Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1192650

Re: [PATCH v3 5/6] iommu/mediatek: Add mt8173 IOMMU driver

Show key headers only | View raw

On Fri, 2015-07-24 at 17:55 +0100, Will Deacon wrote:
> On Fri, Jul 24, 2015 at 06:43:13AM +0100, Yong Wu wrote:
> > On Tue, 2015-07-21 at 15:59 +0100, Will Deacon wrote:
> > > On Thu, Jul 16, 2015 at 10:04:34AM +0100, Yong Wu wrote:
> > > > +static void mtk_iommu_tlb_flush_all(void *cookie)
> > > > +{
> > > > +       struct mtk_iommu_domain *domain = cookie;
> > > > +       void __iomem *base;
> > > > +
> > > > +       base = domain->data->base;
> > > > +       writel(F_INVLD_EN1 | F_INVLD_EN0, base + REG_MMU_INV_SEL);
> > > > +       writel(F_ALL_INVLD, base + REG_MMU_INVALIDATE);
> > > 
> > > This needs to be synchronous, so you probably want to call
> > > mtk_iommu_tlb_sync at the end.
> > 
> > From our spec, we have to wait until HW done after tlb flush range.
> > But it don't need wait after tlb flush all.
> > so It isn't necessary to add mtk_iommu_tlb_sync in tlb_flush_all here.
> 
> Okey doke, but I'm surprised you don't need a subsequent DSB or read-back.
> What if the writel is buffered on the way to the IOMMU?

Then I change to this:
 //==========
    writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0, base + REG_MMU_INV_SEL);
    writel_relaxed(F_ALL_INVLD, base + REG_MMU_INVALIDATE);    
    dsb(ishst);
//===========
    dsb or mb(). which one is better here?

> 
> Will


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

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

Re: [PATCH v3 5/6] iommu/mediatek: Add mt8173 IOMMU driver Yong Wu <yong.wu@mediatek.com> - 2015-07-27 06:30 +0200

csiph-web