LXR linux/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-mapping.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
  25unsigned int ppc_swiotlb_enable;
  26
  27static 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 */
  49struct dma_map_ops swiotlb_dma_ops = {
  50        .alloc = dma_direct_alloc_coherent,
  51        .free = dma_direct_free_coherent,
  52        .mmap = dma_direct_mmap_coherent,
  53        .map_sg = swiotlb_map_sg_attrs,
  54        .unmap_sg = swiotlb_unmap_sg_attrs,
  55        .dma_supported = swiotlb_dma_supported,
  56        .map_page = swiotlb_map_page,
  57        .unmap_page = swiotlb_unmap_page,
  58        .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  59        .sync_single_for_device = swiotlb_sync_single_for_device,
  60        .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  61        .sync_sg_for_device = swiotlb_sync_sg_for_device,
  62        .mapping_error = swiotlb_dma_mapping_error,
  63        .get_required_mask = swiotlb_powerpc_get_required,
  64};
  65
  66void pci_dma_dev_setup_swiotlb(struct pci_dev *pdev)
  67{
  68        struct pci_controller *hose;
  69        struct dev_archdata *sd;
  70
  71        hose = pci_bus_to_host(pdev->bus);
  72        sd = &pdev->dev.archdata;
  73        sd->max_direct_dma_addr =
  74                hose->dma_window_base_cur + hose->dma_window_size;
  75}
  76
  77static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
  78                                  unsigned long action, void *data)
  79{
  80        struct device *dev = data;
  81        struct dev_archdata *sd;
  82
  83        /* We are only intereted in device addition */
  84        if (action != BUS_NOTIFY_ADD_DEVICE)
  85                return 0;
  86
  87        sd = &dev->archdata;
  88        sd->max_direct_dma_addr = 0;
  89
  90        /* May need to bounce if the device can't address all of DRAM */
  91        if ((dma_get_mask(dev) + 1) < memblock_end_of_DRAM())
  92                set_dma_ops(dev, &swiotlb_dma_ops);
  93
  94        return NOTIFY_DONE;
  95}
  96
  97static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
  98        .notifier_call = ppc_swiotlb_bus_notify,
  99        .priority = 0,
 100};
 101
 102int __init swiotlb_setup_bus_notifier(void)
 103{
 104        bus_register_notifier(&platform_bus_type,
 105                              &ppc_swiotlb_plat_bus_notifier);
 106        return 0;
 107}
 108
 109void swiotlb_detect_4g(void)
 110{
 111        if ((memblock_end_of_DRAM() - 1) > 0xffffffff)
 112                ppc_swiotlb_enable = 1;
 113}
 114
 115static int __init swiotlb_late_init(void)
 116{
 117        if (ppc_swiotlb_enable) {
 118                swiotlb_print_info();
 119                set_pci_dma_ops(&swiotlb_dma_ops);
 120                ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_swiotlb;
 121        } else {
 122                swiotlb_free();
 123        }
 124
 125        return 0;
 126}
 127subsys_initcall(swiotlb_late_init);
 128