In kmap_atomic(), kmap_high_get() is invoked for checking already
mapped area. In __flush_dcache_page() and dma_cache_maint_page(),
we explicitly call kmap_high_get() before kmap_atomic()
when cache_is_vipt(), so kmap_high_get() can be invoked twice.
This is useless operation, so remove one.

v2: change cache_is_vipt() to cache_is_vipt_nonaliasing() in order to
be self-documented
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch removes page_address() usage in IOMMU-aware dma-mapping
implementation and replaced it with direct use of the cpu virtual address
provided by the caller. page_address() returned incorrect address for
pages remapped in atomic pool, what caused memory leak.
Reported-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Tested-by: NHiroshi Doyu <hdoyu@nvidia.com>

Alignment order for a dma iommu buffer is set by buffer size. For
large buffer, it is a waste of iommu address space. So configurable
parameter to limit maximum alignment order can reduce the waste.
Signed-off-by: NSeung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: NKyungmin.park <kyungmin.park@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

IOMMU can provide access to any memory page, so there is no point in
limiting the allocated pages only to lowmem, once other parts of
dma-mapping subsystem correctly supports himem pages.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

This patch adds missing pieces to correctly support memory pages served
from CMA regions placed in high memory zones. Please note that the default
global CMA area is still put into lowmem and is limited by optional
architecture specific DMA zone. One can however put device specific CMA
regions in high memory zone to reduce lowmem usage.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>

This patch adds EXPORT_SYMBOL_GPL calls to the three arm iommu
functions - arm_iommu_create_mapping, arm_iommu_free_mapping
and arm_iommu_attach_device. These three functions are arm specific
wrapper functions for creating/freeing/using an iommu mapping and
they are called by various drivers. If any of these drivers need
to be built as dynamic modules, these functions need to be exported.

Changelog v2: using EXPORT_SYMBOL_GPL as suggested by Marek.
Signed-off-by: NPrathyush K <prathyush.k@samsung.com>
[m.szyprowski: extended with recently introduced
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device)]
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

A counter part of arm_iommu_attach_device().
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

