=== Device Tree ===
* Repost "alias" support patch to get both flat-tree and prom-tree
supported, so that it will not break SPARC architecture.
* Had seen another two custom pinmux bindings for Tegra and Exynos,
and the common register-value pair binding will probably make less
sense, so will keep purchasing iomuxc binding I have proposed.
* Per request from Freescale Landing team, published a imx51/53 DT
support tree on git.linaro.org, so that they can starting playing
more DT support on drivers.
=== Misc ===
* Posted a patch series to clean up imx (mxc & mxs) mach/gpio.h to
empty headers, and wait for a global removal from asm/gpio.h.
This is one step to single-image.
* Ran a i.mx53 quick start demo on APM (ARM Parter Meeting?)
* Flight back from UK
--
Regards,
Shawn
=== Highlights ===
* Merged basic Origen enablement patch into the linaro+android tree
* Worked with Mathieu Poirier to get familiar with my new Origen board
and managed to get a working defconfig for the Origen board committed to
the linaro+android tree (serial console functionality, only).
* Did a very rough first draft on Kconfig Fragments talk for LPC
* Got Linaro Connect expenses submitted
* Merged a number of RTC fixes from lkml into my dev tree and submitted
them for 3.1
* Did a major rework of the Alarm Timers internal code to address
comments from the Android developers. Submitted some smaller fixes for
3.1 and queued the rest of the rework for 3.2
* Made the omap3, omap4 and origen android defconfigs consistent.
* Merged fixes for beagle xm revC usb bug from 3.1-rc1 (bug #825343).
Big thanks to Jassi for pointing out the fix!
* Updated the Linaro+Android tree, and made the initial pre-release for
11.08
* Worked with Paul Sokolovsky to push the Linaro+Android tree through
gerrit. There are still some kinks to work out, but its getting there.
=== Plans ===
* Lots more focus on Kconfig presentation. I'm likely going to try to
put the boards away and avoid doing anything else.
=== Issues ===
* N/A
== Dave Martin <dmart> ==
=== Activity Summary ===
* Linaro Connect and ARM Partner Meeting consumed much of the last two weeks
* Main output from Linaro Connect was some progress on vexpress
device tree support (with much help from Lorenzo Pieralisi and Grant
Likely). I have a kernel _building_ now, but I still need to test it,
and write the Makefile rules properly.
* Alignment fault fixup mode patches now merged by Russell for the
3.2 window. If these are included in linux-linaro we will be able to
find and resolve outstanding problems by booting with e.g. alignment=5
on the kernel command-line.
* Posted patches to fix multiplatform kernels for Thumb-2 userspace.
This issue can affect any single kernel image which contains both v6
and v7 support, when running Thumb-2 userspace containing VFP
instructions (i.e., Linaro filesystems fail with a torrent of
SIGILLs). Some rework is needed, but no major objections received so
far.
* Posted a suggestion on the binutils list about a more generic way
to save/restore the assembler state during assembly. Some positive
feedback received; I will draft a more detailed proposal for review.
For now it's just an RFC, and I haven't committed to spending real
time on it.
=== Plans ===
* Test new vexpress devicetree patches, rework and post.
* Rework and repost multiplatform Thumb-2 undef handling patches.
* Write up brief advice for Thumb-2 kernel migration.
* Write up detailed proposal for assembler state save/restore.
* Check whether the new kernel trees work in Thumb-2 on mx51evk and
follow up with Freescale landing team.
* Suggest we disable aligment fixups for linaro images, since
gtk-sharp2 is now the only thing known to be affected, once my
alignment fixup patchas have been posted for review.
=== Work Items ===
no status change
=== Absences ===
probable absence of ~3 days around the start of September
=== Highlights ===
* Posted "Remove define CONSISTENT_DMA_SIZE" patch series to
linux-arm-kernel for review. This was part of the 'single zImage' work
done at Linaro Connect in the previous week.
* As part of the work for blueprint "Investigate block allocation in FS"
wrote program to issue writes to SD in various sequences to try and
get a handle on algorithms used by SD cards. (Seems to be not as
simple as we assume.)
