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Pull in the armv4 "fast out" code for checking whether busdma can bounce

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due to an excluded region of physical memory.
This commit is contained in:
Ian Lepore 2014-07-26 18:19:43 +00:00
parent 9ec89d355f
commit 510b2cb75c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=269136
1 changed files with 16 additions and 0 deletions
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16
sys/arm/arm/busdma_machdep-v6.c
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@ -229,10 +229,26 @@ busdma_init(void *dummy)
*/
SYSINIT(busdma, SI_SUB_KMEM, SI_ORDER_FOURTH, busdma_init, NULL);
/*
* This routine checks the exclusion zone constraints from a tag against the
* physical RAM available on the machine. If a tag specifies an exclusion zone
* but there's no RAM in that zone, then we avoid allocating resources to bounce
* a request, and we can use any memory allocator (as opposed to needing
* kmem_alloc_contig() just because it can allocate pages in an address range).
*
* Most tags have BUS_SPACE_MAXADDR or BUS_SPACE_MAXADDR_32BIT (they are the
* same value on 32-bit architectures) as their lowaddr constraint, and we can't
* possibly have RAM at an address higher than the highest address we can
* express, so we take a fast out.
*/
static __inline int
_bus_dma_can_bounce(vm_offset_t lowaddr, vm_offset_t highaddr)
{
int i;
if (lowaddr >= BUS_SPACE_MAXADDR)
return (0);
for (i = 0; phys_avail[i] && phys_avail[i + 1]; i += 2) {
if ((lowaddr >= phys_avail[i] && lowaddr <= phys_avail[i + 1])
|| (lowaddr < phys_avail[i] &&