struct dma_map_ops iommu_ops doesn't have ->set_dma_mask, which causes
crash when dma_set_mask() is called from some driver.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Realview fails to boot with this warning:
BUG: spinlock lockup suspected on CPU#0, init/1
 lock: 0xcf8bde10, .magic: dead4ead, .owner: init/1, .owner_cpu: 0
Backtrace:
[<c00185d8>] (dump_backtrace+0x0/0x10c) from [<c03294e8>] (dump_stack+0x18/0x1c) r6:cf8bde10 r5:cf83d1c0 r4:cf8bde10 r3:cf83d1c0
[<c03294d0>] (dump_stack+0x0/0x1c) from [<c018926c>] (spin_dump+0x84/0x98)
[<c01891e8>] (spin_dump+0x0/0x98) from [<c0189460>] (do_raw_spin_lock+0x100/0x198)
[<c0189360>] (do_raw_spin_lock+0x0/0x198) from [<c032cbac>] (_raw_spin_lock+0x3c/0x44)
[<c032cb70>] (_raw_spin_lock+0x0/0x44) from [<c01c9224>] (pl011_console_write+0xe8/0x11c)
[<c01c913c>] (pl011_console_write+0x0/0x11c) from [<c002aea8>] (call_console_drivers.clone.7+0xdc/0x104)
[<c002adcc>] (call_console_drivers.clone.7+0x0/0x104) from [<c002b320>] (console_unlock+0x2e8/0x454)
[<c002b038>] (console_unlock+0x0/0x454) from [<c002b8b4>] (vprintk_emit+0x2d8/0x594)
[<c002b5dc>] (vprintk_emit+0x0/0x594) from [<c0329718>] (printk+0x3c/0x44)
[<c03296dc>] (printk+0x0/0x44) from [<c002929c>] (warn_slowpath_common+0x28/0x6c)
[<c0029274>] (warn_slowpath_common+0x0/0x6c) from [<c0029304>] (warn_slowpath_null+0x24/0x2c)
[<c00292e0>] (warn_slowpath_null+0x0/0x2c) from [<c0070ab0>] (lockdep_trace_alloc+0xd8/0xf0)
[<c00709d8>] (lockdep_trace_alloc+0x0/0xf0) from [<c00c0850>] (kmem_cache_alloc+0x24/0x11c)
[<c00c082c>] (kmem_cache_alloc+0x0/0x11c) from [<c00bb044>] (__get_vm_area_node.clone.24+0x7c/0x16c)
[<c00bafc8>] (__get_vm_area_node.clone.24+0x0/0x16c) from [<c00bb7b8>] (get_vm_area_caller+0x48/0x54)
[<c00bb770>] (get_vm_area_caller+0x0/0x54) from [<c0020064>] (__alloc_remap_buffer.clone.15+0x38/0xb8)
[<c002002c>] (__alloc_remap_buffer.clone.15+0x0/0xb8) from [<c0020244>] (__dma_alloc+0x160/0x2c8)
[<c00200e4>] (__dma_alloc+0x0/0x2c8) from [<c00204d8>] (arm_dma_alloc+0x88/0xa0)[<c0020450>] (arm_dma_alloc+0x0/0xa0) from [<c00beb00>] (dma_pool_alloc+0xcc/0x1a8)
[<c00bea34>] (dma_pool_alloc+0x0/0x1a8) from [<c01a9d14>] (pl08x_fill_llis_for_desc+0x28/0x568)
[<c01a9cec>] (pl08x_fill_llis_for_desc+0x0/0x568) from [<c01aab8c>] (pl08x_prep_slave_sg+0x258/0x3b0)
[<c01aa934>] (pl08x_prep_slave_sg+0x0/0x3b0) from [<c01c9f74>] (pl011_dma_tx_refill+0x140/0x288)
[<c01c9e34>] (pl011_dma_tx_refill+0x0/0x288) from [<c01ca748>] (pl011_start_tx+0xe4/0x120)
[<c01ca664>] (pl011_start_tx+0x0/0x120) from [<c01c54a4>] (__uart_start+0x48/0x4c)
[<c01c545c>] (__uart_start+0x0/0x4c) from [<c01c632c>] (uart_start+0x2c/0x3c)
[<c01c6300>] (uart_start+0x0/0x3c) from [<c01c795c>] (uart_write+0xcc/0xf4)
[<c01c7890>] (uart_write+0x0/0xf4) from [<c01b0384>] (n_tty_write+0x1c0/0x3e4)
[<c01b01c4>] (n_tty_write+0x0/0x3e4) from [<c01acfe8>] (tty_write+0x144/0x240)
[<c01acea4>] (tty_write+0x0/0x240) from [<c01ad17c>] (redirected_tty_write+0x98/0xac)
[<c01ad0e4>] (redirected_tty_write+0x0/0xac) from [<c00c371c>] (vfs_write+0xbc/0x150)
[<c00c3660>] (vfs_write+0x0/0x150) from [<c00c39c0>] (sys_write+0x4c/0x78)
[<c00c3974>] (sys_write+0x0/0x78) from [<c0014460>] (ret_fast_syscall+0x0/0x3c)

This happens because the DMA allocation code is not respecting atomic
allocations correctly.

GFP flags should not be tested for GFP_ATOMIC to determine if an
atomic allocation is being requested.  GFP_ATOMIC is not a flag but
a value.  The GFP bitmask flags are all prefixed with __GFP_.

