All V7 platforms can run SMP kernels, so make CONFIG_SMP visible for V7
multi-platform builds.
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Multi-platform requires various kconfig options to be selected, so
platforms don't need to select them individually.
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NStephen Warren <swarren@wwwdotorg.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>

The use of phys_to_machine and machine_to_phys in the phys<=>bus conversions
causes us to lose the top bits of the DMA address if the size of a DMA address is not the same as the size of the phyiscal address.

This can happen in practice on ARM where foreign pages can be above 4GB even
though the local kernel does not have LPAE page tables enabled (which is
totally reasonable if the guest does not itself have >4GB of RAM). In this
case the kernel still maps the foreign pages at a phys addr below 4G (as it
must) but the resulting DMA address (returned by the grant map operation) is
much higher.

This is analogous to a hardware device which has its view of RAM mapped up
high for some reason.

This patch makes I/O to foreign pages (specifically blkif) work on 32-bit ARM
systems with more than 4GB of RAM.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Remove an outdated reference to "most personal computers" having only one
CPU, and change the use of "singleprocessor" and "single processor" in
CONFIG_SMP's documentation to "uniprocessor" across all arches where that
documentation is present.
Signed-off-by: NRobert Graffham <psquid@psquid.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

warning: (ARCH_MULTIPLATFORM && ARCH_CLPS711X && ARCH_PXA &&
 SOC_EXYNOS5440 && ARCH_EMEV2) selects AUTO_ZRELADDR which
 has unmet direct dependencies (!ZBOOT_ROM)

This is because it's possible to have ZBOOT_ROM enabled, but at the
same time have another option enabled which selects AUTO_ZRELADDR
overriding the !ZBOOT_ROM dependency.  Fix this by reversing the
dependencies between ZBOOT_ROM and the options which depend on
!ZBOOT_ROM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The DT based MSM platforms can join the multi-platform builds, so
introduce a DT based ARCH_MSM option. This option allows DT based
MSM platforms to be built into the multi-platform kernel. Also
introduce a hidden ARCH_MSM config that both the DT and non-DT
platform support code select to avoid churn in places that depend
on CONFIG_ARCH_MSM.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

There are two SCHED_HRTICK config entries in Kconfig.
This looks like a merge mistake. Fix it.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Modern ARM CPUs can perform efficient unaligned memory accesses in
hardware and this feature is relied up on by code such as the dcache
word-at-a-time name hashing.

This patch selects HAVE_EFFICIENT_UNALIGNED_ACCESS for these cores and
reworks the kconfig select logic for DCACHE_WORD_ACCESS to use the new
symbol.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

With commit 11ec50ca ("word-at-a-time: provide generic big-endian
zero_bytemask implementation"), the asm-generic word-at-a-time code now
provides a zero_bytemask implementation, allowing us to make use of
DCACHE_WORD_ACCESS on big-endian CPUs, providing our
load_unaligned_zeropad function is endianness-clean.

This patch reworks the load_unaligned_zeropad fixup code to work for
both big- and little-endian CPUs, then removes the !CPU_BIG_ENDIAN check
when selecting DCACHE_WORD_ACCESS.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Enable the compiler intrinsic for byte swapping on arch ARM. This
allows the compiler to detect and be able to optimize out byte
swappings, and has a very modest benefit on vmlinux size (Linaro gcc
4.8):

text data bss dec hex filename
2840310 123932 61960 3026202 2e2d1a vmlinux-lart #orig
2840152 123932 61960 3026044 2e2c7c vmlinux-lart #builtin-bswap

6473120 314840 5616016 12403976 bd4508 vmlinux-mxs #orig
6472586 314848 5616016 12403450 bd42fa vmlinux-mxs #builtin-bswap

7419872 318372 379556 8117800 7bde28 vmlinux-imx_v6_v7 #orig
7419170 318364 379556 8117090 7bdb62 vmlinux-imx_v6_v7 #builtin-bswap
Signed-off-by: NKim Phillips <kim.phillips@freescale.com>
Reviewed-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The MOXA ART SoC is based on Faraday's FA526. This is a ARMv4 32-bit
192 MHz CPU with MMU and 16KB/8KB D/I-cache.

Add platform support for this SoC.

Also add UC-7112-LX as a machine.
Signed-off-by: NJonas Jensen <jonas.jensen@gmail.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NOlof Johansson <olof@lixom.net>

This isolates the custom S3C64xx GPIO definition table to
<linux/platform_data/gpio-samsung-s3x64xx.h> as this is
used in a few different places in the kernel, removing the
need to depend on the implicit inclusion of <mach/gpio.h>
from <linux/gpio.h> and thus getting rid of a few nasty
cross-dependencies.

