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Improve the handling of static DMA buffers that use non-default memory

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attributes (currently just BUS_DMA_NOCACHE):
- Don't call pmap_change_attr() on the returned address, instead use
  kmem_alloc_contig() to ask the VM system for memory with the requested
  attribute.
- As a result, always use kmem_alloc_contig() for non-default memory
  attributes, even for sub-page allocations.  This requires adjusting
  bus_dmamem_free()'s logic for determining which free routine to use.
- For x86, add a new dummy bus_dmamap that is used for static DMA
  buffers allocated via kmem_alloc_contig().  bus_dmamem_free() can then
  use the map pointer to determine which free routine to use.
- For powerpc, add a new flag to the allocated map (bus_dmamem_alloc()
  always creates a real map on powerpc) to indicate which free routine
  should be used.

Note that the BUS_DMA_NOCACHE handling in powerpc is currently #ifdef'd out.
I have left it disabled but updated it to match x86.

Reviewed by:	scottl
MFC after:	1 month
This commit is contained in:
John Baldwin 2012-08-03 13:50:29 +00:00
parent 2c2e2be746
commit 2db99100a4
2 changed files with 43 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
sys/powerpc/powerpc/busdma_machdep.c
View File

@ -46,6 +46,8 @@ __FBSDID("$FreeBSD$");
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
@ -130,6 +132,7 @@ struct bus_dmamap {
bus_dmamap_callback_t *callback;
void *callback_arg;
STAILQ_ENTRY(bus_dmamap) links;
int contigalloc;
};
static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
@ -489,6 +492,7 @@ int
bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
bus_dmamap_t *mapp)
{
vm_memattr_t attr;
int mflags;
if (flags & BUS_DMA_NOWAIT)
@ -500,6 +504,12 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
if (flags & BUS_DMA_ZERO)
mflags |= M_ZERO;
#ifdef NOTYET
if (flags & BUS_DMA_NOCACHE)
attr = VM_MEMATTR_UNCACHEABLE;
else
#endif
attr = VM_MEMATTR_DEFAULT;
/*
* XXX:
@ -511,7 +521,8 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
*/
if ((dmat->maxsize <= PAGE_SIZE) &&
(dmat->alignment < dmat->maxsize) &&
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
attr == VM_MEMATTR_DEFAULT) {
*vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
} else {
/*
@ -520,9 +531,10 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
* multi-seg allocations yet though.
* XXX Certain AGP hardware does.
*/
*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
dmat->boundary);
*vaddr = (void *)kmem_alloc_contig(kernel_map, dmat->maxsize,
mflags, 0ul, dmat->lowaddr, dmat->alignment ?
dmat->alignment : 1ul, dmat->boundary, attr);
(*mapp)->contigalloc = 1;
}
if (*vaddr == NULL) {
CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
@ -531,11 +543,6 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
} else if (vtophys(*vaddr) & (dmat->alignment - 1)) {
printf("bus_dmamem_alloc failed to align memory properly.\n");
}
#ifdef NOTYET
if (flags & BUS_DMA_NOCACHE)
pmap_change_attr((vm_offset_t)*vaddr, dmat->maxsize,
VM_MEMATTR_UNCACHEABLE);
#endif
CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
__func__, dmat, dmat->flags, 0);
return (0);
@ -548,18 +555,12 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
void
bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
{
bus_dmamap_destroy(dmat, map);
#ifdef NOTYET
pmap_change_attr((vm_offset_t)vaddr, dmat->maxsize, VM_MEMATTR_DEFAULT);
#endif
if ((dmat->maxsize <= PAGE_SIZE) &&
(dmat->alignment < dmat->maxsize) &&
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
if (!map->contigalloc)
free(vaddr, M_DEVBUF);
else {
contigfree(vaddr, dmat->maxsize, M_DEVBUF);
}
else
kmem_free(kernel_map, (vm_offset_t)vaddr, dmat->maxsize);
bus_dmamap_destroy(dmat, map);
CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
}

