x86: integrate pci-dma.c

The code in pci-dma_{32,64}.c are now sufficiently
close to each other. We merge them in pci-dma.c.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 175 insertions, 0 deletions

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 00527e74e49c..388b113a7d88 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -38,6 +38,15 @@ EXPORT_SYMBOL(iommu_bio_merge);
 dma_addr_t bad_dma_address __read_mostly = 0;
 EXPORT_SYMBOL(bad_dma_address);
 
+/* Dummy device used for NULL arguments (normally ISA). Better would
+   be probably a smaller DMA mask, but this is bug-to-bug compatible
+   to older i386. */
+struct device fallback_dev = {
+        .bus_id = "fallback device",
+        .coherent_dma_mask = DMA_32BIT_MASK,
+        .dma_mask = &fallback_dev.coherent_dma_mask,
+};
+
 int dma_set_mask(struct device *dev, u64 mask)
 {
         if (!dev->dma_mask || !dma_supported(dev, mask))
@@ -267,6 +276,43 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
         return mem->virt_base + (pos << PAGE_SHIFT);
 }
 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
+
+static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
+                                       dma_addr_t *dma_handle, void **ret)
+{
+        struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+        int order = get_order(size);
+
+        if (mem) {
+                int page = bitmap_find_free_region(mem->bitmap, mem->size,
+                                                     order);
+                if (page >= 0) {
+                        *dma_handle = mem->device_base + (page << PAGE_SHIFT);
+                        *ret = mem->virt_base + (page << PAGE_SHIFT);
+                        memset(*ret, 0, size);
+                }
+                if (mem->flags & DMA_MEMORY_EXCLUSIVE)
+                        *ret = NULL;
+        }
+        return (mem != NULL);
+}
+
+static int dma_release_coherent(struct device *dev, int order, void *vaddr)
+{
+        struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+
+        if (mem && vaddr >= mem->virt_base && vaddr <
+                   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
+                int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+
+                bitmap_release_region(mem->bitmap, page, order);
+                return 1;
+        }
+        return 0;
+}
+#else
+#define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
+#define dma_release_coherent(dev, order, vaddr) (0)
 #endif /* CONFIG_X86_32 */
 
 int dma_supported(struct device *dev, u64 mask)
@@ -310,6 +356,135 @@ int dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(dma_supported);
 
+/* Allocate DMA memory on node near device */
+noinline struct page *
+dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
+{
+        int node;
+
+        node = dev_to_node(dev);
+
+        return alloc_pages_node(node, gfp, order);
+}
+
+/*
+ * Allocate memory for a coherent mapping.
+ */
+void *
+dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
+                   gfp_t gfp)
+{
+        void *memory = NULL;
+        struct page *page;
+        unsigned long dma_mask = 0;
+        dma_addr_t bus;
+
+        /* ignore region specifiers */
+        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+
+        if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
+                return memory;
+
+        if (!dev)
+                dev = &fallback_dev;
+        dma_mask = dev->coherent_dma_mask;
+        if (dma_mask == 0)
+                dma_mask = DMA_32BIT_MASK;
+
+        /* Device not DMA able */
+        if (dev->dma_mask == NULL)
+                return NULL;
+
+        /* Don't invoke OOM killer */
+        gfp |= __GFP_NORETRY;
+
+#ifdef CONFIG_X86_64
+        /* Why <=? Even when the mask is smaller than 4GB it is often
+           larger than 16MB and in this case we have a chance of
+           finding fitting memory in the next higher zone first. If
+           not retry with true GFP_DMA. -AK */
+        if (dma_mask <= DMA_32BIT_MASK)
+                gfp |= GFP_DMA32;
+#endif
+
+ again:
+        page = dma_alloc_pages(dev, gfp, get_order(size));
+        if (page == NULL)
+                return NULL;
+
+        {
+                int high, mmu;
+                bus = page_to_phys(page);
+                memory = page_address(page);
+                high = (bus + size) >= dma_mask;
+                mmu = high;
+                if (force_iommu && !(gfp & GFP_DMA))
+                        mmu = 1;
+                else if (high) {
+                        free_pages((unsigned long)memory,
+                                   get_order(size));
+
+                        /* Don't use the 16MB ZONE_DMA unless absolutely
+                           needed. It's better to use remapping first. */
+                        if (dma_mask < DMA_32BIT_MASK && !(gfp & GFP_DMA)) {
+                                gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
+                                goto again;
+                        }
+
+                        /* Let low level make its own zone decisions */
+                        gfp &= ~(GFP_DMA32|GFP_DMA);
+
+                        if (dma_ops->alloc_coherent)
+                                return dma_ops->alloc_coherent(dev, size,
+                                                           dma_handle, gfp);
+                        return NULL;
+                }
+
+                memset(memory, 0, size);
+                if (!mmu) {
+                        *dma_handle = bus;
+                        return memory;
+                }
+        }
+
+        if (dma_ops->alloc_coherent) {
+                free_pages((unsigned long)memory, get_order(size));
+                gfp &= ~(GFP_DMA|GFP_DMA32);
+                return dma_ops->alloc_coherent(dev, size, dma_handle, gfp);
+        }
+
+        if (dma_ops->map_simple) {
+                *dma_handle = dma_ops->map_simple(dev, virt_to_phys(memory),
+                                              size,
+                                              PCI_DMA_BIDIRECTIONAL);
+                if (*dma_handle != bad_dma_address)
+                        return memory;
+        }
+
+        if (panic_on_overflow)
+                panic("dma_alloc_coherent: IOMMU overflow by %lu bytes\n",
+                      (unsigned long)size);
+        free_pages((unsigned long)memory, get_order(size));
+        return NULL;
+}
+EXPORT_SYMBOL(dma_alloc_coherent);
+
+/*
+ * Unmap coherent memory.
+ * The caller must ensure that the device has finished accessing the mapping.
+ */
+void dma_free_coherent(struct device *dev, size_t size,
+                         void *vaddr, dma_addr_t bus)
+{
+        int order = get_order(size);
+        WARN_ON(irqs_disabled());       /* for portability */
+        if (dma_release_coherent(dev, order, vaddr))
+                return;
+        if (dma_ops->unmap_single)
+                dma_ops->unmap_single(dev, bus, size, 0);
+        free_pages((unsigned long)vaddr, order);
+}
+EXPORT_SYMBOL(dma_free_coherent);
 
 static int __init pci_iommu_init(void)
 {