* Spent time on tasks in preparation for officially starting work at
Linaro in September.
=== Plans ===
* Modify flash simulation program to match real SD cards performance (or
give up trying to match 'difficult' algorithms.)
* Run flash media use cases with different ext4 options.
(I'm using my new Linaro email address to post this weeks summary to see
if I've managed to subvert GMail's broken handling of mailing lists, see
http://mail.google.com/support/bin/answer.py?answer=6588)
== Linus Walleij linusw ==
=== Highlights ===
* Rebased the gpio.h cleanups from Linaro connect on top of
Russells gpio.h cleanup patchset and mailed it out:
http://marc.info/?l=linux-arm-kernel&m=131297866928334&w=2
* Submitted an update of the DBx500 PRCMU drivers
carved out from the internal ST-Ericsson 3.0-based git:
http://marc.info/?l=linux-kernel&m=131313768415616&w=2
* RealView PB11MPCore, TCM support and TCM fixes
merged for 3.1
http://marc.info/?l=linux-arm-kernel&m=130944303522448&w=2http://marc.info/?l=linux-arm-kernel&m=130944291922298&w=2http://marc.info/?l=linux-arm-kernel&m=130944294622342&w=2
* I now have a working Integrator AP setup, also sent two
patches for it:
http://marc.info/?l=linux-arm-kernel&m=131037711822519&w=2http://marc.info/?l=linux-arm-kernel&m=131189136402449&w=2
First patch merged for v3.1-rc1 through Arnds tree
* DMA40 patches merged for 3.1
http://marc.info/?l=linux-kernel&m=130916853306730&w=2
* Fix to RMI4 staging driver merged for 3.1
http://marc.info/?l=linux-kernel&m=130941558024742&w=2
* Fixed a PL022 bug reported by Russell King, merged for 3.1.
* Reviewed David Browns patches for moving and refactoring
the qualcomm GPIO drivers.
* Various upstreamed patches for AB8500, STMPE, MMCI...
* Reviewed Viresh Kumar's patches to the PL08x DMA
driver.
* Reviewed Samsungs patches to the PL08x DMA driver.
* Discussed pinmux/pinctrl subsystem at Linaro Connect,
not much to say about it, input was that the number space
for each pinmux controller need to be local to the controller
and we should avoid a global numberspace.
=== Plans ===
* New iteration of the pinctrl + pinmux subsystem
* Finalize the gpio.h cleanups
* Drive generalization of U300 and Nomadik GPIO
* Get into struct clk generalization and movement of clk
drivers into drivers/clk - handover from Jeremy Kerr.
We will do this in Cambridge or something like that.
=== Issues ===
* GPIO pincontrol aspects stalled on the mailing list,
who cares, directing my attention elsewhere FTM.
* Shanghaiied for some internal conflict resolution
at ST-Ericsson. Not too much though.
Thanks,
Linus Walleij
Hi all,
I wanted to provide an update of what the kernel team accomplished at
Linaro Connect last week for those who were unable to attend.
The team was split into two main groups, the first being led by Grant
Likely and focusing on continuing the work on enabling Device Tree
support on ARM platforms. In addition to Linaro members, David Brown
and Nicolas Ferre also worked on DT support for their platforms
and all together the team got much accomplished in 5 days there
with a number of patches ready for the 3.2 merge windows:
* Several device drivers for the Freescale iMX were converted
to use DT-base discovery.
* Code was written to bridge between the Device Tree model and
TI OMAP's HWMOD.
* Initial support for DT was added to the Samsung Exynos, Qualcomm MSM86,
and Atmel AT91 by Nicolas Ferre
* DT skeleton code was written for the ARM Versatile and ST-E platforms.
