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Date:   Tue, 25 May 2021 12:00:06 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Suman Anna <s-anna@ti.com>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-remoteproc@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] remoteproc: Fix various kernel-doc warnings
Message-ID: <20210525180006.GD1113058@xps15>
References: <20210519180304.23563-1-s-anna@ti.com>
 <20210519180304.23563-3-s-anna@ti.com>
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On Wed, May 19, 2021 at 01:03:04PM -0500, Suman Anna wrote:
> Fix all the kernel-doc warnings in various remoteproc core files.
> Some of them just needed a formatting cleanup change, while others
> needed the Return statement to be added, or documenting the missed
> structure elements.
> 
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
>  drivers/remoteproc/remoteproc_core.c       | 44 +++++++++++++------
>  drivers/remoteproc/remoteproc_elf_loader.c | 12 ++++--
>  drivers/remoteproc/remoteproc_virtio.c     |  6 ++-
>  include/linux/remoteproc.h                 | 50 ++++++++++++----------
>  4 files changed, 69 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 8c279039b6a3..6348aaa42bbb 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -183,12 +183,12 @@ EXPORT_SYMBOL(rproc_va_to_pa);
>   * translations on the internal remoteproc memory regions through a platform
>   * implementation specific da_to_va ops, if present.
>   *
> - * The function returns a valid kernel address on success or NULL on failure.
> - *
>   * Note: phys_to_virt(iommu_iova_to_phys(rproc->domain, da)) will work too,
>   * but only on kernel direct mapped RAM memory. Instead, we're just using
>   * here the output of the DMA API for the carveouts, which should be more
>   * correct.
> + *
> + * Return: a valid kernel address on success or NULL on failure
>   */
>  void *rproc_da_to_va(struct rproc *rproc, u64 da, size_t len, bool *is_iomem)
>  {
> @@ -509,7 +509,7 @@ static int copy_dma_range_map(struct device *to, struct device *from)
>   * use RSC_DEVMEM resource entries to map their required @da to the physical
>   * address of their base CMA region (ouch, hacky!).
>   *
> - * Returns 0 on success, or an appropriate error code otherwise
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
>  			     int offset, int avail)
> @@ -644,7 +644,7 @@ void rproc_vdev_release(struct kref *ref)
>   * support dynamically allocating this address using the generic
>   * DMA API (but currently there isn't a use case for that).
>   *
> - * Returns 0 on success, or an appropriate error code otherwise
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_handle_trace(struct rproc *rproc, void *ptr,
>  			      int offset, int avail)
> @@ -721,6 +721,8 @@ static int rproc_handle_trace(struct rproc *rproc, void *ptr,
>   * tell us ranges of physical addresses the firmware is allowed to request,
>   * and not allow firmwares to request access to physical addresses that
>   * are outside those ranges.
> + *
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_handle_devmem(struct rproc *rproc, void *ptr,
>  			       int offset, int avail)
> @@ -783,6 +785,8 @@ static int rproc_handle_devmem(struct rproc *rproc, void *ptr,
>   *
>   * This function allocate specified memory entry @mem using
>   * dma_alloc_coherent() as default allocator
> + *
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_alloc_carveout(struct rproc *rproc,
>  				struct rproc_mem_entry *mem)
> @@ -889,6 +893,8 @@ static int rproc_alloc_carveout(struct rproc *rproc,
>   *
>   * This function releases specified memory entry @mem allocated via
>   * rproc_alloc_carveout() function by @rproc.
> + *
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_release_carveout(struct rproc *rproc,
>  				  struct rproc_mem_entry *mem)
> @@ -918,6 +924,8 @@ static int rproc_release_carveout(struct rproc *rproc,
>   * (e.g. CMA) more efficiently, and also minimizes the number of TLB entries
>   * needed to map it (in case @rproc is using an IOMMU). Reducing the TLB
>   * pressure is important; it may have a substantial impact on performance.
> + *
> + * Return: 0 on success, or an appropriate error code otherwise
>   */
>  static int rproc_handle_carveout(struct rproc *rproc,
>  				 void *ptr, int offset, int avail)
> @@ -1006,6 +1014,8 @@ EXPORT_SYMBOL(rproc_add_carveout);
>   *
>   * This function allocates a rproc_mem_entry struct and fill it with parameters
>   * provided by client.
> + *
> + * Return: a valid pointer on success, or NULL on failure
>   */
>  __printf(8, 9)
>  struct rproc_mem_entry *
> @@ -1050,6 +1060,8 @@ EXPORT_SYMBOL(rproc_mem_entry_init);
>   *
>   * This function allocates a rproc_mem_entry struct and fill it with parameters
>   * provided by client.
> + *
> + * Return: a valid pointer on success, or NULL on failure
>   */
>  __printf(5, 6)
>  struct rproc_mem_entry *
> @@ -1881,6 +1893,8 @@ static int __rproc_detach(struct rproc *rproc)
>   * remoteproc functional again.
>   *
>   * This function can sleep, so it cannot be called from atomic context.
> + *
> + * Return: 0 on success or a negative value upon failure
>   */
>  int rproc_trigger_recovery(struct rproc *rproc)
>  {
> @@ -1965,7 +1979,7 @@ static void rproc_crash_handler_work(struct work_struct *work)
>   * If the remote processor is already powered on, this function immediately
>   * returns (successfully).
>   *
> - * Returns 0 on success, and an appropriate error value otherwise.
