arm_dma_limit stores physical address of maximal address accessible by DMA,
so the phys_addr_t type makes much more sense for it instead of u32. This
patch fixes the following build warning:

arch/arm/mm/init.c:380: warning: comparison of distinct pointer types lacks a cast
Reported-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

This patch adds support for CMA to dma-mapping subsystem for ARM
architecture. By default a global CMA area is used, but specific devices
are allowed to have their private memory areas if required (they can be
created with dma_declare_contiguous() function during board
initialisation).

Contiguous memory areas reserved for DMA are remapped with 2-level page
tables on boot. Once a buffer is requested, a low memory kernel mapping
is updated to to match requested memory access type.

GFP_ATOMIC allocations are performed from special pool which is created
early during boot. This way remapping page attributes is not needed on
allocation time.

CMA has been enabled unconditionally for ARMv6+ systems.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Tested-by: NRob Clark <rob.clark@linaro.org>
Tested-by: NOhad Ben-Cohen <ohad@wizery.com>
Tested-by: NBenjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: NRobert Nelson <robertcnelson@gmail.com>
Tested-by: NBarry Song <Baohua.Song@csr.com>

Get rid of the TOP_PTE() macro as we now have proper accessor functions
instead.  No one should be directly referencing the top pte table
anymore.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Provide get_top_pte() to complement set_top_pte(), moving the only
users of TOP_PTE to arch/arm/mm/mm.h.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

A number of places establish a PTE in our top page table and
immediately flush the TLB.  Rather than having this at every callsite,
provide an inline function for this purpose.

This changes some global tlb flushes to be local; each time we setup
one of these mappings, we always do it with preemption disabled which
would prevent us migrating to another CPU.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the TOP_PTE address definitions to one central place so that it's
easy to discover what they're being used for.  This helps to ensure
that there are no overlaps.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Now that we have all the static mappings from iotable_init() located
in the vmalloc area, it is trivial to optimize ioremap by reusing those
static mappings when the requested physical area fits in one of them,
and so in a generic way for all platforms.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Tested-by: NJamie Iles <jamie@jamieiles.com>

This patch defines the (pte|pmd)val_t as u32 and changes the page table
types to be based on these. The PMD bits are converted to the
corresponding type using the _AT macro.

The flush_pmd_entry/clean_pmd_entry argument was changed to (void *) to
allow them to be used with both PGD and PMD pointers and avoid code
duplication.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ISA_DMA_THRESHOLD has been unused by non-arch code, so lets now get
rid of it from ARM by replacing it with arm_dma_zone_mask.  Move
dma_supported() and dma_set_mask() out of line, and have
dma_supported() check this new variable instead.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

pmd_off() has only one user, so lets consolidate this into its only
user.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add pud_offset() et.al. between the pgd and pmd code in preparation of
using pgtable-nopud.h rather than 4level-fixup.h.

This incorporates a fix from Jamie Iles <jamie@jamieiles.com> for
uaccess_with_memcpy.c.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This makes everywhere dealing with pte values use the same type.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the platform specific bootmem memory reservations out of
arch/arm/mm/mmu.c into their respective platform files.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Everything should now be using sparsemem rather than discontigmem, so
remove the code supporting discontigmem from ARM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This is the minimum fixmap interface expected to be implemented by
architectures supporting highmem.

We have a second level page table already allocated and covering
0xfff00000-0xffffffff because the exception vector page is located
at 0xffff0000, and various cache tricks already use some entries above
0xffff0000.  Therefore the PTEs covering 0xfff00000-0xfffeffff are free
to be used.

However the XScale cache flushing code already uses virtual addresses
between 0xfffe0000 and 0xfffeffff.

So this reserves the 0xfff00000-0xfffdffff range for fixmap stuff.

The Documentation/arm/memory.txt information is updated accordingly,
including the information about the actual top of DMA memory mapping
region which didn't match the code.
Signed-off-by: NNicolas Pitre <nico@marvell.com>

Update to use the asm/sections.h header rather than declaring these
symbols ourselves.  Change __data_start to _data to conform with the
naming found within asm/sections.h.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Currently there are two instances of struct meminfo: one in
kernel/setup.c marked __initdata, and another in mm/init.c with
permanent storage.  Let's keep only the later to directly populate
the permanent version from arm_add_memory().

Also move common validation tests between the MMU and non-MMU cases
into arm_add_memory() to remove some duplication.  Protection against
overflowing the membank array is also moved in there in order to cover
the kernel cmdline parsing path as well.
Signed-off-by: NNicolas Pitre <nico@marvell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This member is now redundant; the memory type is encoded in the Linux
PTE bits.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

... some of which are now in linux/*.h headers.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add prot_pte_ext to the mem_types table to allow the extended pte
attributes to be passed to set_pte_ext(), thereby permitting us to
specify memory type information for the hardware PTE entries.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We really want to be using the memory type table in ioremap, so we
only have to do the CPU type fixups in one place.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix warnings and errors in arch/arm/mm for nommu build.
Remove commented out function prototype in pgtable-nommu.h
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

If we're going to have mmu.c for code which is specific to the MMU
machines, we might as well move the other MMU initialisation
specific code from mm-armv.c into this new file.  This also allows
us to make some functions static.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the MMU specific code from init.c into mmu.c, and add nommu
fixups to nommu.c
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move top_pmd into arch/arm/mm/mm.h - nothing outside arch/arm/mm
references it.

Move the repeated definition of TOP_PTE into mm/mm.h, as well as
a few function prototypes.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>