[SPARC64]: IOMMU allocations using iommu-helper layer.

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

1 files changed, 81 insertions, 44 deletions

diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c
index 5623a4d59dff..90a5907080a1 100644
--- a/arch/sparc64/kernel/iommu.c
+++ b/arch/sparc64/kernel/iommu.c
@@ -1,6 +1,6 @@
 /* iommu.c: Generic sparc64 IOMMU support.
  *
- * Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1999, 2007, 2008 David S. Miller (davem@davemloft.net)
  * Copyright (C) 1999, 2000 Jakub Jelinek (jakub@redhat.com)
  */
 
@@ -10,6 +10,7 @@
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/iommu-helper.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -41,7 +42,7 @@
                                "i" (ASI_PHYS_BYPASS_EC_E))
 
 /* Must be invoked under the IOMMU lock. */
-static void __iommu_flushall(struct iommu *iommu)
+static void iommu_flushall(struct iommu *iommu)
 {
         if (iommu->iommu_flushinv) {
                 iommu_write(iommu->iommu_flushinv, ~(u64)0);
@@ -83,54 +84,91 @@ static inline void iopte_make_dummy(struct iommu *iommu, iopte_t *iopte)
         iopte_val(*iopte) = val;
 }
 
-/* Based largely upon the ppc64 iommu allocator.  */
-static long arena_alloc(struct iommu *iommu, unsigned long npages)
+/* Based almost entirely upon the ppc64 iommu allocator.  If you use the 'handle'
+ * facility it must all be done in one pass while under the iommu lock.
+ *
+ * On sun4u platforms, we only flush the IOMMU once every time we've passed
+ * over the entire page table doing allocations.  Therefore we only ever advance
+ * the hint and cannot backtrack it.
+ */
+unsigned long iommu_range_alloc(struct device *dev,
+                                struct iommu *iommu,
+                                unsigned long npages,
+                                unsigned long *handle)
 {
+        unsigned long n, end, start, limit, boundary_size;
         struct iommu_arena *arena = &iommu->arena;
-        unsigned long n, i, start, end, limit;
-        int pass;
+        int pass = 0;
+
+        /* This allocator was derived from x86_64's bit string search */
+
+        /* Sanity check */
+        if (unlikely(npages == 0)) {
+                if (printk_ratelimit())
+                        WARN_ON(1);
+                return DMA_ERROR_CODE;
+        }
+
+        if (handle && *handle)
+                start = *handle;
+        else
+                start = arena->hint;
 
         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)) {
+        /* The case below can happen if we have a small segment appended
+         * to a large, or when the previous alloc was at the very end of
+         * the available space. If so, go back to the beginning and flush.
+         */
+        if (start >= limit) {
+                start = 0;
+                if (iommu->flush_all)
+                        iommu->flush_all(iommu);
+        }
+
+ again:
+
+        if (dev)
+                boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+                                      1 << IO_PAGE_SHIFT);
+        else
+                boundary_size = ALIGN(1UL << 32, 1 << IO_PAGE_SHIFT);
+
+        n = iommu_area_alloc(arena->map, limit, start, npages, 0,
+                             boundary_size >> IO_PAGE_SHIFT, 0);
+        if (n == -1) {
                 if (likely(pass < 1)) {
-                        limit = start;
+                        /* First failure, rescan from the beginning.  */
                         start = 0;
-                        __iommu_flushall(iommu);
+                        if (iommu->flush_all)
+                                iommu->flush_all(iommu);
                         pass++;
                         goto again;
                 } else {
-                        /* Scanned the whole thing, give up. */
-                        return -1;
+                        /* Second failure, give up */
+                        return DMA_ERROR_CODE;
                 }
         }
 
-        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);
+        end = n + npages;
 
         arena->hint = end;
 
+        /* Update handle for SG allocations */
+        if (handle)
+                *handle = end;
+
         return n;
 }
 
-static void arena_free(struct iommu_arena *arena, unsigned long base, unsigned long npages)
+void iommu_range_free(struct iommu *iommu, dma_addr_t dma_addr, unsigned long npages)
 {
-        unsigned long i;
+        struct iommu_arena *arena = &iommu->arena;
+        unsigned long entry;
 