Also delete the CONFIG_SAMSUNG_GPIO_EXTRA stuff. Instead
roof the number of GPIOs for this platform:
First sum up all the GPIO banks from A to Q: 187 GPIOs.
Add the 16 "board GPIOs" and the roof for SAMSUNG_GPIO_EXTRA,
128, so in total maximum 187+16+128 = 331 GPIOs, so let's
take the same roof as for S3C24XX: 512. This way we can do
away with the GPIO calculation macros for GPIO_BOARD_START,
BOARD_NR_GPIOS and the definition of ARCH_NR_GPIOS.

Cc: Mark Brown <broonie@kernel.org>
[on Mini6410 board]
Tested-by: NTomasz Figa <t.figa@samsung.com>
[for changes in mach-s3c64xx]
Acked-by: NTomasz Figa <t.figa@samsung.com>
Tested-by: NMark Brown <broonie@linaro.org>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This isolates the custom S3C24xx GPIO definition table to
<linux/platform_data/gpio-samsung-s3x24xx.h> as this is
used in a few different places in the kernel, removing the
need to depend on the implicit inclusion of <mach/gpio.h>
from <linux/gpio.h> and thus getting rid of a few nasty
cross-dependencies.

We also delete the nifty CONFIG_S3C24XX_GPIO_EXTRA stuff.
The biggest this can ever be for the S3C24XX is
CONFIG_S3C24XX_GPIO_EXTRA = 128, and then for CPU_S3C2443 or
CPU_S3C2416 32*12 GPIOs are added, so 32*12+128 = 512
is the absolute roof value on this platform. So we set
the size of ARCH_NR_GPIO to this and the GPIOs array will
fit any S3C24XX platform, as per pattern from other archs.

ChangeLog v2->v3:
- Move the movement of the S3C64XX gpio.h file out of
  this patch and into the follow-up patch where it belongs.
ChangeLog v1->v2:
- Added an #ifdef ARCH_S3C24XX around the header inclusion
  in drivers/gpio/gpio-samsung.c as we would otherwise
  have colliding definitions when compiling S3C64XX.
- Rename inclusion guard in the header file.

Cc: Tomasz Figa <tomasz.figa@gmail.com>
Cc: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: linux-samsung-soc@vger.kernel.org
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Since some new Hisilicon SoCs are not named as hi3xxx, rename mach-hi3xxx
to mach-hisi instead. And the pronounciation of "hisi" is similar to the
chinese pronounciation of Hisilicon. So Hisilicon guys like this name.

ARCH_HI3xxx will be renamed later since other drivers are using it and
they are still in linux-next git tree. So rename ARCH_HI3xxx later.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: NKevin Hilman <khilman@linaro.org>

Instead of duplicating the CC_STACKPROTECTOR Kconfig and
Makefile logic in each architecture, switch to using
HAVE_CC_STACKPROTECTOR and keep everything in one place. This
retains the x86-specific bug verification scripts.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1387481759-14535-2-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add board support with device tree for Hisilicon Hi3620 SoC platform.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@linaro.org>
[khilman: fix checkpatch errors]
[khilman: fold in patch which selects GPIO in Kconfig]
Signed-off-by: NKevin Hilman <khilman@linaro.org>

There are still some missing parts (e.g. board support, device trees),
but with these bits added on top of this patch I can successfully boot a
EFM32GG-DK3750 board that uses an EFM32GG990F1024.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>

All S3C64XX SoCs come with ARM1176JZF-s core, which fully supports
ARMv6K extensions. This patch lets the kernel use them on S3C6410 by
adding selection of CPU_V6K to ARCH_S3C64XX.
To use V6K extensions, these symbols must not be selected at the same
time, so this patch keeps only CPU_V6K selected for S3C64XX.
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

Trusted Foundations is a TrustZone-based secure monitor for ARM that
can be invoked using the same SMC-based API on supported platforms.
This patch adds initial basic support for Trusted Foundations using
the ARM firmware API. Current features are limited to the ability to
boot secondary processors.

