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path: root/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
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* gpu: nvgpu: SGL passthrough implementationSunny He2017-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | The basic nvgpu_mem_sgl implementation provides support for OS specific scatter-gather list implementations by simply copying them node by node. This is inefficient, taking extra time and memory. This patch implements an nvgpu_mem_sgt struct to act as a header which is inserted at the front of any scatter- gather list implementation. This labels every struct with a set of ops which can be used to interact with the attached scatter gather list. Since nvgpu common code only has to interact with these function pointers, any sgl implementation can be used. Initialization only requires the allocation of a single struct, removing the need to copy or iterate through the sgl being converted. Jira NVGPU-186 Change-Id: I2994f804a4a4cc141b702e987e9081d8560ba2e8 Signed-off-by: Sunny He <suhe@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/1541426 Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com> Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
* gpu: nvgpu: nvgpu SGL implementationAlex Waterman2017-09-22
The last major item preventing the core MM code in the nvgpu driver from being platform agnostic is the usage of Linux scattergather tables and scattergather lists. These data structures are used throughout the mapping code to handle discontiguous DMA allocations and also overloaded to represent VIDMEM allocs. The notion of a scatter gather table is crucial to a HW device that can handle discontiguous DMA. The GPU has a MMU which allows the GPU to do page gathering and present a virtually contiguous buffer to the GPU HW. As a result it makes sense for the GPU driver to use some sort of scatter gather concept so maximize memory usage efficiency. To that end this patch keeps the notion of a scatter gather list but implements it in the nvgpu common code. It is based heavily on the Linux SGL concept. It is a singly linked list of blocks - each representing a chunk of memory. To map or use a DMA allocation SW must iterate over each block in the SGL. This patch implements the most basic level of support for this data structure. There are certainly easy optimizations that could be done to speed up the current implementation. However, this patches' goal is to simply divest the core MM code from any last Linux'isms. Speed and efficiency come next. Change-Id: Icf44641db22d87fa1d003debbd9f71b605258e42 Signed-off-by: Alex Waterman <alexw@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/1530867 Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com> Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>