From: Grant Likely <grant.likely@secretlab.ca>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Kristoffer Glembo <kristoffer@gaisler.com>,
Kevin Hilman <khilman@ti.com>,
Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Jeremy Kerr <jeremy.kerr@canonical.com>,
devicetree-discuss@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] drivers/amba: probe via device tree
Date: Mon, 23 May 2011 09:09:41 -0600 [thread overview]
Message-ID: <BANLkTink1rrC8F3Gjhqt84gYzOibX+AgDQ@mail.gmail.com> (raw)
In-Reply-To: <20110523095829.GG17672@n2100.arm.linux.org.uk>
On Mon, May 23, 2011 at 3:58 AM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Mon, May 23, 2011 at 11:37:04AM +0200, Kristoffer Glembo wrote:
>> Grant Likely wrote:
>> > In the case we're talking about the bus really is an AMBA bus, and all
>> > the devices on it are in some sense real amba devices. The problem is
>> > that not all of the devices on the bus implement peripheral ID
>> > registers or other mechanisms that good upstanding AMBA devices are
>> > expected to have.
>>
>> Before we go hardware bashing of non primecell AMBA devices I would just
>> want to point out that the primecell stuff is not part of the AMBA
>> specification.
>
> And before we go down that route, let me point out that the 'amba bus'
> stuff in the kernel is there to support primecells, rather than all
> devices which the AMBA specification covers.
>
> The reason it's called 'amba' is because back in 2001 or so when the
> first primecell drivers were created, there was little information
> available as to what AMBA, AHB, or APB even covered. All I had to go
> on were the primecell documents themselves. The higher level documents
> were not available to me.
>
> So, despite it being called 'amba', it really is just for primecells
> and if we didn't have the exposure to userspace, I'd have renamed it to
> 'apb' or similar instead.
Okay, that clarifies things a lot, and lends weight to the arguement
that it is perfectly normal and acceptable to have both amba_devices
and platform_devices on the same bus segment. Are there any cases
where amba primecells are being driven by platform_drivers? If so,
should those drivers have an amba_driver registration added?
g.
WARNING: multiple messages have this Message-ID (diff)
From: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
To: Russell King - ARM Linux <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
Cc: Kevin Hilman <khilman-l0cyMroinI0@public.gmane.org>,
Linux Kernel Mailing List
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>,
Jeremy Kerr <jeremy.kerr-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 2/2] drivers/amba: probe via device tree
Date: Mon, 23 May 2011 09:09:41 -0600 [thread overview]
Message-ID: <BANLkTink1rrC8F3Gjhqt84gYzOibX+AgDQ@mail.gmail.com> (raw)
In-Reply-To: <20110523095829.GG17672-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
On Mon, May 23, 2011 at 3:58 AM, Russell King - ARM Linux
<linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org> wrote:
> On Mon, May 23, 2011 at 11:37:04AM +0200, Kristoffer Glembo wrote:
>> Grant Likely wrote:
>> > In the case we're talking about the bus really is an AMBA bus, and all
>> > the devices on it are in some sense real amba devices. The problem is
>> > that not all of the devices on the bus implement peripheral ID
>> > registers or other mechanisms that good upstanding AMBA devices are
>> > expected to have.
>>
>> Before we go hardware bashing of non primecell AMBA devices I would just
>> want to point out that the primecell stuff is not part of the AMBA
>> specification.
>
> And before we go down that route, let me point out that the 'amba bus'
> stuff in the kernel is there to support primecells, rather than all
> devices which the AMBA specification covers.
>
> The reason it's called 'amba' is because back in 2001 or so when the
> first primecell drivers were created, there was little information
> available as to what AMBA, AHB, or APB even covered. All I had to go
> on were the primecell documents themselves. The higher level documents
> were not available to me.
>
> So, despite it being called 'amba', it really is just for primecells
> and if we didn't have the exposure to userspace, I'd have renamed it to
> 'apb' or similar instead.
