This commit was manufactured by cvs2svn to create tag

[linux-2.6.git] / arch / sparc64 / kernel / sbus.c

diff --git a/arch/sparc64/kernel/sbus.c b/arch/sparc64/kernel/sbus.c
index 14d9c3a..549e978 100644 (file)
--- a/arch/sparc64/kernel/sbus.c
+++ b/arch/sparc64/kernel/sbus.c
@@ -28,10 +28,10 @@
  *
  * On SYSIO, using an 8K page size we have 1GB of SBUS
  * DMA space mapped.  We divide this space into equally
- * 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.
+ * 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.
  */
 
 #define NCLUSTERS      8UL
@@ -134,17 +134,12 @@ static void strbuf_flush(struct sbus_iommu *iommu, u32 base, unsigned long npage
 
 static iopte_t *alloc_streaming_cluster(struct sbus_iommu *iommu, unsigned long npages)
 {
-       iopte_t *iopte, *limit, *first, *cluster;
-       unsigned long cnum, ent, nent, flush_point, found;
+       iopte_t *iopte, *limit, *first;
+       unsigned long cnum, ent, flush_point;
 
        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)
@@ -157,31 +152,22 @@ static iopte_t *alloc_streaming_cluster(struct sbus_iommu *iommu, unsigned long
        flush_point = iommu->alloc_info[cnum].flush;
 
        first = iopte;
-       cluster = NULL;
-       found = 0;
        for (;;) {
                if (iopte_val(*iopte) == 0UL) {
-                       found++;
-                       if (!cluster)
-                               cluster = iopte;
-               } else {
-                       /* Used cluster in the way */
-                       cluster = NULL;
-                       found = 0;
-               }
-
-               if (found == nent)
+                       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;
-
+               }
                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);
@@ -189,19 +175,8 @@ static iopte_t *alloc_streaming_cluster(struct sbus_iommu *iommu, unsigned long
                        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 cluster;
+       return iopte;
 
 bad:
        printk(KERN_EMERG "sbus: alloc_streaming_cluster of npages(%ld) failed!\n",
@@ -211,23 +186,15 @@ bad:
 
 static void free_streaming_cluster(struct sbus_iommu *iommu, u32 base, unsigned long npages)
 {
-       unsigned long cnum, ent, nent;
+       unsigned long cnum, ent;
        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);
-       do {
-               iopte_val(*iopte) = 0UL;
-               iopte += 1 << cnum;
-       } while(--nent);
+       iopte_val(*iopte) = 0UL;
 
        /* If the global flush might not have caught this entry,
         * adjust the flush point such that we will flush before