Note: The API followed by Trusted Foundations does *not* follow the SMC
calling conventions. It has nothing to do with PSCI neither and is only
relevant to devices that use Trusted Foundations (like most Tegra-based
retail devices).
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NStephen Warren <swarren@nvidia.com>

This adds initial support for the Marvell Berlin SoC family with
Armada 1500 (88DE3100) and Armada 1500-mini (88DE3005) SoCs.
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>

This removes the SAMSUNG_GPIOLIB_4BIT Kconfig parameter,
which was no longer used anywhere in the source code
and Makefiles.
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Reviewed-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

Only the SH-Mobile product name is mentioned in the Kconfig descriptions
and help texts. This makes it difficult for external engineers working
on other Renesas platforms to find upstream platform support as the
combination of the SH-Mobile name and using the product number proved an
effective method of concealment.

Replace the "SH-Mobile" name with "Renesas ARM SoCs" in all the related
descriptions, help texts and comments.
Reported-by: NPhil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

SH-Mobile platforms are transitioning from non-multiplatform to
multiplatform kernel. A new ARCH_SHMOBILE_MULTI configuration symbol has
been created to group all multiplatform-enabled SH-Mobile SoCs. The
existing ARCH_SHMOBILE configuration symbol groups SoCs that haven't
been converted yet.

This arrangement works fine for the arch/ code, but lots of drivers
needed on both ARCH_SHMOBILE and ARCH_SHMOBILE_MULTI depend on
ARCH_SHMOBILE only. In order to avoid changing them, rename
ARCH_SHMOBILE to ARCH_SHMOBILE_LEGACY, and create a new boolean
ARCH_SHMOBILE configuration symbol that is selected by both
ARCH_SHMOBILE_LEGACY and ARCH_SHMOBILE_MULTI.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

ARM_PATCH_PHYS_VIRT and AUTO_ZRELADDR has been enabled as default configs
to integrator platform.

Introduction of PHYS_VIRT config as default would enable phy-to-virt and
virt-to-phy translation function at boot and module loading time
and enforce dynamic reallocation of memory. AUTO_ZRELADDR config would
enable calculation of kernel load address at run time.

PHYS_VIRT config is mutually exclusive to XIP_KERNEL, XIP_KERNEL is used in
systems with NOR flash devices, and ZRELADDR config is mutually exclusive
to ZBOOT_ROM.

Requesting maintainers of Integrator platform to evaluate the changes on the
board and comment, as I dont have the board for testing and also requesting
an ACK.
Signed-off-by: Npanchaxari <panchaxari.prasannamurthy@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Olof Johansson <olof@lixom.net>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch adds all required platform-specific data and initialization
code to support the generic amba-pl08x driver on S3C64xx SoCs.

Also some compatibility definitions are added to make the transition
from legacy API to DMA engine easier. The biggest hack here is passing
const char * pointers through DMA resource, casted to unsigned long,
but this is how Samsung DMA wrappers (used to support both s3c-dma and
DMA engine in drivers) are designed.
Signed-off-by: NTomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Now with dma_mask series merged and max*pfn has consistent meaning on ARM
as rest of the arch's thanks to RMK's mega series, lets switch ARM code
to NO_BOOTMEM. With NO_BOOTMEM change, now we use memblock allocator to
reserve space for crash kernel to have one less dependency with nobootmem
allocator wrapper.

Tested with both flat memory and sparse (faked) memory models with highmem
enabled.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>

The ARM architected timer driver doesn't compile without
GENERIC_CLOCKEVENTS selected, so ensure that we select it when building
for a platform that has the timer.

Without this patch, mach-virt fails to build without something like
mach-vexpress also selected.
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We've switched over every architecture that supports SMP to it, so
remove the new useless config variable.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make sure that seccomp filter won't be built when ARM OABI is in use,
since there is work needed to distinguish calling conventions. Until
that is done (which is likely never since OABI is deprecated), make
sure seccomp filter is unavailable in the OABI world.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NWill Drewry <wad@chromium.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Given recent discussions about the lack of OABI in the wild, switch
CONFIG_OABI_COMPAT to off-by-default to encourage more system builders
to avoid it.
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
provided by lib/iommu_helper.c.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: will.deacon@arm.com
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Changes in v9:
- remove uneeded include asm/cacheflush.h;
- just return 0 if !dev->dma_mask in dma_capable.

Changes in v8:
- use __phys_to_pfn and __pfn_to_phys.

Changes in v7:
- dma_mark_clean: empty implementation;
- in dma_capable use coherent_dma_mask if dma_mask hasn't been
  allocated.

Changes in v6:
- check for dev->dma_mask being NULL in dma_capable.

Changes in v5:
- implement dma_mark_clean using dmac_flush_range.

