Re: [PATCH] SATA: OCTEON: support SATA on OCTEON platform

[Arnd Bergmann <arnd@arndb.de>]

On Monday 19 January 2015 14:30:22 Rob Herring wrote:
> On Mon, Jan 19, 2015 at 1:16 PM, David Daney <ddaney.cavm@gmail.com> wrote:
> > On 01/19/2015 07:43 AM, Mark Rutland wrote:
> >>
> >> On Mon, Jan 19, 2015 at 03:23:58PM +0000, Aleksey Makarov wrote:
> >>>
> >>> The OCTEON SATA controller is currently found on cn71XX devices.
> 
> [...]
> 
> >>> +
> >>> +       /* Set a good dma_mask */
> >>> +       pdev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
> >>> +       pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
> >>
> >>
> >> I thought a dma-ranges property in the DT could be used to set up the
> >> DMA mask appropriately?
> >
> >
> > The DT contains no dma-ranges property, and we know a priori, that it should
> > be 64-bits.
> 
> Neither this code nor dma-ranges should be necessary. The AHCI core
> code will set the mask to 32 or 64 bits based on the AHCI Capabilities
> register.

You should however have a dma-ranges property in the parent bus of the
device that contains the allowed range for DMA. The current dma_set_mask
function is broken and will accept whatever a device driver asks for,
and we need to fix this so masks larger than what is specified in dma-ranges
are rejected.

	Arnd