Date:   Tue, 9 Oct 2018 22:58:23 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Loic Pallardy <loic.pallardy@...com>
Cc:     ohad@...ery.com, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org, arnaud.pouliquen@...com,
        benjamin.gaignard@...aro.org, s-anna@...com
Subject: Re: [PATCH v4 13/17] remoteproc: create vdev subdevice with specific
 dma memory pool

On Fri 27 Jul 06:14 PDT 2018, Loic Pallardy wrote:

> This patch creates a dedicated vdev subdevice for each vdev declared
> in firmware resource table and associates carveout named "vdev%dbuffer"
> (with %d vdev index in resource table) if any as dma coherent memory pool.
> 
> Then vdev subdevice is used as parent for virtio device.
> 
> Signed-off-by: Loic Pallardy <loic.pallardy@...com>
> ---
>  drivers/remoteproc/remoteproc_core.c     | 35 +++++++++++++++++++++++---
>  drivers/remoteproc/remoteproc_internal.h |  1 +
>  drivers/remoteproc/remoteproc_virtio.c   | 42 +++++++++++++++++++++++++++++++-
>  include/linux/remoteproc.h               |  1 +
>  4 files changed, 75 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 4edc6f0..adcc66e 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -39,6 +39,7 @@
>  #include <linux/idr.h>
>  #include <linux/elf.h>
>  #include <linux/crc32.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/virtio_ids.h>
>  #include <linux/virtio_ring.h>
>  #include <asm/byteorder.h>
> @@ -145,7 +146,7 @@ static void rproc_disable_iommu(struct rproc *rproc)
>  	iommu_domain_free(domain);
>  }
>  
> -static phys_addr_t rproc_va_to_pa(void *cpu_addr)
> +phys_addr_t rproc_va_to_pa(void *cpu_addr)
>  {
>  	/*
>  	 * Return physical address according to virtual address location
> @@ -160,6 +161,7 @@ static phys_addr_t rproc_va_to_pa(void *cpu_addr)
>  	WARN_ON(!virt_addr_valid(cpu_addr));
>  	return virt_to_phys(cpu_addr);
>  }
> +EXPORT_SYMBOL(rproc_va_to_pa);
>  
>  /**
>   * rproc_da_to_va() - lookup the kernel virtual address for a remoteproc address
> @@ -423,6 +425,20 @@ static void rproc_vdev_do_stop(struct rproc_subdev *subdev, bool crashed)
>  }
>  
>  /**
> + * rproc_rvdev_release() - release the existence of a rvdev
> + *
> + * @dev: the subdevice's dev
> + */
> +static void rproc_rvdev_release(struct device *dev)
> +{
> +	struct rproc_vdev *rvdev = container_of(dev, struct rproc_vdev, dev);
> +
> +	of_reserved_mem_device_release(dev);
> +
> +	kfree(rvdev);
> +}
> +
> +/**
>   * rproc_handle_vdev() - handle a vdev fw resource
>   * @rproc: the remote processor
>   * @rsc: the vring resource descriptor
> @@ -455,6 +471,7 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  	struct device *dev = &rproc->dev;
>  	struct rproc_vdev *rvdev;
>  	int i, ret;
> +	char name[16];
>  
>  	/* make sure resource isn't truncated */
>  	if (sizeof(*rsc) + rsc->num_of_vrings * sizeof(struct fw_rsc_vdev_vring)
> @@ -488,6 +505,18 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  	rvdev->rproc = rproc;
>  	rvdev->index = rproc->nb_vdev++;
>  
> +	/* Initialise vdev subdevice */
> +	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> +	rvdev->dev.parent = rproc->dev.parent;
> +	rvdev->dev.release = rproc_rvdev_release;
> +	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> +	dev_set_drvdata(&rvdev->dev, rvdev);
> +	dma_set_coherent_mask(&rvdev->dev, DMA_BIT_MASK(32));
> +
> +	ret = device_register(&rvdev->dev);
> +	if (ret)
> +		goto free_rvdev;
> +
>  	/* parse the vrings */
>  	for (i = 0; i < rsc->num_of_vrings; i++) {
>  		ret = rproc_parse_vring(rvdev, rsc, i);
