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amd64 bus dma useless lastaddr variable
Hi,
I think the lastaddr variable in amd64 bus dma is redundant. Instead
of storing the final address of a segment in the caller,
_bus_dmamap_load_buffer() can inspect the previous segment. Also
in _bus_dmamap_load_raw() and _bus_dmamem_alloc_range() the previous
segement is available and can be used directly.
ok?
bluhm
Index: arch/amd64/amd64/bus_dma.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/arch/amd64/amd64/bus_dma.c,v
diff -u -p -r1.57 bus_dma.c
--- arch/amd64/amd64/bus_dma.c 22 Aug 2024 11:36:24 -0000 1.57
+++ arch/amd64/amd64/bus_dma.c 23 Aug 2024 17:48:50 -0000
@@ -102,7 +102,7 @@
#endif
int _bus_dmamap_load_buffer(bus_dma_tag_t, bus_dmamap_t, void *, bus_size_t,
- struct proc *, int, paddr_t *, int *, int *, int);
+ struct proc *, int, int *, int *, int);
/*
* Common function for DMA map creation. May be called by bus-specific
@@ -254,7 +254,6 @@ int
_bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
bus_size_t buflen, struct proc *p, int flags)
{
- bus_addr_t lastaddr = 0;
int seg, used, error;
/*
@@ -269,7 +268,7 @@ _bus_dmamap_load(bus_dma_tag_t t, bus_dm
seg = 0;
used = 0;
error = _bus_dmamap_load_buffer(t, map, buf, buflen, p, flags,
- &lastaddr, &seg, &used, 1);
+ &seg, &used, 1);
if (error == 0) {
map->dm_mapsize = buflen;
map->dm_nsegs = seg + 1;
@@ -285,7 +284,6 @@ int
_bus_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m0,
int flags)
{
- paddr_t lastaddr = 0;
int seg, used, error, first;
struct mbuf *m;
@@ -311,7 +309,7 @@ _bus_dmamap_load_mbuf(bus_dma_tag_t t, b
if (m->m_len == 0)
continue;
error = _bus_dmamap_load_buffer(t, map, m->m_data, m->m_len,
- NULL, flags, &lastaddr, &seg, &used, first);
+ NULL, flags, &seg, &used, first);
first = 0;
}
if (error == 0) {
@@ -329,7 +327,6 @@ int
_bus_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio,
int flags)
{
- paddr_t lastaddr = 0;
int seg, used, i, error, first;
bus_size_t minlen, resid;
struct proc *p = NULL;
@@ -366,7 +363,7 @@ _bus_dmamap_load_uio(bus_dma_tag_t t, bu
addr = (caddr_t)iov[i].iov_base;
error = _bus_dmamap_load_buffer(t, map, addr, minlen,
- p, flags, &lastaddr, &seg, &used, first);
+ p, flags, &seg, &used, first);
first = 0;
resid -= minlen;
@@ -387,7 +384,7 @@ int
_bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map, bus_dma_segment_t *segs,
int nsegs, bus_size_t size, int flags)
{
- bus_addr_t paddr, baddr, bmask, lastaddr = 0;
+ bus_addr_t paddr, baddr, bmask;
bus_size_t plen, sgsize, mapsize;
int first = 1;
int i, seg = 0;
@@ -439,14 +436,15 @@ _bus_dmamap_load_raw(bus_dma_tag_t t, bu
map->dm_segs[seg].ds_len = sgsize;
first = 0;
} else {
- if (paddr == lastaddr &&
+ if (paddr == (map->dm_segs[seg].ds_addr +
+ map->dm_segs[seg].ds_len) &&
(map->dm_segs[seg].ds_len + sgsize) <=
map->_dm_maxsegsz &&
(map->_dm_boundary == 0 ||
(map->dm_segs[seg].ds_addr & bmask) ==
- (paddr & bmask)))
+ (paddr & bmask))) {
map->dm_segs[seg].ds_len += sgsize;
- else {
+ } else {
if (++seg >= map->_dm_segcnt)
return (EINVAL);
map->dm_segs[seg].ds_addr = paddr;
@@ -457,8 +455,6 @@ _bus_dmamap_load_raw(bus_dma_tag_t t, bu
paddr += sgsize;
plen -= sgsize;
size -= sgsize;
-
- lastaddr = paddr;
}
}
@@ -686,18 +682,17 @@ _bus_dmamem_mmap(bus_dma_tag_t t, bus_dm
* DMA utility functions
**********************************************************************/
/*
- * Utility function to load a linear buffer. lastaddrp holds state
- * between invocations (for multiple-buffer loads). segp contains
+ * Utility function to load a linear buffer. segp contains
* the starting segment on entrance, and the ending segment on exit.