> + * Return: 0 on success, and an appropriate error value otherwise
>   */
>  int rproc_boot(struct rproc *rproc)
>  {
> @@ -2100,6 +2114,8 @@ EXPORT_SYMBOL(rproc_shutdown);
>   * no longer available.  From there it should be possible to remove the
>   * platform driver and even power cycle the application processor (if the HW
>   * supports it) without needing to switch off the remote processor.
> + *
> + * Return: 0 on success, and an appropriate error value otherwise
>   */
>  int rproc_detach(struct rproc *rproc)
>  {
> @@ -2152,7 +2168,7 @@ EXPORT_SYMBOL(rproc_detach);
>   * This function increments the remote processor's refcount, so always
>   * use rproc_put() to decrement it back once rproc isn't needed anymore.
>   *
> - * Returns the rproc handle on success, and NULL on failure.
> + * Return: rproc handle on success, and NULL on failure
>   */
>  #ifdef CONFIG_OF
>  struct rproc *rproc_get_by_phandle(phandle phandle)
> @@ -2302,8 +2318,6 @@ static int rproc_validate(struct rproc *rproc)
>   * This is called by the platform-specific rproc implementation, whenever
>   * a new remote processor device is probed.
>   *
> - * Returns 0 on success and an appropriate error code otherwise.
> - *
>   * Note: this function initiates an asynchronous firmware loading
>   * context, which will look for virtio devices supported by the rproc's
>   * firmware.
> @@ -2311,6 +2325,8 @@ static int rproc_validate(struct rproc *rproc)
>   * If found, those virtio devices will be created and added, so as a result
>   * of registering this remote processor, additional virtio drivers might be
>   * probed.
> + *
> + * Return: 0 on success and an appropriate error code otherwise
>   */
>  int rproc_add(struct rproc *rproc)
>  {
> @@ -2364,7 +2380,7 @@ static void devm_rproc_remove(void *rproc)
>   * This function performs like rproc_add() but the registered rproc device will
>   * automatically be removed on driver detach.
>   *
> - * Returns: 0 on success, negative errno on failure
> + * Return: 0 on success, negative errno on failure
>   */
>  int devm_rproc_add(struct device *dev, struct rproc *rproc)
>  {
> @@ -2472,10 +2488,10 @@ static int rproc_alloc_ops(struct rproc *rproc, const struct rproc_ops *ops)
>   * implementations should then call rproc_add() to complete
>   * the registration of the remote processor.
>   *
> - * On success the new rproc is returned, and on failure, NULL.
> - *
>   * Note: _never_ directly deallocate @rproc, even if it was not registered
>   * yet. Instead, when you need to unroll rproc_alloc(), use rproc_free().
> + *
> + * Return: new rproc pointer on success, and NULL on failure
>   */
>  struct rproc *rproc_alloc(struct device *dev, const char *name,
>  			  const struct rproc_ops *ops,
> @@ -2588,7 +2604,7 @@ 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.
> + * Return: 0 on success and -EINVAL if @rproc isn't valid
>   */
>  int rproc_del(struct rproc *rproc)
>  {
> @@ -2635,7 +2651,7 @@ static void devm_rproc_free(struct device *dev, void *res)
>   * This function performs like rproc_alloc() but the acquired rproc device will
>   * automatically be released on driver detach.
>   *
> - * Returns: new rproc instance, or NULL on failure
> + * Return: new rproc instance, or NULL on failure
>   */
>  struct rproc *devm_rproc_alloc(struct device *dev, const char *name,
>  			       const struct rproc_ops *ops,
> @@ -2687,7 +2703,7 @@ EXPORT_SYMBOL(rproc_remove_subdev);
>   * rproc_get_by_child() - acquire rproc handle of @dev's ancestor
>   * @dev:	child device to find ancestor of
>   *
> - * Returns the ancestor rproc instance, or NULL if not found.
> + * Return: the ancestor rproc instance, or NULL if not found
>   */
>  struct rproc *rproc_get_by_child(struct device *dev)
>  {
> diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
> index 11423588965a..469c52e62faf 100644
> --- a/drivers/remoteproc/remoteproc_elf_loader.c
> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
> @@ -31,6 +31,8 @@
>   * @fw: the ELF firmware image
>   *
>   * Make sure this fw image is sane (ie a correct ELF32/ELF64 file).
> + *
> + * Return: 0 on success and -EINVAL upon any failure
>   */
>  int rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw)
>  {
> @@ -117,11 +119,11 @@ EXPORT_SYMBOL(rproc_elf_sanity_check);
>   * @rproc: the remote processor handle
>   * @fw: the ELF firmware image
>   *
> - * This function returns the entry point address of the ELF
> - * image.
> - *
>   * Note that the boot address is not a configurable property of all remote
>   * processors. Some will always boot at a specific hard-coded address.
> + *
> + * Return: entry point address of the ELF image
> + *
>   */
>  u64 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
>  {
> @@ -152,6 +154,8 @@ EXPORT_SYMBOL(rproc_elf_get_boot_addr);
>   * might be different: they might not have iommus, and would prefer to
>   * directly allocate memory for every segment/resource. This is not yet
>   * supported, though.
> + *
> + * Return: 0 on success and an appropriate error code otherwise
>   */
>  int rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
>  {
> @@ -362,7 +366,7 @@ EXPORT_SYMBOL(rproc_elf_load_rsc_table);
>   * This function finds the location of the loaded resource table. Don't
>   * call this function if the table wasn't loaded yet - it's a bug if you do.
>   *
> - * Returns the pointer to the resource table if it is found or NULL otherwise.
> + * Return: pointer to the resource table if it is found or NULL otherwise.

