arch/powerpc/kernel/pci_iommu.c

   1 /*
   2  * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
   3  *
   4  * Rewrite, cleanup, new allocation schemes:
   5  * Copyright (C) 2004 Olof Johansson, IBM Corporation
   6  *
   7  * Dynamic DMA mapping support, platform-independent parts.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  22  */
  23
  24
  25 #include <linux/init.h>
  26 #include <linux/types.h>
  27 #include <linux/slab.h>
  28 #include <linux/mm.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/string.h>
  31 #include <linux/pci.h>
  32 #include <linux/dma-mapping.h>
  33 #include <asm/io.h>
  34 #include <asm/prom.h>
  35 #include <asm/iommu.h>
  36 #include <asm/pci-bridge.h>
  37 #include <asm/machdep.h>
  38 #include <asm/ppc-pci.h>
  39
  40 /*
  41  * We can use ->sysdata directly and avoid the extra work in
  42  * pci_device_to_OF_node since ->sysdata will have been initialised
  43  * in the iommu init code for all devices.
  44  */
  45 #define PCI_GET_DN(dev) ((struct device_node *)((dev)->sysdata))
  46
  47 static inline struct iommu_table *device_to_table(struct device *hwdev)
  48 {
  49         struct pci_dev *pdev;
  50
  51         if (!hwdev) {
  52                 pdev = ppc64_isabridge_dev;
  53                 if (!pdev)
  54                         return NULL;
  55         } else
  56                 pdev = to_pci_dev(hwdev);
  57
  58         return PCI_DN(PCI_GET_DN(pdev))->iommu_table;
  59 }
  60
  61
  62 static inline unsigned long device_to_mask(struct device *hwdev)
  63 {
  64         struct pci_dev *pdev;
  65
  66         if (!hwdev) {
  67                 pdev = ppc64_isabridge_dev;
  68                 if (!pdev) /* This is the best guess we can do */
  69                         return 0xfffffffful;
  70         } else
  71                 pdev = to_pci_dev(hwdev);
  72
  73         if (pdev->dma_mask)
  74                 return pdev->dma_mask;
  75
  76         /* Assume devices without mask can take 32 bit addresses */
  77         return 0xfffffffful;
  78 }
  79
  80
  81 /* Allocates a contiguous real buffer and creates mappings over it.
  82  * Returns the virtual address of the buffer and sets dma_handle
  83  * to the dma address (mapping) of the first page.
  84  */
  85 static void *pci_iommu_alloc_coherent(struct device *hwdev, size_t size,
  86                            dma_addr_t *dma_handle, gfp_t flag)
  87 {
  88         return iommu_alloc_coherent(device_to_table(hwdev), size, dma_handle,
  89                         device_to_mask(hwdev), flag,
  90                         pcibus_to_node(to_pci_dev(hwdev)->bus));
  91 }
  92
  93 static void pci_iommu_free_coherent(struct device *hwdev, size_t size,
  94                          void *vaddr, dma_addr_t dma_handle)
  95 {
  96         iommu_free_coherent(device_to_table(hwdev), size, vaddr, dma_handle);
  97 }
  98
  99 /* Creates TCEs for a user provided buffer.  The user buffer must be
 100  * contiguous real kernel storage (not vmalloc).  The address of the buffer
 101  * passed here is the kernel (virtual) address of the buffer.  The buffer
 102  * need not be page aligned, the dma_addr_t returned will point to the same
 103  * byte within the page as vaddr.
 104  */
 105 static dma_addr_t pci_iommu_map_single(struct device *hwdev, void *vaddr,
 106                 size_t size, enum dma_data_direction direction)
 107 {
 108         return iommu_map_single(device_to_table(hwdev), vaddr, size,
 109                                 device_to_mask(hwdev), direction);
 110 }
 111
 112
 113 static void pci_iommu_unmap_single(struct device *hwdev, dma_addr_t dma_handle,
 114                 size_t size, enum dma_data_direction direction)
 115 {
 116         iommu_unmap_single(device_to_table(hwdev), dma_handle, size, direction);
 117 }
 118
 119
 120 static int pci_iommu_map_sg(struct device *pdev, struct scatterlist *sglist,
 121                 int nelems, enum dma_data_direction direction)
 122 {
 123         return iommu_map_sg(pdev, device_to_table(pdev), sglist,
 124                         nelems, device_to_mask(pdev), direction);
 125 }
 126
 127 static void pci_iommu_unmap_sg(struct device *pdev, struct scatterlist *sglist,
 128                 int nelems, enum dma_data_direction direction)
 129 {
 130         iommu_unmap_sg(device_to_table(pdev), sglist, nelems, direction);
 131 }
 132
 133 /* We support DMA to/from any memory page via the iommu */
 134 static int pci_iommu_dma_supported(struct device *dev, u64 mask)
 135 {
 136         struct iommu_table *tbl = device_to_table(dev);
 137
 138         if (!tbl || tbl->it_offset > mask) {
 139                 printk(KERN_INFO "Warning: IOMMU table offset too big for device mask\n");
 140                 if (tbl)
 141                         printk(KERN_INFO "mask: 0x%08lx, table offset: 0x%08lx\n",
 142                                 mask, tbl->it_offset);
 143                 else
 144                         printk(KERN_INFO "mask: 0x%08lx, table unavailable\n",
 145                                 mask);
 146                 return 0;
 147         } else
 148                 return 1;
 149 }
 150
 151 struct dma_mapping_ops pci_iommu_ops = {
 152         .alloc_coherent = pci_iommu_alloc_coherent,
 153         .free_coherent = pci_iommu_free_coherent,
 154         .map_single = pci_iommu_map_single,
 155         .unmap_single = pci_iommu_unmap_single,
 156         .map_sg = pci_iommu_map_sg,
 157         .unmap_sg = pci_iommu_unmap_sg,
 158         .dma_supported = pci_iommu_dma_supported,
 159 };
 160
 161 void pci_iommu_init(void)
 162 {
 163         pci_dma_ops = pci_iommu_ops;
 164 }