Re: [PATCH 1/7] irqchip/gic-v3: Add a DMA Non-Coherent flag

From: Marc Zyngier
Date: Fri Mar 10 2023 - 06:57:05 EST


On Fri, 10 Mar 2023 11:41:46 +0000,
Peter Geis <pgwipeout@xxxxxxxxx> wrote:
>
> On Fri, Mar 10, 2023 at 3:05 AM Lucas Tanure <lucas.tanure@xxxxxxxxxxxxx> wrote:
> >
> > The GIC600 integration in RK356x, used in rk3588, doesn't support
> > any of the shareability or cacheability attributes, and requires
> > both values to be set to 0b00 for all the ITS and Redistributor
> > tables.
> >
> > This is loosely based on prior work from XiaoDong Huang and
> > Peter Geis fixing this issue specifically for Rockchip 356x.
>
> Good Morning,
>
> Since the gic is using dma, would it be reasonable to have all memory
> allocations be requested with the GFP_DMA flag? Otherwise this doesn't
> fully solve the problem for rk356x, where only the lower 4GB range is
> DMA capable, but this tends to get allocated in the upper 4GB on 8GB
> boards.

That's an erratum. Please treat as such.

M.

--
Without deviation from the norm, progress is not possible.