Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32

2019-09-11 Thread Nicolas Saenz Julienne
On Wed, 2019-09-11 at 15:35 +0100, Catalin Marinas wrote: > On Wed, Sep 11, 2019 at 12:54:38PM +0200, Nicolas Saenz Julienne wrote: > > On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote: > > > /* > > > - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). > > > I

Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32

2019-09-11 Thread Catalin Marinas
On Wed, Sep 11, 2019 at 12:54:38PM +0200, Nicolas Saenz Julienne wrote: > On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote: > > /* > > - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). > > It > > - * currently assumes that for memory starting above 4G, 32-b

Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32

2019-09-11 Thread Nicolas Saenz Julienne
On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote: > + > /* > - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). It > - * currently assumes that for memory starting above 4G, 32-bit devices will > - * use a DMA offset. > + * Return the maximum physical address

[PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32

2019-09-09 Thread Nicolas Saenz Julienne
So far all arm64 devices have supported 32 bit DMA masks for their peripherals. This is not true anymore for the Raspberry Pi 4 as most of it's peripherals can only address the first GB of memory on a total of up to 4 GB. This goes against ZONE_DMA32's intent, as it's expected for ZONE_DMA32 to be