arch/x86_64/mm/ioremap.c - arm/linux-arm64-legacy - Git at Google

 /*
  * arch/x86_64/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 <asm/io.h>
 #include <asm/pgalloc.h>
 #include <asm/fixmap.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 #include <asm/proto.h>

 #define ISA_START_ADDRESS      0xa0000
 #define ISA_END_ADDRESS                0x100000

 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
 	unsigned long phys_addr, unsigned long flags)
 {
 	unsigned long end;
 	unsigned long pfn;

 	address &= ~PMD_MASK;
 	end = address + size;
 	if (end > PMD_SIZE)
 		end = PMD_SIZE;
 	if (address >= end)
 		BUG();
 	pfn = phys_addr >> PAGE_SHIFT;
 	do {
 		if (!pte_none(*pte)) {
 			printk("remap_area_pte: page already exists\n");
 			BUG();
 		}
 		set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW |
 					_PAGE_GLOBAL | _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
 		address += PAGE_SIZE;
 		pfn++;
 		pte++;
 	} while (address && (address < end));
 }

 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
 	unsigned long phys_addr, unsigned long flags)
 {
 	unsigned long end;

 	address &= ~PUD_MASK;
 	end = address + size;
 	if (end > PUD_SIZE)
 		end = PUD_SIZE;
 	phys_addr -= address;
 	if (address >= end)
 		BUG();
 	do {
 		pte_t * pte = pte_alloc_kernel(pmd, address);
 		if (!pte)
 			return -ENOMEM;
 		remap_area_pte(pte, address, end - address, address + phys_addr, flags);
 		address = (address + PMD_SIZE) & PMD_MASK;
 		pmd++;
 	} while (address && (address < end));
 	return 0;
 }

 static inline int remap_area_pud(pud_t * pud, unsigned long address, unsigned long size,
 	unsigned long phys_addr, unsigned long flags)
 {
 	unsigned long end;

 	address &= ~PGDIR_MASK;
 	end = address + size;
 	if (end > PGDIR_SIZE)
 		end = PGDIR_SIZE;
 	phys_addr -= address;
 	if (address >= end)
 		BUG();
 	do {
 		pmd_t * pmd = pmd_alloc(&init_mm, pud, address);
 		if (!pmd)
 			return -ENOMEM;
 		remap_area_pmd(pmd, address, end - address, address + phys_addr, flags);
 		address = (address + PUD_SIZE) & PUD_MASK;
 		pud++;
 	} while (address && (address < end));
 	return 0;
 }

 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
 				 unsigned long size, unsigned long flags)
 {
 	int error;
 	pgd_t *pgd;
 	unsigned long end = address + size;

 	phys_addr -= address;
 	pgd = pgd_offset_k(address);
 	flush_cache_all();
 	if (address >= end)
 		BUG();
 	do {
 		pud_t *pud;
 		pud = pud_alloc(&init_mm, pgd, address);
 		error = -ENOMEM;
 		if (!pud)
 			break;
 		if (remap_area_pud(pud, address, end - address,
 					 phys_addr + address, flags))
 			break;
 		error = 0;
 		address = (address + PGDIR_SIZE) & PGDIR_MASK;
 		pgd++;
 	} while (address && (address < end));
 	flush_tlb_all();
 	return error;
 }

 /*
  * Fix up the linear direct mapping of the kernel to avoid cache attribute
  * conflicts.
  */
 static int
 ioremap_change_attr(unsigned long phys_addr, unsigned long size,
 					unsigned long flags)
 {
 	int err = 0;
 	if (phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) {
 		unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 		unsigned long vaddr = (unsigned long) __va(phys_addr);

 		/*
  		 * Must use a address here and not struct page because the phys addr
 		 * can be a in hole between nodes and not have an memmap entry.
 		 */
 		err = change_page_attr_addr(vaddr,npages,__pgprot(__PAGE_KERNEL|flags));
 		if (!err)
 			global_flush_tlb();
 	}
 	return err;
 }

 /*
  * Generic mapping function
  */

 /*
  * 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 * 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 (__force void __iomem *)phys_to_virt(phys_addr);

 #ifdef CONFIG_FLATMEM
 	/*
 	 * Don't allow anybody to remap normal RAM that we're using..
 	 */
 	if (last_addr < virt_to_phys(high_memory)) {
 		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;
 	}
 #endif

 	/*
 	 * 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 = area->addr;
 	if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 		remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
 		return NULL;
 	}
 	if (flags && ioremap_change_attr(phys_addr, size, flags) < 0) {
 		area->flags &= 0xffffff;
 		vunmap(addr);
 		return NULL;
 	}
 	return (__force void __iomem *) (offset + (char *)addr);
 }

 /**
  * 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)
 {
 	return __ioremap(phys_addr, size, _PAGE_PCD);
 }

