[SPARC64]: Eliminate PCI IOMMU dma mapping size limit.

The hairy fast allocator in the sparc64 PCI IOMMU code
has a hard limit of 256 pages.  Certain devices can
exceed this when performing very large I/Os.

So replace with a more simple allocator, based largely
upon the arch/ppc64/kernel/iommu.c code.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 137 insertions, 228 deletions

diff --git a/arch/sparc64/kernel/pci_iommu.c b/arch/sparc64/kernel/pci_iommu.c
index cdee7d9fed72..a11910be1013 100644
--- a/arch/sparc64/kernel/pci_iommu.c
+++ b/arch/sparc64/kernel/pci_iommu.c
@@ -49,12 +49,6 @@ static void __iommu_flushall(struct pci_iommu *iommu)
 
         /* Ensure completion of previous PIO writes. */
         (void) pci_iommu_read(iommu->write_complete_reg);
-
-        /* Now update everyone's flush point. */
-        for (entry = 0; entry < PBM_NCLUSTERS; entry++) {
-                iommu->alloc_info[entry].flush =
-                        iommu->alloc_info[entry].next;
-        }
 }
 
 #define IOPTE_CONSISTENT(CTX) \
@@ -80,9 +74,61 @@ static void inline iopte_make_dummy(struct pci_iommu *iommu, iopte_t *iopte)
         iopte_val(*iopte) = val;
 }
 
+/* Based largely upon the ppc64 iommu allocator.  */
+static long pci_arena_alloc(struct pci_iommu *iommu, unsigned long npages)
+{
+        struct pci_iommu_arena *arena = &iommu->arena;
+        unsigned long n, i, start, end, limit;
+        int pass;
+
+        limit = arena->limit;
+        start = arena->hint;
+        pass = 0;
+
+again:
+        n = find_next_zero_bit(arena->map, limit, start);
+        end = n + npages;
+        if (unlikely(end >= limit)) {
+                if (likely(pass < 1)) {
+                        limit = start;
+                        start = 0;
+                        __iommu_flushall(iommu);
+                        pass++;
+                        goto again;
+                } else {
+                        /* Scanned the whole thing, give up. */
+                        return -1;
+                }
+        }
+
+        for (i = n; i < end; i++) {
+                if (test_bit(i, arena->map)) {
+                        start = i + 1;
+                        goto again;
+                }
+        }
+
+        for (i = n; i < end; i++)
+                __set_bit(i, arena->map);
+
+        arena->hint = end;
+
+        return n;
+}
+
+static void pci_arena_free(struct pci_iommu_arena *arena, unsigned long base, unsigned long npages)
+{
+        unsigned long i;
+
+        for (i = base; i < (base + npages); i++)
+                __clear_bit(i, arena->map);
+}
+
 void pci_iommu_table_init(struct pci_iommu *iommu, int tsbsize, u32 dma_offset, u32 dma_addr_mask)
 {
-        unsigned long i, tsbbase, order;
+        unsigned long i, tsbbase, order, sz, num_tsb_entries;
+
+        num_tsb_entries = tsbsize / sizeof(iopte_t);
 
         /* Setup initial software IOMMU state. */
         spin_lock_init(&iommu->lock);
@@ -90,27 +136,16 @@ void pci_iommu_table_init(struct pci_iommu *iommu, int tsbsize, u32 dma_offset,
         iommu->page_table_map_base = dma_offset;
         iommu->dma_addr_mask = dma_addr_mask;
 
-        switch (tsbsize / (8 * 1024)) {
-        case 64:
-                iommu->page_table_sz_bits = 16;
-                break;
-        case 128:
-                iommu->page_table_sz_bits = 17;
-                break;
-        default:
-                prom_printf("PCI_IOMMU: Illegal TSB size %d\n",
-                            tsbsize / (8 * 1024));
+        /* Allocate and initialize the free area map.  */
+        sz = num_tsb_entries / 8;
+        sz = (sz + 7UL) & ~7UL;
+        iommu->arena.map = kmalloc(sz, GFP_KERNEL);
+        if (!iommu->arena.map) {
+                prom_printf("PCI_IOMMU: Error, kmalloc(arena.map) failed.\n");
                 prom_halt();
-                break;
-        };
-
-        iommu->lowest_consistent_map =
-                1 << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS);
-
-        for (i = 0; i < PBM_NCLUSTERS; i++) {
-                iommu->alloc_info[i].flush = 0;
-                iommu->alloc_info[i].next = 0;
         }
+        memset(iommu->arena.map, 0, sz);
+        iommu->arena.limit = num_tsb_entries;
 
