openwrt-xburst/target/linux/ixp4xx/patches-2.6.36/050-disable_dmabounce.patch

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -435,7 +435,6 @@ config ARCH_IXP4XX
 	select CPU_XSCALE
 	select GENERIC_GPIO
 	select GENERIC_CLOCKEVENTS
-	select DMABOUNCE if PCI
 	help
 	  Support for Intel's IXP4XX (XScale) family of processors.
 
--- a/arch/arm/mach-ixp4xx/Kconfig
+++ b/arch/arm/mach-ixp4xx/Kconfig
@@ -199,6 +199,43 @@ config IXP4XX_INDIRECT_PCI
 	  need to use the indirect method instead. If you don't know
 	  what you need, leave this option unselected.
 
+config IXP4XX_LEGACY_DMABOUNCE
+	bool "Legacy PCI DMA bounce support"
+	depends on PCI
+	default n
+	select DMABOUNCE
+	help
+	  The IXP4xx is limited to a 64MB window for PCI DMA, which
+	  requires that PCI accesses >= 64MB are bounced via buffers
+	  below 64MB.
+
+	  The kernel has traditionally handled this issue by using ARM
+	  specific DMA bounce support code for all accesses >= 64MB.
+	  That code causes problems of its own, so it is desirable to
+	  disable it.
+
+	  Enabling this option makes IXP4xx continue to use the problematic
+	  ARM DMA bounce code. Disabling this option makes IXP4xx use the
+	  kernel's generic bounce code.
+
+	  Say 'N'.
+
+config IXP4XX_ZONE_DMA
+	bool "Support > 64MB RAM"
+	depends on !IXP4XX_LEGACY_DMABOUNCE
+	default y
+	select ZONE_DMA
+	help
+	  The IXP4xx is limited to a 64MB window for PCI DMA, which
+	  requires that PCI accesses above 64MB are bounced via buffers
+	  below 64MB.
+
+	  Disabling this option allows you to omit the support code for
+	  DMA-able memory allocations and DMA bouncing, but the kernel
+	  will then not work properly if more than 64MB of RAM is present.
+
+	  Say 'Y' unless your platform is limited to <= 64MB of RAM.
+
 config IXP4XX_QMGR
 	tristate "IXP4xx Queue Manager support"
 	help
--- a/arch/arm/mach-ixp4xx/common-pci.c
+++ b/arch/arm/mach-ixp4xx/common-pci.c
@@ -321,27 +321,33 @@ static int abort_handler(unsigned long a
  */
 static int ixp4xx_pci_platform_notify(struct device *dev)
 {
-	if(dev->bus == &pci_bus_type) {
-		*dev->dma_mask =  SZ_64M - 1;
+	if (dev->bus == &pci_bus_type) {
+		*dev->dma_mask = SZ_64M - 1;
 		dev->coherent_dma_mask = SZ_64M - 1;
+#ifdef CONFIG_DMABOUNCE
 		dmabounce_register_dev(dev, 2048, 4096);
+#endif
 	}
 	return 0;
 }
 
 static int ixp4xx_pci_platform_notify_remove(struct device *dev)
 {
-	if(dev->bus == &pci_bus_type) {
+#ifdef CONFIG_DMABOUNCE
+	if (dev->bus == &pci_bus_type)
 		dmabounce_unregister_dev(dev);
-	}
+#endif
 	return 0;
 }
 
-int dma_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
+#ifdef CONFIG_DMABOUNCE
+int dma_needs_bounce_2(struct device *dev, dma_addr_t dma_addr, size_t size)
 {
-	return (dev->bus == &pci_bus_type ) && ((dma_addr + size) >= SZ_64M);
+	return (dev->bus == &pci_bus_type ) && ((dma_addr + size) > SZ_64M);
 }
+#endif
 
+#ifdef CONFIG_ZONE_DMA
 /*
  * Only first 64MB of memory can be accessed via PCI.
  * We use GFP_DMA to allocate safe buffers to do map/unmap.
@@ -364,6 +370,7 @@ void __init ixp4xx_adjust_zones(unsigned
 	zhole_size[1] = zhole_size[0];
 	zhole_size[0] = 0;
 }
+#endif
 
 void __init ixp4xx_pci_preinit(void)
 {
--- a/arch/arm/mach-ixp4xx/include/mach/memory.h
+++ b/arch/arm/mach-ixp4xx/include/mach/memory.h
@@ -16,10 +16,12 @@
 
 #if !defined(__ASSEMBLY__) && defined(CONFIG_PCI)
 
+#ifdef CONFIG_ZONE_DMA
 void ixp4xx_adjust_zones(unsigned long *size, unsigned long *holes);
 
 #define arch_adjust_zones(size, holes) \
 	ixp4xx_adjust_zones(size, holes)
+#endif
 
 #define ISA_DMA_THRESHOLD (SZ_64M - 1)
 #define MAX_DMA_ADDRESS		(PAGE_OFFSET + SZ_64M)
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -30,6 +30,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
 #include <linux/list.h>
+#include <linux/pci.h>
 #include <linux/scatterlist.h>
 
 #include <asm/cacheflush.h>
@@ -248,7 +249,13 @@ static inline dma_addr_t map_single(stru
 		needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
 	}
 
-	if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
+#ifdef CONFIG_DMABOUNCE
+int dma_needs_bounce_2(struct device *dev, dma_addr_t dma_addr, size_t size)
+{
+	return (dev->bus == &pci_bus_type ) && ((dma_addr + size) > SZ_64M);
+}
+
+	if (device_info && (needs_bounce || dma_needs_bounce_2(dev, dma_addr, size))) {
 		struct safe_buffer *buf;
 
 		buf = alloc_safe_buffer(device_info, ptr, size, dir);
@@ -282,6 +289,7 @@ static inline dma_addr_t map_single(stru
 
 	return dma_addr;
 }
+#endif
 
 static inline void unmap_single(struct device *dev, dma_addr_t dma_addr,
 		size_t size, enum dma_data_direction dir)