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Small fixes for the IOMMU code:

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1.) Handle maximum segment sizes which are smaller than the IOMMU page
    size by splitting up pages across multiple segments if needed; this case
    was previously unimplemented, and would cause panics.
2.) KASSERT that the physical address is in range; remove a KASSERT that
    has become pointless.
3.) Add a comment describing what remains to be fixed in the IOMMU code;
    I plan to address these issues soon.

Desired by:	dwhite (1)
This commit is contained in:
Thomas Moestl 2003-06-28 21:52:16 +00:00
parent 4a309ab44c
commit d462b4f058
1 changed files with 47 additions and 16 deletions
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63
sys/sparc64/sparc64/iommu.c
View File

@ -115,6 +115,27 @@
* is to be loaded for is not possible with the current busdma code.
* The code is structured so that the IOMMUs can be easily divorced when that
* is fixed.
*
* TODO:
* - As soon as there is a newbus way to get a parent dma tag, divorce the
* IOTSBs.
* - Support sub-page boundaries.
* - Fix alignment handling for small allocations (the possible page offset
* of malloc()ed memory is not handled at all). Revise interaction of
* alignment with the load_mbuf and load_uio functions.
* - Handle lowaddr and highaddr in some way, and try to work out a way
* for filter callbacks to work. Currently, only lowaddr is honored
* in that no addresses above it are considered at all.
* - Implement BUS_DMA_ALLOCNOW in bus_dma_tag_create as far as possible.
* - Check the possible return values and callback error arguments;
* the callback currently gets called in error conditions where it should
* not be.
* - When running out of DVMA space, return EINPROGRESS in the non-
* BUS_DMA_NOWAIT case and delay the callback until sufficient space
* becomes available.
* - Use the streaming cache unless BUS_DMA_COHERENT is specified; do not
* flush the streaming cache when coherent mappings are synced.
* - Add bounce buffers to support machines with more than 16GB of RAM.
*/
#include "opt_iommu.h"
@ -408,6 +429,8 @@ iommu_enter(struct iommu_state *is, vm_offset_t va, vm_paddr_t pa, int flags)
KASSERT(va >= is->is_dvmabase,
("iommu_enter: va %#lx not in DVMA space", va));
KASSERT(pa < IOMMU_MAXADDR,
("iommu_enter: XXX: physical address too large (%#lx)", pa));
tte = MAKEIOTTE(pa, !(flags & BUS_DMA_NOWRITE),
!(flags & BUS_DMA_NOCACHE), (flags & BUS_DMA_STREAMING));
@ -714,8 +737,6 @@ iommu_dvmamap_create(bus_dma_tag_t dt, int flags, bus_dmamap_t *mapp)
if ((error = sparc64_dma_alloc_map(dt, mapp)) != 0)
return (error);
KASSERT(SLIST_EMPTY(&(*mapp)->dm_reslist),
("iommu_dvmamap_create: hierarchy botched"));
iommu_map_insq(*mapp);
/*
* Preallocate DVMA space; if this fails now, it is retried at load
@ -768,7 +789,7 @@ iommu_dvmamap_load_buffer(bus_dma_tag_t dt, struct iommu_state *is,
bus_size_t buflen, struct thread *td, int flags, int *segp, int align)
{
bus_addr_t amask, dvmaddr;
bus_size_t sgsize;
bus_size_t sgsize, esize;
vm_offset_t vaddr, voffs;
vm_paddr_t curaddr;
int error, sgcnt, firstpg;
@ -809,15 +830,24 @@ iommu_dvmamap_load_buffer(bus_dma_tag_t dt, struct iommu_state *is,
if (buflen < sgsize)
sgsize = buflen;
buflen -= sgsize;
vaddr += sgsize;
iommu_enter(is, trunc_io_page(dvmaddr), trunc_io_page(curaddr),
flags);
if (firstpg || sgs[sgcnt].ds_len + sgsize > dt->dt_maxsegsz) {
if (sgsize > dt->dt_maxsegsz) {
/* XXX: add fixup */
panic("iommu_dvmamap_load_buffer: magsegsz too "
"small\n");
}
/*
* Chop the chunk up into segments of at most maxsegsz, but try
* to fill each segment as well as possible.
*/
if (!firstpg) {
esize = ulmin(sgsize,
dt->dt_maxsegsz - sgs[sgcnt].ds_len);
sgs[sgcnt].ds_len += esize;
sgsize -= esize;
dvmaddr += esize;
}
while (sgsize > 0) {
sgcnt++;
if (sgcnt >= dt->dt_nsegments ||
sgcnt >= BUS_DMAMAP_NSEGS)
@ -826,15 +856,16 @@ iommu_dvmamap_load_buffer(bus_dma_tag_t dt, struct iommu_state *is,
* No extra alignment here - the common practice in the
* busdma code seems to be that only the first segment
* needs to satisfy the alignment constraints (and that
* only for bus_dmamem_alloc()ed maps).
* only for bus_dmamem_alloc()ed maps). It is assumed
* that such tags have maxsegsize >= maxsize.
*/
esize = ulmin(sgsize, dt->dt_maxsegsz);
sgs[sgcnt].ds_addr = dvmaddr;
sgs[sgcnt].ds_len = sgsize;
} else
sgs[sgcnt].ds_len += sgsize;
dvmaddr += sgsize;
vaddr += sgsize;
buflen -= sgsize;
sgs[sgcnt].ds_len = esize;
sgsize -= esize;
dvmaddr += esize;
}
firstpg = 0;
}
*segp = sgcnt;