RFC ARM: vf610m4: Add Vybrid Cortex-M4 support

This adds Vybrid SoC support for the !MMU Cortex-M4 core. The patchset is its current state is more a collection of hacks than anything mergabel, advice and ideas how to beat it in good shape are welcome. I added some thoughts as comments in the individual patches.

I wrote also some more info about Vybrid Cortex-M4 support in my blog post:
http://falstaff.agner.ch/2014/10/05/make-it-two-tuxes-on-one-soc/

One thing I noticed that when I move the xipImage below the DRAM base address, the kernel freezes:
...
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) [freeze]

I think it happens when the scheduler gets started. Any idea what could go wrong here?

Stefan Agner (7):
ARM: vf610: add low level debug support for !MMU
clocksource: add dependencies for Vybrid pit clocksource
ARM: vf610m4: add new machine and SoC for Vybrid on Cortex-M4
ARM: dts: add support for Vybrid running on Cortex-M4
irqchip: nvic: increase number of external interrupts to 112
ARM: vf610m4: HACK: get dtb pointer from SRC_GPR3
ARM: vf610m4: add defconfig for Linux on Vybrids Cortex-M4

 arch/arm/Kconfig                   |  12 ++++
 arch/arm/Kconfig.debug             |   4 +-
 arch/arm/Makefile                  |   1 +
 arch/arm/boot/dts/Makefile         |   1 +
 arch/arm/boot/dts/armv7-m.dtsi     |   1 -
 arch/arm/boot/dts/vf610m4.dts      | 144 +++++++++++++++++++++++++++++++++++++
 arch/arm/configs/vf610m4_defconfig |  37 ++++++++++
 arch/arm/include/debug/vf.S        |  10 +++
 arch/arm/kernel/entry-v7m.S        |   4 +-
 arch/arm/kernel/head-nommu.S       |   8 +++
 arch/arm/mach-imx/Kconfig          |  22 ++++++
 arch/arm/mach-imx/Makefile         |   1 +
 arch/arm/mach-imx/Makefile.boot    |   0
 arch/arm/mach-imx/mach-vf610m4.c   |  16 +++++
 drivers/clocksource/Kconfig        |   2 +
 drivers/irqchip/irq-nvic.c         |   2 +
 drivers/mmc/host/Kconfig           |   2 +-
 drivers/pinctrl/Kconfig            |   2 +-
 18 files changed, 262 insertions(+), 7 deletions(-)
 create mode 100644 arch/arm/boot/dts/vf610m4.dts
 create mode 100644 arch/arm/configs/vf610m4_defconfig
 create mode 100644 arch/arm/mach-imx/Makefile.boot
 create mode 100644 arch/arm/mach-imx/mach-vf610m4.c

2.1.2