* first indicates if this is the first invocation of this function.
*/
int
_bus_dmamap_load_buffer(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
- bus_size_t buflen, struct proc *p, int flags, paddr_t *lastaddrp,
+ bus_size_t buflen, struct proc *p, int flags,
int *segp, int *usedp, int first)
{
bus_size_t sgsize;
- bus_addr_t curaddr, lastaddr, baddr, bmask;
+ bus_addr_t curaddr, baddr, bmask;
vaddr_t pgva = -1, vaddr = (vaddr_t)buf;
int seg, page, off;
pmap_t pmap;
@@ -710,7 +705,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t t,
pmap = pmap_kernel();
page = *usedp;
- lastaddr = *lastaddrp;
bmask = ~(map->_dm_boundary - 1);
for (seg = *segp; buflen > 0 ; ) {
@@ -762,7 +756,8 @@ _bus_dmamap_load_buffer(bus_dma_tag_t t,
map->dm_segs[seg]._ds_bounce_va = pgva;
first = 0;
} else {
- if (curaddr == lastaddr &&
+ if (curaddr == (map->dm_segs[seg].ds_addr +
+ map->dm_segs[seg].ds_len) &&
(map->dm_segs[seg].ds_len + sgsize) <=
map->_dm_maxsegsz &&
(map->_dm_boundary == 0 ||
@@ -781,14 +776,12 @@ _bus_dmamap_load_buffer(bus_dma_tag_t t,
}
}
- lastaddr = curaddr + sgsize;
vaddr += sgsize;
buflen -= sgsize;
}
*segp = seg;
*usedp = page;
- *lastaddrp = lastaddr;
/*
* Did we fit?
@@ -807,7 +800,7 @@ _bus_dmamem_alloc_range(bus_dma_tag_t t,
bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs,
int flags, bus_addr_t low, bus_addr_t high)
{
- paddr_t curaddr, lastaddr;
+ paddr_t curaddr;
struct vm_page *m;
struct pglist mlist;
int curseg, error, plaflag;
@@ -837,7 +830,7 @@ _bus_dmamem_alloc_range(bus_dma_tag_t t,
*/
m = TAILQ_FIRST(&mlist);
curseg = 0;
- lastaddr = segs[curseg].ds_addr = VM_PAGE_TO_PHYS(m);
+ segs[curseg].ds_addr = VM_PAGE_TO_PHYS(m);
segs[curseg].ds_len = PAGE_SIZE;
for (m = TAILQ_NEXT(m, pageq); m != NULL; m = TAILQ_NEXT(m, pageq)) {
@@ -853,14 +846,13 @@ _bus_dmamem_alloc_range(bus_dma_tag_t t,
panic("_bus_dmamem_alloc_range");
}
#endif
- if (curaddr == (lastaddr + PAGE_SIZE))
+ if (curaddr == (segs[curseg].ds_addr + segs[curseg].ds_len)) {
segs[curseg].ds_len += PAGE_SIZE;
- else {
+ } else {
curseg++;
segs[curseg].ds_addr = curaddr;
segs[curseg].ds_len = PAGE_SIZE;
}
- lastaddr = curaddr;
}
*rsegs = curseg + 1;
amd64 bus dma useless lastaddr variable