Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\dma\swiotlb.c Create Date:2022-07-28 10:35:58
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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Name:Statically reserve bounce buffer space and initialize bounce buffer data* structures for the software IO TLB used to implement the DMA API.

Proto:void __init swiotlb_init(int verbose)

Type:void

Parameter:

TypeParameterName
intverbose
248  default_size = default to 64MB
252  If Not The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages. Then
253  The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages. = default_size >> log of the size of each IO TLB slab. The number of slabs is command line* controllable.
254  The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages. = @a is a power of 2 value (The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages., Maximum allowable number of contiguous slabs to map,* must be a power of 2. What is the appropriate value ?* The complexity of {map,unmap}_single is linearly dependent on this value.)
257  bytes = The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages. << log of the size of each IO TLB slab. The number of slabs is command line* controllable.
260  vstart = memblock_alloc_low( align the pointer to the (next) page boundary (bytes), PAGE_SIZE)
261  If vstart && Not swiotlb_init_with_tbl(vstart, The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages., verbose) Then Return
264  If Used to do a quick range check in swiotlb_tbl_unmap_single and* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this* API. Then memblock_free_early(Used to do a quick range check in swiotlb_tbl_unmap_single and* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this* API., align the pointer to the (next) page boundary (The number of IO TLB blocks (in groups of 64) between io_tlb_start and* io_tlb_end. This is command line adjustable via setup_io_tlb_npages. << log of the size of each IO TLB slab. The number of slabs is command line* controllable.))
267  pr_warn("Cannot allocate buffer")
268  no_iotlb_memory = true