*
* On SYSIO, using an 8K page size we have 1GB of SBUS
* DMA space mapped. We divide this space into equally
- * sized clusters. Currently we allow clusters up to a
- * size of 1MB. If anything begins to generate DMA
- * mapping requests larger than this we will need to
- * increase things a bit.
+ * sized clusters. We allocate a DMA mapping from the
+ * cluster that matches the order of the allocation, or
+ * if the order is greater than the number of clusters,
+ * we try to allocate from the last cluster.
*/
#define NCLUSTERS 8UL
static iopte_t *alloc_streaming_cluster(struct sbus_iommu *iommu, unsigned long npages)
{
- iopte_t *iopte, *limit, *first;
- unsigned long cnum, ent, flush_point;
+ iopte_t *iopte, *limit, *first, *cluster;
+ unsigned long cnum, ent, nent, flush_point, found;
cnum = 0;
+ nent = 1;
while ((1UL << cnum) < npages)
cnum++;
+ if(cnum >= NCLUSTERS) {
+ nent = 1UL << (cnum - NCLUSTERS);
+ cnum = NCLUSTERS - 1;
+ }
iopte = iommu->page_table + (cnum * CLUSTER_NPAGES);
if (cnum == 0)
flush_point = iommu->alloc_info[cnum].flush;
first = iopte;
+ cluster = NULL;
+ found = 0;
for (;;) {
if (iopte_val(*iopte) == 0UL) {
- if ((iopte + (1 << cnum)) >= limit)
- ent = 0;
- else
- ent = ent + 1;
- iommu->alloc_info[cnum].next = ent;
- if (ent == flush_point)
- __iommu_flushall(iommu);
- break;
+ found++;
+ if (!cluster)
+ cluster = iopte;
+ } else {
+ /* Used cluster in the way */
+ cluster = NULL;
+ found = 0;
}
+
+ if (found == nent)
+ break;
+
iopte += (1 << cnum);
ent++;
if (iopte >= limit) {
iopte = (iommu->page_table + (cnum * CLUSTER_NPAGES));
ent = 0;
+
+ /* Multiple cluster allocations must not wrap */
+ cluster = NULL;
+ found = 0;
}
if (ent == flush_point)
__iommu_flushall(iommu);
goto bad;
}
+ /* ent/iopte points to the last cluster entry we're going to use,
+ * so save our place for the next allocation.
+ */
+ if ((iopte + (1 << cnum)) >= limit)
+ ent = 0;
+ else
+ ent = ent + 1;
+ iommu->alloc_info[cnum].next = ent;
+ if (ent == flush_point)
+ __iommu_flushall(iommu);
+
/* I've got your streaming cluster right here buddy boy... */
- return iopte;
+ return cluster;
bad:
printk(KERN_EMERG "sbus: alloc_streaming_cluster of npages(%ld) failed!\n",
static void free_streaming_cluster(struct sbus_iommu *iommu, u32 base, unsigned long npages)
{
- unsigned long cnum, ent;
+ unsigned long cnum, ent, nent;
iopte_t *iopte;
cnum = 0;
+ nent = 1;
while ((1UL << cnum) < npages)
cnum++;
+ if(cnum >= NCLUSTERS) {
+ nent = 1UL << (cnum - NCLUSTERS);
+ cnum = NCLUSTERS - 1;
+ }
ent = (base & CLUSTER_MASK) >> (IO_PAGE_SHIFT + cnum);
iopte = iommu->page_table + ((base - MAP_BASE) >> IO_PAGE_SHIFT);
- iopte_val(*iopte) = 0UL;
+ do {
+ iopte_val(*iopte) = 0UL;
+ iopte += 1 << cnum;
+ } while(--nent);
/* If the global flush might not have caught this entry,
* adjust the flush point such that we will flush before