Messages in this thread | | | Date | Mon, 4 Jun 2018 13:16:37 -0700 | From | Bjorn Andersson <> | Subject | Re: [PATCH] virtio_ring: switch to dma_XX barriers for rpmsg |
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On Thu 19 Apr 10:48 PDT 2018, Paolo Bonzini wrote:
> On 19/04/2018 19:46, Michael S. Tsirkin wrote: > >> This should be okay, but I wonder if there should be a virtio_wmb(...) > >> or an "if (weak_barriers) wmb()" before the "writel" in vm_notify > >> (drivers/virtio/virtio_mmio.c). > >> > >> Thanks, > >> > >> Paolo > > That one uses weak barriers AFAIK. > > > > IIUC you mean rproc_virtio_notify. > > > > I suspect it works because specific kick callbacks have a barrier internally. > > Yes, that one. At least keystone_rproc_kick doesn't seem to have a barrier. >
Afaict you're correct. My expectation is that the kick ensures write ordering internally and if I read this correct keystone_rproc_kick() results in a writel_relaxed() in the gpio driver.
@Suman, can you please have a look at this.
Thanks Paolo, Bjorn
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