arch/i386/mm/ioremap.c - kernel/msm - Gitiles

 /*
  * arch/i386/mm/ioremap.c
  *
  * 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/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <asm/io.h>
 #include <asm/fixmap.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 #include <asm/pgtable.h>

 #define ISA_START_ADDRESS	0xa0000
 #define ISA_END_ADDRESS		0x100000

 static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
 		unsigned long end, unsigned long phys_addr, unsigned long flags)
 {
 	pte_t *pte;
 	unsigned long pfn;

 	pfn = phys_addr >> PAGE_SHIFT;
 	pte = pte_alloc_kernel(&init_mm, pmd, addr);
 	if (!pte)
 		return -ENOMEM;
 	do {
 		BUG_ON(!pte_none(*pte));
 		set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW |
 					_PAGE_DIRTY | _PAGE_ACCESSED | flags)));
 		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, unsigned long phys_addr, unsigned long flags)
 {
 	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_pte_range(pmd, addr, next, phys_addr + addr, flags))
 			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, unsigned long phys_addr, unsigned long flags)
 {
 	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_pmd_range(pud, addr, next, phys_addr + addr, flags))
 			return -ENOMEM;
 	} while (pud++, addr = next, addr != end);
 	return 0;
 }

 static int ioremap_page_range(unsigned long addr,
 		unsigned long end, unsigned long phys_addr, unsigned long flags)
 {
 	pgd_t *pgd;
 	unsigned long next;
 	int err;

 	BUG_ON(addr >= end);
 	flush_cache_all();
 	phys_addr -= addr;
 	pgd = pgd_offset_k(addr);
 	spin_lock(&init_mm.page_table_lock);
 	do {
 		next = pgd_addr_end(addr, end);
 		err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags);
 		if (err)
 			break;
 	} while (pgd++, addr = next, addr != end);
 	spin_unlock(&init_mm.page_table_lock);
 	flush_tlb_all();
 	return err;
 }

 /*
  * Generic mapping function (not visible outside):
  */

 /*
  * Remap an arbitrary physical address space into the kernel virtual
  * address space. Needed when the kernel wants to access high addresses
  * directly.
  *
  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  * have to convert them into an offset in a page-aligned mapping, but the
  * caller shouldn't need to know that small detail.
  */
 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 {
 	void __iomem * addr;
 	struct vm_struct * area;
 	unsigned long offset, last_addr;

 	/* Don't allow wraparound or zero size */
 	last_addr = phys_addr + size - 1;
 	if (!size || last_addr < phys_addr)
 		return NULL;

 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
 	 */
 	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
 		return (void __iomem *) phys_to_virt(phys_addr);

 	/*
 	 * Don't allow anybody to remap normal RAM that we're using..
 	 */
 	if (phys_addr <= virt_to_phys(high_memory - 1)) {
 		char *t_addr, *t_end;
 		struct page *page;

 		t_addr = __va(phys_addr);
 		t_end = t_addr + (size - 1);

 		for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 			if(!PageReserved(page))
 				return NULL;
 	}

 	/*
 	 * Mappings have to be page-aligned
 	 */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;
 	size = PAGE_ALIGN(last_addr+1) - phys_addr;

 	/*
 	 * Ok, go for it..
 	 */
 	area = get_vm_area(size, VM_IOREMAP | (flags << 20));
 	if (!area)
 		return NULL;
 	area->phys_addr = phys_addr;
 	addr = (void __iomem *) area->addr;
 	if (ioremap_page_range((unsigned long) addr,
 			(unsigned long) addr + size, phys_addr, flags)) {
 		vunmap((void __force *) addr);
 		return NULL;
 	}
 	return (void __iomem *) (offset + (char __iomem *)addr);
 }
 EXPORT_SYMBOL(__ioremap);