The rest of the kernel tests for __GFP_WAIT not being set to indicate
an atomic allocation.  We need to do the same.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Subhash Jadavani reported this partial backtrace:
  Now consider this call stack from MMC block driver (this is on the ARMv7
  based board):

  [<c001b50c>] (v7_dma_inv_range+0x30/0x48) from [<c0017b8c>] (dma_cache_maint_page+0x1c4/0x24c)
  [<c0017b8c>] (dma_cache_maint_page+0x1c4/0x24c) from [<c0017c28>] (___dma_page_cpu_to_dev+0x14/0x1c)
  [<c0017c28>] (___dma_page_cpu_to_dev+0x14/0x1c) from [<c0017ff8>] (dma_map_sg+0x3c/0x114)

This is caused by incrementing the struct page pointer, and running off
the end of the sparsemem page array.  Fix this by incrementing by pfn
instead, and convert the pfn to a struct page.

Cc: <stable@vger.kernel.org>
Suggested-by: NJames Bottomley <JBottomley@Parallels.com>
Tested-by: NSubhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch adds support for DMA_ATTR_FORCE_CONTIGUOUS attribute for
dma_alloc_attrs() in IOMMU-aware implementation. For allocating physically
contiguous buffers Contiguous Memory Allocator is used.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Expose another DMA operations function: arm_dma_set_mask. This
function will be added to a custom DMA ops for Armada 370/XP.
Depending of its configuration Armada 370/XP can be set as a "nearly"
coherent architecture. In this case the DMA ops is made of:
- specific functions for this architecture
- already exposed arm DMA related functions
- the arm_dma_set_mask which was not exposed yet.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Fix build warning in __dma_alloc() as below:

arch/arm/mm/dma-mapping.c: In function '__dma_alloc':
arch/arm/mm/dma-mapping.c:653:29: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Remove arch_is_coherent() from iommu dma ops and implement separate
coherent ops functions.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

arch_is_coherent is problematic as it is a global symbol. This
doesn't work for multi-platform kernels or platforms which can support
per device coherent DMA.

This adds arm_coherent_dma_ops to be used for devices which connected
coherently (i.e. to the ACP port on Cortex-A9 or A15). The arm_dma_ops
are modified at boot when arch_is_coherent is true.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

With many IOMMU'able devices, console gets noisy.

Tegra30 has a few dozen of IOMMU'able devices.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Skip unnecessary operations if order == 0. A little bit easier to
read.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

When either of __alloc_from_contiguous or __alloc_remap_buffer fails
to provide a valid pointer, allocated memory is freed up and an error
is returned. 'pages' was however not freed before returning error.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

The __free_from_pool() function was changed in
e9da6e99. Unfortunately, the test that
checks whether the provided (start,size) is within the DMA pool has
been improperly modified. It used to be:

  if (start < coherent_head.vm_start || end > coherent_head.vm_end)

Where coherent_head.vm_end was non-inclusive (i.e, it did not include
the first byte after the pool). The test has been changed to:

  if (start < pool->vaddr || start > pool->vaddr + pool->size)

So now pool->vaddr + pool->size is inclusive (i.e, it includes the
first byte after the pool), so the test should be >= instead of >.

This bug causes the following message when freeing the *first* DMA
coherent buffer that has been allocated, because its virtual address
is exactly equal to pool->vaddr + pool->size :

WARNING: at /home/thomas/projets/linux-2.6/arch/arm/mm/dma-mapping.c:463 __free_from_pool+0xa4/0xc0()
freeing wrong coherent size from pool
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Lior Amsalem <alior@marvell.com>
Cc: Maen Suleiman <maen@marvell.com>
Cc: Tawfik Bayouk <tawfik@marvell.com>
Cc: Shadi Ammouri <shadi@marvell.com>
Cc: Eran Ben-Avi <benavi@marvell.com>
Cc: Yehuda Yitschak <yehuday@marvell.com>
Cc: Nadav Haklai <nadavh@marvell.com>
[m.szyprowski: rebased onto v3.6-rc5 and resolved conflict]
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Make use of the same atomic pool as DMA does, and skip a kernel page
mapping which can involve sleep'able operations at allocating a kernel
page table.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Support atomic allocation in __iommu_get_pages().
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
[moved __atomic_get_pages() under #ifdef CONFIG_ARM_DMA_USE_IOMMU
 to avoid unused fuction warning for no-IOMMU case]
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Check the given range("start", "size") is included in "atomic_pool" or not.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

