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/arch/mips/mm/ioremap.c

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
C | 192 lines | 132 code | 26 blank | 34 comment | 26 complexity | df83bf4a4a287be01a97f4767d126011 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * This file is subject to the terms and conditions of the GNU General Public
  3 * License.  See the file "COPYING" in the main directory of this archive
  4 * for more details.
  5 *
  6 * (C) Copyright 1995 1996 Linus Torvalds
  7 * (C) Copyright 2001, 2002 Ralf Baechle
  8 */
  9#include <linux/module.h>
 10#include <asm/addrspace.h>
 11#include <asm/byteorder.h>
 12#include <linux/sched.h>
 13#include <linux/slab.h>
 14#include <linux/vmalloc.h>
 15#include <asm/cacheflush.h>
 16#include <asm/io.h>
 17#include <asm/tlbflush.h>
 18
 19static inline void remap_area_pte(pte_t * pte, unsigned long address,
 20	phys_t size, phys_t phys_addr, unsigned long flags)
 21{
 22	phys_t end;
 23	unsigned long pfn;
 24	pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
 25	                           | __WRITEABLE | flags);
 26
 27	address &= ~PMD_MASK;
 28	end = address + size;
 29	if (end > PMD_SIZE)
 30		end = PMD_SIZE;
 31	BUG_ON(address >= end);
 32	pfn = phys_addr >> PAGE_SHIFT;
 33	do {
 34		if (!pte_none(*pte)) {
 35			printk("remap_area_pte: page already exists\n");
 36			BUG();
 37		}
 38		set_pte(pte, pfn_pte(pfn, pgprot));
 39		address += PAGE_SIZE;
 40		pfn++;
 41		pte++;
 42	} while (address && (address < end));
 43}
 44
 45static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
 46	phys_t size, phys_t phys_addr, unsigned long flags)
 47{
 48	phys_t end;
 49
 50	address &= ~PGDIR_MASK;
 51	end = address + size;
 52	if (end > PGDIR_SIZE)
 53		end = PGDIR_SIZE;
 54	phys_addr -= address;
 55	BUG_ON(address >= end);
 56	do {
 57		pte_t * pte = pte_alloc_kernel(pmd, address);
 58		if (!pte)
 59			return -ENOMEM;
 60		remap_area_pte(pte, address, end - address, address + phys_addr, flags);
 61		address = (address + PMD_SIZE) & PMD_MASK;
 62		pmd++;
 63	} while (address && (address < end));
 64	return 0;
 65}
 66
 67static int remap_area_pages(unsigned long address, phys_t phys_addr,
 68	phys_t size, unsigned long flags)
 69{
 70	int error;
 71	pgd_t * dir;
 72	unsigned long end = address + size;
 73
 74	phys_addr -= address;
 75	dir = pgd_offset(&init_mm, address);
 76	flush_cache_all();
 77	BUG_ON(address >= end);
 78	do {
 79		pud_t *pud;
 80		pmd_t *pmd;
 81
 82		error = -ENOMEM;
 83		pud = pud_alloc(&init_mm, dir, address);
 84		if (!pud)
 85			break;
 86		pmd = pmd_alloc(&init_mm, pud, address);
 87		if (!pmd)
 88			break;
 89		if (remap_area_pmd(pmd, address, end - address,
 90					 phys_addr + address, flags))
 91			break;
 92		error = 0;
 93		address = (address + PGDIR_SIZE) & PGDIR_MASK;
 94		dir++;
 95	} while (address && (address < end));
 96	flush_tlb_all();
 97	return error;
 98}
 99
100/*
101 * Generic mapping function (not visible outside):
102 */
103
104/*
105 * Remap an arbitrary physical address space into the kernel virtual
106 * address space. Needed when the kernel wants to access high addresses
107 * directly.
108 *
109 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
110 * have to convert them into an offset in a page-aligned mapping, but the
111 * caller shouldn't need to know that small detail.
112 */
113
114#define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
115
116void __iomem * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags)
117{
118	struct vm_struct * area;
119	unsigned long offset;
120	phys_t last_addr;
121	void * addr;
122
123	phys_addr = fixup_bigphys_addr(phys_addr, size);
124
125	/* Don't allow wraparound or zero size */
126	last_addr = phys_addr + size - 1;
127	if (!size || last_addr < phys_addr)
128		return NULL;
129
130	/*
131	 * Map uncached objects in the low 512mb of address space using KSEG1,
132	 * otherwise map using page tables.
133	 */
134	if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
135	    flags == _CACHE_UNCACHED)
136		return (void __iomem *) CKSEG1ADDR(phys_addr);
137
138	/*
139	 * Don't allow anybody to remap normal RAM that we're using..
140	 */
141	if (phys_addr < virt_to_phys(high_memory)) {
142		char *t_addr, *t_end;
143		struct page *page;
144
145		t_addr = __va(phys_addr);
146		t_end = t_addr + (size - 1);
147
148		for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
149			if(!PageReserved(page))
150				return NULL;
151	}
152
153	/*
154	 * Mappings have to be page-aligned
155	 */
156	offset = phys_addr & ~PAGE_MASK;
157	phys_addr &= PAGE_MASK;
158	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
159
160	/*
161	 * Ok, go for it..
162	 */
163	area = get_vm_area(size, VM_IOREMAP);
164	if (!area)
165		return NULL;
166	addr = area->addr;
167	if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
168		vunmap(addr);
169		return NULL;
170	}
171
172	return (void __iomem *) (offset + (char *)addr);
173}
174
175#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
176
177void __iounmap(const volatile void __iomem *addr)
178{
179	struct vm_struct *p;
180
181	if (IS_KSEG1(addr))
182		return;
183
184	p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
185	if (!p)
186		printk(KERN_ERR "iounmap: bad address %p\n", addr);
187
188        kfree(p);
189}
190
191EXPORT_SYMBOL(__ioremap);
192EXPORT_SYMBOL(__iounmap);