 /**
  * ioremap_nocache     -   map bus memory into CPU space
  * @offset:    bus address of the memory
  * @size:      size of the resource to map
  *
  * ioremap_nocache performs a platform specific sequence of operations to
  * make bus memory CPU accessible via the readb/readw/readl/writeb/
  * writew/writel functions and the other mmio helpers. The returned
  * address is not guaranteed to be usable directly as a virtual
  * address.
  *
  * This version of ioremap ensures that the memory is marked uncachable
  * on the CPU as well as honouring existing caching rules from things like
  * the PCI bus. Note that there are other caches and buffers on many
  * busses. In particular driver authors should read up on PCI writes
  *
  * It's useful if some control registers are in such an area and
  * write combining or read caching is not desirable:
  *
  * Must be freed with iounmap.
  */

 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
 {
 	unsigned long last_addr;
 	void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
 	if (!p)
 		return p;

 	/* Guaranteed to be > phys_addr, as per __ioremap() */
 	last_addr = phys_addr + size - 1;

 	if (last_addr < virt_to_phys(high_memory) - 1) {
 		struct page *ppage = virt_to_page(__va(phys_addr));
 		unsigned long npages;

 		phys_addr &= PAGE_MASK;

 		/* This might overflow and become zero.. */
 		last_addr = PAGE_ALIGN(last_addr);

 		/* .. but that's ok, because modulo-2**n arithmetic will make
 	 	* the page-aligned "last - first" come out right.
 	 	*/
 		npages = (last_addr - phys_addr) >> PAGE_SHIFT;

 		if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) {
 			iounmap(p);
 			p = NULL;
 		}
 		global_flush_tlb();
 	}

 	return p;
 }
 EXPORT_SYMBOL(ioremap_nocache);

 void iounmap(volatile void __iomem *addr)
 {
 	struct vm_struct *p;

 	if ((void __force *)addr <= high_memory)
 		return;

 	/*
 	 * __ioremap special-cases the PCI/ISA range by not instantiating a
 	 * vm_area and by simply returning an address into the kernel mapping
 	 * of ISA space.   So handle that here.
 	 */
 	if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
 			addr < phys_to_virt(ISA_END_ADDRESS))
 		return;

 	write_lock(&vmlist_lock);
 	p = __remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
 	if (!p) {
 		printk(KERN_WARNING "iounmap: bad address %p\n", addr);
 		dump_stack();
 		goto out_unlock;
 	}

 	if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
 		change_page_attr(virt_to_page(__va(p->phys_addr)),
 				 p->size >> PAGE_SHIFT,
 				 PAGE_KERNEL);
 		global_flush_tlb();
 	}
 out_unlock:
 	write_unlock(&vmlist_lock);
 	kfree(p);
 }
 EXPORT_SYMBOL(iounmap);

 void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
 {
 	unsigned long offset, last_addr;
 	unsigned int nrpages;
 	enum fixed_addresses idx;

 	/* Don't allow wraparound or zero size */
 	last_addr = phys_addr + size - 1;
 	if (!size || last_addr < phys_addr)
 		return NULL;

 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
 	 */
 	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
 		return phys_to_virt(phys_addr);

 	/*
 	 * Mappings have to be page-aligned
 	 */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;
 	size = PAGE_ALIGN(last_addr) - phys_addr;

 	/*
 	 * Mappings have to fit in the FIX_BTMAP area.
 	 */
 	nrpages = size >> PAGE_SHIFT;
 	if (nrpages > NR_FIX_BTMAPS)
 		return NULL;

 	/*
 	 * Ok, go for it..
 	 */
 	idx = FIX_BTMAP_BEGIN;
 	while (nrpages > 0) {
 		set_fixmap(idx, phys_addr);
 		phys_addr += PAGE_SIZE;
 		--idx;
 		--nrpages;
 	}
 	return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
 }

 void __init bt_iounmap(void *addr, unsigned long size)
 {
 	unsigned long virt_addr;
 	unsigned long offset;
 	unsigned int nrpages;
 	enum fixed_addresses idx;

 	virt_addr = (unsigned long)addr;
 	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
 		return;
 	offset = virt_addr & ~PAGE_MASK;
 	nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;

 	idx = FIX_BTMAP_BEGIN;
 	while (nrpages > 0) {
 		clear_fixmap(idx);
 		--idx;
 		--nrpages;
 	}
 }
	/*
	* arch/i386/mm/ioremap.c
	*
	* 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/init.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <asm/io.h>
	#include <asm/fixmap.h>
	#include <asm/cacheflush.h>
	#include <asm/tlbflush.h>
	#include <asm/pgtable.h>