         /* Allocate and initialize the dummy page which we
          * set inactive IO PTEs to point to.
@@ -132,114 +167,24 @@ void pci_iommu_table_init(struct pci_iommu *iommu, int tsbsize, u32 dma_offset,
         }
         iommu->page_table = (iopte_t *)tsbbase;
 
-        for (i = 0; i < tsbsize / sizeof(iopte_t); i++)
+        for (i = 0; i < num_tsb_entries; i++)
                 iopte_make_dummy(iommu, &iommu->page_table[i]);
 }
 
-static iopte_t *alloc_streaming_cluster(struct pci_iommu *iommu, unsigned long npages)
+static inline iopte_t *alloc_npages(struct pci_iommu *iommu, unsigned long npages)
 {
-        iopte_t *iopte, *limit, *first;
-        unsigned long cnum, ent, flush_point;
-
-        cnum = 0;
-        while ((1UL << cnum) < npages)
-                cnum++;
-        iopte  = (iommu->page_table +
-                  (cnum << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS)));
-
-        if (cnum == 0)
-                limit = (iommu->page_table +
-                         iommu->lowest_consistent_map);
-        else
-                limit = (iopte +
-                         (1 << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS)));
+        long entry;
 
-        iopte += ((ent = iommu->alloc_info[cnum].next) << cnum);
-        flush_point = iommu->alloc_info[cnum].flush;
-        
-        first = iopte;
-        for (;;) {
-                if (IOPTE_IS_DUMMY(iommu, iopte)) {
-                        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 <<
-                                  (iommu->page_table_sz_bits - PBM_LOGCLUSTERS)));
-                        ent = 0;
-                }
-                if (ent == flush_point)
-                        __iommu_flushall(iommu);
-                if (iopte == first)
-                        goto bad;
-        }
-
-        /* I've got your streaming cluster right here buddy boy... */
-        return iopte;
+        entry = pci_arena_alloc(iommu, npages);
+        if (unlikely(entry < 0))
+                return NULL;
 
-bad:
-        printk(KERN_EMERG "pci_iommu: alloc_streaming_cluster of npages(%ld) failed!\n",
-               npages);
-        return NULL;
+        return iommu->page_table + entry;
 }
 
-static void free_streaming_cluster(struct pci_iommu *iommu, dma_addr_t base,
-                                   unsigned long npages, unsigned long ctx)
+static inline void free_npages(struct pci_iommu *iommu, dma_addr_t base, unsigned long npages)
 {
-        unsigned long cnum, ent;
-
-        cnum = 0;
-        while ((1UL << cnum) < npages)
-                cnum++;
-
-        ent = (base << (32 - IO_PAGE_SHIFT + PBM_LOGCLUSTERS - iommu->page_table_sz_bits))
-                >> (32 + PBM_LOGCLUSTERS + cnum - iommu->page_table_sz_bits);
-
-        /* If the global flush might not have caught this entry,
-         * adjust the flush point such that we will flush before
-         * ever trying to reuse it.
-         */
-#define between(X,Y,Z)  (((Z) - (Y)) >= ((X) - (Y)))
-        if (between(ent, iommu->alloc_info[cnum].next, iommu->alloc_info[cnum].flush))
-                iommu->alloc_info[cnum].flush = ent;
-#undef between
-}
-
-/* We allocate consistent mappings from the end of cluster zero. */
-static iopte_t *alloc_consistent_cluster(struct pci_iommu *iommu, unsigned long npages)
-{
-        iopte_t *iopte;
-
-        iopte = iommu->page_table + (1 << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS));
-        while (iopte > iommu->page_table) {
-                iopte--;
-                if (IOPTE_IS_DUMMY(iommu, iopte)) {
-                        unsigned long tmp = npages;
-
-                        while (--tmp) {
-                                iopte--;
-                                if (!IOPTE_IS_DUMMY(iommu, iopte))
-                                        break;
-                        }
-                        if (tmp == 0) {
-                                u32 entry = (iopte - iommu->page_table);
-
-                                if (entry < iommu->lowest_consistent_map)
-                                        iommu->lowest_consistent_map = entry;
-                                return iopte;
-                        }
-                }
-        }
-        return NULL;
+        pci_arena_free(&iommu->arena, base >> IO_PAGE_SHIFT, npages);
 }
 
