Hello!
I note the following in the serial console:
if (is_rproc_serial(vdev)) {
/*
* Allocate DMA memory from ancestor. When a virtio
* device is created by remoteproc, the DMA memory is
* associated with the grandparent device:
* vdev => rproc => platform-dev.
*/
if (!vdev->dev.parent || !vdev->dev.parent->parent)
goto free_buf;
buf->dev = vdev->dev.parent->parent;
/* Increase device refcnt to avoid freeing it */
get_device(buf->dev);
buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
GFP_KERNEL);
}
Added here:
commit 1b6370463e88b0c1c317de16d7b962acc1dab4f2
Author: Sjur Brændeland <[email protected]>
Date: Fri Dec 14 14:40:51 2012 +1030
virtio_console: Add support for remoteproc serial
I am not familiar with rproc so I have a question:
why is it required to use coherent memory here,
and why through a grandparent device?
Would it work to instead change vring_use_dma_api
to whitelist rproc (like we do for xen)?
I can sent a patch for your testing.
Thanks!
--
MST
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