The rest of the team primarilly focused on code cleanup and development
to work towards a multi-SOC zImage. Nicolas posted and original
email with info at http://bit.ly/oVQRQm and folks took individual
bits to work on. Russel King was also in attendance and there was
good discussion around some of these topics. What we discovered
is that many of these issues are multi-layered and as we start
cleaning up one bit of code, we need to fix other areas to make
them work consistently. The areas we looked into were:
* Replacing low level IO accessor macros with runtime selected functions
based on platform type.
* Replacing the global NR_IRQS constant with per-board information
* Removing duplicated low-level serial output functions. Currently the
code to print "Uncompressing kernel..." and the code for low-level
in-kernel serial output are completely different but could be made
to be the same. At the end of the day, the method we're looking
at using is providing a special node in the DT that contains the
physical mapping of the debug serial registers in place.
* Removing CLOCK_TICK_RATE from the kernel
* Replace CONSISTENT_DMA_SIZE with a runtime variable
* Removing arch_idle() and moving to using the run time
selected pm_idle hooks. Similar work to be done with
arch_reset()
* Getting rid of VMALLOC_END. Russel and Nicolas agreed
that we'll just use a static VMALLOC_END for everyone
and insert static I/O mappings in there.
In addition the the above work, KWG members also were involved in
discussions about continuous integration and testing of the upstream
kernels on ARM platforms, kernel development process at Linaro and
how to better stay in sync with upstream, -stable patches for ARM
platforms, Android development, and flash storage roadmap to name a few.
Overall, the team had an extremely productive week of hacking on existing
projects and on coming up with more detailed plans on what other items
on which we need to focus.
I want to thank everone on the team for their hard work last week
and also the non-Linaro developers David Brown, Will Deacon, Nicolas
Ferre, and Marc Zyngier for taking time to join us in hacking and planning.
All together connect was a great technically focused event and I highly
encourage folks to join us in Orlando in November. You can register now
at http://connect.linaro.org/events/event/linaro-connect-q411/.
Thanks,
~Deepak
== Per Forlin <perfor> ==
=== Highlights ===
* Sent out patches to improve performance in usb gadget mass storage
* https://lkml.org/lkml/2011/8/8/107
* https://lkml.org/lkml/2011/8/8/411
* It's not necessary to make any further optimizations in the usb
gadget buffer pipeline form a throughput point of view.
=== Completed work items ===
* https://blueprints.edge.launchpad.net/linux-linaro/+spec/usb-gadget-mass-st…
* Run tests and analysis to identify performance issues in usb
gadget mass storage: DONE
* Implementation will be broken down and added here when the design
decision is made: DONE
* Make the number of gadget pipeline buffers variable: DONE
=== Plans ===
* Leaving for vacation today (Aug 10) back again Aug 17.
* Update design and status on my storage BPs.
== Jason Liu <jasnliu> ==
== Highlights ==
* Â Attended Linaro Q3 connect, has some good discussion for:
the 11.11 task assignment and one zImage support,
* Uboot patch review, one imx5 patch upstream, accepted.
* 2 kernel patch upstream, one is accepted and one is waiting for feedback.
== Plan ==
* 11.11 task
* uboot upstream
* kernel upstream
Best Regards,
Jason Liu
== Deepak Saxena <dsaxena> ==
== Highlights ==
* Attended Linaro connect, had lots of good discussions re:
- Kernel process
- Testing
- Storage work direction
- Future KWG work
* Wrote code, posted patches!
== Upcoming Travel/Holiday ==
* Off this friday
* At Linuxcon next Tue - Friday
* Linux Plumber's Conf first week of september
To everyone, and especially to those who are expected to work on this
topic next week, please find below a list of tasks that needs to be
investigated and/or accomplished. I'll coordinate the work and collect
patches for the team.
If you have comments on this, or if you know about some omissions,
please feel free to provide them as a reply to this message.
I'd like to know if people are particularly interested in one (or more :-))
items they would like to work on. If so please say so as well.
Without further ado, here it is:
<><><><><>
0) The so called "single zImage" project
We wish to provide the ability to build as many ARM platforms as
possible into a single kernel binary image. This will greatly simplify
the archive packaging and maintenance effort by having only one kernel
that could be built and booted on multiple ARM targets. A side effect
of this is also to enforce better source code architecture even if the
resulting binaries are not always supporting multiple targets.