 static int iommu_alloc_ctx(struct pci_iommu *iommu)
@@ -279,7 +224,7 @@ void *pci_alloc_consistent(struct pci_dev *pdev, size_t size, dma_addr_t *dma_ad
         struct pcidev_cookie *pcp;
         struct pci_iommu *iommu;
         iopte_t *iopte;
-        unsigned long flags, order, first_page, ctx;
+        unsigned long flags, order, first_page;
         void *ret;
         int npages;
 
@@ -297,9 +242,10 @@ void *pci_alloc_consistent(struct pci_dev *pdev, size_t size, dma_addr_t *dma_ad
         iommu = pcp->pbm->iommu;
 
         spin_lock_irqsave(&iommu->lock, flags);
-        iopte = alloc_consistent_cluster(iommu, size >> IO_PAGE_SHIFT);
-        if (iopte == NULL) {
-                spin_unlock_irqrestore(&iommu->lock, flags);
+        iopte = alloc_npages(iommu, size >> IO_PAGE_SHIFT);
+        spin_unlock_irqrestore(&iommu->lock, flags);
+
+        if (unlikely(iopte == NULL)) {
                 free_pages(first_page, order);
                 return NULL;
         }
@@ -308,31 +254,15 @@ void *pci_alloc_consistent(struct pci_dev *pdev, size_t size, dma_addr_t *dma_ad
                       ((iopte - iommu->page_table) << IO_PAGE_SHIFT));
         ret = (void *) first_page;
         npages = size >> IO_PAGE_SHIFT;
-        ctx = 0;
-        if (iommu->iommu_ctxflush)
-                ctx = iommu_alloc_ctx(iommu);
         first_page = __pa(first_page);
         while (npages--) {
-                iopte_val(*iopte) = (IOPTE_CONSISTENT(ctx) |
+                iopte_val(*iopte) = (IOPTE_CONSISTENT(0UL) |
                                      IOPTE_WRITE |
                                      (first_page & IOPTE_PAGE));
                 iopte++;
                 first_page += IO_PAGE_SIZE;
         }
 
-        {
-                int i;
-                u32 daddr = *dma_addrp;
-
-                npages = size >> IO_PAGE_SHIFT;
-                for (i = 0; i < npages; i++) {
-                        pci_iommu_write(iommu->iommu_flush, daddr);
-                        daddr += IO_PAGE_SIZE;
-                }
-        }
-
-        spin_unlock_irqrestore(&iommu->lock, flags);
-
         return ret;
 }
 
@@ -342,7 +272,7 @@ void pci_free_consistent(struct pci_dev *pdev, size_t size, void *cpu, dma_addr_
         struct pcidev_cookie *pcp;
         struct pci_iommu *iommu;
         iopte_t *iopte;
-        unsigned long flags, order, npages, i, ctx;
+        unsigned long flags, order, npages;
 
         npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
         pcp = pdev->sysdata;
@@ -352,46 +282,7 @@ void pci_free_consistent(struct pci_dev *pdev, size_t size, void *cpu, dma_addr_
 
         spin_lock_irqsave(&iommu->lock, flags);
 
-        if ((iopte - iommu->page_table) ==
-            iommu->lowest_consistent_map) {
-                iopte_t *walk = iopte + npages;
-                iopte_t *limit;
-
-                limit = (iommu->page_table +
-                         (1 << (iommu->page_table_sz_bits - PBM_LOGCLUSTERS)));
-                while (walk < limit) {
-                        if (!IOPTE_IS_DUMMY(iommu, walk))
-                                break;
-                        walk++;
-                }
-                iommu->lowest_consistent_map =
-                        (walk - iommu->page_table);
-        }
-
-        /* Data for consistent mappings cannot enter the streaming
-         * buffers, so we only need to update the TSB.  We flush
-         * the IOMMU here as well to prevent conflicts with the
-         * streaming mapping deferred tlb flush scheme.
-         */
-
-        ctx = 0;
-        if (iommu->iommu_ctxflush)
-                ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
-
-        for (i = 0; i < npages; i++, iopte++)
-                iopte_make_dummy(iommu, iopte);
-
-        if (iommu->iommu_ctxflush) {
-                pci_iommu_write(iommu->iommu_ctxflush, ctx);
-        } else {
-                for (i = 0; i < npages; i++) {
-                        u32 daddr = dvma + (i << IO_PAGE_SHIFT);
-
-                        pci_iommu_write(iommu->iommu_flush, daddr);
-                }
-        }
-
-        iommu_free_ctx(iommu, ctx);
+        free_npages(iommu, dvma, npages);
 
