From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2] devicetree: Add generic IOMMU device tree bindings
Date: Mon, 30 Jun 2014 10:52:20 +0100 [thread overview]
Message-ID: <20140630095220.GA25779@arm.com> (raw)
In-Reply-To: <53ADEEDF.7060902@codeaurora.org>
Hi Olav,
On Fri, Jun 27, 2014 at 11:23:27PM +0100, Olav Haugan wrote:
> On 6/25/2014 2:18 AM, Will Deacon wrote:
> > Why can't it be dynamically detected? Whilst the StreamIDs are fixed in
> > hardware (from the SMMU architecture perspective), the SMRs are completely
> > programmable. Why doesn't something like Andreas's proposal work for you?
> > The idea there was to find the constant bits among the StreamIDs for a
> > master and create the mask accordingly.
> >
> Lets say I have an IOMMU with 2 masters and 2 SMRn slots with the
> following stream IDs coming from the masters:
>
> Master 1: 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28
> Master 2: 0x30
>
> To make this work I would program SMR[0] with StreamID 0x20 and mask 0xF
> to ignore lower 4 bits. SMR[1] would just be StreamID 0x30 with mask 0x0.
>
> However, I could also have an IOMMU with 2 masters and 9 SMRn slots with
> the following stream IDs:
>
> Master 1: 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28
> Master 2: 0x29
>
> Here I would program all SMRn and leave the mask to be 0 for all SMRn's.
> So how do I detect when to apply a mask or not?
You would aim to use the smallest number of SMRs per master possible.
You could probably use:
Master 1: SMR[0].id == 0x20, SMR[0].mask = 0x07
SMR[1].id == 0x28, SMR[1].mask = 0x00
Master 2: SMR[2].id == 0x29, SMR[2].mask = 0x00
> I am not familiar with Andreas's proposal. Do you have a link?
http://marc.info/?l=linux-arm-kernel&m=139110598005846&w=2
Note that since Calxeda went under, Andreas is unfortunately no longer
working on this.
Will
next prev parent reply other threads:[~2014-06-30 9:52 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1400877218-4113-1-git-send-email-thierry.reding@gmail.com>
2014-05-30 13:16 ` [PATCH v2] devicetree: Add generic IOMMU device tree bindings Rob Herring
2014-05-30 19:06 ` Arnd Bergmann
2014-05-30 19:29 ` Hiroshi Doyu
2014-05-30 19:54 ` Arnd Bergmann
2014-06-01 9:55 ` Will Deacon
2014-06-04 13:39 ` Thierry Reding
2014-06-04 13:44 ` Thierry Reding
2014-06-04 13:53 ` Arnd Bergmann
2014-06-04 13:56 ` Will Deacon
2014-06-04 14:01 ` Arnd Bergmann
2014-06-04 16:39 ` Will Deacon
2014-05-30 19:31 ` Rob Herring
2014-05-30 19:49 ` Arnd Bergmann
2014-06-02 10:41 ` Dave Martin
2014-06-04 14:35 ` Thierry Reding
2014-06-04 16:41 ` Will Deacon
2014-06-04 21:00 ` Thierry Reding
2014-06-05 19:10 ` Varun Sethi
2014-06-16 15:27 ` Will Deacon
2014-06-16 16:56 ` Stuart Yoder
2014-06-16 17:04 ` Will Deacon
2014-06-16 17:30 ` Arnd Bergmann
2014-06-16 18:53 ` Stuart Yoder
2014-06-17 10:26 ` Varun Sethi
2014-06-17 10:43 ` Will Deacon
2014-06-17 11:21 ` Varun Sethi
2014-06-17 14:50 ` Stuart Yoder
2014-06-18 9:29 ` Will Deacon
2014-06-17 14:39 ` Stuart Yoder
2014-06-20 23:16 ` Olav Haugan
2014-06-24 9:18 ` Will Deacon
2014-06-24 17:57 ` Olav Haugan
2014-06-24 18:11 ` Will Deacon
2014-06-24 18:20 ` Arnd Bergmann
2014-06-25 9:17 ` Will Deacon
2014-06-25 9:27 ` Arnd Bergmann
2014-06-25 9:38 ` Will Deacon
2014-06-25 9:48 ` Arnd Bergmann
2014-06-25 9:57 ` Will Deacon
2014-06-25 10:12 ` Arnd Bergmann
2014-06-25 10:14 ` Will Deacon
2014-06-24 21:35 ` Olav Haugan
2014-06-25 9:18 ` Will Deacon
2014-06-27 22:23 ` Olav Haugan
2014-06-30 9:52 ` Will Deacon [this message]
2014-07-09 1:07 ` Olav Haugan
2014-07-09 10:54 ` Will Deacon
2014-07-10 22:32 ` Olav Haugan
2014-07-11 12:24 ` Will Deacon
[not found] <20140606224542.GA22188@mithrandir>
2014-06-07 13:22 ` Arnd Bergmann
2014-06-09 10:49 ` Thierry Reding
2014-05-23 20:36 Thierry Reding
2014-05-29 15:52 ` Stephen Warren
2014-05-30 7:30 ` Thierry Reding
2014-05-30 11:27 ` Dave Martin
2014-05-30 19:11 ` Arnd Bergmann
2014-06-02 10:56 ` Dave Martin
2014-06-04 21:12 ` Thierry Reding
2014-06-16 12:57 ` Will Deacon
2014-06-17 11:58 ` Thierry Reding
2014-06-17 12:18 ` Will Deacon
2014-06-17 23:37 ` Thierry Reding
2014-06-18 10:14 ` Will Deacon
2014-06-20 15:53 ` Arnd Bergmann
2014-06-20 17:50 ` Will Deacon
2014-06-20 18:55 ` Arnd Bergmann
2014-05-30 11:22 ` Dave Martin
2014-05-30 19:01 ` Arnd Bergmann
2014-06-02 11:44 ` Dave Martin
2014-06-04 21:32 ` Thierry Reding
2014-06-05 9:42 ` Arnd Bergmann
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