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arm64 busdma: Fix loading of small bounced buffers.

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- Don't oversize the buffer fragment. PAGE_SIZE - (curaddr & PAGE_MASK)
   may be greater than the total length of the buffer.
 - Don't use roundup2(len, alignment) to calculate the buffer fragment
   size. The length of current bounced fragment is not subject to alignment
   restriction, and next fragment should start at the page boundary.

Tested by:	bz, s199p.wa1k9r@gmail.com
This commit is contained in:
Michal Meloun 2021-01-13 13:50:54 +01:00
parent 24f44a445c
commit f635cef2a4
1 changed files with 16 additions and 17 deletions
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33
sys/arm64/arm64/busdma_bounce.c
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@ -845,9 +845,7 @@ bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
KASSERT(dmat->common.alignment <= PAGE_SIZE,
("bounced buffer cannot have alignment bigger "
"than PAGE_SIZE: %lu", dmat->common.alignment));
sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
sgsize = roundup2(sgsize, dmat->common.alignment);
sgsize = MIN(sgsize, dmat->common.maxsegsz);
sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
curaddr = add_bounce_page(dmat, map, 0, curaddr,
sgsize);
} else if ((map->flags & DMAMAP_COHERENT) == 0) {
@ -879,7 +877,11 @@ bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
/*
* Did we fit?
*/
return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
if (buflen != 0) {
bus_dmamap_unload(dmat, map);
return (EFBIG); /* XXX better return value here? */
}
return (0);
}
/*
@ -892,7 +894,7 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
int *segp)
{
struct sync_list *sl;
bus_size_t sgsize, max_sgsize;
bus_size_t sgsize;
bus_addr_t curaddr, sl_pend;
vm_offset_t kvaddr, vaddr, sl_vend;
int error;
@ -931,7 +933,7 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
/*
* Get the physical address for this segment.
*/
if (pmap == kernel_pmap) {
if (__predict_true(pmap == kernel_pmap)) {
curaddr = pmap_kextract(vaddr);
kvaddr = vaddr;
} else {
@ -942,13 +944,9 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
/*
* Compute the segment size, and adjust counts.
*/
max_sgsize = MIN(buflen, dmat->common.maxsegsz);
if ((map->flags & DMAMAP_FROM_DMAMEM) != 0) {
sgsize = max_sgsize;
} else {
sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
sgsize = MIN(sgsize, max_sgsize);
}
sgsize = MIN(buflen, dmat->common.maxsegsz);
if ((map->flags & DMAMAP_FROM_DMAMEM) == 0)
sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
if (map->pagesneeded != 0 &&
must_bounce(dmat, map, curaddr, sgsize)) {
@ -956,9 +954,6 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
KASSERT(dmat->common.alignment <= PAGE_SIZE,
("bounced buffer cannot have alignment bigger "
"than PAGE_SIZE: %lu", dmat->common.alignment));
sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
sgsize = roundup2(sgsize, dmat->common.alignment);
sgsize = MIN(sgsize, max_sgsize);
curaddr = add_bounce_page(dmat, map, kvaddr, curaddr,
sgsize);
} else if ((map->flags & DMAMAP_COHERENT) == 0) {
@ -999,7 +994,11 @@ bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
/*
* Did we fit?
*/
return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
if (buflen != 0) {
bus_dmamap_unload(dmat, map);
return (EFBIG); /* XXX better return value here? */
}
return (0);
}
static void