arch/powerpc/kernel/dma-swiotlb.c

   1 /*
   2  * Contains routines needed to support swiotlb for ppc.
   3  *
   4  * Copyright (C) 2009-2010 Freescale Semiconductor, Inc.
   5  * Author: Becky Bruce
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  */
  13
  14 #include <linux/dma-direct.h>
  15 #include <linux/memblock.h>
  16 #include <linux/pfn.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pci.h>
  20
  21 #include <asm/machdep.h>
  22 #include <asm/swiotlb.h>
  23 #include <asm/dma.h>
  24
  25 unsigned int ppc_swiotlb_enable;
  26
  27 static u64 swiotlb_powerpc_get_required(struct device *dev)
  28 {
  29         u64 end, mask, max_direct_dma_addr = dev->archdata.max_direct_dma_addr;
  30
  31         end = memblock_end_of_DRAM();
  32         if (max_direct_dma_addr && end > max_direct_dma_addr)
  33                 end = max_direct_dma_addr;
  34         end += get_dma_offset(dev);
  35
  36         mask = 1ULL << (fls64(end) - 1);
  37         mask += mask - 1;
  38
  39         return mask;
  40 }
  41
  42 /*
  43  * At the moment, all platforms that use this code only require
  44  * swiotlb to be used if we're operating on HIGHMEM.  Since
  45  * we don't ever call anything other than map_sg, unmap_sg,
  46  * map_page, and unmap_page on highmem, use normal dma_ops
  47  * for everything else.
  48  */
  49 const struct dma_map_ops powerpc_swiotlb_dma_ops = {
  50         .alloc = __dma_nommu_alloc_coherent,
  51         .free = __dma_nommu_free_coherent,
  52         .mmap = dma_nommu_mmap_coherent,
  53         .map_sg = dma_direct_map_sg,
  54         .unmap_sg = dma_direct_unmap_sg,
  55         .dma_supported = swiotlb_dma_supported,
  56         .map_page = dma_direct_map_page,
  57         .unmap_page = dma_direct_unmap_page,
  58         .sync_single_for_cpu = dma_direct_sync_single_for_cpu,
  59         .sync_single_for_device = dma_direct_sync_single_for_device,
  60         .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
  61         .sync_sg_for_device = dma_direct_sync_sg_for_device,
  62         .get_required_mask = swiotlb_powerpc_get_required,
  63 };
  64
  65 void pci_dma_dev_setup_swiotlb(struct pci_dev *pdev)
  66 {
  67         struct pci_controller *hose;
  68         struct dev_archdata *sd;
  69
  70         hose = pci_bus_to_host(pdev->bus);
  71         sd = &pdev->dev.archdata;
  72         sd->max_direct_dma_addr =
  73                 hose->dma_window_base_cur + hose->dma_window_size;
  74 }
  75
  76 static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
  77                                   unsigned long action, void *data)
  78 {
  79         struct device *dev = data;
  80         struct dev_archdata *sd;
  81
  82         /* We are only intereted in device addition */
  83         if (action != BUS_NOTIFY_ADD_DEVICE)
  84                 return 0;
  85
  86         sd = &dev->archdata;
  87         sd->max_direct_dma_addr = 0;
  88
  89         /* May need to bounce if the device can't address all of DRAM */
  90         if ((dma_get_mask(dev) + 1) < memblock_end_of_DRAM())
  91                 set_dma_ops(dev, &powerpc_swiotlb_dma_ops);
  92
  93         return NOTIFY_DONE;
  94 }
  95
  96 static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
  97         .notifier_call = ppc_swiotlb_bus_notify,
  98         .priority = 0,
  99 };
 100
 101 int __init swiotlb_setup_bus_notifier(void)
 102 {
 103         bus_register_notifier(&platform_bus_type,
 104                               &ppc_swiotlb_plat_bus_notifier);
 105         return 0;
 106 }
 107
 108 void __init swiotlb_detect_4g(void)
 109 {
 110         if ((memblock_end_of_DRAM() - 1) > 0xffffffff)
 111                 ppc_swiotlb_enable = 1;
 112 }
 113
 114 static int __init check_swiotlb_enabled(void)
 115 {
 116         if (ppc_swiotlb_enable)
 117                 swiotlb_print_info();
 118         else
 119                 swiotlb_exit();
 120
 121         return 0;
 122 }
 123 subsys_initcall(check_swiotlb_enabled);