Okay, that clarifies things a lot, and lends weight to the arguement
that it is perfectly normal and acceptable to have both amba_devices
and platform_devices on the same bus segment. Are there any cases
where amba primecells are being driven by platform_drivers? If so,
should those drivers have an amba_driver registration added?
g.
WARNING: multiple messages have this Message-ID (diff)
From: grant.likely@secretlab.ca (Grant Likely)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] drivers/amba: probe via device tree
Date: Mon, 23 May 2011 09:09:41 -0600 [thread overview]
Message-ID: <BANLkTink1rrC8F3Gjhqt84gYzOibX+AgDQ@mail.gmail.com> (raw)
In-Reply-To: <20110523095829.GG17672@n2100.arm.linux.org.uk>
On Mon, May 23, 2011 at 3:58 AM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Mon, May 23, 2011 at 11:37:04AM +0200, Kristoffer Glembo wrote:
>> Grant Likely wrote:
>> > In the case we're talking about the bus really is an AMBA bus, and all
>> > the devices on it are in some sense real amba devices. ?The problem is
>> > that not all of the devices on the bus implement peripheral ID
>> > registers or other mechanisms that good upstanding AMBA devices are
>> > expected to have.
>>
>> Before we go hardware bashing of non primecell AMBA devices I would just
>> want to point out that the primecell stuff is not part of the AMBA
>> specification.
>
> And before we go down that route, let me point out that the 'amba bus'
> stuff in the kernel is there to support primecells, rather than all
> devices which the AMBA specification covers.
>
> The reason it's called 'amba' is because back in 2001 or so when the
> first primecell drivers were created, there was little information
> available as to what AMBA, AHB, or APB even covered. ?All I had to go
> on were the primecell documents themselves. ?The higher level documents
> were not available to me.
>
> So, despite it being called 'amba', it really is just for primecells
> and if we didn't have the exposure to userspace, I'd have renamed it to
> 'apb' or similar instead.
Okay, that clarifies things a lot, and lends weight to the arguement
that it is perfectly normal and acceptable to have both amba_devices
and platform_devices on the same bus segment. Are there any cases
where amba primecells are being driven by platform_drivers? If so,
should those drivers have an amba_driver registration added?
g.
next prev parent reply other threads:[~2011-05-23 15:10 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-19 18:28 [PATCH v2 0/2] amba bus device tree probing Rob Herring
2011-05-19 18:28 ` Rob Herring
[not found] ` <1305829704-11774-1-git-send-email-robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-19 18:28 ` [PATCH 1/2] dt: check for devices already created fron DT scan Rob Herring
2011-05-19 18:28 ` Rob Herring
[not found] ` <1305829704-11774-2-git-send-email-robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-19 19:54 ` Grant Likely
2011-05-19 19:54 ` Grant Likely
2011-05-19 18:28 ` [PATCH 2/2] drivers/amba: probe via device tree Rob Herring
2011-05-19 18:28 ` Rob Herring
[not found] ` <1305829704-11774-3-git-send-email-robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-19 20:01 ` Grant Likely
2011-05-19 20:01 ` Grant Likely
[not found] ` <20110519200158.GW5109-e0URQFbLeQY2iJbIjFUEsiwD8/FfD2ys@public.gmane.org>
2011-05-19 23:30 ` Rob Herring
