2 * Support for DMA from PCI devices to main memory on
3 * machines without an iommu or with directly addressable
4 * RAM (typically a pmac with 2Gb of RAM or less)
6 * Copyright (C) 2003 Benjamin Herrenschmidt (benh@kernel.crashing.org)
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
14 #include <linux/kernel.h>
15 #include <linux/pci.h>
16 #include <linux/delay.h>
17 #include <linux/string.h>
18 #include <linux/init.h>
19 #include <linux/bootmem.h>
21 #include <linux/dma-mapping.h>
23 #include <asm/sections.h>
26 #include <asm/pci-bridge.h>
27 #include <asm/machdep.h>
28 #include <asm/pmac_feature.h>
29 #include <asm/abs_addr.h>
33 static void *pci_direct_alloc_consistent(struct pci_dev *hwdev, size_t size,
34 dma_addr_t *dma_handle)
38 ret = (void *)__get_free_pages(GFP_ATOMIC, get_order(size));
41 *dma_handle = virt_to_abs(ret);
46 static void pci_direct_free_consistent(struct pci_dev *hwdev, size_t size,
47 void *vaddr, dma_addr_t dma_handle)
49 free_pages((unsigned long)vaddr, get_order(size));
52 static dma_addr_t pci_direct_map_single(struct pci_dev *hwdev, void *ptr,
53 size_t size, enum dma_data_direction direction)
55 return virt_to_abs(ptr);
58 static void pci_direct_unmap_single(struct pci_dev *hwdev, dma_addr_t dma_addr,
59 size_t size, enum dma_data_direction direction)
63 static int pci_direct_map_sg(struct pci_dev *hwdev, struct scatterlist *sg,
64 int nents, enum dma_data_direction direction)
68 for (i = 0; i < nents; i++, sg++) {
69 sg->dma_address = page_to_phys(sg->page) + sg->offset;
70 sg->dma_length = sg->length;
76 static void pci_direct_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sg,
77 int nents, enum dma_data_direction direction)
81 void __init pci_direct_iommu_init(void)
83 pci_dma_ops.pci_alloc_consistent = pci_direct_alloc_consistent;
84 pci_dma_ops.pci_free_consistent = pci_direct_free_consistent;
85 pci_dma_ops.pci_map_single = pci_direct_map_single;
86 pci_dma_ops.pci_unmap_single = pci_direct_unmap_single;
87 pci_dma_ops.pci_map_sg = pci_direct_map_sg;
88 pci_dma_ops.pci_unmap_sg = pci_direct_unmap_sg;