diff options
Diffstat (limited to 'sys/arm64')
| -rw-r--r-- | sys/arm64/arm64/busdma_bounce.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/sys/arm64/arm64/busdma_bounce.c b/sys/arm64/arm64/busdma_bounce.c index aff1e23..31eaf05 100644 --- a/sys/arm64/arm64/busdma_bounce.c +++ b/sys/arm64/arm64/busdma_bounce.c @@ -461,22 +461,35 @@ bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags, (*mapp)->flags = DMAMAP_FROM_DMAMEM; /* - * XXX: - * (dmat->alignment <= dmat->maxsize) is just a quick hack; the exact - * alignment guarantees of malloc need to be nailed down, and the - * code below should be rewritten to take that into account. + * Allocate the buffer from the malloc(9) allocator if... + * - It's small enough to fit into a single power of two sized bucket. + * - The alignment is less than or equal to the maximum size + * - The low address requirement is fulfilled. + * else allocate non-contiguous pages if... + * - The page count that could get allocated doesn't exceed + * nsegments also when the maximum segment size is less + * than PAGE_SIZE. + * - The alignment constraint isn't larger than a page boundary. + * - There are no boundary-crossing constraints. + * else allocate a block of contiguous pages because one or more of the + * constraints is something that only the contig allocator can fulfill. * - * In the meantime, we'll warn the user if malloc gets it wrong. + * NOTE: The (dmat->common.alignment <= dmat->maxsize) check + * below is just a quick hack. The exact alignment guarantees + * of malloc(9) need to be nailed down, and the code below + * should be rewritten to take that into account. + * + * In the meantime warn the user if malloc gets it wrong. */ if ((dmat->common.maxsize <= PAGE_SIZE) && (dmat->common.alignment <= dmat->common.maxsize) && dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) && attr == VM_MEMATTR_DEFAULT) { *vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags); - } else if (dmat->common.nsegments >= btoc(dmat->common.maxsize) && + } else if (dmat->common.nsegments >= + howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz, PAGE_SIZE)) && dmat->common.alignment <= PAGE_SIZE && - (dmat->common.boundary == 0 || - dmat->common.boundary >= dmat->common.lowaddr)) { + (dmat->common.boundary % PAGE_SIZE) == 0) { /* Page-based multi-segment allocations allowed */ *vaddr = (void *)kmem_alloc_attr(kernel_arena, dmat->common.maxsize, mflags, 0ul, dmat->common.lowaddr, |
