Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-07 Thread Henrik Nordström
fre 2013-06-07 klockan 09:02 +0100 skrev luke.leighton:

  ok.  so.  we come back to the question again: what shall i propose to
 them that they consider doing, and what benefit would it be to them to
 do so?

Just tell them that the kernel is moving to a different configuration
syntax called Device Tree, but apart from updating kernel drivers to the
new way of configuring things it only have minor impact on their
envionment. It is still possible to use the fex file for all board
configuration details, only requires a small tool for translating fex to
device tree.

The change only impacts kernel, and a small change to their SDK build
scripts to also build the device tree from the fex.

It is no big deal really in structural terms. There is far bigger
structural changes in the kernel which coincides with this and will
require some developer time to adjust for. Had they upstreamed their
changes earlier then...

Regards
Henrik




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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-06 Thread Henrik Nordström
tor 2013-06-06 klockan 13:19 +0100 skrev luke.leighton:

  mass-volume tablet, mass-volume IPTV box.  android OS, nothing else.

Which still includes a number of possible configurations with different
i2c, spi, usb etc devices connected on the board. Because Allwinner is
not using mainline methods for configuration their customers are stuck
in only selecting between a very limited set of Allwinner compatible
auxillary chips (g-sensors, led controls, wifi modules, gps modules etc)
in their designs.

By using DT their customers are free to choose any device supported
mainline.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-06 Thread Henrik Nordström
tor 2013-06-06 klockan 13:22 +0100 skrev luke.leighton:

  idea: hook into devicetree gpio functions to allow script-fex gpio
functions to gain access in a separate module?  that sort of thing.

No. Drop FEX from the kernel, use DT. There is no reason why the kernel
shold care about the FEX format.

Translate from FEX to DT where needed in the firmware image build
process to allow Allwinner to keep the FEX as hardware description to
the ODMs.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
ons 2013-06-05 klockan 22:24 +0100 skrev Luke Kenneth Casson Leighton:

  And Then Some, stephen.  there are two versions of u-boot being used:
 one is the community-assembled [GPL-compliant] one, and the other
 includes a [as-of-a-few-days-ago-but-no-longer, yay!]
 formerly-GPL-violating one from allwinner.
 
  the community-based one *doesn't* have fex integration (i don't
 think, but henrik will know for sure), but the allwinner one
 definitely does.

Correct.

   and then there's the boot0 and boot1 loaders, these *do* have
 fex integration: they're absolutely tiny and they're designed to fit
 into the 1st level cache.  the job of these bootloaders is to set up
 the DDR3 RAM timings (so that you can access DRAM!!) and to then
 decide whether to load from NAND, SD/MMC etc. and many other things.

no, these are not tiny. boot0 is 24KB to fit the initial embedded SRAM
(not cache), but boot1 is on pair with u-boot in size and runs from
DRAM.
 
boot0 do NOT read the script.bin at all. It can't, there isn't space
fore it. There is tools in the build process that reads the script.bin
and adds some information to a header of boot0, but it's irrelevant to
the device tree question. Exactly the same can be done from a device
tree, or from a fex, it does not matter.

even most of boot1 is not using script.bin. The important parameters are
all recorded in a heaeder of boot1 when the image is composed using the
Allwinner pack tools. Currently based on those tools reading script.bin
to prepare the boot1 part of the image.

  these boot0 and boot1 loaders are themselves configureable so that
 you can specify, through script.fex, what GPIO is to be the reset
 key and so on.  that's a much simplified story btw.

No. That info is in the boot0 and boot1 file headers, not script.bin. 

  so the point is: if anyone wishes me to propose to allwinner that
 they convert over to devicetree, or any other proposal which involves
 significant low-level changes to their working practices that could
 potentially have a massive knock-on effect onto their
 multi-million-dollar clients, it had better be a damn good story.

Calm down. It isn't really a significant difference to them outside of
the kernel. They do not need to change any of their configuraiton
methods, only a small toolchain change in how the resultig images are
built to have a corresponding device tree built.

But it is a fair bit of one-time changes kernel side. And some
scratching to figure out how to use/improve/ignore the stuff being
mainlined.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
ons 2013-06-05 klockan 22:15 +0100 skrev Luke Kenneth Casson Leighton:

 what we do not want to happen is that they see upstream patches being
 submitted, they merge them into their internal tree (which to date has
 had zero upstream changes: they're currently only just getting round
 to doing 3.4 as we speak), and they *completely* ignore *absolutely
 everything* that's being done by the community, duplicating yet
 another set of device drivers (named drivers/*/sun8i_* and so on).

Well, that will obviously happen one or two more rounds, a bit depending
on which kernel releases Android will use. But I hope the Allwinner
kernel team will rethink when they hit more current kernels.

  this proposal is a start: however what you have to bear in mind is
 that you now have to convince a very busy company that it is in their
 best interests to disrupt their schedule, to drop their existing
 working practices, to tell all their customers please stop using the
 existing tools and please use these ones instead.

Why?

  you also need to convince the creators of the proprietary
 firmware-flashing tools livesuite and phoenix to *also* convert
 their tools over to the new proposed idea.

Why?

  can you provide such a supporting argument which would convince
 allwinner to accept the modifications to their working practices that
 you propose?

