linux-kernel - Re: [PATCH v5 04/27] dt-bindings: memory: mediatek: Add domain definition

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Date:   Thu, 24 Dec 2020 19:26:52 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     Tomasz Figa <tfiga@...omium.org>
CC:     Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>, <youlin.pei@...iatek.com>,
        <devicetree@...r.kernel.org>,
        Nicolas Boichat <drinkcat@...omium.org>,
        <srv_heupstream@...iatek.com>, <chao.hao@...iatek.com>,
        <linux-kernel@...r.kernel.org>, Evan Green <evgreen@...omium.org>,
        Tomasz Figa <tfiga@...gle.com>,
        <iommu@...ts.linux-foundation.org>,
        <linux-mediatek@...ts.infradead.org>,
        Krzysztof Kozlowski <krzk@...nel.org>, <anan.sun@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v5 04/27] dt-bindings: memory: mediatek: Add domain
 definition

On Wed, 2020-12-23 at 17:15 +0900, Tomasz Figa wrote:
> Hi Yong,
> 
> On Wed, Dec 09, 2020 at 04:00:39PM +0800, Yong Wu wrote:
> > In the latest SoC, there are several HW IP require a sepecial iova
> > range, mainly CCU and VPU has this requirement. Take CCU as a example,
> > CCU require its iova locate in the range(0x4000_0000 ~ 0x43ff_ffff).
> 
> Is this really a domain? Does the address range come from the design of
> the IOMMU?

It is not a really a domain. The address range comes from CCU HW
requirement. That HW can only access this iova range. thus I create a
special iommu domain for it.

> 
> Best regards,
> Tomasz
> 
> > 
> > In this patch we add a domain definition for the special port. In the
> > example of CCU, If we preassign CCU port in domain1, then iommu driver
> > will prepare a independent iommu domain of the special iova range for it,
> > then the iova got from dma_alloc_attrs(ccu-dev) will locate in its special
> > range.
> > 
> > This is a preparing patch for multi-domain support.
> > 
> > Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> > Acked-by: Krzysztof Kozlowski <krzk@...nel.org>
> > Acked-by: Rob Herring <robh@...nel.org>
> > ---
> >  include/dt-bindings/memory/mtk-smi-larb-port.h | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/dt-bindings/memory/mtk-smi-larb-port.h b/include/dt-bindings/memory/mtk-smi-larb-port.h
> > index 7d64103209af..2d4c973c174f 100644
> > --- a/include/dt-bindings/memory/mtk-smi-larb-port.h
> > +++ b/include/dt-bindings/memory/mtk-smi-larb-port.h
> > @@ -7,9 +7,16 @@
> >  #define __DT_BINDINGS_MEMORY_MTK_MEMORY_PORT_H_
> >  
> >  #define MTK_LARB_NR_MAX			32
> > +#define MTK_M4U_DOM_NR_MAX		8
> > +
> > +#define MTK_M4U_DOM_ID(domid, larb, port)	\
> > +	(((domid) & 0x7) << 16 | (((larb) & 0x1f) << 5) | ((port) & 0x1f))
> > +
> > +/* The default dom id is 0. */
> > +#define MTK_M4U_ID(larb, port)		MTK_M4U_DOM_ID(0, larb, port)
> >  
> > -#define MTK_M4U_ID(larb, port)		(((larb) << 5) | (port))
> >  #define MTK_M4U_TO_LARB(id)		(((id) >> 5) & 0x1f)
> >  #define MTK_M4U_TO_PORT(id)		((id) & 0x1f)
> > +#define MTK_M4U_TO_DOM(id)		(((id) >> 16) & 0x7)
> >  
> >  #endif
> > -- 
> > 2.18.0
> > 
> > _______________________________________________
> > iommu mailing list
> > iommu@...ts.linux-foundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/iommu

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