[deliverable/linux.git] / arch / i386 / mm / ioremap.c

/*
 * 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 <linux/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

/*
 * 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;
	pgprot_t prot;

	/* 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;
	}

	prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY
			| _PAGE_ACCESSED | flags);

	/*
	 * 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, prot)) {
		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);

/**
 * iounmap - Free a IO remapping
 * @addr: virtual address from ioremap_*
 *
 * Caller must ensure there is only one unmapping for the same pointer.
 */
void iounmap(volatile void __iomem *addr)
{
	struct vm_struct *p, *o;

	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;

	addr = (volatile void __iomem *)(PAGE_MASK & (unsigned long __force)addr);

	/* Use the vm area unlocked, assuming the caller
	   ensures there isn't another iounmap for the same address
	   in parallel. Reuse of the virtual address is prevented by
	   leaving it in the global lists until we're done with it.
	   cpa takes care of the direct mappings. */
	read_lock(&vmlist_lock);
	for (p = vmlist; p; p = p->next) {
		if (p->addr == addr)
			break;
	}
	read_unlock(&vmlist_lock);

	if (!p) {
		printk("iounmap: bad address %p\n", addr);
		dump_stack();
		return;
	}

	/* Reset the direct mapping. Can block */
	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();
	} 

	/* Finally remove it */
	o = remove_vm_area((void *)addr);
	BUG_ON(p != o || o == NULL);
	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;
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* arch/i386/mm/ioremap.c
	3	*
	4	* Re-map IO memory to kernel address space so that we can access it.
	5	* This is needed for high PCI addresses that aren't mapped in the
	6	* 640k-1MB IO memory area on PC's
	7	*
	8	* (C) Copyright 1995 1996 Linus Torvalds
	9	*/
	10
	11	#include <linux/vmalloc.h>
	12	#include <linux/init.h>
	13	#include <linux/slab.h>
129f6946	14	#include <linux/module.h>
a148ecfd	15	#include <linux/io.h>
1da177e4 LT	16	#include <asm/fixmap.h>
	17	#include <asm/cacheflush.h>
	18	#include <asm/tlbflush.h>
	19	#include <asm/pgtable.h>
	20
	21	#define ISA_START_ADDRESS 0xa0000
	22	#define ISA_END_ADDRESS 0x100000
	23
1da177e4 LT	24	/*
	25	* Generic mapping function (not visible outside):
	26	*/
	27
	28	/*
	29	* Remap an arbitrary physical address space into the kernel virtual
	30	* address space. Needed when the kernel wants to access high addresses
	31	* directly.
	32	*
	33	* NOTE! We need to allow non-page-aligned mappings too: we will obviously
	34	* have to convert them into an offset in a page-aligned mapping, but the
	35	* caller shouldn't need to know that small detail.
	36	*/
	37	void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
	38	{
	39	void __iomem * addr;
	40	struct vm_struct * area;
	41	unsigned long offset, last_addr;
a148ecfd	42	pgprot_t prot;
1da177e4 LT	43
	44	/* Don't allow wraparound or zero size */
	45	last_addr = phys_addr + size - 1;
	46	if (!size \|\| last_addr < phys_addr)
	47	return NULL;
	48
	49	/*
	50	* Don't remap the low PCI/ISA area, it's always mapped..
	51	*/
	52	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
	53	return (void __iomem *) phys_to_virt(phys_addr);
	54
	55	/*
	56	* Don't allow anybody to remap normal RAM that we're using..
	57	*/
	58	if (phys_addr <= virt_to_phys(high_memory - 1)) {
	59	char t_addr, t_end;
	60	struct page *page;
	61
	62	t_addr = __va(phys_addr);
	63	t_end = t_addr + (size - 1);
	64
	65	for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
	66	if(!PageReserved(page))
	67	return NULL;
	68	}
	69
a148ecfd HS	70	prot = __pgprot(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_DIRTY
	71	\| _PAGE_ACCESSED \| flags);
	72
1da177e4 LT	73	/*
	74	* Mappings have to be page-aligned
	75	*/
	76	offset = phys_addr & ~PAGE_MASK;
	77	phys_addr &= PAGE_MASK;
	78	size = PAGE_ALIGN(last_addr+1) - phys_addr;
	79
	80	/*
	81	* Ok, go for it..
	82	*/
	83	area = get_vm_area(size, VM_IOREMAP \| (flags << 20));
	84	if (!area)
	85	return NULL;
	86	area->phys_addr = phys_addr;
	87	addr = (void __iomem *) area->addr;
	88	if (ioremap_page_range((unsigned long) addr,
a148ecfd	89	(unsigned long) addr + size, phys_addr, prot)) {
1da177e4 LT	90	vunmap((void __force *) addr);
	91	return NULL;
	92	}
	93	return (void __iomem ) (offset + (char __iomem )addr);
	94	}
129f6946	95	EXPORT_SYMBOL(__ioremap);
1da177e4 LT	96
	97	/**
	98	* ioremap_nocache - map bus memory into CPU space
	99	* @offset: bus address of the memory
	100	* @size: size of the resource to map
	101	*
	102	* ioremap_nocache performs a platform specific sequence of operations to
	103	* make bus memory CPU accessible via the readb/readw/readl/writeb/
	104	* writew/writel functions and the other mmio helpers. The returned
	105	* address is not guaranteed to be usable directly as a virtual
	106	* address.
	107	*
