Re: [PATCH v4 13/17] remoteproc: create vdev subdevice with specific dma memory pool

[Suman Anna <s-anna@ti.com>]

On 10/10/18 2:17 PM, Loic PALLARDY wrote:
> 
> 
>> -----Original Message-----
>> From: Bjorn Andersson [mailto:bjorn.andersson@linaro.org]
>> Sent: mercredi 10 octobre 2018 07:58
>> To: Loic PALLARDY <loic.pallardy@st.com>
>> Cc: ohad@wizery.com; linux-remoteproc@vger.kernel.org; linux-
>> kernel@vger.kernel.org; Arnaud POULIQUEN <arnaud.pouliquen@st.com>;
>> benjamin.gaignard@linaro.org; s-anna@ti.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@st.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?
> 
> Thank you for the review.
> I'll check how to use virtio device. An additional ops for memory registration may be needed at virtio level. 
> 
>>
>> That way the resulting allocation in e.g. virtio_rpmsg would be on the
>> virtio device itself, not its parent.

> Yes agree, it will simplify allocation/inheritance...

+ Anup.

Anup,
Since you are currently interested in patch 17 (dma allocations from
vdev parent), may we get some information on how your device hierarchy
is looking like inside the VM/Guest?

regards
Suman

> 
> Regards,
> Loic
>>
>> 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
>>>