43
sys/x86/x86/busdma_machdep.c
View File

@ -42,6 +42,8 @@ __FBSDID("$FreeBSD$");
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
@ -131,7 +133,7 @@ struct bus_dmamap {
static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
static struct bus_dmamap nobounce_dmamap;
static struct bus_dmamap nobounce_dmamap, contig_dmamap;
static void init_bounce_pages(void *dummy);
static int alloc_bounce_zone(bus_dma_tag_t dmat);
@ -465,7 +467,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
int
bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
{
if (map != NULL && map != &nobounce_dmamap) {
if (map != NULL && map != &nobounce_dmamap && map != &contig_dmamap) {
if (STAILQ_FIRST(&map->bpages) != NULL) {
CTR3(KTR_BUSDMA, "%s: tag %p error %d",
__func__, dmat, EBUSY);
@ -490,6 +492,7 @@ int
bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
bus_dmamap_t *mapp)
{
vm_memattr_t attr;
int mflags;
if (flags & BUS_DMA_NOWAIT)
@ -512,6 +515,10 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
}
if (flags & BUS_DMA_ZERO)
mflags |= M_ZERO;
if (flags & BUS_DMA_NOCACHE)
attr = VM_MEMATTR_UNCACHEABLE;
else
attr = VM_MEMATTR_DEFAULT;
/*
* XXX:
@ -523,7 +530,8 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
*/
if ((dmat->maxsize <= PAGE_SIZE) &&
(dmat->alignment < dmat->maxsize) &&
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
attr == VM_MEMATTR_DEFAULT) {
*vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
} else {
/*
@ -532,9 +540,10 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
* multi-seg allocations yet though.
* XXX Certain AGP hardware does.
*/
*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
dmat->boundary);
*vaddr = (void *)kmem_alloc_contig(kernel_map, dmat->maxsize,
mflags, 0ul, dmat->lowaddr, dmat->alignment ?
dmat->alignment : 1ul, dmat->boundary, attr);
*mapp = &contig_dmamap;
}
if (*vaddr == NULL) {
CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
@ -543,9 +552,6 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
} else if (vtophys(*vaddr) & (dmat->alignment - 1)) {
printf("bus_dmamem_alloc failed to align memory properly.\n");
}
if (flags & BUS_DMA_NOCACHE)
pmap_change_attr((vm_offset_t)*vaddr, dmat->maxsize,
PAT_UNCACHEABLE);
CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
__func__, dmat, dmat->flags, 0);
return (0);
@ -560,18 +566,15 @@ bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
{
/*
* dmamem does not need to be bounced, so the map should be
* NULL
* NULL if malloc() was used and contig_dmamap if
* contigmalloc() was used.
*/
if (map != NULL)
if (!(map == NULL || map == &contig_dmamap))
panic("bus_dmamem_free: Invalid map freed\n");
pmap_change_attr((vm_offset_t)vaddr, dmat->maxsize, PAT_WRITE_BACK);
if ((dmat->maxsize <= PAGE_SIZE) &&
(dmat->alignment < dmat->maxsize) &&
dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
if (map == NULL)
free(vaddr, M_DEVBUF);
else {
contigfree(vaddr, dmat->maxsize, M_DEVBUF);
}
else
kmem_free(kernel_map, (vm_offset_t)vaddr, dmat->maxsize);
CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
}
@ -662,7 +665,7 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
vm_offset_t vaddr;
int seg, error;
if (map == NULL)
if (map == NULL || map == &contig_dmamap)
map = &nobounce_dmamap;
if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
@ -1139,7 +1142,7 @@ add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
struct bounce_page *bpage;
KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
KASSERT(map != NULL && map != &nobounce_dmamap,
KASSERT(map != NULL && map != &nobounce_dmamap && map != &contig_dmamap,
("add_bounce_page: bad map %p", map));
bz = dmat->bounce_zone;