	108	* This version of ioremap ensures that the memory is marked uncachable
	109	* on the CPU as well as honouring existing caching rules from things like
	110	* the PCI bus. Note that there are other caches and buffers on many
	111	* busses. In particular driver authors should read up on PCI writes
	112	*
	113	* It's useful if some control registers are in such an area and
	114	* write combining or read caching is not desirable:
	115	*
	116	* Must be freed with iounmap.
	117	*/
	118
	119	void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
	120	{
	121	unsigned long last_addr;
	122	void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
	123	if (!p)
	124	return p;
	125
	126	/* Guaranteed to be > phys_addr, as per __ioremap() */
	127	last_addr = phys_addr + size - 1;
	128
	129	if (last_addr < virt_to_phys(high_memory) - 1) {
	130	struct page *ppage = virt_to_page(__va(phys_addr));
	131	unsigned long npages;
	132
	133	phys_addr &= PAGE_MASK;
	134
	135	/* This might overflow and become zero.. */
	136	last_addr = PAGE_ALIGN(last_addr);
	137
	138	/* .. but that's ok, because modulo-2**n arithmetic will make
	139	* the page-aligned "last - first" come out right.
	140	*/
	141	npages = (last_addr - phys_addr) >> PAGE_SHIFT;
	142
	143	if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) {
	144	iounmap(p);
	145	p = NULL;
	146	}
	147	global_flush_tlb();
	148	}
	149
	150	return p;
	151	}
129f6946	152	EXPORT_SYMBOL(ioremap_nocache);
1da177e4	153
bf5421c3 AK	154	/**
	155	* iounmap - Free a IO remapping
	156	* @addr: virtual address from ioremap_*
	157	*
	158	* Caller must ensure there is only one unmapping for the same pointer.
	159	*/
1da177e4 LT	160	void iounmap(volatile void __iomem *addr)
1da177e4 LT	161	{
bf5421c3	162	struct vm_struct p, o;
c23a4e96 AM	163
c23a4e96 AM	164	if ((void __force *)addr <= high_memory)
1da177e4 LT	165	return;
	166
	167	/*
	168	* __ioremap special-cases the PCI/ISA range by not instantiating a
	169	* vm_area and by simply returning an address into the kernel mapping
	170	* of ISA space. So handle that here.
	171	*/
	172	if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
	173	addr < phys_to_virt(ISA_END_ADDRESS))
	174	return;
	175
b16b88e5	176	addr = (volatile void __iomem *)(PAGE_MASK & (unsigned long __force)addr);
bf5421c3 AK	177
	178	/* Use the vm area unlocked, assuming the caller
	179	ensures there isn't another iounmap for the same address
	180	in parallel. Reuse of the virtual address is prevented by
	181	leaving it in the global lists until we're done with it.
	182	cpa takes care of the direct mappings. */
	183	read_lock(&vmlist_lock);
	184	for (p = vmlist; p; p = p->next) {
	185	if (p->addr == addr)
	186	break;
	187	}
	188	read_unlock(&vmlist_lock);
	189
	190	if (!p) {
	191	printk("iounmap: bad address %p\n", addr);
c23a4e96	192	dump_stack();
bf5421c3	193	return;
1da177e4 LT	194	}
1da177e4 LT	195
bf5421c3	196	/* Reset the direct mapping. Can block */
1da177e4	197	if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
1da177e4 LT	198	change_page_attr(virt_to_page(__va(p->phys_addr)),
	199	p->size >> PAGE_SHIFT,
	200	PAGE_KERNEL);
	201	global_flush_tlb();
	202	}
bf5421c3 AK	203
	204	/* Finally remove it */
	205	o = remove_vm_area((void *)addr);
	206	BUG_ON(p != o \|\| o == NULL);
1da177e4 LT	207	kfree(p);
1da177e4 LT	208	}
129f6946	209	EXPORT_SYMBOL(iounmap);
1da177e4 LT	210
	211	void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
	212	{
	213	unsigned long offset, last_addr;
	214	unsigned int nrpages;
	215	enum fixed_addresses idx;
	216
	217	/* Don't allow wraparound or zero size */
	218	last_addr = phys_addr + size - 1;
	219	if (!size \|\| last_addr < phys_addr)
	220	return NULL;
	221
	222	/*
	223	* Don't remap the low PCI/ISA area, it's always mapped..
	224	*/
	225	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
	226	return phys_to_virt(phys_addr);
	227
	228	/*
	229	* Mappings have to be page-aligned
	230	*/
	231	offset = phys_addr & ~PAGE_MASK;
	232	phys_addr &= PAGE_MASK;
	233	size = PAGE_ALIGN(last_addr) - phys_addr;
	234
	235	/*
	236	* Mappings have to fit in the FIX_BTMAP area.
	237	*/
	238	nrpages = size >> PAGE_SHIFT;
	239	if (nrpages > NR_FIX_BTMAPS)
	240	return NULL;
	241
	242	/*
	243	* Ok, go for it..
	244	*/
	245	idx = FIX_BTMAP_BEGIN;
	246	while (nrpages > 0) {
	247	set_fixmap(idx, phys_addr);
	248	phys_addr += PAGE_SIZE;
	249	--idx;
	250	--nrpages;
	251	}
	252	return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
	253	}
	254
	255	void __init bt_iounmap(void *addr, unsigned long size)
	256	{
	257	unsigned long virt_addr;
	258	unsigned long offset;
	259	unsigned int nrpages;
	260	enum fixed_addresses idx;
	261
	262	virt_addr = (unsigned long)addr;
	263	if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
	264	return;
	265	offset = virt_addr & ~PAGE_MASK;
	266	nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
	267
	268	idx = FIX_BTMAP_BEGIN;
	269	while (nrpages > 0) {
	270	clear_fixmap(idx);
	271	--idx;
	272	--nrpages;
	273	}
274	}