patch-2.3.41 linux/arch/i386/kernel/pci-dma.c

• Lines: 52
• Date: Thu Jan 27 08:58:15 2000
• Orig file: v2.3.40/linux/arch/i386/kernel/pci-dma.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.40/linux/arch/i386/kernel/pci-dma.c linux/arch/i386/kernel/pci-dma.c
@@ -0,0 +1,51 @@
+/*
+ * Dynamic DMA mapping support.
+ *
+ * On i386 there is no hardware dynamic DMA address translation,
+ * so consistent alloc/free are merely page allocation/freeing.
+ * The rest of the dynamic DMA mapping interface is implemented
+ * in asm/pci.h.
+ */
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/pci.h>
+#include <asm/io.h>
+
+/* Pure 2^n version of get_order */
+extern __inline__ int __get_order(unsigned long size)
+{
+	int order;
+
+	size = (size-1) >> (PAGE_SHIFT-1);
+	order = -1;
+	do {
+		size >>= 1;
+		order++;
+	} while (size);
+	return order;
+}
+
+void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size,
+			   dma_addr_t *dma_handle)
+{
+	void *ret;
+	int gfp = GFP_ATOMIC;
+
+	if (hwdev == NULL || hwdev->dma_mask != 0xffffffff)
+		gfp |= GFP_DMA;
+	ret = (void *)__get_free_pages(gfp, __get_order(size));
+
+	if (ret != NULL) {
+		memset(ret, 0, size);
+		*dma_handle = virt_to_bus(ret);
+	}
+	return ret;
+}
+
+void pci_free_consistent(struct pci_dev *hwdev, size_t size,
+			 void *vaddr, dma_addr_t dma_handle)
+{
+	free_pages((unsigned long)vaddr, __get_order(size));
+}