Here the '.' has been kept while it was remove for all of the above.  I don't
know that the right guidelines are for this. 

>   * If the table wasn't loaded yet the result is unspecified.
>   */
>  struct resource_table *rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
> diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> index 0cc617f76068..cf4d54e98e6a 100644
> --- a/drivers/remoteproc/remoteproc_virtio.c
> +++ b/drivers/remoteproc/remoteproc_virtio.c
> @@ -45,7 +45,7 @@ static bool rproc_virtio_notify(struct virtqueue *vq)
>   * when the remote processor signals that a specific virtqueue has pending
>   * messages available.
>   *
> - * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
> + * Return: IRQ_NONE if no message was found in the @notifyid virtqueue,
>   * and otherwise returns IRQ_HANDLED.

Same

>   */
>  irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
> @@ -325,7 +325,7 @@ static void rproc_virtio_dev_release(struct device *dev)
>   * This function registers a virtio device. This vdev's partent is
>   * the rproc device.
>   *
> - * Returns 0 on success or an appropriate error value otherwise.
> + * Return: 0 on success or an appropriate error value otherwise
>   */
>  int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
>  {
> @@ -432,6 +432,8 @@ int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
>   * @data: must be null
>   *
>   * This function unregisters an existing virtio device.
> + *
> + * Return: 0
>   */
>  int rproc_remove_virtio_dev(struct device *dev, void *data)
>  {
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index 8b795b544f75..42a1f30e33a7 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -243,7 +243,7 @@ struct fw_rsc_trace {
>   * @da: device address
>   * @align: the alignment between the consumer and producer parts of the vring
>   * @num: num of buffers supported by this vring (must be power of two)
> - * @notifyid is a unique rproc-wide notify index for this vring. This notify
> + * @notifyid: a unique rproc-wide notify index for this vring. This notify
>   * index is used when kicking a remote processor, to let it know that this
>   * vring is triggered.
>   * @pa: physical address
> @@ -266,18 +266,18 @@ struct fw_rsc_vdev_vring {
>  /**
>   * struct fw_rsc_vdev - virtio device header
>   * @id: virtio device id (as in virtio_ids.h)
> - * @notifyid is a unique rproc-wide notify index for this vdev. This notify
> + * @notifyid: a unique rproc-wide notify index for this vdev. This notify
>   * index is used when kicking a remote processor, to let it know that the
>   * status/features of this vdev have changes.
> - * @dfeatures specifies the virtio device features supported by the firmware
> - * @gfeatures is a place holder used by the host to write back the
> + * @dfeatures: specifies the virtio device features supported by the firmware
> + * @gfeatures: a place holder used by the host to write back the
>   * negotiated features that are supported by both sides.
> - * @config_len is the size of the virtio config space of this vdev. The config
> + * @config_len: the size of the virtio config space of this vdev. The config
>   * space lies in the resource table immediate after this vdev header.
> - * @status is a place holder where the host will indicate its virtio progress.
> - * @num_of_vrings indicates how many vrings are described in this vdev header
> + * @status: a place holder where the host will indicate its virtio progress.
> + * @num_of_vrings: indicates how many vrings are described in this vdev header
>   * @reserved: reserved (must be zero)
> - * @vring is an array of @num_of_vrings entries of 'struct fw_rsc_vdev_vring'.
> + * @vring: an array of @num_of_vrings entries of 'struct fw_rsc_vdev_vring'.
>   *
>   * This resource is a virtio device header: it provides information about
>   * the vdev, and is then used by the host and its peer remote processors
> @@ -287,16 +287,17 @@ struct fw_rsc_vdev_vring {
>   * to statically allocate a vdev upon registration of the rproc (dynamic vdev
>   * allocation is not yet supported).
>   *
> - * Note: unlike virtualization systems, the term 'host' here means
> - * the Linux side which is running remoteproc to control the remote
> - * processors. We use the name 'gfeatures' to comply with virtio's terms,
> - * though there isn't really any virtualized guest OS here: it's the host
> - * which is responsible for negotiating the final features.
> - * Yeah, it's a bit confusing.
> - *
> - * Note: immediately following this structure is the virtio config space for
> - * this vdev (which is specific to the vdev; for more info, read the virtio
> - * spec). the size of the config space is specified by @config_len.
> + * Note:
> + * 1. unlike virtualization systems, the term 'host' here means
> + *    the Linux side which is running remoteproc to control the remote
> + *    processors. We use the name 'gfeatures' to comply with virtio's terms,
> + *    though there isn't really any virtualized guest OS here: it's the host
> + *    which is responsible for negotiating the final features.
> + *    Yeah, it's a bit confusing.
> + *
> + * 2. immediately following this structure is the virtio config space for
> + *    this vdev (which is specific to the vdev; for more info, read the virtio
> + *    spec). the size of the config space is specified by @config_len.

