linux-kernel - Re: [PATCH RESEND] rpmsg: virtio_rpmsg_bus: fix rpmsg

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Date:   Tue, 23 Jan 2018 19:16:13 +0530
From:   Anup Patel <anup@...infault.org>
To:     Ohad Ben-Cohen <ohad@...ery.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     linux-remoteproc@...r.kernel.org,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
        Anup Patel <anup@...infault.org>, stable@...r.kernel.org
Subject: Re: [PATCH RESEND] rpmsg: virtio_rpmsg_bus: fix rpmsg_probe() for
 virtio-mmio transport

On Wed, Jan 10, 2018 at 6:46 PM, Anup Patel <anup@...infault.org> wrote:
> When virtio-rpmsg device is provided via virtio-mmio transport, the
> dma_alloc_coherent() (called by rpmsg_probe()) fails on ARM/ARM64
> systems because "vdev->dev.parent->parent" device is used as parameter
> to dma_alloc_coherent().
>
> The "vdev->dev.parent->parent" device represents underlying remoteproc
> platform device when virtio-rpmsg device is provided via virtio-remoteproc
> transport. When virtio-rpmsg device is provided via virtio-mmio transport,
> the "vdev->dev.parent->parent" device represents the parent device of
> virtio-mmio platform device and dma_alloc_coherent() fails for this device
> because generally there is no corresponding platform device and dma_ops
> are not setup for "vdev->dev.parent->parent".
>
> This patch fixes dma_alloc_coherent() usage in rpmsg_probe() by trying
> dma_alloc_coherent() with "vdev->dev.parent" device when it fails with
> "vdev->dev.parent->parent" device.
>
> Fixes: b5ab5e24e960 ("remoteproc: maintain a generic child device for
> each rproc")
>
> Signed-off-by: Anup Patel <anup@...infault.org>
> Cc: stable@...r.kernel.org
> ---
>  drivers/rpmsg/virtio_rpmsg_bus.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
> index 82b8300..7f8710a 100644
> --- a/drivers/rpmsg/virtio_rpmsg_bus.c
> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c
> @@ -64,6 +64,7 @@
>  struct virtproc_info {
>         struct virtio_device *vdev;
>         struct virtqueue *rvq, *svq;
> +       struct device *bufs_dev;
>         void *rbufs, *sbufs;
>         unsigned int num_bufs;
>         unsigned int buf_size;
> @@ -924,9 +925,16 @@ static int rpmsg_probe(struct virtio_device *vdev)
>                                      total_buf_space, &vrp->bufs_dma,
>                                      GFP_KERNEL);
>         if (!bufs_va) {
> -               err = -ENOMEM;
> -               goto vqs_del;
> -       }
> +               bufs_va = dma_alloc_coherent(vdev->dev.parent,
> +                                            total_buf_space, &vrp->bufs_dma,
> +                                            GFP_KERNEL);
> +               if (!bufs_va) {
> +                       err = -ENOMEM;
> +                       goto vqs_del;
> +               } else
> +                       vrp->bufs_dev = vdev->dev.parent;
> +       } else
> +               vrp->bufs_dev = vdev->dev.parent->parent;
>
>         dev_dbg(&vdev->dev, "buffers: va %p, dma %pad\n",
>                 bufs_va, &vrp->bufs_dma);
> @@ -988,7 +996,7 @@ static int rpmsg_probe(struct virtio_device *vdev)
>         return 0;
>
>  free_coherent:
> -       dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
> +       dma_free_coherent(vrp->bufs_dev, total_buf_space,
>                           bufs_va, vrp->bufs_dma);
>  vqs_del:
>         vdev->config->del_vqs(vrp->vdev);
> @@ -1023,7 +1031,7 @@ static void rpmsg_remove(struct virtio_device *vdev)
>
>         vdev->config->del_vqs(vrp->vdev);
>
> -       dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
> +       dma_free_coherent(vrp->bufs_dev, total_buf_space,
>                           vrp->rbufs, vrp->bufs_dma);
>
>         kfree(vrp);
> --
> 2.7.4
>

Hi All,

Any comments on this??

Regards,
Anup