Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
		
			
				
	
	
		
			263 lines
		
	
	
	
		
			8.9 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			263 lines
		
	
	
	
		
			8.9 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 *  linux/arch/cris/arch-v10/mm/init.c
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 *
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 */
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#include <linux/mmzone.h>
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#include <linux/init.h>
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#include <linux/bootmem.h>
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#include <linux/mm.h>
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#include <asm/pgtable.h>
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#include <asm/page.h>
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#include <asm/types.h>
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#include <asm/mmu.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <arch/svinto.h>
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extern void tlb_init(void);
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/*
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 * The kernel is already mapped with a kernel segment at kseg_c so 
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 * we don't need to map it with a page table. However head.S also
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 * temporarily mapped it at kseg_4 so we should set up the ksegs again,
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 * clear the TLB and do some other paging setup stuff.
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 */
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void __init 
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paging_init(void)
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{
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	int i;
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	unsigned long zones_size[MAX_NR_ZONES];
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	printk("Setting up paging and the MMU.\n");
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	/* clear out the init_mm.pgd that will contain the kernel's mappings */
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	for(i = 0; i < PTRS_PER_PGD; i++)
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		swapper_pg_dir[i] = __pgd(0);
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	/* make sure the current pgd table points to something sane
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	 * (even if it is most probably not used until the next 
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	 *  switch_mm)
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	 */
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	per_cpu(current_pgd, smp_processor_id()) = init_mm.pgd;
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	/* initialise the TLB (tlb.c) */
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	tlb_init();
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	/* see README.mm for details on the KSEG setup */
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#ifdef CONFIG_CRIS_LOW_MAP
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	/* Etrax-100 LX version 1 has a bug so that we cannot map anything
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	 * across the 0x80000000 boundary, so we need to shrink the user-virtual
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	 * area to 0x50000000 instead of 0xb0000000 and map things slightly
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	 * different. The unused areas are marked as paged so that we can catch
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	 * freak kernel accesses there.
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	 *
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	 * The ARTPEC chip is mapped at 0xa so we pass that segment straight
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	 * through. We cannot vremap it because the vmalloc area is below 0x8
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	 * and Juliette needs an uncached area above 0x8.
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	 *
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	 * Same thing with 0xc and 0x9, which is memory-mapped I/O on some boards.
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	 * We map them straight over in LOW_MAP, but use vremap in LX version 2.
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	 */
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#define CACHED_BOOTROM (KSEG_F | 0x08000000UL)
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	*R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, seg  ) |  /* bootrom */
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			IO_STATE(R_MMU_KSEG, seg_e, page ) |
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			IO_STATE(R_MMU_KSEG, seg_d, page ) | 
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			IO_STATE(R_MMU_KSEG, seg_c, page ) |   
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			IO_STATE(R_MMU_KSEG, seg_b, seg  ) |  /* kernel reg area */
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#ifdef CONFIG_JULIETTE
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			IO_STATE(R_MMU_KSEG, seg_a, seg  ) |  /* ARTPEC etc. */
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#else
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			IO_STATE(R_MMU_KSEG, seg_a, page ) |
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#endif
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			IO_STATE(R_MMU_KSEG, seg_9, seg  ) |  /* LED's on some boards */
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			IO_STATE(R_MMU_KSEG, seg_8, seg  ) |  /* CSE0/1, flash and I/O */
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			IO_STATE(R_MMU_KSEG, seg_7, page ) |  /* kernel vmalloc area */
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			IO_STATE(R_MMU_KSEG, seg_6, seg  ) |  /* kernel DRAM area */
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			IO_STATE(R_MMU_KSEG, seg_5, seg  ) |  /* cached flash */
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			IO_STATE(R_MMU_KSEG, seg_4, page ) |  /* user area */
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			IO_STATE(R_MMU_KSEG, seg_3, page ) |  /* user area */
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			IO_STATE(R_MMU_KSEG, seg_2, page ) |  /* user area */
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			IO_STATE(R_MMU_KSEG, seg_1, page ) |  /* user area */
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			IO_STATE(R_MMU_KSEG, seg_0, page ) ); /* user area */
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	*R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x3 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_e, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_c, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
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#ifdef CONFIG_JULIETTE
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			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0xa ) |
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#else
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			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0x0 ) |
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#endif
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			    IO_FIELD(R_MMU_KBASE_HI, base_9, 0x9 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_8, 0x8 ) );
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	*R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_6, 0x4 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
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#else
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	/* This code is for the corrected Etrax-100 LX version 2... */
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#define CACHED_BOOTROM (KSEG_A | 0x08000000UL)
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	*R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, seg  ) | /* cached flash */
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			IO_STATE(R_MMU_KSEG, seg_e, seg  ) | /* uncached flash */
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			IO_STATE(R_MMU_KSEG, seg_d, page ) | /* vmalloc area */
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			IO_STATE(R_MMU_KSEG, seg_c, seg  ) | /* kernel area */
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			IO_STATE(R_MMU_KSEG, seg_b, seg  ) | /* kernel reg area */
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			IO_STATE(R_MMU_KSEG, seg_a, seg  ) | /* bootrom */
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			IO_STATE(R_MMU_KSEG, seg_9, page ) | /* user area */
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			IO_STATE(R_MMU_KSEG, seg_8, page ) |
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			IO_STATE(R_MMU_KSEG, seg_7, page ) |
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			IO_STATE(R_MMU_KSEG, seg_6, page ) |
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			IO_STATE(R_MMU_KSEG, seg_5, page ) |
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			IO_STATE(R_MMU_KSEG, seg_4, page ) |
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			IO_STATE(R_MMU_KSEG, seg_3, page ) |