s/the/The

>   */
>  struct fw_rsc_vdev {
>  	u32 id;
> @@ -440,7 +441,7 @@ enum rproc_state {
>   * enum rproc_crash_type - remote processor crash types
>   * @RPROC_MMUFAULT:	iommu fault
>   * @RPROC_WATCHDOG:	watchdog bite
> - * @RPROC_FATAL_ERROR	fatal error
> + * @RPROC_FATAL_ERROR:	fatal error
>   *
>   * Each element of the enum is used as an array index. So that, the value of
>   * the elements should be always something sane.
> @@ -457,9 +458,9 @@ enum rproc_crash_type {
>   * enum rproc_dump_mechanism - Coredump options for core
>   * @RPROC_COREDUMP_DISABLED:	Don't perform any dump
>   * @RPROC_COREDUMP_ENABLED:	Copy dump to separate buffer and carry on with
> -				recovery
> + *				recovery
>   * @RPROC_COREDUMP_INLINE:	Read segments directly from device memory. Stall
> -				recovery until all segments are read
> + *				recovery until all segments are read
>   */
>  enum rproc_dump_mechanism {
>  	RPROC_COREDUMP_DISABLED,
> @@ -475,6 +476,7 @@ enum rproc_dump_mechanism {
>   * @priv:	private data associated with the dump_segment
>   * @dump:	custom dump function to fill device memory segment associated
>   *		with coredump
> + * @offset:	offset of the segment
>   */
>  struct rproc_dump_segment {
>  	struct list_head node;
> @@ -524,7 +526,9 @@ struct rproc_dump_segment {
>   * @auto_boot: flag to indicate if remote processor should be auto-started
>   * @dump_segments: list of segments in the firmware
>   * @nb_vdev: number of vdev currently handled by rproc
> - * @char_dev: character device of the rproc
> + * @elf_class: firmware ELF class
> + * @elf_machine: firmware ELF machine
> + * @cdev: character device of the rproc
>   * @cdev_put_on_release: flag to indicate if remoteproc should be shutdown on @char_dev release
>   */
>  struct rproc {
> @@ -613,10 +617,10 @@ struct rproc_vring {
>   * struct rproc_vdev - remoteproc state for a supported virtio device
>   * @refcount: reference counter for the vdev and vring allocations
>   * @subdev: handle for registering the vdev as a rproc subdevice
> + * @dev: device struct used for reference count semantics
>   * @id: virtio device id (as in virtio_ids.h)
>   * @node: list node
>   * @rproc: the rproc handle
> - * @vdev: the virio device
>   * @vring: the vrings for this vdev
>   * @rsc_offset: offset of the vdev's resource entry
>   * @index: vdev position versus other vdev declared in resource table

With or without the above:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> -- 
> 2.30.1
>