It does not really need to be such big modifications to their working
practices. Their configuration working practices is all built around the
fex file, and the new practices can be

0. Assuming kernel drivers gets ported over to using device tree.

1. Do configuration as you have always done in the .fex

2. Modify the build script to build a device tree from the fex +
template, in addition to script.bin.

3. Tell u-boot to load the device tree for the kernel.

That's it really.

licesuit do not modify script.bin. script.bin is compiled from the .fex
at image creation time. A couple more lines in the build script (and a
suitable translation tool) and there is also a device tree built and
installed and you get a nice and smoot transition.

  Device tree on ARM's goal is to achieve a single kernel across vendors, not
  just a single kernel for a single vendor.
 
  you'll be aware that i've mentioned a number of times and have
 discussed at some length why this is a goal that is completely
 impossible to achieve [*1].  sadly.

Here I disagree. It is possible. Not across all vendors but a
significant share.

Regards
enrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
ons 2013-06-05 klockan 16:54 -0600 skrev Stephen Warren:

 1) Put all the parameters in the U-Boot configuration header. This is
 normal.

Yes, we do so today for U-Boot SPL. But this won't fit very well with
the Allwinner ODM workflow where one binary image works on a wide range
of board configurations probed while flashing the image to the board,
but on the other hand there is no real need for them to use u-boot as
the primary boot loader, just keep using boot0 + boot1 + u-boot chain as
they have always done.

 2) Read some data structure at run-time. This data structure could in
 theory be some SoC-specific blob format (e.g. the packed version of
 information that some tool extracts from FEX/DT), a whole FEX blob, or
 device tree.

This is likely to happen for the sunxi U-Boot SPL due to the sheer
amount of boards involved, and is done to some extents for other boards
as well. In the SPL there generally isn't room for full DT support. Main
u-boot HW configuration could be done runtime via DT alone but we are
not quite there yet, nothing major missing however other than getting it
done.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
tor 2013-06-06 klockan 00:26 +0100 skrev luke.leighton:

  no john - they've only added it to the multiplexed sections of the
 drivers which they themselves have written.  such as
 drivers/usb/sun{N}i_usb/*.[ch], drivers/block/nand/sun{N}_i,
 arch/arm/mach-sun{N}i and so on.

And a number of SPI device drivers, USB device drivers, vendor provided
device drivers, ..

 the script.fex system deals with the pinmux issue in a very neat way that:
 
   a) has very little impact on the rest of the kernel tree [citation
 needed!  i'm saying that: could someone please confirm if it's true]

Not really the case. Actually the opposite. DT have this as well, and
integrated in device probing. Allwinner need to hack every driver used
to add their gpio requests to have pinmuxing triggered.

It is just layered a bit differently when using DT.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
tor 2013-06-06 klockan 00:52 +0100 skrev luke.leighton:
  How is the Allwinner kernel going to load the driver for the pca9532?
  The mainline pca9532 driver does not understand fex so it can't read
  the necessary initialization data.
 
  jon: you're immediately outside of the target market for which
 allwinner designed and deployed script.fex.

You missed the point. Mainlne Kernel drivers do take advantege of DT to
ease their bindings and configuration, much further than the fex can
express.

The exact same thing is experienced in designing a tablet. You add a
pheriperal device, and it needs to be configured somehow. DT does this
and it integrated in the kernel framework. fex also attemtps in doing
part of this, but lacks integration and requires much more driver
patching to fly.

And I don't see how you can say that pca9532 is off the grid in the
target market. It would fit nicely as a key backlight / edge colour
controller in a tablet to give the tablet a personal touch.

  fex is only supported on the small number of peripheral chips
  Allwinner has blessed. Use any chip outside of that set and it isn't
  going to boot.
 
  eeexactly.  i did say target market.

Yes you repeat that over an over. But what does it mean?

I think what you really mean is something else more in the line of ODMs
not allowed to step outside a very narrow range of possible designs or
using less than a handful approved providers, typical lockin
conditions. I don't know what you really mean here, only that it's not
target market.

Regards
Henrik


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Re: [Arm-netbook] getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

2013-06-05 Thread Henrik Nordström
tor 2013-06-06 klockan 00:54 +0100 skrev luke.leighton:

  Not really the case. Actually the opposite. DT have this as well, and
  integrated in device probing. Allwinner need to hack every driver used
  to add their gpio requests to have pinmuxing triggered.
 
  augh.  ok.  solutions.  what are the solutions here?

What I said before.

Go with DT for the kernel. There is no need for two configuration
mechanisms doing the same thing. Disguise it in fex form (and
translator) if too hard for people with a DOS editior to configure.

Regards
Henrik


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Re: [Arm-netbook] ARM port(s) BoF at DebConf

2012-07-25 Thread Henrik Nordström
tis 2012-07-24 klockan 00:02 +0100 skrev Luke Kenneth Casson Leighton:
  rright.  many thanks to the person on arm-netbooks who found that the
 netgear ReadyNAS boxes can take standard DDR3 SO-DIMMs.
  apparently there are lots of people who have been upgrading them from
 the pathetic 256mb they come with to at least 1gb, with some degree of
 success:
 
   http://www.readynas.com/forum/viewtopic.php?f=110t=49254

That thread is for DUO v1 only (LEON SPARC based).

I have not seen any claims that DUO v2 can be upgraded before the post
on this mailinglist. Only numerous claims and complaints about it not
being upgradeable, and wrote it off as not interesting when it came ot
due to being restricted to 256MB.

Regards
Henrik


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