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			IO_STATE(R_MMU_KSEG, seg_2, page ) |
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			IO_STATE(R_MMU_KSEG, seg_1, page ) |
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			IO_STATE(R_MMU_KSEG, seg_0, page ) );
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	*R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_e, 0x8 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_c, 0x4 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_b, 0xb ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_a, 0x3 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_9, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_HI, base_8, 0x0 ) );
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	*R_MMU_KBASE_LO = ( IO_FIELD(R_MMU_KBASE_LO, base_7, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_6, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_5, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_4, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_3, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_2, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_1, 0x0 ) |
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			    IO_FIELD(R_MMU_KBASE_LO, base_0, 0x0 ) );
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#endif
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	*R_MMU_CONTEXT = ( IO_FIELD(R_MMU_CONTEXT, page_id, 0 ) );
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	/* The MMU has been enabled ever since head.S but just to make
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	 * it totally obvious we do it here as well.
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	 */
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	*R_MMU_CTRL = ( IO_STATE(R_MMU_CTRL, inv_excp, enable ) |
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			IO_STATE(R_MMU_CTRL, acc_excp, enable ) |
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			IO_STATE(R_MMU_CTRL, we_excp,  enable ) );
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	*R_MMU_ENABLE = IO_STATE(R_MMU_ENABLE, mmu_enable, enable);
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	/*
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	 * initialize the bad page table and bad page to point
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	 * to a couple of allocated pages
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	 */
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	empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
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	memset((void *)empty_zero_page, 0, PAGE_SIZE);
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	/* All pages are DMA'able in Etrax, so put all in the DMA'able zone */
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	zones_size[0] = ((unsigned long)high_memory - PAGE_OFFSET) >> PAGE_SHIFT;
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	for (i = 1; i < MAX_NR_ZONES; i++)
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		zones_size[i] = 0;
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	/* Use free_area_init_node instead of free_area_init, because the former
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	 * is designed for systems where the DRAM starts at an address substantially
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	 * higher than 0, like us (we start at PAGE_OFFSET). This saves space in the
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	 * mem_map page array.
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	 */
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	free_area_init_node(0, zones_size, PAGE_OFFSET >> PAGE_SHIFT, 0);
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}
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/* Initialize remaps of some I/O-ports. It is important that this
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 * is called before any driver is initialized.
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 */
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static int
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__init init_ioremap(void)
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{
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	/* Give the external I/O-port addresses their values */
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#ifdef CONFIG_CRIS_LOW_MAP
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	/* Simply a linear map (see the KSEG map above in paging_init) */
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	port_cse1_addr = (volatile unsigned long *)(MEM_CSE1_START | 
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	                                            MEM_NON_CACHEABLE);
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	port_csp0_addr = (volatile unsigned long *)(MEM_CSP0_START |
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	                                            MEM_NON_CACHEABLE);
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	port_csp4_addr = (volatile unsigned long *)(MEM_CSP4_START |
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	                                            MEM_NON_CACHEABLE);
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#else
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	/* Note that nothing blows up just because we do this remapping 
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	 * it's ok even if the ports are not used or connected 
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	 * to anything (or connected to a non-I/O thing) */        
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	port_cse1_addr = (volatile unsigned long *)
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	  ioremap((unsigned long)(MEM_CSE1_START | MEM_NON_CACHEABLE), 16);
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	port_csp0_addr = (volatile unsigned long *)
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	  ioremap((unsigned long)(MEM_CSP0_START | MEM_NON_CACHEABLE), 16);
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	port_csp4_addr = (volatile unsigned long *)
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	  ioremap((unsigned long)(MEM_CSP4_START | MEM_NON_CACHEABLE), 16);
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#endif	
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	return 0;
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}
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__initcall(init_ioremap);
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/* Helper function for the two below */
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static inline void
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flush_etrax_cacherange(void *startadr, int length)
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{
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	/* CACHED_BOOTROM is mapped to the boot-rom area (cached) which
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	 * we can use to get fast dummy-reads of cachelines
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	 */
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	volatile short *flushadr = (volatile short *)(((unsigned long)startadr & ~PAGE_MASK) |
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						      CACHED_BOOTROM);
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	length = length > 8192 ? 8192 : length;  /* No need to flush more than cache size */
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	while(length > 0) {
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		*flushadr; /* dummy read to flush */
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		flushadr += (32/sizeof(short));  /* a cacheline is 32 bytes */
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		length -= 32;
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	}
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}
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/* Due to a bug in Etrax100(LX) all versions, receiving DMA buffers
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 * will occasionally corrupt certain CPU writes if the DMA buffers
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 * happen to be hot in the cache.
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 * 
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 * As a workaround, we have to flush the relevant parts of the cache
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 * before (re) inserting any receiving descriptor into the DMA HW.
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 */
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void
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prepare_rx_descriptor(struct etrax_dma_descr *desc)
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{
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	flush_etrax_cacherange((void *)desc->buf, desc->sw_len ? desc->sw_len : 65536);
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}
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/* Do the same thing but flush the entire cache */
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void
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flush_etrax_cache(void)
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{
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	flush_etrax_cacherange(0, 8192);
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}
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