This work started a while ago. Some initial description can be found
here:
https://wiki.ubuntu.com/Specs/ARMSingleKernel
Part of it has been implemented already, namely the runtime determined
PHYS_OFFSET, the AUTO_ZRELADDR and some other items referenced below.
But there is still a large amount of work remaining.
1) Removal of any dependencies on <mach/*.h> from generic header files
To see the current culprits:
$ git grep "#include <mach/.*.h>" arch/arm/include/
arch/arm/include/asm/clkdev.h:#include <mach/clkdev.h>
arch/arm/include/asm/dma.h:#include <mach/isa-dma.h>
arch/arm/include/asm/floppy.h:#include <mach/floppy.h>
arch/arm/include/asm/gpio.h:#include <mach/gpio.h>
arch/arm/include/asm/hardware/dec21285.h:#include <mach/hardware.h>
arch/arm/include/asm/hardware/iop3xx-adma.h:#include <mach/hardware.h>
arch/arm/include/asm/hardware/iop3xx-gpio.h:#include <mach/hardware.h>
arch/arm/include/asm/hardware/sa1111.h:#include <mach/bitfield.h>
arch/arm/include/asm/io.h:#include <mach/io.h>
arch/arm/include/asm/irq.h:#include <mach/irqs.h>
arch/arm/include/asm/mc146818rtc.h:#include <mach/irqs.h>
arch/arm/include/asm/memory.h:#include <mach/memory.h>
arch/arm/include/asm/mtd-xip.h:#include <mach/mtd-xip.h>
arch/arm/include/asm/pci.h:#include <mach/hardware.h> /* for PCIBIOS_MIN_* */
arch/arm/include/asm/pgtable.h:#include <mach/vmalloc.h>
arch/arm/include/asm/system.h:#include <mach/barriers.h>
arch/arm/include/asm/timex.h:#include <mach/timex.h>
arch/arm/include/asm/vga.h:#include <mach/hardware.h>
1.1) mach/memory.h
This may contain the following defines:
1.1.1) ARM_DMA_ZONE_SIZE
This can be eliminated by moving that value into struct machine_desc.
The work is done already, but presented as an example for other tasks:
http://git.linaro.org/gitweb?p=people/nico/linux.git;a=shortlog;h=refs/head…
And as of now this is merged in mainline already for v3.1-rc1.
1.1.2) PLAT_PHYS_OFFSET
Most occurrences can be eliminated. With CONFIG_ARM_PATCH_PHYS_VIRT, it
is possible to determine PHYS_OFFSET at run time. Remains to remove the
direct uses, mostly by mdesc->boot_params initializers. Changing
boot_params into atag_offset has two effects: that makes it clearer that
it is only about ATAGs and not DT, and a relative offset plays more
nicely with a runtime determined PHYS_OFFSET.
This work is done but not yet accepted:
http://news.gmane.org/group/gmane.linux.ports.arm.kernel/thread=123480
1.1.3) FLUSH_BASE, FLUSH_BASE_PHYS, FLUSH_BASE_MINICACHE, UNCACHEABLE_ADDR
Those are StrongARM related constants, and different for each variants.
Fixing this involves making the virtual addresses constant for all
variants, and hiding the differences in the physical addresses during
the actual mapping.
The solution is here:
http://news.gmane.org/group/gmane.linux.ports.arm.kernel/thread=123477/forc…
1.1.4) CONSISTENT_DMA_SIZE
Maybe the CMA work will make this obsolete and the consistent DMA area
could be dynamically adjusted. In the mean time, the easiest solution
is probably to store this in the machine_desc structure just like with
ARM_DMA_ZONE_SIZE.
This has not been addressed yet.
