[PATCH v2] arm: Add basic support for new Marvell Armada 370 and Armada XP SoC

[dmarlin@redhat.com (David Marlin)]

I noticed that you are using mach-mvebu in these patches.  I have seen 
these machines referred to as 'armada', 'axp', 'armadaxp', etc.  Will 
'mvebu' be the official machine name to use for these systems?  I'm 
looking for a 'name' to identify the common kernel for these systems. 
For reference, the names of the ARM kernels we are currently building in 
Fedora include: 'highbank', 'imx', 'kirkwood', 'omap', and 'tegra'.


Thank you,

d.marlin
===========


Gregory CLEMENT wrote:
> Arnd, Olof,
> 
> You'll find in this patch set the new version of the initial support for a
> new family of ARMv7-compatible Marvell SoCs initially submitted by my
> colleague Thomas Petazzoni. Following the conclusion of the discussion when
> we submitted our first version we have chosen to add this support for this
> SoC family in the to support in the arch/arm/mach-mvebu/ directory.
> 
> As for the previous release, both the Armada 370 and the Armada XP SoCs are
> supported in this directory, and we are able to build a single kernel image
> that boots on both SoCs. Both SoCs use the PJ4B processor, a
> Marvell-developed ARM core that implements the ARMv7 instruction set. We are
> currently using Marvell evaluation boards for both of those SoCs, and the
> support for those boards is added in this patch set.
> 
> We remained focused on a limited preliminary support which only includes the
> necessary code for timer and IRQ support, the serial controller is a
> standard 16550-compatible one. The diffstat looks like:
> 
>  Documentation/devicetree/bindings/arm/armada_370_xp-mpic.txt  |   23 +
>  Documentation/devicetree/bindings/arm/armada_370_xp-timer.txt |   11 +
>  Documentation/devicetree/bindings/arm/armada_370_xp.txt       |   24 +
>  MAINTAINERS                                                   |    8 +
>  arch/arm/Kconfig                                              |   15 +
>  arch/arm/Makefile                                             |    1 +
>  arch/arm/boot/dts/armada-370-db.dts                           |   41 ++
>  arch/arm/boot/dts/armada-370-xp.dtsi                          |   66 +++
>  arch/arm/boot/dts/armada-370.dtsi                             |   29 +
>  arch/arm/boot/dts/armada-xp-db.dts                            |   40 ++
>  arch/arm/boot/dts/armada-xp.dtsi                              |   49 ++
>  arch/arm/configs/mvebu_defconfig                              |   47 ++
>  arch/arm/mach-mvebu/Kconfig                                   |   14 +
>  arch/arm/mach-mvebu/Makefile                                  |    2 +
>  arch/arm/mach-mvebu/Makefile.boot                             |    1 +
>  arch/arm/mach-mvebu/armada-370-xp-dt.c                        |   65 +++
>  arch/arm/mach-mvebu/common.c                                  |   36 ++
>  arch/arm/mach-mvebu/common.h                                  |   24 +
>  arch/arm/mach-mvebu/include/mach/armada-370-xp.h              |   22 +
>  arch/arm/mach-mvebu/include/mach/debug-macro.S                |   24 +
>  arch/arm/mach-mvebu/include/mach/mvebu.h                      |   22 +
>  arch/arm/mach-mvebu/include/mach/timex.h                      |   13 +
>  arch/arm/mach-mvebu/include/mach/uncompress.h                 |   41 ++
>  arch/arm/mach-mvebu/irq-armada-370-xp.c                       |  133 +++++
>  arch/arm/mach-mvebu/time-armada-370-xp.c                      |  244 +++++++++
>  25 files changed, 995 insertions(+)
> 
> This patch set, and the support for those SoCs, started as a collaborative
> effort from Marvell engineers (who have done the initial development work)
> and Free Electrons engineers (who are reshaping the code for mainline
> submission, adding device tree support, etc.). And for this new version we
> got contributions from Ben Dooks from Codethink.
> 
> The patch set is based on your arm-soc/for-next branch (updated on Monday
> 11th June).
> 