-        for (i = base; i < (base + npages); i++)
-                __clear_bit(i, arena->map);
+        entry = (dma_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
+
+        iommu_area_free(arena->map, entry, npages);
 }
 
 int iommu_table_init(struct iommu *iommu, int tsbsize,
@@ -156,6 +194,9 @@ int iommu_table_init(struct iommu *iommu, int tsbsize,
         }
         iommu->arena.limit = num_tsb_entries;
 
+        if (tlb_type != hypervisor)
+                iommu->flush_all = iommu_flushall;
+
         /* Allocate and initialize the dummy page which we
          * set inactive IO PTEs to point to.
          */
@@ -192,22 +233,18 @@ out_free_map:
         return -ENOMEM;
 }
 
-static inline iopte_t *alloc_npages(struct iommu *iommu, unsigned long npages)
+static inline iopte_t *alloc_npages(struct device *dev, struct iommu *iommu,
+                                    unsigned long npages)
 {
-        long entry;
+        unsigned long entry;
 
-        entry = arena_alloc(iommu, npages);
-        if (unlikely(entry < 0))
+        entry = iommu_range_alloc(dev, iommu, npages, NULL);
+        if (unlikely(entry == DMA_ERROR_CODE))
                 return NULL;
 
         return iommu->page_table + entry;
 }
 
-static inline void free_npages(struct iommu *iommu, dma_addr_t base, unsigned long npages)
-{
-        arena_free(&iommu->arena, base >> IO_PAGE_SHIFT, npages);
-}
-
 static int iommu_alloc_ctx(struct iommu *iommu)
 {
         int lowest = iommu->ctx_lowest_free;
@@ -258,7 +295,7 @@ static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
         iommu = dev->archdata.iommu;
 
         spin_lock_irqsave(&iommu->lock, flags);
-        iopte = alloc_npages(iommu, size >> IO_PAGE_SHIFT);
+        iopte = alloc_npages(dev, iommu, size >> IO_PAGE_SHIFT);
         spin_unlock_irqrestore(&iommu->lock, flags);
 
         if (unlikely(iopte == NULL)) {
@@ -296,7 +333,7 @@ static void dma_4u_free_coherent(struct device *dev, size_t size,
 
         spin_lock_irqsave(&iommu->lock, flags);
 
-        free_npages(iommu, dvma - iommu->page_table_map_base, npages);
+        iommu_range_free(iommu, dvma, npages);
 
         spin_unlock_irqrestore(&iommu->lock, flags);
 
@@ -327,7 +364,7 @@ static dma_addr_t dma_4u_map_single(struct device *dev, void *ptr, size_t sz,
         npages >>= IO_PAGE_SHIFT;
 
         spin_lock_irqsave(&iommu->lock, flags);
-        base = alloc_npages(iommu, npages);
+        base = alloc_npages(dev, iommu, npages);
         ctx = 0;
         if (iommu->iommu_ctxflush)
                 ctx = iommu_alloc_ctx(iommu);
@@ -465,7 +502,7 @@ static void dma_4u_unmap_single(struct device *dev, dma_addr_t bus_addr,
         for (i = 0; i < npages; i++)
                 iopte_make_dummy(iommu, base + i);
 
-        free_npages(iommu, bus_addr - iommu->page_table_map_base, npages);
+        iommu_range_free(iommu, bus_addr, npages);
 
         iommu_free_ctx(iommu, ctx);
 
@@ -503,7 +540,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 
         spin_lock_irqsave(&iommu->lock, flags);
 
-        base = alloc_npages(iommu, npages);
+        base = alloc_npages(dev, iommu, npages);
         ctx = 0;
         if (iommu->iommu_ctxflush)
                 ctx = iommu_alloc_ctx(iommu);
@@ -592,7 +629,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
         for (i = 0; i < npages; i++)
                 iopte_make_dummy(iommu, base + i);
 
-        free_npages(iommu, bus_addr - iommu->page_table_map_base, npages);
+        iommu_range_free(iommu, bus_addr, npages);
 
         iommu_free_ctx(iommu, ctx);