Clang doesn't like that (1ULL<<(64)) overflows when initializing a
global scope variable, even if that part of the ternary isn't used when
n = 64. The same initialization can be done without warnings in function
scopes, and GCC doesn't mind either way.

The build failure that highlighted this was already fixed in a different
way [1], which also has detailed links to the Clang issues. However it's
not going to be long before the same thing happens again, so it's better
to fix the root cause.

Fix it by using GENMASK_ULL() which does exactly the same thing, is much
more readable anyway, and doesn't have a shift that overflows.

[1]: https://lore.kernel.org/all/20250918-mmp-pdma-simplify-dma-addressing-v1-1-5c2be2b85696@riscstar.com/

Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20251030-james-fix-dma_bit_mask-v1-1-ad1ce7cfab6e@linaro.org

Introduce new DMA mapping functions dma_map_phys() and dma_unmap_phys()
that operate directly on physical addresses instead of page+offset
parameters. This provides a more efficient interface for drivers that
already have physical addresses available.

The new functions are implemented as the primary mapping layer, with
the existing dma_map_page_attrs()/dma_map_resource() and
dma_unmap_page_attrs()/dma_unmap_resource() functions converted to simple
wrappers around the phys-based implementations.

In case dma_map_page_attrs(), the struct page is converted to physical
address with help of page_to_phys() function and dma_map_resource()
provides physical address as is together with addition of DMA_ATTR_MMIO
attribute.

The old page-based API is preserved in mapping.c to ensure that existing
code won't be affected by changing EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
variant for dma_*map_phys().

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/54cc52af91777906bbe4a386113437ba0bcfba9c.1757423202.git.leonro@nvidia.com

This patch introduces the DMA_ATTR_MMIO attribute to mark DMA buffers
that reside in memory-mapped I/O (MMIO) regions, such as device BARs
exposed through the host bridge, which are accessible for peer-to-peer
(P2P) DMA.

This attribute is especially useful for exporting device memory to other
devices for DMA without CPU involvement, and avoids unnecessary or
potentially detrimental CPU cache maintenance calls.

DMA_ATTR_MMIO is supposed to provide dma_map_resource() functionality
without need to call to special function and perform branching when
processing generic containers like bio_vec by the callers.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/6f058ec395c5348014860dbc2eed348c17975843.1757423202.git.leonro@nvidia.com

Pull dma-mapping updates from Marek Szyprowski:
 "New two step DMA mapping API, which is is a first step to a long path
  to provide alternatives to scatterlist and to remove hacks, abuses and
  design mistakes related to scatterlists.

  This new approach optimizes some calls to DMA-IOMMU layer and cache
  maintenance by batching them, reduces memory usage as it is no need to
  store mapped DMA addresses to unmap them, and reduces some function
  call overhead.  It is a combination effort of many people, lead and
  developed by Christoph Hellwig and Leon Romanovsky"

* tag 'dma-mapping-6.16-2025-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
  docs: core-api: document the IOVA-based API
  dma-mapping: add a dma_need_unmap helper
  dma-mapping: Implement link/unlink ranges API
  iommu/dma: Factor out a iommu_dma_map_swiotlb helper
  dma-mapping: Provide an interface to allow allocate IOVA
  iommu: add kernel-doc for iommu_unmap_fast
  iommu: generalize the batched sync after map interface
  dma-mapping: move the PCI P2PDMA mapping helpers to pci-p2pdma.h
  PCI/P2PDMA: Refactor the p2pdma mapping helpers

Add helper that allows a driver to skip calling dma_unmap_*
if the DMA layer can guarantee that they are no-nops.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

Introduce new DMA APIs to perform DMA linkage of buffers
in layers higher than DMA.

In proposed API, the callers will perform the following steps.
In map path:
	if (dma_can_use_iova(...))
	    dma_iova_alloc()
	    for (page in range)
	       dma_iova_link_next(...)
	    dma_iova_sync(...)
	else
	     /* Fallback to legacy map pages */
             for (all pages)
	       dma_map_page(...)

In unmap path:
	if (dma_can_use_iova(...))
	     dma_iova_destroy()
	else
	     for (all pages)
		dma_unmap_page(...)

Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

The existing .map_pages() callback provides both allocating of IOVA
and linking DMA pages. That combination works great for most of the
callers who use it in control paths, but is less effective in fast
paths where there may be multiple calls to map_page().

These advanced callers already manage their data in some sort of
database and can perform IOVA allocation in advance, leaving range
linkage operation to be in fast path.

Provide an interface to allocate/deallocate IOVA and next patch
link/unlink DMA ranges to that specific IOVA.

In the new API a DMA mapping transaction is identified by a
struct dma_iova_state, which holds some recomputed information
for the transaction which does not change for each page being
mapped, so add a check if IOVA can be used for the specific
transaction.

The API is exported from dma-iommu as it is the only implementation
supported, the namespace is clearly different from iommu_* functions
which are not allowed to be used. This code layout allows us to save
function call per API call used in datapath as well as a lot of boilerplate
code.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

When CONFIG_NEED_DMA_MAP_STATE is not defined, dma-mapping clients might
report unused data compilation warnings for dma_unmap_*() calls
arguments. Redefine macros for those calls to let compiler to notice that
it is okay when the provided arguments are not used.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250415075659.428549-1-m.szyprowski@samsung.com

Back in the day a lot of logic was implemented inline in dma-mapping.h and
needed various includes.  Move of this has long been moved out of line,
so we can drop various includes to improve kernel rebuild times.

Signed-off-by: Christoph Hellwig <hch@lst.de>

A NULL dev->dma_parms indicates either a bus that is not DMA capable or
grave bug in the implementation of the bus code.

There isn't much the driver can do in terms of error handling for either
case, so just warn and continue as DMA operations will fail anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC