1 files changed, 158 insertions, 73 deletions

diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c
index 90a5907080a1..d3276ebcfb47 100644
--- a/arch/sparc64/kernel/iommu.c
+++ b/arch/sparc64/kernel/iommu.c
@@ -512,124 +512,209 @@ static void dma_4u_unmap_single(struct device *dev, dma_addr_t bus_addr,
 static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
                          int nelems, enum dma_data_direction direction)
 {
-        unsigned long flags, ctx, i, npages, iopte_protection;
-        struct scatterlist *sg;
+        struct scatterlist *s, *outs, *segstart;
+        unsigned long flags, handle, prot, ctx;
+        dma_addr_t dma_next = 0, dma_addr;
+        unsigned int max_seg_size;
+        int outcount, incount, i;
         struct strbuf *strbuf;
         struct iommu *iommu;
-        iopte_t *base;
-        u32 dma_base;
-
-        /* Fast path single entry scatterlists. */
-        if (nelems == 1) {
-                sglist->dma_address =
-                        dma_4u_map_single(dev, sg_virt(sglist),
-                                          sglist->length, direction);
-                if (unlikely(sglist->dma_address == DMA_ERROR_CODE))
-                        return 0;
-                sglist->dma_length = sglist->length;
-                return 1;
-        }
+
+        BUG_ON(direction == DMA_NONE);
 
         iommu = dev->archdata.iommu;
         strbuf = dev->archdata.stc;
-
-        if (unlikely(direction == DMA_NONE))
-                goto bad_no_ctx;
-
-        npages = calc_npages(sglist, nelems);
+        if (nelems == 0 || !iommu)
+                return 0;
 
         spin_lock_irqsave(&iommu->lock, flags);
 
-        base = alloc_npages(dev, iommu, npages);
         ctx = 0;
         if (iommu->iommu_ctxflush)
                 ctx = iommu_alloc_ctx(iommu);
 
-        spin_unlock_irqrestore(&iommu->lock, flags);
-
-        if (base == NULL)
-                goto bad;
-
-        dma_base = iommu->page_table_map_base +
-                ((base - iommu->page_table) << IO_PAGE_SHIFT);
-
         if (strbuf->strbuf_enabled)
-                iopte_protection = IOPTE_STREAMING(ctx);
+                prot = IOPTE_STREAMING(ctx);
         else
-                iopte_protection = IOPTE_CONSISTENT(ctx);
+                prot = IOPTE_CONSISTENT(ctx);
         if (direction != DMA_TO_DEVICE)
-                iopte_protection |= IOPTE_WRITE;
-
-        for_each_sg(sglist, sg, nelems, i) {
-                unsigned long paddr = SG_ENT_PHYS_ADDRESS(sg);
-                unsigned long slen = sg->length;
-                unsigned long this_npages;
+                prot |= IOPTE_WRITE;
+
+        outs = s = segstart = &sglist[0];
+        outcount = 1;
+        incount = nelems;
+        handle = 0;
+
+        /* Init first segment length for backout at failure */
+        outs->dma_length = 0;
+
+        max_seg_size = dma_get_max_seg_size(dev);
+        for_each_sg(sglist, s, nelems, i) {
+                unsigned long paddr, npages, entry, slen;
+                iopte_t *base;
+
+                slen = s->length;
+                /* Sanity check */
+                if (slen == 0) {
+                        dma_next = 0;
+                        continue;
+                }
+                /* Allocate iommu entries for that segment */
+                paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
+                npages = iommu_num_pages(paddr, slen);
+                entry = iommu_range_alloc(dev, iommu, npages, &handle);
+
+                /* Handle failure */
+                if (unlikely(entry == DMA_ERROR_CODE)) {
+                        if (printk_ratelimit())
+                                printk(KERN_INFO "iommu_alloc failed, iommu %p paddr %lx"
+                                       " npages %lx\n", iommu, paddr, npages);
+                        goto iommu_map_failed;
+                }
 
-                this_npages = iommu_num_pages(paddr, slen);
+                base = iommu->page_table + entry;
 
-                sg->dma_address = dma_base | (paddr & ~IO_PAGE_MASK);
-                sg->dma_length = slen;
+                /* Convert entry to a dma_addr_t */
+                dma_addr = iommu->page_table_map_base +
+                        (entry << IO_PAGE_SHIFT);
+                dma_addr |= (s->offset & ~IO_PAGE_MASK);
 
