generic: per-device coherent dma allocator

Currently x86_32, sh and cris-v32 provide per-device coherent dma
memory allocator.

However their implementation is nearly identical. Refactor out
common code to be reused by them.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/asm-generic/dma-coherent.h b/include/asm-generic/dma-coherent.h
new file mode 100644 (file)
index 0000000..85a3ffa
--- /dev/null
+++ b/include/asm-generic/dma-coherent.h
@@ -0,0 +1,32 @@
+#ifndef DMA_COHERENT_H
+#define DMA_COHERENT_H
+
+#ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
+/*
+ * These two functions are only for dma allocator.
+ * Don't use them in device drivers.
+ */
+int dma_alloc_from_coherent(struct device *dev, ssize_t size,
+                                      dma_addr_t *dma_handle, void **ret);
+int dma_release_from_coherent(struct device *dev, int order, void *vaddr);
+
+/*
+ * Standard interface
+ */
+#define ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY
+extern int
+dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+                           dma_addr_t device_addr, size_t size, int flags);
+
+extern void
+dma_release_declared_memory(struct device *dev);
+
+extern void *
+dma_mark_declared_memory_occupied(struct device *dev,
+                                 dma_addr_t device_addr, size_t size);
+#else
+#define dma_alloc_from_coherent(dev, size, handle, ret) (0)
+#define dma_release_from_coherent(dev, order, vaddr) (0)
+#endif
+
+#endif

diff --git a/init/Kconfig b/init/Kconfig
index 6199d11..63cdbd8 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -802,6 +802,10 @@ config PROC_PAGE_MONITOR
 
 endmenu                # General setup
 
+config HAVE_GENERIC_DMA_COHERENT
+       bool
+       default n
+
 config SLABINFO
        bool
        depends on PROC_FS

diff --git a/kernel/Makefile b/kernel/Makefile
index 1c9938a..9e287d8 100644 (file)
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
 obj-$(CONFIG_MARKERS) += marker.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
 
 ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
 # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is

diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c
new file mode 100644 (file)
index 0000000..89a554c
--- /dev/null
+++ b/kernel/dma-coherent.c
@@ -0,0 +1,127 @@
+/*
+ * Coherent per-device memory handling.
+ * Borrowed from i386
+ */
+#include <linux/kernel.h>
+#include <linux/dma-mapping.h>
+
+struct dma_coherent_mem {
+       void            *virt_base;
+       u32             device_base;
+       int             size;
+       int             flags;
+       unsigned long   *bitmap;
+};
+
+int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+                               dma_addr_t device_addr, size_t size, int flags)
+{
+       void __iomem *mem_base = NULL;
+       int pages = size >> PAGE_SHIFT;
+       int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
+
+       if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
+               goto out;
+       if (!size)
+               goto out;
+       if (dev->dma_mem)
+               goto out;
+
+       /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
+
+       mem_base = ioremap(bus_addr, size);
+       if (!mem_base)
+               goto out;
+
+       dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
+       if (!dev->dma_mem)
+               goto out;
+       dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+       if (!dev->dma_mem->bitmap)
+               goto free1_out;
+
+       dev->dma_mem->virt_base = mem_base;
+       dev->dma_mem->device_base = device_addr;
+       dev->dma_mem->size = pages;
+       dev->dma_mem->flags = flags;
+
+       if (flags & DMA_MEMORY_MAP)
+               return DMA_MEMORY_MAP;
+
+       return DMA_MEMORY_IO;
+
+ free1_out:
+       kfree(dev->dma_mem);
+ out:
+       if (mem_base)
+               iounmap(mem_base);
+       return 0;
+}
+EXPORT_SYMBOL(dma_declare_coherent_memory);
+
+void dma_release_declared_memory(struct device *dev)
+{
+       struct dma_coherent_mem *mem = dev->dma_mem;
+
+       if (!mem)
+               return;
+       dev->dma_mem = NULL;
+       iounmap(mem->virt_base);
+       kfree(mem->bitmap);
+       kfree(mem);
+}
+EXPORT_SYMBOL(dma_release_declared_memory);
+
+void *dma_mark_declared_memory_occupied(struct device *dev,
+                                       dma_addr_t device_addr, size_t size)
+{
+       struct dma_coherent_mem *mem = dev->dma_mem;
+       int pos, err;
+       int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);
+
+       pages >>= PAGE_SHIFT;
+
+       if (!mem)
+               return ERR_PTR(-EINVAL);
+
+       pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
+       err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
+       if (err != 0)
+               return ERR_PTR(err);
+       return mem->virt_base + (pos << PAGE_SHIFT);
+}
+EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
+
+int dma_alloc_from_coherent(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);
+}
+
+int dma_release_from_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;
+}