From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [RFC 1/5] dt-bindings: iommu: Add reserved-dma-region for IOMMU device Date: Tue, 6 Mar 2018 11:41:01 +0000 Message-ID: <23f7c879-2dfe-dbdf-f259-dcc44f045c96@arm.com> References: <1520312368-7068-1-git-send-email-jitendra.bhivare@broadcom.com> <1520312368-7068-2-git-send-email-jitendra.bhivare@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1520312368-7068-2-git-send-email-jitendra.bhivare-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Jitendra Bhivare , will.deacon-5wv7dgnIgG8@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org On 06/03/18 04:59, Jitendra Bhivare wrote: > Certain regions in IO virtual address space may need to be reserved to be > not used for devices configured behind IOMMU. > > Add documentation of the property to allow such regions to be specified in > DT to be reserved using IOMMU_RESV_RESERVED type. That sounds like software policy; DT is for describing hardware. > Reviewed-by: Ray Jui > Reviewed-by: Vikram Prakash > Reviewed-by: Scott Branden > Signed-off-by: Jitendra Bhivare > --- > Documentation/devicetree/bindings/iommu/iommu.txt | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/Documentation/devicetree/bindings/iommu/iommu.txt b/Documentation/devicetree/bindings/iommu/iommu.txt > index 5a8b462..5a58ef2 100644 > --- a/Documentation/devicetree/bindings/iommu/iommu.txt > +++ b/Documentation/devicetree/bindings/iommu/iommu.txt > @@ -98,6 +98,20 @@ requirements of that use-case haven't been fully determined yet. Implementing > this is therefore not recommended without further discussion and extension of > this binding. > > +Optional properties: > +-------------------- > +- reserved-dma-region: This specifies DMA region to be reserved with specific > + prot in IOVA space. It is in tuples of (busno,prot,bus_addr,size). What do busno and prot actually mean, and what are valid values for them? Robin. > +- #region-address-cells: specifies number of cells needed to encode bus_addr > + > +- #region-size-cells: specifies number of cells needed to encode size > + > +Notes: > +====== > +This can be applied to IOMMU master node or to children (such as PCI host > +bridges) on the bus behind IOMMU. > + > > Examples: > ========= > @@ -173,6 +187,9 @@ Multiple-master IOMMU with configurable DMA window: > * master (i.e. the I/O virtual address space). > */ > #iommu-cells = <4>; > + #region-address-cells = <2>; > + #region-size-cells = <2>; > + reserved-dma-region = <0x0 0x0 0x04 0x0 0x04 0x0>; > }; > > master { >