* Query about include/linux/mailbox.h
@ 2013-08-31 4:57 Craig McGeachie
2013-08-31 5:33 ` Jassi Brar
0 siblings, 1 reply; 6+ messages in thread
From: Craig McGeachie @ 2013-08-31 4:57 UTC (permalink / raw)
To: linux-arm-kernel
Hello,
At the end of all this, my question is should I put the BCM2835 mailbox
driver in drivers somewhere, and try to make use of
include/linux/mailbox.h, or should go with the view that mailbox drivers
are inherently machine specific, have no common driver framework, and
belongs in arch/arm/mach-bcm2835?
The background to this is that I'm trying to help bring Raspberry Pi
support into the mainline kernel. Lubomir Rintel coded a mailbox driver
[1] that I liked the look off and want to fix up and push upstream.
Stephen Warren suggested that Lubmir's patch had the benefit of using a
new mailbox sub-system [2] and that I should have a look at that.
I've looked at include/linux/mailbox.h, and it only has 3 function
declarations, which are all specific to the PL320. Unless there is
something I've missed, then there is no mailbox sub-system to speak of.
Just a header file that will quickly a dependency nightmare.
I found a patch submission series from Jassi Brar [3] that looks like
the start of an actual mailbox framework, but there is no indication of
it in the current kernel source. I assume it was dropped for some reason.
I don't see much benefit to a mailbox sub-system. The BCM2835 one is
quite a small piece of code, and I really see it as a machine-specific
layer for other device drivers that implement a standard sub-system
interface, like framebuffers.
Which all leads back to my opening question - which way do I jump? What
I'd prefer to do is submit arch/arm/mach-bcm2835.c etc, and maybe even a
patch to move include/linux/mailbox.h somewhere less inviting.
Cheers,
Craig.
[1]
http://lists.infradead.org/pipermail/linux-rpi-kernel/2013-April/000528.html
[2]
http://lists.infradead.org/pipermail/linux-rpi-kernel/2013-May/000546.html
[3] http://lkml.indiana.edu/hypermail/linux/kernel/1305.0/01978.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* Query about include/linux/mailbox.h
2013-08-31 4:57 Query about include/linux/mailbox.h Craig McGeachie
@ 2013-08-31 5:33 ` Jassi Brar
2013-08-31 11:19 ` Craig McGeachie
0 siblings, 1 reply; 6+ messages in thread
From: Jassi Brar @ 2013-08-31 5:33 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Aug 31, 2013 at 10:27 AM, Craig McGeachie <slapdau@yahoo.com.au> wrote:
>
> Hello,
>
> At the end of all this, my question is should I put the BCM2835 mailbox driver in drivers somewhere, and try to make use of include/linux/mailbox.h, or should go with the view that mailbox drivers are inherently machine specific, have no common driver framework, and belongs in arch/arm/mach-bcm2835?
>
> The background to this is that I'm trying to help bring Raspberry Pi support into the mainline kernel. Lubomir Rintel coded a mailbox driver [1] that I liked the look off and want to fix up and push upstream. Stephen Warren suggested that Lubmir's patch had the benefit of using a new mailbox sub-system [2] and that I should have a look at that.
>
> I've looked at include/linux/mailbox.h, and it only has 3 function declarations, which are all specific to the PL320. Unless there is something I've missed, then there is no mailbox sub-system to speak of. Just a header file that will quickly a dependency nightmare.
>
> I found a patch submission series from Jassi Brar [3] that looks like the start of an actual mailbox framework, but there is no indication of it in the current kernel source. I assume it was dropped for some reason.
>
It wasn't dropped.
Just the development was taken offline by the three of us I (for
Fujitsu), Suman Anna (for TI) and Loic (for STE). Later we were
joined by LF.Tan (for Intel). Please join us.
https://github.com/sumananna/mailbox/commits/jassiv3-3.10-omap should
be good to base on.
Thanks,
Jassi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Query about include/linux/mailbox.h
2013-08-31 5:33 ` Jassi Brar
@ 2013-08-31 11:19 ` Craig McGeachie
2013-08-31 13:39 ` Jassi Brar
0 siblings, 1 reply; 6+ messages in thread
From: Craig McGeachie @ 2013-08-31 11:19 UTC (permalink / raw)
To: linux-arm-kernel
On 08/31/2013 05:33 PM, Jassi Brar wrote:
> It wasn't dropped.
> Just the development was taken offline by the three of us I (for
> Fujitsu), Suman Anna (for TI) and Loic (for STE). Later we were
> joined by LF.Tan (for Intel). Please join us.