	#define ISA_START_ADDRESS 0xa0000
	#define ISA_END_ADDRESS 0x100000

	static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
	unsigned long end, unsigned long phys_addr, unsigned long flags)
	{
	pte_t *pte;
	unsigned long pfn;

	pfn = phys_addr >> PAGE_SHIFT;
	pte = pte_alloc_kernel(&init_mm, pmd, addr);
	if (!pte)
	return -ENOMEM;
	do {
	BUG_ON(!pte_none(*pte));
	set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT \| _PAGE_RW \|
	_PAGE_DIRTY \| _PAGE_ACCESSED \| flags)));
	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, unsigned long phys_addr, unsigned long flags)
	{
	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_pte_range(pmd, addr, next, phys_addr + addr, flags))
	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, unsigned long phys_addr, unsigned long flags)
	{
	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_pmd_range(pud, addr, next, phys_addr + addr, flags))
	return -ENOMEM;
	} while (pud++, addr = next, addr != end);
	return 0;
	}

	static int ioremap_page_range(unsigned long addr,
	unsigned long end, unsigned long phys_addr, unsigned long flags)
	{
	pgd_t *pgd;
	unsigned long next;
	int err;

	BUG_ON(addr >= end);
	flush_cache_all();
	phys_addr -= addr;
	pgd = pgd_offset_k(addr);
	spin_lock(&init_mm.page_table_lock);
	do {
	next = pgd_addr_end(addr, end);
	err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags);
	if (err)
	break;
	} while (pgd++, addr = next, addr != end);
	spin_unlock(&init_mm.page_table_lock);
	flush_tlb_all();
	return err;
	}

	/*
	* Generic mapping function (not visible outside):
	*/

	/*
	* Remap an arbitrary physical address space into the kernel virtual
	* address space. Needed when the kernel wants to access high addresses
	* directly.
	*
	* NOTE! We need to allow non-page-aligned mappings too: we will obviously
	* have to convert them into an offset in a page-aligned mapping, but the
	* caller shouldn't need to know that small detail.
	*/
	void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
	{
	void __iomem * addr;
	struct vm_struct * area;
	unsigned long offset, last_addr;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;
	if (!size \|\| last_addr < phys_addr)
	return NULL;

	/*
	* Don't remap the low PCI/ISA area, it's always mapped..
	*/
	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
	return (void __iomem *) phys_to_virt(phys_addr);

	/*
	* Don't allow anybody to remap normal RAM that we're using..
	*/
	if (phys_addr <= virt_to_phys(high_memory - 1)) {
	char t_addr, t_end;
	struct page *page;

	t_addr = __va(phys_addr);
	t_end = t_addr + (size - 1);

	for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
	if(!PageReserved(page))
	return NULL;
	}

	/*
	* Mappings have to be page-aligned
	*/
	offset = phys_addr & ~PAGE_MASK;
	phys_addr &= PAGE_MASK;
	size = PAGE_ALIGN(last_addr+1) - phys_addr;

	/*
	* Ok, go for it..
	*/
	area = get_vm_area(size, VM_IOREMAP \| (flags << 20));
	if (!area)
	return NULL;
	area->phys_addr = phys_addr;
	addr = (void __iomem *) area->addr;
	if (ioremap_page_range((unsigned long) addr,
	(unsigned long) addr + size, phys_addr, flags)) {
	vunmap((void __force *) addr);
	return NULL;
	}
	return (void __iomem ) (offset + (char __iomem )addr);
	}
	EXPORT_SYMBOL(__ioremap);

