arch/powerpc/kernel/dma-swiotlb.c

   1 /*
   2  * Contains routines needed to support swiotlb for ppc.
   3  *
   4  * Copyright (C) 2009 Becky Bruce, Freescale Semiconductor
   5  *
   6  * This program is free software; you can redistribute  it and/or modify it
   7  * under  the terms of  the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the  License, or (at your
   9  * option) any later version.
  10  *
  11  */
  12
  13 #include <linux/dma-mapping.h>
  14 #include <linux/pfn.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/pci.h>
  18
  19 #include <asm/machdep.h>
  20 #include <asm/swiotlb.h>
  21 #include <asm/dma.h>
  22 #include <asm/abs_addr.h>
  23
  24 int swiotlb __read_mostly;
  25 unsigned int ppc_swiotlb_enable;
  26
  27 void *swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t addr)
  28 {
  29         unsigned long pfn = PFN_DOWN(swiotlb_bus_to_phys(hwdev, addr));
  30         void *pageaddr = page_address(pfn_to_page(pfn));
  31
  32         if (pageaddr != NULL)
  33                 return pageaddr + (addr % PAGE_SIZE);
  34         return NULL;
  35 }
  36
  37 dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
  38 {
  39         return paddr + get_dma_direct_offset(hwdev);
  40 }
  41
  42 phys_addr_t swiotlb_bus_to_phys(struct device *hwdev, dma_addr_t baddr)
  43
  44 {
  45         return baddr - get_dma_direct_offset(hwdev);
  46 }
  47
  48 /*
  49  * Determine if an address needs bounce buffering via swiotlb.
  50  * Going forward I expect the swiotlb code to generalize on using
  51  * a dma_ops->addr_needs_map, and this function will move from here to the
  52  * generic swiotlb code.
  53  */
  54 int
  55 swiotlb_arch_address_needs_mapping(struct device *hwdev, dma_addr_t addr,
  56                                    size_t size)
  57 {
  58         struct dma_mapping_ops *dma_ops = get_dma_ops(hwdev);
  59
  60         BUG_ON(!dma_ops);
  61         return dma_ops->addr_needs_map(hwdev, addr, size);
  62 }
  63
  64 /*
  65  * Determine if an address is reachable by a pci device, or if we must bounce.
  66  */
  67 static int
  68 swiotlb_pci_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
  69 {
  70         u64 mask = dma_get_mask(hwdev);
  71         dma_addr_t max;
  72         struct pci_controller *hose;
  73         struct pci_dev *pdev = to_pci_dev(hwdev);
  74
  75         hose = pci_bus_to_host(pdev->bus);
  76         max = hose->dma_window_base_cur + hose->dma_window_size;
  77
  78         /* check that we're within mapped pci window space */
  79         if ((addr + size > max) | (addr < hose->dma_window_base_cur))
  80                 return 1;
  81
  82         return !is_buffer_dma_capable(mask, addr, size);
  83 }
  84
  85 static int
  86 swiotlb_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
  87 {
  88         return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
  89 }
  90
  91
  92 /*
  93  * At the moment, all platforms that use this code only require
  94  * swiotlb to be used if we're operating on HIGHMEM.  Since
  95  * we don't ever call anything other than map_sg, unmap_sg,
  96  * map_page, and unmap_page on highmem, use normal dma_ops
  97  * for everything else.
  98  */
  99 struct dma_mapping_ops swiotlb_dma_ops = {
 100         .alloc_coherent = dma_direct_alloc_coherent,
 101         .free_coherent = dma_direct_free_coherent,
 102         .map_sg = swiotlb_map_sg_attrs,
 103         .unmap_sg = swiotlb_unmap_sg_attrs,
 104         .dma_supported = swiotlb_dma_supported,
 105         .map_page = swiotlb_map_page,
 106         .unmap_page = swiotlb_unmap_page,
 107         .addr_needs_map = swiotlb_addr_needs_map,
 108         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
 109         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
 110         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
 111         .sync_sg_for_device = swiotlb_sync_sg_for_device
 112 };
 113
 114 struct dma_mapping_ops swiotlb_pci_dma_ops = {
 115         .alloc_coherent = dma_direct_alloc_coherent,
 116         .free_coherent = dma_direct_free_coherent,
 117         .map_sg = swiotlb_map_sg_attrs,
 118         .unmap_sg = swiotlb_unmap_sg_attrs,
 119         .dma_supported = swiotlb_dma_supported,
 120         .map_page = swiotlb_map_page,
 121         .unmap_page = swiotlb_unmap_page,
 122         .addr_needs_map = swiotlb_pci_addr_needs_map,
 123         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
 124         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
 125         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
 126         .sync_sg_for_device = swiotlb_sync_sg_for_device
 127 };
 128
 129 static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
 130                                   unsigned long action, void *data)
 131 {
 132         struct device *dev = data;
 133
 134         /* We are only intereted in device addition */
 135         if (action != BUS_NOTIFY_ADD_DEVICE)
 136                 return 0;
 137
 138         /* May need to bounce if the device can't address all of DRAM */
 139         if (dma_get_mask(dev) < lmb_end_of_DRAM())
 140                 set_dma_ops(dev, &swiotlb_dma_ops);
 141
 142         return NOTIFY_DONE;
 143 }
 144
 145 static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
 146         .notifier_call = ppc_swiotlb_bus_notify,
 147         .priority = 0,
 148 };
 149
 150 static struct notifier_block ppc_swiotlb_of_bus_notifier = {
 151         .notifier_call = ppc_swiotlb_bus_notify,
 152         .priority = 0,
 153 };
 154
 155 int __init swiotlb_setup_bus_notifier(void)
 156 {
 157         bus_register_notifier(&platform_bus_type,
 158                               &ppc_swiotlb_plat_bus_notifier);
 159         bus_register_notifier(&of_platform_bus_type,
 160                               &ppc_swiotlb_of_bus_notifier);
 161
 162         return 0;
 163 }