Re: [PATCH v4 17/17] remoteproc: Refactor rproc delete and cdev release path

[Arnaud POULIQUEN <arnaud.pouliquen@st.com>]

look good to me
Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>

On 12/18/20 6:32 PM, Mathieu Poirier wrote:
> Refactor function rproc_del() and rproc_cdev_release() to take
> into account the policy specified in the device tree.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>  drivers/remoteproc/remoteproc_cdev.c | 18 +++++++++++---
>  drivers/remoteproc/remoteproc_core.c | 36 ++++++++++++++++++++++++----
>  include/linux/remoteproc.h           |  4 ++++
>  3 files changed, 51 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_cdev.c b/drivers/remoteproc/remoteproc_cdev.c
> index f7645f289563..9b2fb6fbf8e7 100644
> --- a/drivers/remoteproc/remoteproc_cdev.c
> +++ b/drivers/remoteproc/remoteproc_cdev.c
> @@ -87,11 +87,23 @@ static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned l
>  static int rproc_cdev_release(struct inode *inode, struct file *filp)
>  {
>  	struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
> +	int ret;
>  
> -	if (rproc->cdev_put_on_release && rproc->state == RPROC_RUNNING)
> -		rproc_shutdown(rproc);
> +	if (!rproc->cdev_put_on_release)
> +		return 0;
>  
> -	return 0;
> +	/*
> +	 * The application has crashed or is releasing its file handle.  Detach
> +	 * or shutdown the remote processor based on the policy specified in the
> +	 * DT.  No need to check rproc->state right away, it will be done
> +	 * in either rproc_detach() or rproc_shutdown().
> +	 */
> +	if (rproc->autonomous_on_core_shutdown)
> +		ret = rproc_detach(rproc);
> +	else
> +		ret = rproc_shutdown(rproc);
> +
> +	return ret;
>  }
>  
>  static const struct file_operations rproc_fops = {
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 2fe42ac7ca89..9f47a4ec0ec6 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -2254,6 +2254,22 @@ static int rproc_alloc_ops(struct rproc *rproc, const struct rproc_ops *ops)
>  	return 0;
>  }
>  
> +static void rproc_set_automation_flags(struct rproc *rproc)
> +{
> +	struct device *dev = rproc->dev.parent;
> +	struct device_node *np = dev->of_node;
> +	bool core_shutdown;
> +
> +	/*
> +	 * When function rproc_cdev_release() or rproc_del() are called and
> +	 * the remote processor has been attached to, it will be detached from
> +	 * (rather than turned off) if "autonomous-on-core-shutdown is specified
> +	 * in the DT.
> +	 */
> +	core_shutdown = of_property_read_bool(np, "autonomous-on-core-shutdown");
> +	rproc->autonomous_on_core_shutdown = core_shutdown;
> +}
> +
>  /**
>   * rproc_alloc() - allocate a remote processor handle
>   * @dev: the underlying device
> @@ -2312,6 +2328,8 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
>  	if (rproc_alloc_ops(rproc, ops))
>  		goto put_device;
>  
> +	rproc_set_automation_flags(rproc);
> +
>  	/* Assign a unique device index and name */
>  	rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
>  	if (rproc->index < 0) {
> @@ -2388,15 +2406,25 @@ EXPORT_SYMBOL(rproc_put);
>   * of the outstanding reference created by rproc_alloc. To decrement that
>   * one last refcount, one still needs to call rproc_free().
>   *
> - * Returns 0 on success and -EINVAL if @rproc isn't valid.
> + * Returns 0 on success and a negative error code on failure.
>   */
>  int rproc_del(struct rproc *rproc)
>  {
> +	int ret;
> +
>  	if (!rproc)
>  		return -EINVAL;
>  
> -	/* TODO: make sure this works with rproc->power > 1 */
> -	rproc_shutdown(rproc);
> +	/*
> +	 * TODO: make sure this works with rproc->power > 1
> +	 *
> +	 * No need to check rproc->state right away, it will be done in either
> +	 * rproc_detach() or rproc_shutdown().
> +	 */
> +	if (rproc->autonomous_on_core_shutdown)
> +		ret = rproc_detach(rproc);
> +	else
> +		ret = rproc_shutdown(rproc);
>  
>  	mutex_lock(&rproc->lock);
>  	rproc->state = RPROC_DELETED;
> @@ -2415,7 +2443,7 @@ int rproc_del(struct rproc *rproc)
>  
>  	device_del(&rproc->dev);
>  
> -	return 0;
> +	return ret;
>  }
>  EXPORT_SYMBOL(rproc_del);
>  
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index aa5bceb72015..012bebbd324b 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -519,6 +519,9 @@ struct rproc_dump_segment {
>   * @nb_vdev: number of vdev currently handled by rproc
>   * @char_dev: character device of the rproc
>   * @cdev_put_on_release: flag to indicate if remoteproc should be shutdown on @char_dev release
> + * @autonomous_on_core_shutdown: true if the remote processor should be detached
> + *				 from (rather than turned off) when the remoteproc
> + *				 core goes away.
>   */
>  struct rproc {
>  	struct list_head node;
> @@ -557,6 +560,7 @@ struct rproc {
>  	u16 elf_machine;
>  	struct cdev cdev;
>  	bool cdev_put_on_release;
> +	bool autonomous_on_core_shutdown;
>  };
>  
>  /**
>