+                /* Insert into HW table */
                 paddr &= IO_PAGE_MASK;
-                while (this_npages--) {
-                        iopte_val(*base) = iopte_protection | paddr;
-
+                while (npages--) {
+                        iopte_val(*base) = prot | paddr;
                         base++;
                         paddr += IO_PAGE_SIZE;
-                        dma_base += IO_PAGE_SIZE;
                 }
+
+                /* If we are in an open segment, try merging */
+                if (segstart != s) {
+                        /* We cannot merge if:
+                         * - allocated dma_addr isn't contiguous to previous allocation
+                         */
+                        if ((dma_addr != dma_next) ||
+                            (outs->dma_length + s->length > max_seg_size)) {
+                                /* Can't merge: create a new segment */
+                                segstart = s;
+                                outcount++;
+                                outs = sg_next(outs);
+                        } else {
+                                outs->dma_length += s->length;
+                        }
+                }
+
+                if (segstart == s) {
+                        /* This is a new segment, fill entries */
+                        outs->dma_address = dma_addr;
+                        outs->dma_length = slen;
+                }
+
+                /* Calculate next page pointer for contiguous check */
+                dma_next = dma_addr + slen;
         }
 
-        return nelems;
+        spin_unlock_irqrestore(&iommu->lock, flags);
+
+        if (outcount < incount) {
+                outs = sg_next(outs);
+                outs->dma_address = DMA_ERROR_CODE;
+                outs->dma_length = 0;
+        }
+
+        return outcount;
+
+iommu_map_failed:
+        for_each_sg(sglist, s, nelems, i) {
+                if (s->dma_length != 0) {
+                        unsigned long vaddr, npages, entry, i;
+                        iopte_t *base;
+
+                        vaddr = s->dma_address & IO_PAGE_MASK;
+                        npages = iommu_num_pages(s->dma_address, s->dma_length);
+                        iommu_range_free(iommu, vaddr, npages);
+
+                        entry = (vaddr - iommu->page_table_map_base)
+                                >> IO_PAGE_SHIFT;
+                        base = iommu->page_table + entry;
+
+                        for (i = 0; i < npages; i++)
+                                iopte_make_dummy(iommu, base + i);
+
+                        s->dma_address = DMA_ERROR_CODE;
+                        s->dma_length = 0;
+                }
+                if (s == outs)
+                        break;
+        }
+        spin_unlock_irqrestore(&iommu->lock, flags);
 
-bad:
-        iommu_free_ctx(iommu, ctx);
-bad_no_ctx:
-        if (printk_ratelimit())
-                WARN_ON(1);
         return 0;
 }
 
+/* If contexts are being used, they are the same in all of the mappings
+ * we make for a particular SG.
+ */
+static unsigned long fetch_sg_ctx(struct iommu *iommu, struct scatterlist *sg)
+{
+        unsigned long ctx = 0;
+
+        if (iommu->iommu_ctxflush) {
+                iopte_t *base;
+                u32 bus_addr;
+
+                bus_addr = sg->dma_address & IO_PAGE_MASK;
+                base = iommu->page_table +
+                        ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+
+                ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
+        }
+        return ctx;
+}
+
 static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
                             int nelems, enum dma_data_direction direction)
 {
-        unsigned long flags, ctx, i, npages;
+        unsigned long flags, ctx;
+        struct scatterlist *sg;
         struct strbuf *strbuf;
         struct iommu *iommu;
-        iopte_t *base;
-        u32 bus_addr;
 
-        if (unlikely(direction == DMA_NONE)) {
-                if (printk_ratelimit())
-                        WARN_ON(1);
-        }
+        BUG_ON(direction == DMA_NONE);
 
         iommu = dev->archdata.iommu;
         strbuf = dev->archdata.stc;
 
-        bus_addr = sglist->dma_address & IO_PAGE_MASK;
+        ctx = fetch_sg_ctx(iommu, sglist);
 
-        npages = calc_npages(sglist, nelems);
+        spin_lock_irqsave(&iommu->lock, flags);
 
-        base = iommu->page_table +
-                ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+        sg = sglist;
+        while (nelems--) {
+                dma_addr_t dma_handle = sg->dma_address;
+                unsigned int len = sg->dma_length;
+                unsigned long npages, entry;
+                iopte_t *base;
+                int i;
 
-        spin_lock_irqsave(&iommu->lock, flags);
+                if (!len)
+                        break;
+                npages = iommu_num_pages(dma_handle, len);
+                iommu_range_free(iommu, dma_handle, npages);
 
-        /* Record the context, if any. */
-        ctx = 0;
-        if (iommu->iommu_ctxflush)
-                ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
+                entry = ((dma_handle - iommu->page_table_map_base)
+                         >> IO_PAGE_SHIFT);
+                base = iommu->page_table + entry;
 
-        /* Step 1: Kick data out of streaming buffers if necessary. */
-        if (strbuf->strbuf_enabled)
-                strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
+                dma_handle &= IO_PAGE_MASK;
+                if (strbuf->strbuf_enabled)
+                        strbuf_flush(strbuf, iommu, dma_handle, ctx,
+                                     npages, direction);
 
-        /* Step 2: Clear out the TSB entries. */
-        for (i = 0; i < npages; i++)
-                iopte_make_dummy(iommu, base + i);
+                for (i = 0; i < npages; i++)
+                        iopte_make_dummy(iommu, base + i);
 
-        iommu_range_free(iommu, bus_addr, npages);
+                sg = sg_next(sg);
+        }
 
         iommu_free_ctx(iommu, ctx);