arch/sparc/mm/generic.c

/*
 * generic.c: Generic Sparc mm routines that are not dependent upon
 *            MMU type but are Sparc specific.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pagemap.h>

#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>

/* Remap IO memory, the same way as remap_pfn_range(), but use
 * the obio memory space.
 *
 * They use a pgprot that sets PAGE_IO and does not check the
 * mem_map table as this is independent of normal memory.
 */
static inline void io_remap_pte_range(struct mm_struct *mm, pte_t * pte, unsigned long address, unsigned long size,
	unsigned long offset, pgprot_t prot, int space)
{
	unsigned long end;

	address &= ~PMD_MASK;
	end = address + size;
	if (end > PMD_SIZE)
		end = PMD_SIZE;
	do {
		set_pte_at(mm, address, pte, mk_pte_io(offset, prot, space));
		address += PAGE_SIZE;
		offset += PAGE_SIZE;
		pte++;
	} while (address < end);
}

static inline int io_remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
	unsigned long offset, pgprot_t prot, int space)
{
	unsigned long end;

	address &= ~PGDIR_MASK;
	end = address + size;
	if (end > PGDIR_SIZE)
		end = PGDIR_SIZE;
	offset -= address;
	do {
		pte_t * pte = pte_alloc_map(mm, pmd, address);
		if (!pte)
			return -ENOMEM;
		io_remap_pte_range(mm, pte, address, end - address, address + offset, prot, space);
		address = (address + PMD_SIZE) & PMD_MASK;
		pmd++;
	} while (address < end);
	return 0;
}

int io_remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
		       unsigned long pfn, unsigned long size, pgprot_t prot)
{
	int error = 0;
	pgd_t * dir;
	unsigned long beg = from;
	unsigned long end = from + size;
	struct mm_struct *mm = vma->vm_mm;
	int space = GET_IOSPACE(pfn);
	unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;

	/* See comment in mm/memory.c remap_pfn_range */
	vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
	vma->vm_pgoff = (offset >> PAGE_SHIFT) |
		((unsigned long)space << 28UL);

	offset -= from;
	dir = pgd_offset(mm, from);
	flush_cache_range(vma, beg, end);

	while (from < end) {
		pmd_t *pmd = pmd_alloc(mm, dir, from);
		error = -ENOMEM;
		if (!pmd)
			break;
		error = io_remap_pmd_range(mm, pmd, from, end - from, offset + from, prot, space);
		if (error)
			break;
		from = (from + PGDIR_SIZE) & PGDIR_MASK;
		dir++;
	}

	flush_tlb_range(vma, beg, end);
	return error;
}