target/linux/ixp4xx/patches-2.6.30/050-disable_dmabounce.patch

   1 --- a/arch/arm/Kconfig
   2 +++ b/arch/arm/Kconfig
   3 @@ -375,7 +375,6 @@ config ARCH_IXP4XX
   4         select GENERIC_GPIO
   5         select GENERIC_TIME
   6         select GENERIC_CLOCKEVENTS
   7 -       select DMABOUNCE if PCI
   8         help
   9           Support for Intel's IXP4XX (XScale) family of processors.
  10
  11 --- a/arch/arm/mach-ixp4xx/Kconfig
  12 +++ b/arch/arm/mach-ixp4xx/Kconfig
  13 @@ -193,6 +193,45 @@ config IXP4XX_INDIRECT_PCI
  14           need to use the indirect method instead. If you don't know
  15           what you need, leave this option unselected.
  16
  17 +config IXP4XX_LEGACY_DMABOUNCE
  18 +       bool "legacy PCI DMA bounce support"
  19 +       depends on PCI
  20 +       default n
  21 +       select DMABOUNCE
  22 +       help
  23 +         The IXP4xx is limited to a 64MB window for PCI DMA, which
  24 +         requires that PCI accesses above 64MB are bounced via buffers
  25 +         below 64MB. Furthermore the IXP4xx has an erratum where PCI
  26 +         read prefetches just below the 64MB limit can trigger lockups.
  27 +
  28 +         The kernel has traditionally handled these two issue by using
  29 +         ARM specific DMA bounce support code for all accesses >= 64MB.
  30 +         That code causes problems of its own, so it is desirable to
  31 +         disable it. As the kernel now has a workaround for the PCI read
  32 +         prefetch erratum, it no longer requires the ARM bounce code.
  33 +
  34 +         Enabling this option makes IXP4xx continue to use the problematic
  35 +         ARM DMA bounce code. Disabling this option makes IXP4xx use the
  36 +         kernel's generic bounce code.
  37 +
  38 +         Say 'N'.
  39 +
  40 +config IXP4XX_ZONE_DMA
  41 +       bool "Support > 64MB RAM"
  42 +       depends on !IXP4XX_LEGACY_DMABOUNCE
  43 +       default y
  44 +       select ZONE_DMA
  45 +       help
  46 +         The IXP4xx is limited to a 64MB window for PCI DMA, which
  47 +         requires that PCI accesses above 64MB are bounced via buffers
  48 +         below 64MB.
  49 +
  50 +         Disabling this option allows you to omit the support code for
  51 +         DMA-able memory allocations and DMA bouncing, but the kernel
  52 +         will then not work properly if more than 64MB of RAM is present.
  53 +
  54 +         Say 'Y' unless your platform is limited to <= 64MB of RAM.
  55 +
  56  config IXP4XX_QMGR
  57         tristate "IXP4xx Queue Manager support"
  58         help
  59 --- a/arch/arm/mach-ixp4xx/common-pci.c
  60 +++ b/arch/arm/mach-ixp4xx/common-pci.c
  61 @@ -321,27 +321,38 @@ static int abort_handler(unsigned long a
  62   */
  63  static int ixp4xx_pci_platform_notify(struct device *dev)
  64  {
  65 -       if(dev->bus == &pci_bus_type) {
  66 -               *dev->dma_mask =  SZ_64M - 1;
  67 +       if (dev->bus == &pci_bus_type) {
  68 +               *dev->dma_mask = SZ_64M - 1;
  69                 dev->coherent_dma_mask = SZ_64M - 1;
  70 +#ifdef CONFIG_DMABOUNCE
  71                 dmabounce_register_dev(dev, 2048, 4096);
  72 +#endif
  73         }
  74         return 0;
  75  }
  76
  77  static int ixp4xx_pci_platform_notify_remove(struct device *dev)
  78  {
  79 -       if(dev->bus == &pci_bus_type) {
  80 +#ifdef CONFIG_DMABOUNCE
  81 +       if (dev->bus == &pci_bus_type)
  82                 dmabounce_unregister_dev(dev);
  83 -       }
  84 +#endif
  85         return 0;
  86  }
  87
  88 +#ifdef CONFIG_DMABOUNCE
  89  int dma_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
  90  {
  91 +       /* Note that this returns true for the last page below 64M due to
  92 +        * IXP4xx erratum 15 (SCR 1289), which states that PCI prefetches
  93 +        * can cross the boundary between valid memory and a reserved region
  94 +        * causing AHB bus errors and a lock-up.
  95 +        */
  96         return (dev->bus == &pci_bus_type ) && ((dma_addr + size) >= SZ_64M);
  97  }
  98 +#endif
  99
 100 +#ifdef CONFIG_ZONE_DMA
 101  /*
 102   * Only first 64MB of memory can be accessed via PCI.
 103   * We use GFP_DMA to allocate safe buffers to do map/unmap.
 104 @@ -364,6 +375,7 @@ void __init ixp4xx_adjust_zones(int node
 105         zhole_size[1] = zhole_size[0];
 106         zhole_size[0] = 0;
 107  }
 108 +#endif
 109
 110  void __init ixp4xx_pci_preinit(void)
 111  {
 112 @@ -517,19 +529,35 @@ struct pci_bus * __devinit ixp4xx_scan_b
 113  int
 114  pci_set_dma_mask(struct pci_dev *dev, u64 mask)
 115  {
 116 -       if (mask >= SZ_64M - 1 )
 117 +#ifdef CONFIG_DMABOUNCE
 118 +       if (mask >= SZ_64M - 1)
 119                 return 0;
 120
 121         return -EIO;
 122 +#else
 123 +       /* Only honour masks < SZ_64M. Silently ignore masks >= SZ_64M
 124 +          as generic drivers do not know about IXP4xx PCI DMA quirks. */
 125 +       if (mask < SZ_64M)
 126 +               dev->dma_mask = mask;
 127 +       return 0;
 128 +#endif
 129  }
 130
 131  int
 132  pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
 133  {
 134 -       if (mask >= SZ_64M - 1 )
 135 +#ifdef CONFIG_DMABOUNCE
 136 +       if (mask >= SZ_64M - 1)
 137                 return 0;
 138
 139         return -EIO;
 140 +#else
 141 +       /* Only honour masks < SZ_64M. Silently ignore masks >= SZ_64M
 142 +          as generic drivers do not know about IXP4xx PCI DMA quirks. */
 143 +       if (mask < SZ_64M)
 144 +               dev->dev.coherent_dma_mask = mask;
 145 +       return 0;
 146 +#endif
 147  }
 148
 149  EXPORT_SYMBOL(ixp4xx_pci_read);
 150 --- a/arch/arm/mach-ixp4xx/include/mach/memory.h
 151 +++ b/arch/arm/mach-ixp4xx/include/mach/memory.h
 152 @@ -16,10 +16,12 @@
 153
 154  #if !defined(__ASSEMBLY__) && defined(CONFIG_PCI)
 155
 156 +#ifdef CONFIG_ZONE_DMA
 157  void ixp4xx_adjust_zones(int node, unsigned long *size, unsigned long *holes);
 158
 159  #define arch_adjust_zones(node, size, holes) \
 160         ixp4xx_adjust_zones(node, size, holes)
 161 +#endif
 162
 163  #define ISA_DMA_THRESHOLD (SZ_64M - 1)
 164  #define MAX_DMA_ADDRESS                (PAGE_OFFSET + SZ_64M)