> https://github.com/sumananna/mailbox/commits/jassiv3-3.10-omap should
> be good to base on.
So, this would be a good place to start?
https://github.com/sumananna/mailbox/commit/635c24eba19f67d1eb1ef7e7447f319c850b01e5#drivers/mailbox
See if I can get my head around that framework and what it does, and try
fitting the BCM2835 mailbox into it?
Cheers,
Craig.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Query about include/linux/mailbox.h
2013-08-31 11:19 ` Craig McGeachie
@ 2013-08-31 13:39 ` Jassi Brar
2013-09-01 8:53 ` Craig McGeachie
2013-09-06 8:48 ` Craig McGeachie
0 siblings, 2 replies; 6+ messages in thread
From: Jassi Brar @ 2013-08-31 13:39 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Aug 31, 2013 at 4:49 PM, Craig McGeachie <slapdau@yahoo.com.au> wrote:
> On 08/31/2013 05:33 PM, Jassi Brar wrote:
>>
>> It wasn't dropped.
>> Just the development was taken offline by the three of us I (for
>> Fujitsu), Suman Anna (for TI) and Loic (for STE). Later we were
>> joined by LF.Tan (for Intel). Please join us.
>> https://github.com/sumananna/mailbox/commits/jassiv3-3.10-omap should
>> be good to base on.
>
>
> So, this would be a good place to start?
>
> https://github.com/sumananna/mailbox/commit/635c24eba19f67d1eb1ef7e7447f319c850b01e5#drivers/mailbox
>
> See if I can get my head around that framework and what it does, and try
> fitting the BCM2835 mailbox into it?
>
Yes. If you point me to your mailbox client drivers, I could also give
it a look to see if we need some changes.
Regards
Jassi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Query about include/linux/mailbox.h
2013-08-31 13:39 ` Jassi Brar
@ 2013-09-01 8:53 ` Craig McGeachie
2013-09-06 8:48 ` Craig McGeachie
1 sibling, 0 replies; 6+ messages in thread
From: Craig McGeachie @ 2013-09-01 8:53 UTC (permalink / raw)
To: linux-arm-kernel
On 09/01/2013 01:39 AM, Jassi Brar wrote:
> Yes. If you point me to your mailbox client drivers, I could also give
> it a look to see if we need some changes.
This should be a reasonably concise view of things.
https://github.com/rickytarr/linux/commit/a9b131c63c73c450a567eb5fa527e8919e71bfd8
There is no header for the BCM2835 mailbox. At the point I started to
add one, I learnt more about the multi-architecture approach to SoC
code, and realised I'm going to have to rethink what I'm doing.
I don't think your code will need to change much, if at all. I'll try
applying your patches and see what happens.
Cheers,
Craig.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Query about include/linux/mailbox.h
2013-08-31 13:39 ` Jassi Brar
2013-09-01 8:53 ` Craig McGeachie
@ 2013-09-06 8:48 ` Craig McGeachie
1 sibling, 0 replies; 6+ messages in thread
From: Craig McGeachie @ 2013-09-06 8:48 UTC (permalink / raw)
To: linux-arm-kernel
On 09/01/2013 01:39 AM, Jassi Brar wrote:
>> See if I can get my head around that framework and what it does, and try
>> fitting the BCM2835 mailbox into it?
>>
> Yes. If you point me to your mailbox client drivers, I could also give
> it a look to see if we need some changes.
Righty ho. This seems to be a reasonable attempt.
https://github.com/rickytarr/linux/tree/subsys-mailbox
https://github.com/rickytarr/linux/commit/e0c25371581d125e3f6a46f452ce3e95f1d267ee
It compiles cleanly and boots. Start with bcm2835_defconfig, and then
enable Device Drivers -> Mailbox Hardware Support -> BCM 2835 Mailbox. I
think it validates that BCM2835 mailbox support can fit into your
generic device.
But that's as far as I know. I'm offering this as an early look only
(comments and defects welcome). I've got to build something that uses it
next. For all I know it might cause the Raspberry Pi to explode and
vaporise any desk it is sitting on.
Out of interest, do you have a roadmap for moving this into the kernel
mainline?
Cheers,
Craig.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-09-06 8:48 UTC | newest]
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2013-08-31 4:57 Query about include/linux/mailbox.h Craig McGeachie
2013-08-31 5:33 ` Jassi Brar
2013-08-31 11:19 ` Craig McGeachie
2013-08-31 13:39 ` Jassi Brar
2013-09-01 8:53 ` Craig McGeachie
2013-09-06 8:48 ` Craig McGeachie
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