1.1.5) Other weird things
Some machines have non linear memory maps or bus address translations,
sparsemem, etc. Examples of that are:
arch/arm/mach-realview/include/mach/memory.h
arch/arm/mach-integrator/include/mach/memory.h
I think solving this is out of scope for this round. Deleting
arch/arm/mach-*/include/mach/memory.h can't be done universally. So a
new Kconfig symbol (NO_MACH_MEMORY_H) is introduced to indicate which
machine class has its legacy <mach/memory.h> file removed. The single
zImage for multiple targets will be restricted, amongst other things, to
those machines or SOCs with that symbol selected. Partial result here:
http://git.linaro.org/gitweb?p=people/nico/linux.git;a=shortlog;h=refs/head…
1.2) mach/io.h
This contains things like IO_SPACE_LIMIT, __io(), __mem_pci(), and
sometimes __arch_ioremap()/__arch_unmap(). but in most cases, the
definitions here are pretty similar from one machine class to another.
Arnd says:
|I have a plan. When CONFIG_PCI is disabled (along with CONFIG_ISA and
|CONFIG_PCMCIA), we should have neither of IO_SPACE_LIMIT, __io()
|and get no inb/outb functions as a result.
|
|When it is enabled, the 'common' platforms need only one I/O window
|of 64KB, so we should find a common place in the virtual address space
|for that and hardcode __io, while the platform specific PCI initialization
|code (or map_io for that matter) ensures that the window is pointing
|to the physical window.
|
|__arch_ioremap()/__arch_unmap() are not really needed as far as I can
|tell but are used as an optimization to redirect ioremap to the
|hardcoded virtal address mapping. In the first step we can disable
|this for combined kernels, later we can find a generic way so
|__arch_ioremap walks the list of static mappings.
1.3) mach/timex.h
Most instances simply define a dummy CLOCK_TICK_RATE value. This can
probably be removed altogether, or simply have a common value in
arch/arm/include/asm/timex.h, as nothing seriously uses that anymore.
Reference: http://lkml.org/lkml/2011/2/21/323
1.4) mach/vmalloc.h
This universally contains only a definition for VMALLOC_END, but not an
universal definition. Would be nice to have VMALLOC_eND dynamically
determined from the static IO mappings, but the highmem threshold
depends on the value of VMALLOC_END, and memory has to be initialized
before the static IO mappings can be processed.
Therefore the best solution so far appears to use another value in
struct machine_desc for it so it can be set at run time. this is a
mechanical conversion that has to be done.
1.5) mach/irqs.h
The only information globally required from those files is the value of
NR_IRQS. Yet there is already a nr_irqs member in the machine_desc
structure for this, used by arch_probe_nr_irqs() in
arch/arm/kernel/irq.c).
So the first step would be to add
.nr_irqs = NR_IRQS,
to all machine_desc instances, making sure that <mach/irqs.h> is
included in those files. Then, <mach/irqs.h> should be removed from
arch/arm/include/asm/irq.h, and adjust things so everything still
compiles.
1.6) mach/gpio.h
This is a tough one. This depends on CONFIG_GENERIC_GPIO which is
selected by many machine types. They should all be converted to (or
configurable with) CONFIG_GPIOLIB so each SOC's specific GPIO handling
is made into runtime code instead of static inline functions. Care to
preserve the ability to not use gpiolib might be desireable in some
cases for performance reasons.
Definitely in need of serious investigation.
1.7) mach/mtd-xip.h
No need to care about those. This is for running the kernel XIP from
ROM memory. A XIP kernel is already incompatible with the notion of a
single kernel image since it obviously can't be modified at run time (as
needed by CONFIG_ARM_PATCH_PHYS_VIRT).
1.8) mach/isa-dma.h, mach/floppy.h
Those are used by old targets we might not care much about.
1.9) mach/entry-macro.S
This one gets included directly from arch/arm/kernel/entry-armv.S.
The only relevant macro still widely used is get_irqnr_preamble and
get_irqnr_and_base. They can be overridden by CONFIG_MULTI_IRQ_HANDLER
and the equivalent code hooked to the handle_irq member of the
machine_desc structure.