         spin_unlock_irqrestore(&iommu->lock, flags);
 
@@ -418,25 +309,27 @@ dma_addr_t pci_map_single(struct pci_dev *pdev, void *ptr, size_t sz, int direct
         iommu = pcp->pbm->iommu;
         strbuf = &pcp->pbm->stc;
 
-        if (direction == PCI_DMA_NONE)
-                BUG();
+        if (unlikely(direction == PCI_DMA_NONE))
+                goto bad_no_ctx;
 
         oaddr = (unsigned long)ptr;
         npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
         npages >>= IO_PAGE_SHIFT;
 
         spin_lock_irqsave(&iommu->lock, flags);
+        base = alloc_npages(iommu, npages);
+        ctx = 0;
+        if (iommu->iommu_ctxflush)
+                ctx = iommu_alloc_ctx(iommu);
+        spin_unlock_irqrestore(&iommu->lock, flags);
 
-        base = alloc_streaming_cluster(iommu, npages);
-        if (base == NULL)
+        if (unlikely(!base))
                 goto bad;
+
         bus_addr = (iommu->page_table_map_base +
                     ((base - iommu->page_table) << IO_PAGE_SHIFT));
         ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
         base_paddr = __pa(oaddr & IO_PAGE_MASK);
-        ctx = 0;
-        if (iommu->iommu_ctxflush)
-                ctx = iommu_alloc_ctx(iommu);
         if (strbuf->strbuf_enabled)
                 iopte_protection = IOPTE_STREAMING(ctx);
         else
@@ -447,12 +340,13 @@ dma_addr_t pci_map_single(struct pci_dev *pdev, void *ptr, size_t sz, int direct
         for (i = 0; i < npages; i++, base++, base_paddr += IO_PAGE_SIZE)
                 iopte_val(*base) = iopte_protection | base_paddr;
 
-        spin_unlock_irqrestore(&iommu->lock, flags);
-
         return ret;
 
 bad:
-        spin_unlock_irqrestore(&iommu->lock, flags);
+        iommu_free_ctx(iommu, ctx);
+bad_no_ctx:
+        if (printk_ratelimit())
+                WARN_ON(1);
         return PCI_DMA_ERROR_CODE;
 }
 
@@ -527,10 +421,13 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
         struct pci_iommu *iommu;
         struct pci_strbuf *strbuf;
         iopte_t *base;
-        unsigned long flags, npages, ctx;
+        unsigned long flags, npages, ctx, i;
 
-        if (direction == PCI_DMA_NONE)
-                BUG();
+        if (unlikely(direction == PCI_DMA_NONE)) {
+                if (printk_ratelimit())
+                        WARN_ON(1);
+                return;
+        }
 
         pcp = pdev->sysdata;
         iommu = pcp->pbm->iommu;
@@ -556,13 +453,14 @@ void pci_unmap_single(struct pci_dev *pdev, dma_addr_t bus_addr, size_t sz, int
 
         /* Step 1: Kick data out of streaming buffers if necessary. */
         if (strbuf->strbuf_enabled)
-                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
+                pci_strbuf_flush(strbuf, iommu, bus_addr, ctx,
+                                 npages, direction);
 
-        /* Step 2: Clear out first TSB entry. */
-        iopte_make_dummy(iommu, base);
+        /* Step 2: Clear out TSB entries. */
+        for (i = 0; i < npages; i++)
+                iopte_make_dummy(iommu, base + i);
 
-        free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base,
-                               npages, ctx);
+        free_npages(iommu, bus_addr - iommu->page_table_map_base, npages);
 
         iommu_free_ctx(iommu, ctx);
 