struct page **pages is necessary to align with non atomic path in
__iommu_get_pages(). atomic_pool() has the intialized **pages instead
of just *page.
Signed-off-by: NHiroshi Doyu <hdoyu@nvidia.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Print a loud warning when system runs out of memory from atomic DMA
coherent pool to let users notice the potential problem.
Reported-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Some platforms might require to increase atomic coherent pool to make
sure that their device will be able to allocate all their buffers from
atomic context. This function can be also used to decrease atomic
coherent pool size if coherent allocations are not used for the given
sub-platform.
Suggested-by: NJosh Coombs <josh.coombs@gmail.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Commit e9da6e99 (ARM: dma-mapping:
remove custom consistent dma region) changed the way atomic allocations
are handled. However, arm_dma_free() was not modified accordingly, and
as a result freeing of atomic allocations does not work correctly when
CMA is disabled. Memory is leaked and following WARNINGs are seen:

[   57.698911] ------------[ cut here ]------------
[   57.753518] WARNING: at arch/arm/mm/dma-mapping.c:263 arm_dma_free+0x88/0xe4()
[   57.811473] trying to free invalid coherent area: e0848000
[   57.867398] Modules linked in: sata_mv(-)
[   57.921373] [<c000d270>] (unwind_backtrace+0x0/0xf0) from [<c0015430>] (warn_slowpath_common+0x50/0x68)
[   58.033924] [<c0015430>] (warn_slowpath_common+0x50/0x68) from [<c00154dc>] (warn_slowpath_fmt+0x30/0x40)
[   58.152024] [<c00154dc>] (warn_slowpath_fmt+0x30/0x40) from [<c000dc18>] (arm_dma_free+0x88/0xe4)
[   58.219592] [<c000dc18>] (arm_dma_free+0x88/0xe4) from [<c008fa30>] (dma_pool_destroy+0x100/0x148)
[   58.345526] [<c008fa30>] (dma_pool_destroy+0x100/0x148) from [<c019a64c>] (release_nodes+0x144/0x218)
[   58.475782] [<c019a64c>] (release_nodes+0x144/0x218) from [<c0197e10>] (__device_release_driver+0x60/0xb8)
[   58.614260] [<c0197e10>] (__device_release_driver+0x60/0xb8) from [<c0198608>] (driver_detach+0xd8/0xec)
[   58.756527] [<c0198608>] (driver_detach+0xd8/0xec) from [<c0197c54>] (bus_remove_driver+0x7c/0xc4)
[   58.901648] [<c0197c54>] (bus_remove_driver+0x7c/0xc4) from [<c004bfac>] (sys_delete_module+0x19c/0x220)
[   59.051447] [<c004bfac>] (sys_delete_module+0x19c/0x220) from [<c0009140>] (ret_fast_syscall+0x0/0x2c)
[   59.207996] ---[ end trace 0745420412c0325a ]---
[   59.287110] ------------[ cut here ]------------
[   59.366324] WARNING: at arch/arm/mm/dma-mapping.c:263 arm_dma_free+0x88/0xe4()
[   59.450511] trying to free invalid coherent area: e0847000
[   59.534357] Modules linked in: sata_mv(-)
[   59.616785] [<c000d270>] (unwind_backtrace+0x0/0xf0) from [<c0015430>] (warn_slowpath_common+0x50/0x68)
[   59.790030] [<c0015430>] (warn_slowpath_common+0x50/0x68) from [<c00154dc>] (warn_slowpath_fmt+0x30/0x40)
[   59.972322] [<c00154dc>] (warn_slowpath_fmt+0x30/0x40) from [<c000dc18>] (arm_dma_free+0x88/0xe4)
[   60.070701] [<c000dc18>] (arm_dma_free+0x88/0xe4) from [<c008fa30>] (dma_pool_destroy+0x100/0x148)
[   60.256817] [<c008fa30>] (dma_pool_destroy+0x100/0x148) from [<c019a64c>] (release_nodes+0x144/0x218)
[   60.445201] [<c019a64c>] (release_nodes+0x144/0x218) from [<c0197e10>] (__device_release_driver+0x60/0xb8)
[   60.634148] [<c0197e10>] (__device_release_driver+0x60/0xb8) from [<c0198608>] (driver_detach+0xd8/0xec)
[   60.823623] [<c0198608>] (driver_detach+0xd8/0xec) from [<c0197c54>] (bus_remove_driver+0x7c/0xc4)
[   61.013268] [<c0197c54>] (bus_remove_driver+0x7c/0xc4) from [<c004bfac>] (sys_delete_module+0x19c/0x220)
[   61.203472] [<c004bfac>] (sys_delete_module+0x19c/0x220) from [<c0009140>] (ret_fast_syscall+0x0/0x2c)
[   61.393390] ---[ end trace 0745420412c0325b ]---