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

 	if (addr <= high_memory)
 		return;
 	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 *)((unsigned long)addr & PAGE_MASK));
 	if (!p)
 		printk("iounmap: bad address %p\n", addr);
 	else if (p->flags >> 20)
 		ioremap_change_attr(p->phys_addr, p->size, 0);
 	write_unlock(&vmlist_lock);
 	kfree(p);
 }
	/*
	* arch/x86_64/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 <asm/io.h>
	#include <asm/pgalloc.h>
	#include <asm/fixmap.h>
	#include <asm/cacheflush.h>
	#include <asm/tlbflush.h>
	#include <asm/proto.h>

	#define ISA_START_ADDRESS 0xa0000
	#define ISA_END_ADDRESS 0x100000

	static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
	unsigned long phys_addr, unsigned long flags)
	{
	unsigned long end;
	unsigned long pfn;

	address &= ~PMD_MASK;
	end = address + size;
	if (end > PMD_SIZE)
	end = PMD_SIZE;
	if (address >= end)
	BUG();
	pfn = phys_addr >> PAGE_SHIFT;
	do {
	if (!pte_none(*pte)) {
	printk("remap_area_pte: page already exists\n");
	BUG();
	}
	set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT \| _PAGE_RW \|
	_PAGE_GLOBAL \| _PAGE_DIRTY \| _PAGE_ACCESSED \| flags)));
	address += PAGE_SIZE;
	pfn++;
	pte++;
	} while (address && (address < end));
	}

	static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
	unsigned long phys_addr, unsigned long flags)
	{
	unsigned long end;

	address &= ~PUD_MASK;
	end = address + size;
	if (end > PUD_SIZE)
	end = PUD_SIZE;
	phys_addr -= address;
	if (address >= end)
	BUG();
	do {
	pte_t * pte = pte_alloc_kernel(pmd, address);
	if (!pte)
	return -ENOMEM;
	remap_area_pte(pte, address, end - address, address + phys_addr, flags);
	address = (address + PMD_SIZE) & PMD_MASK;
	pmd++;
	} while (address && (address < end));
	return 0;
	}

	static inline int remap_area_pud(pud_t * pud, unsigned long address, unsigned long size,
	unsigned long phys_addr, unsigned long flags)
	{
	unsigned long end;

	address &= ~PGDIR_MASK;
	end = address + size;
	if (end > PGDIR_SIZE)
	end = PGDIR_SIZE;
	phys_addr -= address;
	if (address >= end)
	BUG();
	do {
	pmd_t * pmd = pmd_alloc(&init_mm, pud, address);
	if (!pmd)
	return -ENOMEM;
	remap_area_pmd(pmd, address, end - address, address + phys_addr, flags);
	address = (address + PUD_SIZE) & PUD_MASK;
	pud++;
	} while (address && (address < end));
	return 0;
	}

	static int remap_area_pages(unsigned long address, unsigned long phys_addr,
	unsigned long size, unsigned long flags)
	{
	int error;
	pgd_t *pgd;
	unsigned long end = address + size;

	phys_addr -= address;
	pgd = pgd_offset_k(address);
	flush_cache_all();
	if (address >= end)
	BUG();
	do {
	pud_t *pud;
	pud = pud_alloc(&init_mm, pgd, address);
	error = -ENOMEM;
	if (!pud)
	break;
	if (remap_area_pud(pud, address, end - address,
	phys_addr + address, flags))
	break;
	error = 0;
	address = (address + PGDIR_SIZE) & PGDIR_MASK;
	pgd++;
	} while (address && (address < end));
	flush_tlb_all();
	return error;
	}

	/*
	* Fix up the linear direct mapping of the kernel to avoid cache attribute
	* conflicts.
	*/
	static int
	ioremap_change_attr(unsigned long phys_addr, unsigned long size,
	unsigned long flags)
	{
	int err = 0;
	if (phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) {
	unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
	unsigned long vaddr = (unsigned long) __va(phys_addr);

	/*
	* Must use a address here and not struct page because the phys addr
	* can be a in hole between nodes and not have an memmap entry.
	*/
	err = change_page_attr_addr(vaddr,npages,__pgprot(__PAGE_KERNEL\|flags));
	if (!err)
	global_flush_tlb();
	}
	return err;
	}

	/*
	* Generic mapping function
	*/

	/*
	* 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 * 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 (__force void __iomem *)phys_to_virt(phys_addr);

	#ifdef CONFIG_FLATMEM
	/*
	* Don't allow anybody to remap normal RAM that we're using..
	*/
	if (last_addr < virt_to_phys(high_memory)) {
	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;
	}
	#endif

	/*
	* 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 = area->addr;
	if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
	remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
	return NULL;
	}
	if (flags && ioremap_change_attr(phys_addr, size, flags) < 0) {
	area->flags &= 0xffffff;
	vunmap(addr);
	return NULL;
	}
	return (__force void __iomem ) (offset + (char )addr);
	}

	/**
	* 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)
	{
	return __ioremap(phys_addr, size, _PAGE_PCD);
	}

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

	if (addr <= high_memory)
	return;
	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 *)((unsigned long)addr & PAGE_MASK));
	if (!p)
	printk("iounmap: bad address %p\n", addr);
	else if (p->flags >> 20)
	ioremap_change_attr(p->phys_addr, p->size, 0);
	write_unlock(&vmlist_lock);
	kfree(p);
	}