2011-05-19 23:30 ` Rob Herring
2011-05-19 23:39 ` Grant Likely
2011-05-19 23:39 ` Grant Likely
[not found] ` <20110519233958.GB18181-e0URQFbLeQY2iJbIjFUEsiwD8/FfD2ys@public.gmane.org>
2011-05-20 13:24 ` Rob Herring
2011-05-20 13:24 ` Rob Herring
[not found] ` <4DD66B8A.5040404-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-20 14:21 ` Arnd Bergmann
2011-05-20 14:21 ` Arnd Bergmann
[not found] ` <201105201621.03801.arnd-r2nGTMty4D4@public.gmane.org>
2011-05-20 15:17 ` Rob Herring
2011-05-20 15:17 ` Rob Herring
[not found] ` <4DD68614.6090209-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-20 16:08 ` Stephen Neuendorffer
2011-05-20 16:08 ` Stephen Neuendorffer
2011-05-21 17:42 ` Grant Likely
2011-05-21 17:42 ` Grant Likely
2011-05-21 23:47 ` Russell King - ARM Linux
2011-05-21 23:47 ` Russell King - ARM Linux
2011-05-21 23:47 ` Russell King - ARM Linux
2011-05-22 10:00 ` Rafael J. Wysocki
2011-05-22 10:00 ` Rafael J. Wysocki
2011-05-22 10:00 ` Rafael J. Wysocki
2011-05-22 15:46 ` Rob Herring
2011-05-22 15:46 ` Rob Herring
2011-05-22 15:46 ` Rob Herring
2011-05-23 15:23 ` Grant Likely
2011-05-23 15:23 ` Grant Likely
2011-05-22 10:03 ` Arnd Bergmann
2011-05-22 10:03 ` Arnd Bergmann
2011-05-22 10:03 ` Arnd Bergmann
2011-05-25 9:03 ` Linus Walleij
2011-05-25 9:03 ` Linus Walleij
2011-05-23 9:37 ` Kristoffer Glembo
2011-05-23 9:37 ` Kristoffer Glembo
2011-05-23 9:37 ` Kristoffer Glembo
2011-05-23 9:58 ` Russell King - ARM Linux
2011-05-23 9:58 ` Russell King - ARM Linux
2011-05-23 15:09 ` Grant Likely [this message]
2011-05-23 15:09 ` Grant Likely
2011-05-23 15:09 ` Grant Likely
2011-05-24 15:03 ` Rob Herring
2011-05-24 15:03 ` Rob Herring
2011-05-24 15:03 ` Rob Herring
2011-05-25 3:02 ` Shawn Guo
2011-05-25 3:02 ` Shawn Guo
2011-05-25 3:02 ` Shawn Guo
2011-05-25 9:07 ` Linus Walleij
2011-05-25 9:07 ` Linus Walleij
[not found] ` <a42f0c27-2811-4b68-bedf-7dfaa7bff6ff-+Ck8Kgl/v0/6UOWq+LNw4LjjLBE8jN/0@public.gmane.org>
2011-05-21 23:35 ` Russell King - ARM Linux
2011-05-21 23:35 ` Russell King - ARM Linux
[not found] ` <20110521233558.GA17672-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2011-05-23 15:00 ` Stephen Neuendorffer
2011-05-23 15:00 ` Stephen Neuendorffer
[not found] ` <1007bcf2-7786-4f03-bff7-8d8af83939f1-+Ck8Kgl/v0+GljRhoabY2LjjLBE8jN/0@public.gmane.org>
2011-05-23 15:47 ` Russell King - ARM Linux
2011-05-23 15:47 ` Russell King - ARM Linux
2011-05-21 4:00 ` Segher Boessenkool
2011-05-21 4:00 ` Segher Boessenkool
[not found] ` <80f20ac921a33e9f0bf3e249f539a8ef-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
2011-05-21 14:55 ` Rob Herring
2011-05-21 14:55 ` Rob Herring
[not found] ` <4DD7D24D.2070604-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2011-05-21 15:18 ` Segher Boessenkool
2011-05-21 15:18 ` Segher Boessenkool
[not found] ` <ad5605c2a3d4b36f63f36f52afe89cfd-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
2011-05-21 17:43 ` Grant Likely
2011-05-21 17:43 ` Grant Likely
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BANLkTink1rrC8F3Gjhqt84gYzOibX+AgDQ@mail.gmail.com \
--to=grant.likely@secretlab.ca \
--cc=devicetree-discuss@lists.ozlabs.org \
--cc=jeremy.kerr@canonical.com \
--cc=khilman@ti.com \
--cc=kristoffer@gaisler.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=rjw@sisk.pl \
--cc=stephen.neuendorffer@xilinx.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.