> The main change between V1 and V2 is the use of a new mach-mvebu directory
> as this directory is aimed to receive most of the Marvell SOC converted to
> the device tree, we intended to make the code less specific. The other main
> part was to remove all the unnecessary code or even files.
> 
> Here comes a pretty exhaustive list of the changes:
> 
> * Created a new mach- directory called mach-mvebu as suggested on the
>  mainling-list. Converted most the "armada" word by the "mvebu", but as some
>  code remains specific to the armada 370 and armada XP SOC, then created
>  also the aramada_370_xp suffix for this part. This suffix was dedicated for
>  the irq and timer part. It was also used for the register related to the
>  reset part. And of course it was also used for the device tree part.
> 
> * Merged axp-dt.c and a370-dt.c files in one single armada_370_xp-dt.c file.
> 
> * Deleted most of the mapping address in include/mach/armada.h and split it
>   in two headers file:
> 
>   - mvebu.h which contains the virtual and physical mapping for the internal
>     registers of the mvebu SOC. This ones are mainly used for the early
>     print during boot.
> 
>   - armada_370_xp which contains the registers offset and mask for resetting
>     the CPU.
> 
> * Removed unused headers such as
>   - hardware.h by directly including accurate header when needed
>   - gpio.h by removing the dependencies to PLAT-ORION
>   - io.h no more needed for CPI
>   - irqs.h by using SPARSE_IRQ
>   - system.h no more needed for new SOC
> 
> * Removed the PCI related code as it was not necessary for the initial
>   submission
> 
> * Removed all the PLAT-ORION dependencies remaining
> 
> * Ensured property reading checks for error when getting data from device
>   tree in the timer file. This was a patch from Ben Dooks with the following
>   comments:
> 
>   "The call to of_property_read_u32() only checks for the value that the clk
>    variable is set to being non-zero, and not the return value of the call
>    itself.
> 
>    This caused a system without the clock-frequency attribute to fail to
>    boot as it used a random value on the stack to setup the system timers
>    and thus cause an interrupt storm.
> 
>    Also ensure clk is set to zero, to avoid warnings."
> 
> * Converted irq.c to use SPARSE_IRQ
> 
> * Added the following bug fixes and improvements in irq.c from Ben Dooks
>   
>   - MPIC: BUG_ON() if the of_iomap() fails: Ensure that if either resource
>     is missing, we stop the kernel in a reasonably fatal way.
> 
>   - MPIC: Move main register base to base of MPIC registers: The current
>     kernel driver had the MPIC base at the base of the block containing the
>     MPIC and not the MPIC itself. Change this value in the driver and the
>     .dtsi file
> 
> 	Also change the register size in the .dtsi to be the size of the
> 	register range for the MIPC and not the block it is in.
> 
>   - MPIC: Move per-cpu register base: The current kernel driver had the MPIC
>   	per-cpu register base at the base of the per-cpu register block and not
>   	at the base of the specific per-cpu interrupt registers.
> 
> 	Move the driver and .dtsi to use the correct base and size.
> 
>   - MPIC: number fetch should use irqd_to_hwirq(): The mask and unmask
>   	routines are assuming that d->irq is a 1:1 mapping with the interrupt
>   	hardware. Use the irqd_to_hwirq() call to map the irq_data to the
>   	hardware irq number directly.
> 
>   - MPIC: read number of interrupts from control register: Read the number
>    	of MPIC interrupts from the controller and only register that many.
> 
> Andrew Lunn asked for refactoring the _restart() function to being used by
> any MVEBU SOC, but we didn't find a nice way to do it. Indeed the registers
> mapping differs between the SOC and the bit mask too. A solution could be to
> get this mapping through the device tree, but we are not sure it was a good
> usage of the device tree.
> 
> 
> Best regards,
> 
> Gregory Clement