fe2e680d9b5e 100644 --- a/include/linux/iio/buffer.h +++ b/include/linux/iio/buffer.h @@ -11,8 +11,15 @@ struct iio_buffer; +enum iio_buffer_direction { + IIO_BUFFER_DIRECTION_IN, + IIO_BUFFER_DIRECTION_OUT, +}; + int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data); +int iio_pop_from_buffer(struct iio_buffer *buffer, void *data); + /** * iio_push_to_buffers_with_timestamp() - push data and timestamp to buffers * @indio_dev: iio_dev structure for device. diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h index 245b32918ae1..e2ca8ea23e19 100644 --- a/include/linux/iio/buffer_impl.h +++ b/include/linux/iio/buffer_impl.h @@ -7,6 +7,7 @@ #ifdef CONFIG_IIO_BUFFER #include <uapi/linux/iio/buffer.h> +#include <linux/iio/buffer.h> struct iio_dev; struct iio_buffer; @@ -23,6 +24,10 @@ struct iio_buffer; * @read: try to get a specified number of bytes (must exist) * @data_available: indicates how much data is available for reading from * the buffer. + * @remove_from: remove scan from buffer. Drivers should calls this to + * remove a scan from a buffer. + * @write: try to write a number of bytes + * @space_available: returns the amount of bytes available in a buffer * @request_update: if a parameter change has been marked, update underlying * storage. * @set_bytes_per_datum:set number of bytes per datum @@ -49,6 +54,9 @@ struct iio_buffer_access_funcs { int (*store_to)(struct iio_buffer *buffer, const void *data); int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf); size_t (*data_available)(struct iio_buffer *buffer); + int (*remove_from)(struct iio_buffer *buffer, void *data); + int (*write)(struct iio_buffer *buffer, size_t n, const char __user *buf); + size_t (*space_available)(struct iio_buffer *buffer); int (*request_update)(struct iio_buffer *buffer); @@ -80,6 +88,9 @@ struct iio_buffer { /** @bytes_per_datum: Size of individual datum including timestamp. */ size_t bytes_per_datum; + /* @direction: Direction of the data stream (in/out). */ + enum iio_buffer_direction direction; + /** * @access: Buffer access functions associated with the * implementation.