/* * Re-map IO memory to kernel address space so that we can access it. * This is needed for high PCI addresses that aren't mapped in the * 640k-1MB IO memory area on PC's * * (C) Copyright 1995 1996 Linus Torvalds */#include <linux/vmalloc.h>#include <linux/mm.h>#include <linux/sched.h>#include <linux/io.h>#include <linux/export.h>#include <asm/cacheflush.h>#include <asm/pgtable.h> #ifdef CONFIG_HAVE_ARCH_HUGE_VMAPstatic int __read_mostly ioremap_pud_capable;static int __read_mostly ioremap_pmd_capable;static int __read_mostly ioremap_huge_disabled; static int __init set_nohugeiomap(char *str){	ioremap_huge_disabled = 1;	return 0;}early_param("nohugeiomap", set_nohugeiomap); void __init ioremap_huge_init(void){	if (!ioremap_huge_disabled) {		if (arch_ioremap_pud_supported())			ioremap_pud_capable = 1;		if (arch_ioremap_pmd_supported())			ioremap_pmd_capable = 1;	}} static inline int ioremap_pud_enabled(void){	return ioremap_pud_capable;} static inline int ioremap_pmd_enabled(void){	return ioremap_pmd_capable;} #else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */static inline int ioremap_pud_enabled(void) { return 0; }static inline int ioremap_pmd_enabled(void) { return 0; }#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,		unsigned long end, phys_addr_t phys_addr, pgprot_t prot){	pte_t *pte;	u64 pfn; 	pfn = phys_addr >> PAGE_SHIFT;	pte = pte_alloc_kernel(pmd, addr);	if (!pte)		return -ENOMEM;	do {		BUG_ON(!pte_none(*pte));		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));		pfn++;	} while (pte++, addr += PAGE_SIZE, addr != end);	return 0;} static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,		unsigned long end, phys_addr_t phys_addr, pgprot_t prot){	pmd_t *pmd;	unsigned long next; 	phys_addr -= addr;	pmd = pmd_alloc(&init_mm, pud, addr);	if (!pmd)		return -ENOMEM;	do {		next = pmd_addr_end(addr, end); 		if (ioremap_pmd_enabled() &&		    ((next - addr) == PMD_SIZE) &&		    IS_ALIGNED(phys_addr + addr, PMD_SIZE)) {			if (pmd_set_huge(pmd, phys_addr + addr, prot))				continue;		} 		if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))			return -ENOMEM;	} while (pmd++, addr = next, addr != end);	return 0;} static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,		unsigned long end, phys_addr_t phys_addr, pgprot_t prot){	pud_t *pud;	unsigned long next; 	phys_addr -= addr;	pud = pud_alloc(&init_mm, pgd, addr);	if (!pud)		return -ENOMEM;	do {		next = pud_addr_end(addr, end); 		if (ioremap_pud_enabled() &&		    ((next - addr) == PUD_SIZE) &&		    IS_ALIGNED(phys_addr + addr, PUD_SIZE)) {			if (pud_set_huge(pud, phys_addr + addr, prot))				continue;		} 		if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))			return -ENOMEM;	} while (pud++, addr = next, addr != end);	return 0;} int ioremap_page_range(unsigned long addr,		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot){	pgd_t *pgd;	unsigned long start;	unsigned long next;	int err; 	BUG_ON(addr >= end); 	start = addr;	phys_addr -= addr;	pgd = pgd_offset_k(addr);	do {		next = pgd_addr_end(addr, end);		err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);		if (err)			break;	} while (pgd++, addr = next, addr != end); 	flush_cache_vmap(start, end); 	return err;}EXPORT_SYMBOL_GPL(ioremap_page_range);