1.10) mach/debug-macro.S
This is used when CONFIG_DEBUG_LL is set. Supporting that option with a
single kernel image might prove very difficult with a rapidly
diminishing return on the investment.
This code is in need of some refactoring already:
http://article.gmane.org/gmane.linux.ports.arm.kernel/118525
To still benefit from the most likely needed debugging aid, we might
consider the ability to still allow the selection of one amongst the
existing implementation when building a kernel with many SOC support.
Obviously that would only work on the one hardware platform for which the selected printch implementation was
designed, but that should be good enough for debugging purposes.
1.11) mach/system.h
This is included from arch/arm/kernel/process.c and expected to provide
the following static inline functions or equivalent:
1.11.1) arch_idle()
Called when system is idle. Most of them just call cpu_do_idle().
The call to cpu_do_idle() should be moved to default_idle() and the exception
cases moved out of line where they can be hooked to the pm_idle callback.
1.11.2) arch_reset()
Used to reset the system. This is far from being a hot path and doesn't
justify a static inline function. An out-of-line version hooked to a
global arch_reset function pointer would work just fine.
1.12) mach/uncompress.h
This is used to define per SOC methods to output some progress feedback
from the kernel decompressor over a serial port. Once again, supporting
this with a single kernel image might prove very difficult with a
rapidly diminishing return on the investment. So it is probably best to
simply use generic empty stubs whenever more than one SOC family is
configured in a common kernel image.
2) Removal of any dependencies on <mach/*.h> from driver code
A couple possibilities:
a) We move the required header files next to the driver code. In many
cases, having a .h file with only the defines relevant to the concerned
driver is best. But this is a _lot_ of work.
b) We change those <mach/foo.h> into something more absolute, such as
<mach/omap2/foo.h>. This can be done on a per SOC basis, first by
moving the header files one level deeper, and then fixing up all
affected drivers.
c) We change those <mach/foo.h> files into something more precise, e.g.
<mach/omap2_foo.h> and fix concerned drivers.
I think the best solution here is (b) which doesn't preclude (a)
eventually or if it is trivial. But (c) is dangerous as files might be
added easily without paying too much attention to the file prefix.
3) Change thes to the build system
We need to move towards the ability to actually build more than one SOC
family at the same time.
3.1) Kconfig
This involves changes to Kconfig where currently only one out of all the
different architectures is selected through the big "ARM system type"
choice prompt. We need to determine a good way to move some of them
into simply bool prompts and keep track of which architecture can be
built concurrently with which. We know for instance that it is unlikely
that pre-ARMv6 and ARMv6/7 will ever be buildable together. Today we
know that nothing can be built with anything else and therefore this
should be the starting default. This needs investigating.
3.2) Makefile
Currently the arch/arm/Makefile is organized so the lowest instruction
set level and the highest optimization level are selected from all the
configured options. So this part should already be fine.
However the machine-$(*), plat-$(*), machdirs and platdirs variables
must go. In (2) above we should have removed the need for adding to the
global KBUILD_CPPFLAGS to add a path to some specific architecture
includes already. Keeping them only for the code under each
architecture subdirectory should be sufficient.
For example, this might be all that is needed:
obj-$(CONFIG_ARCH_MSM) += mach-msm/
or
obj-$(CONFIG_ARCH_KIRKWOOD) += mach-kirkwood/ plat-orion/
obj-$(CONFIG_ARCH_ORION5X) += mach-orion5x/ plat-orion/
Etc.
And within each of these directories, using the subdir-ccflags-y
variable to include the locally needed architecture specific include
files will do the trick.
3.3) defconfig
We need a defconfig file adding as many architectures to it as possible
for build coverage. Ideally the resulting binary should be boot tested
on as many targets it supports as possible.
4) Picking up broken pieces
Things will certainly break along the way. There are certainly issues
that I didn't foresee. My experience so far tend to indicate that
this is a somewhat recursive process where the tackling of one work item
reveals a few more which are prerequisite to the first one, etc. So any
estimate for this work needs to consider a large fudge factor.
Nicolas
