original_kernel/include/asm-arm/arch-ixp4xx/memory.h

/*
 * linux/include/asm-arm/arch-ixp4xx/memory.h
 *
 * Copyright (c) 2001-2004 MontaVista Software, Inc.
 */

#ifndef __ASM_ARCH_MEMORY_H
#define __ASM_ARCH_MEMORY_H

#include <asm/sizes.h>

/*
 * Physical DRAM offset.
 */
#define PHYS_OFFSET	UL(0x00000000)

#ifndef __ASSEMBLY__

/*
 * Only first 64MB of memory can be accessed via PCI.
 * We use GFP_DMA to allocate safe buffers to do map/unmap.
 * This is really ugly and we need a better way of specifying
 * DMA-capable regions of memory.
 */
static inline void __arch_adjust_zones(int node, unsigned long *zone_size, 
	unsigned long *zhole_size) 
{
	unsigned int sz = SZ_64M >> PAGE_SHIFT;

	/*
	 * Only adjust if > 64M on current system
	 */
	if (node || (zone_size[0] <= sz))
		return;

	zone_size[1] = zone_size[0] - sz;
	zone_size[0] = sz;
	zhole_size[1] = zhole_size[0];
	zhole_size[0] = 0;
}

#define arch_adjust_zones(node, size, holes) \
	__arch_adjust_zones(node, size, holes)

#define ISA_DMA_THRESHOLD (SZ_64M - 1)

#endif

/*
 * Virtual view <-> DMA view memory address translations
 * virt_to_bus: Used to translate the virtual address to an
 *		address suitable to be passed to set_dma_addr
 * bus_to_virt: Used to convert an address for DMA operations
 *		to an address that the kernel can use.
 *
 * These are dummies for now.
 */
#define __virt_to_bus(x)	 __virt_to_phys(x)
#define __bus_to_virt(x)	 __phys_to_virt(x)

#endif