patch-2.4.21 linux-2.4.21/drivers/ieee1394/dma.c

• Lines: 237
• Date: 2003-06-13 07:51:34.000000000 -0700
• Orig file: linux-2.4.20/drivers/ieee1394/dma.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/drivers/ieee1394/dma.c linux-2.4.21/drivers/ieee1394/dma.c
@@ -0,0 +1,236 @@
+/*
+ * DMA region bookkeeping routines
+ *
+ * Copyright (C) 2002 Maas Digital LLC
+ *
+ * This code is licensed under the GPL.  See the file COPYING in the root
+ * directory of the kernel sources for details.
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include "dma.h"
+
+/* dma_prog_region */
+
+void dma_prog_region_init(struct dma_prog_region *prog)
+{
+	prog->kvirt = NULL;
+	prog->dev = NULL;
+	prog->n_pages = 0;
+	prog->bus_addr = 0;
+}
+
+int  dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes, struct pci_dev *dev)
+{
+	/* round up to page size */
+	n_bytes = round_up_to_page(n_bytes);
+
+	prog->n_pages = n_bytes / PAGE_SIZE;
+
+	prog->kvirt = pci_alloc_consistent(dev, prog->n_pages * PAGE_SIZE, &prog->bus_addr);
+	if(!prog->kvirt) {
+		printk(KERN_ERR "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
+		dma_prog_region_free(prog);
+		return -ENOMEM;
+	}
+
+	prog->dev = dev;
+
+	return 0;
+}
+
+void dma_prog_region_free(struct dma_prog_region *prog)
+{
+	if(prog->kvirt) {
+		pci_free_consistent(prog->dev, prog->n_pages * PAGE_SIZE, prog->kvirt, prog->bus_addr);
+	}
+
+	prog->kvirt = NULL;
+	prog->dev = NULL;
+	prog->n_pages = 0;
+	prog->bus_addr = 0;
+}
+
+/* dma_region */
+
+void dma_region_init(struct dma_region *dma)
+{
+	dma->kvirt = NULL;
+	dma->dev = NULL;
+	dma->n_pages = 0;
+	dma->n_dma_pages = 0;
+	dma->sglist = NULL;
+}
+
+int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes, struct pci_dev *dev, int direction)
+{
+	unsigned int i, n_pages;
+
+	/* round up to page size */
+	n_bytes = round_up_to_page(n_bytes);
+
+	n_pages = n_bytes / PAGE_SIZE;
+
+	dma->kvirt = vmalloc_32(n_pages * PAGE_SIZE);
+	if(!dma->kvirt) {
+		printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
+		goto err;
+	}
+
+	dma->n_pages = n_pages;
+
+	/* Clear the ram out, no junk to the user */
+	memset(dma->kvirt, 0, n_pages * PAGE_SIZE);
+
+	/* allocate scatter/gather list */
+	dma->sglist = kmalloc(dma->n_pages * sizeof(struct scatterlist), GFP_KERNEL);
+	if(!dma->sglist) {
+		printk(KERN_ERR "dma_region_alloc: kmalloc(sglist) failed\n");
+		goto err;
+	}
+
+	/* just to be safe - this will become unnecessary once sglist->address goes away */
+	memset(dma->sglist, 0, dma->n_pages * sizeof(struct scatterlist));
+
+	/* fill scatter/gather list with pages */
+	for(i = 0; i < dma->n_pages; i++) {
+		unsigned long va = (unsigned long) dma->kvirt + i * PAGE_SIZE;
+			
+		dma->sglist[i].page = vmalloc_to_page((void *)va);
+		dma->sglist[i].length = PAGE_SIZE;
+	}
+
+	/* map sglist to the IOMMU */
+	dma->n_dma_pages = pci_map_sg(dev, &dma->sglist[0], dma->n_pages, direction);
+
+	if(dma->n_dma_pages == 0) {
+		printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
+		goto err;
+	}
+
+	dma->dev = dev;
+	dma->direction = direction;
+
+	return 0;
+
+err:
+	dma_region_free(dma);
+	return -ENOMEM;
+}
+
+void dma_region_free(struct dma_region *dma)
+{
+	if(dma->n_dma_pages) {
+		pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages, dma->direction);
+		dma->n_dma_pages = 0;
+		dma->dev = NULL;
+	}
+
+	if(dma->sglist) {
+		kfree(dma->sglist);
+		dma->sglist = NULL;
+	}
+
+	if(dma->kvirt) {
+		vfree(dma->kvirt);
+		dma->kvirt = NULL;
+		dma->n_pages = 0;
+	}
+}
+
+/* find the scatterlist index and remaining offset corresponding to a
+   given offset from the beginning of the buffer */
+static inline int dma_region_find(struct dma_region *dma, unsigned long offset, unsigned long *rem)
+{
+	int i;
+	unsigned long off = offset;
+
+	for(i = 0; i < dma->n_dma_pages; i++) {
+		if(off < sg_dma_len(&dma->sglist[i])) {
+			*rem = off;
+			return i;
+		}
+
+		off -= sg_dma_len(&dma->sglist[i]);
+	}
+
+	panic("dma_region_find: offset %lu beyond end of DMA mapping\n", offset);
+}
+
+dma_addr_t dma_region_offset_to_bus(struct dma_region *dma, unsigned long offset)
+{
+	unsigned long rem;
+
+	struct scatterlist *sg = &dma->sglist[dma_region_find(dma, offset, &rem)];
+	return sg_dma_address(sg) + rem;
+}
+
+void dma_region_sync(struct dma_region *dma, unsigned long offset, unsigned long len)
+{
+	int first, last;
+	unsigned long rem;
+
+	if(!len)
+		len = 1;
+
+	first = dma_region_find(dma, offset, &rem);
+	last = dma_region_find(dma, offset + len - 1, &rem);
+
+	pci_dma_sync_sg(dma->dev, &dma->sglist[first], last - first + 1, dma->direction);
+}
+
+/* nopage() handler for mmap access */
+
+static struct page*
+dma_region_pagefault(struct vm_area_struct *area, unsigned long address, int write_access)
+{
+	unsigned long offset;
+	unsigned long kernel_virt_addr;
+	struct page *ret = NOPAGE_SIGBUS;
+
+	struct dma_region *dma = (struct dma_region*) area->vm_private_data;
+
+	if(!dma->kvirt)
+		goto out;
+
+	if( (address < (unsigned long) area->vm_start) ||
+	    (address > (unsigned long) area->vm_start + (PAGE_SIZE * dma->n_pages)) )
+		goto out;
+
+	offset = address - area->vm_start;
+	kernel_virt_addr = (unsigned long) dma->kvirt + offset;
+	ret = vmalloc_to_page((void*) kernel_virt_addr);
+	get_page(ret);
+out:
+	return ret;
+}
+
+static struct vm_operations_struct dma_region_vm_ops = {
+	.nopage	= dma_region_pagefault,
+};
+
+int dma_region_mmap(struct dma_region *dma, struct file *file, struct vm_area_struct *vma)
+{
+	unsigned long size;
+
+	if(!dma->kvirt)
+		return -EINVAL;
+
+	/* must be page-aligned */
+	if(vma->vm_pgoff != 0)
+		return -EINVAL;
+
+	/* check the length */
+	size = vma->vm_end - vma->vm_start;
+	if(size > (PAGE_SIZE * dma->n_pages))
+		return -EINVAL;
+
+	vma->vm_ops = &dma_region_vm_ops;
+	vma->vm_private_data = dma;
+	vma->vm_file = file;
+	vma->vm_flags |= VM_RESERVED;
+
+	return 0;
+}