From: hdoyu@nvidia•com (Hiroshi Doyu)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v5] devicetree: Add generic IOMMU device tree bindings
Date: Thu, 14 Aug 2014 09:47:42 +0300 [thread overview]
Message-ID: <87a9774lf5.fsf@nvidia.com> (raw)
In-Reply-To: <1406803383-11601-1-git-send-email-thierry.reding@gmail.com>
Thierry Reding <thierry.reding@gmail•com> writes:
> +Multiple-master IOMMU:
> +----------------------
> +
> + iommu {
> + /* the specifier represents the ID of the master */
> + #iommu-cells = <1>;
> + };
> +
> + master at 1 {
> + /* device has master ID 42 in the IOMMU */
> + iommus = <&{/iommu} 42>;
> + };
> +
> + master at 2 {
> + /* device has master IDs 23 and 24 in the IOMMU */
> + iommus = <&{/iommu} 23>, <&{/iommu} 24>;
> + };
I think that this "master ID" will be parsed in IOMMU driver. For
example, ARM,SMMU expects "streamID" as "master ID", right?
If a SoC has a feature to configure to assign streamID to devices at
runtime, "streamID" is not equal to "master ID".
iommus = <&{/smmu} "soc specific master ID">;
"soc master ID" needs to be translated into "streamID" by SoC SW. It
seems that ARM,SMMU kernel driver doesn't expect this kind of ID
translation. If ARM,SMMU kernel driver is used as is, "soc master ID"
would be incompatible? ARM,SMMU needs such translation before
parsing. Is this my understanding right?
If so I think that this master ID configuration/translation may be quite
reasonable requirment for SoC using ARM,SMMU.
Can we consider this ID translation within ARM,SMMU compatibility?
IOW, is it possible to implement some SoC specific hook for ID
translation/configuration in ARM,SMMU kernel driver?
next prev parent reply other threads:[~2014-08-14 6:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-31 10:43 [PATCH v5] devicetree: Add generic IOMMU device tree bindings Thierry Reding
2014-07-31 10:54 ` Mark Rutland
2014-07-31 12:04 ` Joerg Roedel
2014-07-31 15:38 ` Olof Johansson
2014-07-31 16:36 ` Joerg Roedel
2014-07-31 17:14 ` Olof Johansson
2014-07-31 17:23 ` Joerg Roedel
2014-07-31 18:09 ` Laurent Pinchart
2014-08-14 6:47 ` Hiroshi Doyu [this message]
2014-08-14 14:45 ` Varun Sethi
2014-08-14 16:04 ` Hiroshi Doyu
2014-08-19 9:52 ` Varun Sethi
2014-08-19 10:03 ` Hiroshi Doyu
2014-08-19 10:47 ` Varun Sethi
2014-08-19 11:03 ` Hiroshi Doyu
2014-08-19 12:01 ` Varun Sethi
2014-08-15 11:51 ` Will Deacon
2014-08-15 12:29 ` Hiroshi Doyu
2014-08-15 13:14 ` Will Deacon
2014-08-19 12:11 ` Varun Sethi
2014-08-22 15:33 ` Will Deacon
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