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 /*
  28  * Determine if an address is reachable by a pci device, or if we must bounce.
  29  */
  30 static int
  31 swiotlb_pci_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
  32 {
  33         dma_addr_t max;
  34         struct pci_controller *hose;
  35         struct pci_dev *pdev = to_pci_dev(hwdev);
  36
  37         hose = pci_bus_to_host(pdev->bus);
  38         max = hose->dma_window_base_cur + hose->dma_window_size;
  39
  40         /* check that we're within mapped pci window space */
  41         if ((addr + size > max) | (addr < hose->dma_window_base_cur))
  42                 return 1;
  43
  44         return 0;
  45 }
  46
  47 /*
  48  * At the moment, all platforms that use this code only require
  49  * swiotlb to be used if we're operating on HIGHMEM.  Since
  50  * we don't ever call anything other than map_sg, unmap_sg,
  51  * map_page, and unmap_page on highmem, use normal dma_ops
  52  * for everything else.
  53  */
  54 struct dma_mapping_ops swiotlb_dma_ops = {
  55         .alloc_coherent = dma_direct_alloc_coherent,
  56         .free_coherent = dma_direct_free_coherent,
  57         .map_sg = swiotlb_map_sg_attrs,
  58         .unmap_sg = swiotlb_unmap_sg_attrs,
  59         .dma_supported = swiotlb_dma_supported,
  60         .map_page = swiotlb_map_page,
  61         .unmap_page = swiotlb_unmap_page,
  62         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  63         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  64         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  65         .sync_sg_for_device = swiotlb_sync_sg_for_device
  66 };
  67
  68 struct dma_mapping_ops swiotlb_pci_dma_ops = {
  69         .alloc_coherent = dma_direct_alloc_coherent,
  70         .free_coherent = dma_direct_free_coherent,
  71         .map_sg = swiotlb_map_sg_attrs,
  72         .unmap_sg = swiotlb_unmap_sg_attrs,
  73         .dma_supported = swiotlb_dma_supported,
  74         .map_page = swiotlb_map_page,
  75         .unmap_page = swiotlb_unmap_page,
  76         .addr_needs_map = swiotlb_pci_addr_needs_map,
  77         .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
  78         .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
  79         .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  80         .sync_sg_for_device = swiotlb_sync_sg_for_device
  81 };
  82
  83 static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
  84                                   unsigned long action, void *data)
  85 {
  86         struct device *dev = data;
  87
  88         /* We are only intereted in device addition */
  89         if (action != BUS_NOTIFY_ADD_DEVICE)
  90                 return 0;
  91
  92         /* May need to bounce if the device can't address all of DRAM */
  93         if (dma_get_mask(dev) < lmb_end_of_DRAM())
  94                 set_dma_ops(dev, &swiotlb_dma_ops);
  95
  96         return NOTIFY_DONE;
  97 }
  98
  99 static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
 100         .notifier_call = ppc_swiotlb_bus_notify,
 101         .priority = 0,
 102 };
 103
 104 static struct notifier_block ppc_swiotlb_of_bus_notifier = {
 105         .notifier_call = ppc_swiotlb_bus_notify,
 106         .priority = 0,
 107 };
 108
 109 int __init swiotlb_setup_bus_notifier(void)
 110 {
 111         bus_register_notifier(&platform_bus_type,
 112                               &ppc_swiotlb_plat_bus_notifier);
 113         bus_register_notifier(&of_platform_bus_type,
 114                               &ppc_swiotlb_of_bus_notifier);
 115
 116         return 0;
 117 }