m68k: ColdFire V4e MMU paging init code and miss handler

	__asm__ __volatile__ ("nop");

}

int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word);

#endif

#endif	/* MCFMMU_H */

/*

 * Based upon linux/arch/m68k/mm/sun3mmu.c

 * Based upon linux/arch/ppc/mm/mmu_context.c

 *

 * Implementations of mm routines specific to the Coldfire MMU.

 *

 * Copyright (c) 2008 Freescale Semiconductor, Inc.

 */

#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/mm.h>

#include <linux/init.h>

#include <linux/string.h>

#include <linux/bootmem.h>

#include <asm/setup.h>

#include <asm/page.h>

#include <asm/pgtable.h>

#include <asm/mmu_context.h>

#include <asm/mcf_pgalloc.h>

#include <asm/tlbflush.h>

#define KMAPAREA(x)	((x >= VMALLOC_START) && (x < KMAP_END))

mm_context_t next_mmu_context;

unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];

atomic_t nr_free_contexts;

struct mm_struct *context_mm[LAST_CONTEXT+1];

extern unsigned long num_pages;

void free_initmem(void)

{

}

/*

 * ColdFire paging_init derived from sun3.

 */

void __init paging_init(void)

{

	pgd_t *pg_dir;

	pte_t *pg_table;

	unsigned long address, size;

	unsigned long next_pgtable, bootmem_end;

	unsigned long zones_size[MAX_NR_ZONES];

	enum zone_type zone;

	int i;

	empty_zero_page = (void *) alloc_bootmem_pages(PAGE_SIZE);

	memset((void *) empty_zero_page, 0, PAGE_SIZE);

	pg_dir = swapper_pg_dir;

	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

	size = num_pages * sizeof(pte_t);

	size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);

	next_pgtable = (unsigned long) alloc_bootmem_pages(size);

	bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;

	pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;

	address = PAGE_OFFSET;

	while (address < (unsigned long)high_memory) {

		pg_table = (pte_t *) next_pgtable;

		next_pgtable += PTRS_PER_PTE * sizeof(pte_t);

		pgd_val(*pg_dir) = (unsigned long) pg_table;

		pg_dir++;

		/* now change pg_table to kernel virtual addresses */

		for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {

			pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);

			if (address >= (unsigned long) high_memory)

				pte_val(pte) = 0;

			set_pte(pg_table, pte);

			address += PAGE_SIZE;

		}

	}

	current->mm = NULL;

	for (zone = 0; zone < MAX_NR_ZONES; zone++)

		zones_size[zone] = 0x0;

	zones_size[ZONE_DMA] = num_pages;

	free_area_init(zones_size);

}

int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)

{

	unsigned long flags, mmuar;

	struct mm_struct *mm;

	pgd_t *pgd;

	pmd_t *pmd;

	pte_t *pte;

	int asid;

	local_irq_save(flags);

	mmuar = (dtlb) ? mmu_read(MMUAR) :

		regs->pc + (extension_word * sizeof(long));

	mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;

	if (!mm) {

		local_irq_restore(flags);

		return -1;

	}

	pgd = pgd_offset(mm, mmuar);

	if (pgd_none(*pgd))  {

		local_irq_restore(flags);

		return -1;

	}

	pmd = pmd_offset(pgd, mmuar);

	if (pmd_none(*pmd)) {

		local_irq_restore(flags);

		return -1;

	}

	pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)

				: pte_offset_map(pmd, mmuar);

	if (pte_none(*pte) || !pte_present(*pte)) {

		local_irq_restore(flags);

		return -1;

	}

	if (write) {

		if (!pte_write(*pte)) {

			local_irq_restore(flags);

			return -1;

		}

		set_pte(pte, pte_mkdirty(*pte));

	}

	set_pte(pte, pte_mkyoung(*pte));

	asid = mm->context & 0xff;

	if (!pte_dirty(*pte) && !KMAPAREA(mmuar))

		set_pte(pte, pte_wrprotect(*pte));

	mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |

		(((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)

		>> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);

	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |

		((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);

	if (dtlb)

		mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);

	else

		mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);

	local_irq_restore(flags);

	return 0;

}

/*

 * Initialize the context management stuff.

 * The following was taken from arch/ppc/mmu_context.c

 */

void __init mmu_context_init(void)

{

	/*

	 * Some processors have too few contexts to reserve one for

	 * init_mm, and require using context 0 for a normal task.

	 * Other processors reserve the use of context zero for the kernel.

	 * This code assumes FIRST_CONTEXT < 32.

	 */

	context_map[0] = (1 << FIRST_CONTEXT) - 1;

	next_mmu_context = FIRST_CONTEXT;

	atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);

}

/*

 * Steal a context from a task that has one at the moment.

 * This is only used on 8xx and 4xx and we presently assume that

 * they don't do SMP.  If they do then thicfpgalloc.hs will have to check

 * whether the MM we steal is in use.

 * We also assume that this is only used on systems that don't

 * use an MMU hash table - this is true for 8xx and 4xx.

 * This isn't an LRU system, it just frees up each context in

 * turn (sort-of pseudo-random replacement :).  This would be the

 * place to implement an LRU scheme if anyone was motivated to do it.

 *  -- paulus

 */

void steal_context(void)

{

	struct mm_struct *mm;

	/*

	 * free up context `next_mmu_context'

	 * if we shouldn't free context 0, don't...

	 */

	if (next_mmu_context < FIRST_CONTEXT)

		next_mmu_context = FIRST_CONTEXT;

	mm = context_mm[next_mmu_context];

	flush_tlb_mm(mm);

	destroy_context(mm);

}