@@ -667,6 +565,8 @@ int pci_map_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems, int
                         pci_map_single(pdev,
                                        (page_address(sglist->page) + sglist->offset),
                                        sglist->length, direction);
+                if (unlikely(sglist->dma_address == PCI_DMA_ERROR_CODE))
+                        return 0;
                 sglist->dma_length = sglist->length;
                 return 1;
         }
@@ -675,21 +575,29 @@ int pci_map_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems, int
         iommu = pcp->pbm->iommu;
         strbuf = &pcp->pbm->stc;
         
-        if (direction == PCI_DMA_NONE)
-                BUG();
+        if (unlikely(direction == PCI_DMA_NONE))
+                goto bad_no_ctx;
 
         /* Step 1: Prepare scatter list. */
 
         npages = prepare_sg(sglist, nelems);
 
-        /* Step 2: Allocate a cluster. */
+        /* Step 2: Allocate a cluster and context, if necessary. */
 
         spin_lock_irqsave(&iommu->lock, flags);
 
-        base = alloc_streaming_cluster(iommu, npages);
+        base = alloc_npages(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);
+
+        dma_base = iommu->page_table_map_base +
+                ((base - iommu->page_table) << IO_PAGE_SHIFT);
 
         /* Step 3: Normalize DMA addresses. */
         used = nelems;
@@ -702,30 +610,28 @@ int pci_map_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems, int
         }
         used = nelems - used;
 
-        /* Step 4: Choose a context if necessary. */
-        ctx = 0;
-        if (iommu->iommu_ctxflush)
-                ctx = iommu_alloc_ctx(iommu);
-
-        /* Step 5: Create the mappings. */
+        /* Step 4: Create the mappings. */
         if (strbuf->strbuf_enabled)
                 iopte_protection = IOPTE_STREAMING(ctx);
         else
                 iopte_protection = IOPTE_CONSISTENT(ctx);
         if (direction != PCI_DMA_TODEVICE)
                 iopte_protection |= IOPTE_WRITE;
-        fill_sg (base, sglist, used, nelems, iopte_protection);
+
+        fill_sg(base, sglist, used, nelems, iopte_protection);
+
 #ifdef VERIFY_SG
         verify_sglist(sglist, nelems, base, npages);
 #endif
 
-        spin_unlock_irqrestore(&iommu->lock, flags);
-
         return used;
 
 bad:
-        spin_unlock_irqrestore(&iommu->lock, flags);
-        return PCI_DMA_ERROR_CODE;
+        iommu_free_ctx(iommu, ctx);
+bad_no_ctx:
+        if (printk_ratelimit())
+                WARN_ON(1);
+        return 0;
 }
 
 /* Unmap a set of streaming mode DMA translations. */
@@ -738,8 +644,10 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
         unsigned long flags, ctx, i, npages;
         u32 bus_addr;
 
-        if (direction == PCI_DMA_NONE)
-                BUG();
+        if (unlikely(direction == PCI_DMA_NONE)) {
+                if (printk_ratelimit())
+                        WARN_ON(1);
+        }
 
         pcp = pdev->sysdata;
         iommu = pcp->pbm->iommu;
@@ -751,7 +659,8 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
                 if (sglist[i].dma_length == 0)
                         break;
         i--;
-        npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) - bus_addr) >> IO_PAGE_SHIFT;
+        npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+                  bus_addr) >> IO_PAGE_SHIFT;
 
         base = iommu->page_table +
                 ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
@@ -772,11 +681,11 @@ void pci_unmap_sg(struct pci_dev *pdev, struct scatterlist *sglist, int nelems,
         if (strbuf->strbuf_enabled)
                 pci_strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
-        /* Step 2: Clear out first TSB entry. */
-        iopte_make_dummy(iommu, base);
+        /* Step 2: Clear out the TSB entries. */
+        for (i = 0; i < npages; i++)
+                iopte_make_dummy(iommu, base + i);
 
-        free_streaming_cluster(iommu, bus_addr - iommu->page_table_map_base,
-                               npages, ctx);
+        free_npages(iommu, bus_addr - iommu->page_table_map_base, npages);
 
         iommu_free_ctx(iommu, ctx);