The patch fixes this.
Signed-off-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

The alignment mask is calculated incorrectly. Fixing the calculation
makes strange hangs/lockups disappear during the boot with Amstrad E3
and 3.6-rc1 kernel.
Signed-off-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Fix dma_contiguous_remap() so that it continues through all the
regions, even after encountering one that is outside lowmem.
Without this change, if you have two CMA regions, the first outside
lowmem and the seocnd inside lowmem, only the second one will get
set up in the MMU. Data written to that region then doesn't get
automatically flushed from the cache into memory.
Signed-off-by: NChris Brand <cbrand@broadcom.com>
[extended patch subject with 'fix' word]
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

This patch adds support for DMA_ATTR_SKIP_CPU_SYNC attribute for
dma_(un)map_(single,page,sg) functions family. It lets dma mapping clients
to create a mapping for the buffer for the given device without performing
a CPU cache synchronization. CPU cache synchronization can be skipped for
the buffers which it is known that they are already in 'device' domain (CPU
caches have been already synchronized or there are only coherent mappings
for the buffer). For advanced users only, please use it with care.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>

This patch adds support for dma_get_sgtable() function which is required
to let drivers to share the buffers allocated by DMA-mapping subsystem.

Generic implementation based on virt_to_page() is not suitable for ARM
dma-mapping subsystem.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>

This patch adds support for DMA_ATTR_NO_KERNEL_MAPPING attribute for
IOMMU allocations, what let drivers to save precious kernel virtual
address space for large buffers that are intended to be accessed only
from userspace.

This patch is heavily based on initial work kindly provided by Abhinav
Kochhar <abhinav.k@samsung.com>.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>

This patch fixes incorrect check in error path. When the allocation of
first page fails, the kernel ops appears due to accessing -1 element of
the pages array.
Reported-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Add some sanity checks and forbid mmaping of buffers into vma areas larger
than allocated dma buffer.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

This patch changes dma-mapping subsystem to use generic vmalloc areas
for all consistent dma allocations. This increases the total size limit
of the consistent allocations and removes platform hacks and a lot of
duplicated code.

Atomic allocations are served from special pool preallocated on boot,
because vmalloc areas cannot be reliably created in atomic context.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: NMinchan Kim <minchan@kernel.org>