Changes in v3:
- dma_capable: do not treat dma_mask as a limit;
- remove SWIOTLB dependency on NEED_SG_DMA_LENGTH.

This removes the XSCALE_PMU Kconfig param, which is defined
but no longer used in makefiles and source files.
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Our spinlocks are only 32-bit (2x16-bit tickets) and, on processors
with 64-bit atomic instructions, cmpxchg64 makes use of the double-word
exclusive accessors.

This patch wires up the cmpxchg-based lockless lockref implementation
for ARM.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The SA1100 was implementing its own variants of gpio_get_value()
and gpio_set_value() and only selectively falling back to
gpiolib for extended (EGPIO) handling. However the driver in
gpio/gpio-sa1100.c already handles the same functionality for
these lines, yet remain unused.

The only upside would be things like a timing-critical hotpath
on bit-banged GPIO, but that kind of things does not seem to
happen on these GPIOs, so it is not worth having the extra
complexity.

Tested with some buttons on the Compaq iPAQ H3630.

Cc: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This converts the gemini machine to use generic clockevents
by rewriting the timer driver.

Cc: arm@kernel.org
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NOlof Johansson <olof@lixom.net>

Architectures which support CONFIG_PARPORT_PC should select
ARCH_MIGHT_HAVE_PC_PARPORT.
Signed-off-by: NMark Salter <msalter@redhat.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: linux-arm-kernel@lists.infradead.org

The Kconfig for arch/arm/mach-ixp4xx has a local definition
of ARCH_SUPPORTS_BIG_ENDIAN which could be used elsewhere.
This means that if IXP4xx is selected and this symbol is
selected eleswhere then an warning is produced.

Clean the following error up by making the symbol be
selected by the main ARCH_IXP4XX definition and have a
common definition in arch/arm/mm/Kconfig

warning: (ARCH_xxx) selects ARCH_SUPPORTS_BIG_ENDIAN which has unmet direct dependencies (ARCH_IXP4XX)
warning: (ARCH_xxx) selects ARCH_SUPPORTS_BIG_ENDIAN which has unmet direct dependencies (ARCH_IXP4XX)
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>

The Device Tree boot path now supports everything the ATAG
boot can provide, and the two are equivalent. This deletes
the ATAG boot path from the Integrator/AP and
Integrator/CP platforms to move them on to the future.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to
program the hardware with mfns rather than pfns for dma addresses.
Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select
SWIOTLB_XEN on arm and arm64.

At the moment always rely on swiotlb-xen, but when Xen starts supporting
hardware IOMMUs we'll be able to avoid it conditionally on the presence
of an IOMMU on the platform.

Implement xen_create_contiguous_region on arm and arm64: for the moment
we assume that dom0 has been mapped 1:1 (physical addresses == machine
addresses) therefore we don't need to call XENMEM_exchange. Simply
return the physical address as dma address.

Initialize the xen-swiotlb from xen_early_init (before the native
dma_ops are initialized), set xen_dma_ops to &xen_swiotlb_dma_ops.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>


Changes in v8:
- assume dom0 is mapped 1:1, no need to call XENMEM_exchange.

Changes in v7:
- call __set_phys_to_machine_multi from xen_create_contiguous_region and
xen_destroy_contiguous_region to update the P2M;
- don't call XENMEM_unpin, it has been removed;
- call XENMEM_exchange instead of XENMEM_exchange_and_pin;
- set nr_exchanged to 0 before calling the hypercall.

Changes in v6:
- introduce and export xen_dma_ops;
- call xen_mm_init from as arch_initcall.

Changes in v4:
- remove redefinition of DMA_ERROR_CODE;
- update the code to use XENMEM_exchange_and_pin and XENMEM_unpin;
- add a note about hardware IOMMU in the commit message.

Changes in v3:
- code style changes;
- warn on XENMEM_put_dma_buf failures.

IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
provided by lib/iommu_helper.c.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: will.deacon@arm.com
CC: linux@arm.linux.org.uk


Changes in v8:
- use __phys_to_pfn and __pfn_to_phys.

Changes in v7:
- dma_mark_clean: empty implementation;
- in dma_capable use coherent_dma_mask if dma_mask hasn't been
  allocated.

Changes in v6:
- check for dev->dma_mask being NULL in dma_capable.

Changes in v5:
- implement dma_mark_clean using dmac_flush_range.

Changes in v3:
- dma_capable: do not treat dma_mask as a limit;
- remove SWIOTLB dependency on NEED_SG_DMA_LENGTH.