> @@ -518,7 +547,7 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  	for (i--; i >= 0; i--)
>  		rproc_free_vring(&rvdev->vring[i]);
>  free_rvdev:
> -	kfree(rvdev);
> +	device_unregister(&rvdev->dev);
>  	return ret;
>  }
>  
> @@ -536,7 +565,7 @@ void rproc_vdev_release(struct kref *ref)
>  
>  	rproc_remove_subdev(rproc, &rvdev->subdev);
>  	list_del(&rvdev->node);
> -	kfree(rvdev);
> +	device_unregister(&rvdev->dev);
>  }
>  
>  /**
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index f6cad24..bfeacfd 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -52,6 +52,7 @@ struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
>  int rproc_alloc_vring(struct rproc_vdev *rvdev, int i);
>  
>  void *rproc_da_to_va(struct rproc *rproc, u64 da, int len);
> +phys_addr_t rproc_va_to_pa(void *cpu_addr);
>  int rproc_trigger_recovery(struct rproc *rproc);
>  
>  int rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw);
> diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> index de21f62..9ee63c0 100644
> --- a/drivers/remoteproc/remoteproc_virtio.c
> +++ b/drivers/remoteproc/remoteproc_virtio.c
> @@ -17,7 +17,9 @@
>   * GNU General Public License for more details.
>   */
>  
> +#include <linux/dma-mapping.h>
>  #include <linux/export.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/remoteproc.h>
>  #include <linux/virtio.h>
>  #include <linux/virtio_config.h>
> @@ -315,10 +317,48 @@ static void rproc_virtio_dev_release(struct device *dev)
>  int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
>  {
>  	struct rproc *rproc = rvdev->rproc;
> -	struct device *dev = &rproc->dev;
> +	struct device *dev = &rvdev->dev;
>  	struct virtio_device *vdev = &rvdev->vdev;
> +	struct rproc_mem_entry *mem;
>  	int ret;
>  
> +	/* Try to find dedicated vdev buffer carveout */
> +	mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer", rvdev->index);
> +	if (mem) {
> +		phys_addr_t pa;
> +
> +		if (mem->of_resm_idx != -1) {
> +			struct device_node *np = rproc->dev.parent->of_node;
> +
> +			/* Associate reserved memory to vdev device */
> +			ret = of_reserved_mem_device_init_by_idx(dev, np,
> +								 mem->of_resm_idx);
> +			if (ret) {
> +				dev_err(dev, "Can't associate reserved memory\n");
> +				goto out;
> +			}
> +		} else {
> +			if (mem->va) {
> +				dev_warn(dev, "vdev %d buffer already mapped\n",
> +					 rvdev->index);
> +				pa = rproc_va_to_pa(mem->va);
> +			} else {
> +				/* Use dma address as carveout no memmapped yet */
> +				pa = (phys_addr_t)mem->dma;
> +			}
> +
> +			/* Associate vdev buffer memory pool to vdev subdev */
> +			ret = dmam_declare_coherent_memory(dev, pa,
> +							   mem->da,
> +							   mem->len,
> +							   DMA_MEMORY_EXCLUSIVE);

Is it not possible to associate the dma_mem with vdev->dev directly,
instead of injecting yet another device in-between the remoteproc
platform device and the virtio device?

That way the resulting allocation in e.g. virtio_rpmsg would be on the
virtio device itself, not its parent.

Regards,
Bjorn

> +			if (ret < 0) {
> +				dev_err(dev, "Failed to associate buffer\n");
> +				goto out;
> +			}
> +		}
> +	}
> +
>  	vdev->id.device	= id,
>  	vdev->config = &rproc_virtio_config_ops,
>  	vdev->dev.parent = dev;
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index 6b3a234..2921dd2 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -547,6 +547,7 @@ struct rproc_vdev {
>  	struct kref refcount;
>  
>  	struct rproc_subdev subdev;
> +	struct device dev;
>  
>  	unsigned int id;
>  	struct list_head node;
> -- 
> 1.9.1
> 

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