WARNING: at mm/vmalloc.c:1471 __iommu_free_buffer+0xcc/0xd0()
Trying to vfree() nonexistent vm area (ef095000)
Modules linked in:
[<c0015a18>] (unwind_backtrace+0x0/0xfc) from [<c0025a94>] (warn_slowpath_common+0x54/0x64)
[<c0025a94>] (warn_slowpath_common+0x54/0x64) from [<c0025b38>] (warn_slowpath_fmt+0x30/0x40)
[<c0025b38>] (warn_slowpath_fmt+0x30/0x40) from [<c0016de0>] (__iommu_free_buffer+0xcc/0xd0)
[<c0016de0>] (__iommu_free_buffer+0xcc/0xd0) from [<c0229a5c>] (exynos_drm_free_buf+0xe4/0x138)
[<c0229a5c>] (exynos_drm_free_buf+0xe4/0x138) from [<c022b358>] (exynos_drm_gem_destroy+0x80/0xfc)
[<c022b358>] (exynos_drm_gem_destroy+0x80/0xfc) from [<c0211230>] (drm_gem_object_free+0x28/0x34)
[<c0211230>] (drm_gem_object_free+0x28/0x34) from [<c0211bd0>] (drm_gem_object_release_handle+0xcc/0xd8)
[<c0211bd0>] (drm_gem_object_release_handle+0xcc/0xd8) from [<c01abe10>] (idr_for_each+0x74/0xb8)
[<c01abe10>] (idr_for_each+0x74/0xb8) from [<c02114e4>] (drm_gem_release+0x1c/0x30)
[<c02114e4>] (drm_gem_release+0x1c/0x30) from [<c0210ae8>] (drm_release+0x608/0x694)
[<c0210ae8>] (drm_release+0x608/0x694) from [<c00b75a0>] (fput+0xb8/0x228)
[<c00b75a0>] (fput+0xb8/0x228) from [<c00b40c4>] (filp_close+0x64/0x84)
[<c00b40c4>] (filp_close+0x64/0x84) from [<c0029d54>] (put_files_struct+0xe8/0x104)
[<c0029d54>] (put_files_struct+0xe8/0x104) from [<c002b930>] (do_exit+0x608/0x774)
[<c002b930>] (do_exit+0x608/0x774) from [<c002bae4>] (do_group_exit+0x48/0xb4)
[<c002bae4>] (do_group_exit+0x48/0xb4) from [<c002bb60>] (sys_exit_group+0x10/0x18)
[<c002bb60>] (sys_exit_group+0x10/0x18) from [<c000ee80>] (ret_fast_syscall+0x0/0x30)

This patch modifies the condition while freeing to match the condition
used while allocation. This fixes the above warning which arises when
array size is equal to PAGE_SIZE where allocation is done using kzalloc
but free is done using vfree.
Signed-off-by: NPrathyush K <prathyush.k@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Signed-off-by: NAlessandro Rubini <rubini@gnudd.com>
Acked-by: NGiancarlo Asnaghi <giancarlo.asnaghi@st.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

IOMMU-aware dma_alloc_attrs() implementation allocates buffers in
power-of-two chunks to improve performance and take advantage of large
page mappings provided by some IOMMU hardware. However current code, due
to a subtle bug, allocated those chunks in the smallest-to-largest
order, what completely killed all the advantages of using larger than
page chunks. If a 4KiB chunk has been mapped as a first chunk, the
consecutive chunks are not aligned correctly to the power-of-two which
match their size and IOMMU drivers were not able to use internal
mappings of size other than the 4KiB (largest common denominator of
alignment and chunk size).

This patch fixes this issue by changing to the correct largest-to-smallest
chunk size allocation sequence.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

Fixes the following sparse warnings:
arch/arm/mm/dma-mapping.c:231:15: warning: symbol 'consistent_base' was not
declared. Should it be static?
arch/arm/mm/dma-mapping.c:326:8: warning: symbol 'coherent_pool_size' was not
declared. Should it be static?
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

CMA has been enabled unconditionally on all ARMv6+ systems to solve the
long standing issue of double kernel mappings for all dma coherent
buffers. This however created a dependency on CONFIG_EXPERIMENTAL for
the whole ARM architecture what should be really avoided. This patch
removes this dependency and lets one use old, well-tested dma-mapping
implementation also on ARMv6+ systems without the need to use
EXPERIMENTAL stuff.
Reported-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>