RE: [PATCH v2 1/3] dma-mapping: introduce new dma unmap and sync api variants

From: Laurentiu Tudor
Date: Tue Oct 29 2019 - 03:06:43 EST

> -----Original Message-----
> From: hch@xxxxxx <hch@xxxxxx>
> Sent: Monday, October 28, 2019 2:38 PM
> On Thu, Oct 24, 2019 at 12:41:41PM +0000, Laurentiu Tudor wrote:
> > From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
> >
> > Introduce a few new dma unmap and sync variants that, on top of the
> > original variants, return the virtual address corresponding to the
> > input dma address.
> > In order to implement this a new dma map op is added and used:
> > void *get_virt_addr(dev, dma_handle);
> > It does the actual conversion of an input dma address to the output
> > virtual address.
> We'll definitively need an implementation for dma-direct at least as
> well. Also as said previously we need a dma_can_unmap_by_dma_addr()
> or similar helper that tells the driver beforehand if this works, so
> that the driver can either use a sub-optimal workaround or fail the
> probe if this functionality isn't implemented.

Alright. On top of that I need to make this work on booke ppc as we have one driver that runs both on arm and ppc and will use these APIs.

Best Regards, Laurentiu