linux/kernel/dma/mapping.c, branch v5.14

dma-mapping: add a dma_alloc_noncontiguous API

2021-03-15T09:02:31Z

Add a new API that returns a potentiall virtually non-contigous sg_table and a DMA address. This API is only properly implemented for dma-iommu and will simply return a contigious chunk as a fallback. The intent is that drivers can use this API if either: - no kernel mapping or only temporary kernel mappings are required. That is as a better replacement for DMA_ATTR_NO_KERNEL_MAPPING - a kernel mapping is required for cached and DMA mapped pages, but the driver also needs the pages to e.g. map them to userspace. In that sense it is a replacement for some aspects of the recently removed and never fully implemented DMA_ATTR_NON_CONSISTENT Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda

dma-mapping: refactor dma_{alloc,free}_pages

2021-03-15T09:02:31Z

Factour out internal versions without the dma_debug calls in preparation for callers that will need different dma_debug calls. Note that this changes the dma_debug calls to get the not page aligned size values, but as long as alloc and free agree on one variant we are fine. Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda

dma-mapping: add a dma_mmap_pages helper

2021-03-15T09:02:31Z

Add a helper to map memory allocated using dma_alloc_pages into a user address space, similar to the dma_alloc_attrs function for coherent allocations. Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda

Merge tag 'dma-mapping-5.12' of git://git.infradead.org/users/hch/dma-mapping

2021-02-24T17:54:24Z

Pull dma-mapping updates from Christoph Hellwig: - add support to emulate processing delays in the DMA API benchmark selftest (Barry Song) - remove support for non-contiguous noncoherent allocations, which aren't used and will be replaced by a different API * tag 'dma-mapping-5.12' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: remove the {alloc,free}_noncoherent methods dma-mapping: benchmark: pretend DMA is transmitting

driver core: lift dma_default_coherent into common code

2021-02-13T08:51:45Z

Lift the dma_default_coherent variable from the mips architecture code to the driver core. This allows an architecture to sdefault all device to be DMA coherent at run time, even if the kernel is build with support for DMA noncoherent device. By allowing device_initialize to set the ->dma_coherent field to this default the amount of arch hooks required for this behavior can be greatly reduced. Signed-off-by: Christoph Hellwig Acked-by: Greg Kroah-Hartman Signed-off-by: Thomas Bogendoerfer

dma-mapping: remove the {alloc,free}_noncoherent methods

2021-02-09T17:01:38Z

It turns out allowing non-contigous allocations here was a rather bad idea, as we'll now need to define ways to get the pages for mmaping or dma_buf sharing. Revert this change and stick to the original concept. A different API for the use case of non-contigous allocations will be added back later. Signed-off-by: Christoph Hellwig Reviewed-by: Tomasz Figa Tested-by: Ricardo Ribalda :wq

dma-mapping: Allow mixing bypass and mapped DMA operation

2020-11-27T09:33:40Z

At the moment we allow bypassing DMA ops only when we can do this for the entire RAM. However there are configs with mixed type memory where we could still allow bypassing IOMMU in most cases; POWERPC with persistent memory is one example. This adds an arch hook to determine where bypass can still work and we invoke direct DMA API. The following patch checks the bus limit on POWERPC to allow or disallow direct mapping. This adds a ARCH_HAS_DMA_MAP_DIRECT config option to make the arch_xxxx hooks no-op by default. Signed-off-by: Alexey Kardashevskiy Signed-off-by: Christoph Hellwig

dma-mapping: move large parts of to kernel/dma

2020-10-06T05:07:06Z

Most of the dma_direct symbols should only be used by direct.c and mapping.c, so move them to kernel/dma. In fact more of dma-direct.h should eventually move, but that will require more coordination with other subsystems. Signed-off-by: Christoph Hellwig

dma-mapping: move dma-debug.h to kernel/dma/

2020-10-06T05:07:05Z

Most of dma-debug.h is not required by anything outside of kernel/dma. Move the four declarations needed by dma-mappin.h or dma-ops providers into dma-mapping.h and dma-map-ops.h, and move the remainder of the file to kernel/dma/debug.h. Signed-off-by: Christoph Hellwig

dma-mapping: split

2020-10-06T05:07:03Z

Split out all the bits that are purely for dma_map_ops implementations and related code into a new header so that they don't get pulled into all the drivers. That also means the architecture specific is not pulled in by any more, which leads to a missing includes that were pulled in by the x86 or arm versions in a few not overly portable drivers. Signed-off-by: Christoph Hellwig