Re: [PATCH 2/5] iommu/mediatek: Add mt8173 IOMMU driver

From: Yingjoe Chen
Date: Mon Mar 09 2015 - 10:47:50 EST


On Mon, 2015-03-09 at 20:11 +0900, Tomasz Figa wrote:
<...>
> > +/*
> > + * pimudev is a global var for dma_alloc_coherent.
> > + * It is not accepatable, we will delete it if "domain_alloc" is enabled
> > + */
> > +static struct device *pimudev;
>
> This is indeed not acceptable. Could you replace dma_alloc_coherent()
> with something that doesn't require device pointer, e.g.
> alloc_pages()? (Although that would require you to handle cache
> maintenance in the driver, due to cached memory allocated.) I need to
> think about a better solution for this.

Hi,

For 2nd level page table, we use cached memory now. Currently we are
using __dma_flush_range to flush the cache, which is also unacceptable.

For proper cache management, we'll need to use dma_map_single or
dma_sync_*, which still need a deivce*.

Joe.C


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/