	/**
	* ioremap_nocache - map bus memory into CPU space
	* @offset: bus address of the memory
	* @size: size of the resource to map
	*
	* ioremap_nocache performs a platform specific sequence of operations to
	* make bus memory CPU accessible via the readb/readw/readl/writeb/
	* writew/writel functions and the other mmio helpers. The returned
	* address is not guaranteed to be usable directly as a virtual
	* address.
	*
	* This version of ioremap ensures that the memory is marked uncachable
	* on the CPU as well as honouring existing caching rules from things like
	* the PCI bus. Note that there are other caches and buffers on many
	* busses. In particular driver authors should read up on PCI writes
	*
	* It's useful if some control registers are in such an area and
	* write combining or read caching is not desirable:
	*
	* Must be freed with iounmap.
	*/

	void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
	{
	unsigned long last_addr;
	void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
	if (!p)
	return p;

	/* Guaranteed to be > phys_addr, as per __ioremap() */
	last_addr = phys_addr + size - 1;

	if (last_addr < virt_to_phys(high_memory) - 1) {
	struct page *ppage = virt_to_page(__va(phys_addr));
	unsigned long npages;

	phys_addr &= PAGE_MASK;

	/* This might overflow and become zero.. */
	last_addr = PAGE_ALIGN(last_addr);

	/* .. but that's ok, because modulo-2**n arithmetic will make
	* the page-aligned "last - first" come out right.
	*/
	npages = (last_addr - phys_addr) >> PAGE_SHIFT;

	if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) {
	iounmap(p);
	p = NULL;
	}
	global_flush_tlb();
	}

	return p;
	}
	EXPORT_SYMBOL(ioremap_nocache);

	void iounmap(volatile void __iomem *addr)
	{
	struct vm_struct *p;

	if ((void __force *)addr <= high_memory)
	return;

	/*
	* __ioremap special-cases the PCI/ISA range by not instantiating a
	* vm_area and by simply returning an address into the kernel mapping
	* of ISA space. So handle that here.
	*/
	if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
	addr < phys_to_virt(ISA_END_ADDRESS))
	return;

	write_lock(&vmlist_lock);
	p = __remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
	if (!p) {
	printk(KERN_WARNING "iounmap: bad address %p\n", addr);
	dump_stack();
	goto out_unlock;
	}

	if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
	change_page_attr(virt_to_page(__va(p->phys_addr)),
	p->size >> PAGE_SHIFT,
	PAGE_KERNEL);
	global_flush_tlb();
	}
	out_unlock:
	write_unlock(&vmlist_lock);
	kfree(p);
	}
	EXPORT_SYMBOL(iounmap);

	void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
	{
	unsigned long offset, last_addr;
	unsigned int nrpages;
	enum fixed_addresses idx;

	/* Don't allow wraparound or zero size */
	last_addr = phys_addr + size - 1;
	if (!size \|\| last_addr < phys_addr)
	return NULL;

	/*
	* Don't remap the low PCI/ISA area, it's always mapped..
	*/
	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
	return phys_to_virt(phys_addr);

	/*
	* Mappings have to be page-aligned
	*/
	offset = phys_addr & ~PAGE_MASK;
	phys_addr &= PAGE_MASK;
	size = PAGE_ALIGN(last_addr) - phys_addr;

	/*
	* Mappings have to fit in the FIX_BTMAP area.
	*/
	nrpages = size >> PAGE_SHIFT;
	if (nrpages > NR_FIX_BTMAPS)
	return NULL;

	/*
	* Ok, go for it..
	*/
	idx = FIX_BTMAP_BEGIN;
	while (nrpages > 0) {
	set_fixmap(idx, phys_addr);
	phys_addr += PAGE_SIZE;
	--idx;
	--nrpages;
	}
	return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
	}

	void __init bt_iounmap(void *addr, unsigned long size)
	{
	unsigned long virt_addr;
	unsigned long offset;
	unsigned int nrpages;
	enum fixed_addresses idx;

	virt_addr = (unsigned long)addr;
	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
	return;
	offset = virt_addr & ~PAGE_MASK;
	nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;

	idx = FIX_BTMAP_BEGIN;
	while (nrpages > 0) {
	clear_fixmap(idx);
	--idx;
	--nrpages;
	}
	}