xen: cleancache shim to Xen Transcendent Memory
[linux-2.6/next.git] / arch / unicore32 / mm / ioremap.c
blobb7a605597b08cf914f501628b552612844078378
1 /*
2 * linux/arch/unicore32/mm/ioremap.c
4 * Code specific to PKUnity SoC and UniCore ISA
6 * Copyright (C) 2001-2010 GUAN Xue-tao
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 * Re-map IO memory to kernel address space so that we can access it.
15 * This allows a driver to remap an arbitrary region of bus memory into
16 * virtual space. One should *only* use readl, writel, memcpy_toio and
17 * so on with such remapped areas.
19 * Because UniCore only has a 32-bit address space we can't address the
20 * whole of the (physical) PCI space at once. PCI huge-mode addressing
21 * allows us to circumvent this restriction by splitting PCI space into
22 * two 2GB chunks and mapping only one at a time into processor memory.
23 * We use MMU protection domains to trap any attempt to access the bank
24 * that is not currently mapped. (This isn't fully implemented yet.)
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/mm.h>
29 #include <linux/vmalloc.h>
30 #include <linux/io.h>
32 #include <asm/cputype.h>
33 #include <asm/cacheflush.h>
34 #include <asm/mmu_context.h>
35 #include <asm/pgalloc.h>
36 #include <asm/tlbflush.h>
37 #include <asm/sizes.h>
39 #include <mach/map.h>
40 #include "mm.h"
43 * Used by ioremap() and iounmap() code to mark (super)section-mapped
44 * I/O regions in vm_struct->flags field.
46 #define VM_UNICORE_SECTION_MAPPING 0x80000000
48 int ioremap_page(unsigned long virt, unsigned long phys,
49 const struct mem_type *mtype)
51 return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
52 __pgprot(mtype->prot_pte));
54 EXPORT_SYMBOL(ioremap_page);
57 * Section support is unsafe on SMP - If you iounmap and ioremap a region,
58 * the other CPUs will not see this change until their next context switch.
59 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
60 * which requires the new ioremap'd region to be referenced, the CPU will
61 * reference the _old_ region.
63 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
64 * mask the size back to 4MB aligned or we will overflow in the loop below.
66 static void unmap_area_sections(unsigned long virt, unsigned long size)
68 unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
69 pgd_t *pgd;
71 flush_cache_vunmap(addr, end);
72 pgd = pgd_offset_k(addr);
73 do {
74 pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);
76 pmd = *pmdp;
77 if (!pmd_none(pmd)) {
79 * Clear the PMD from the page table, and
80 * increment the kvm sequence so others
81 * notice this change.
83 * Note: this is still racy on SMP machines.
85 pmd_clear(pmdp);
88 * Free the page table, if there was one.
90 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
91 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
94 addr += PGDIR_SIZE;
95 pgd++;
96 } while (addr < end);
98 flush_tlb_kernel_range(virt, end);
101 static int
102 remap_area_sections(unsigned long virt, unsigned long pfn,
103 size_t size, const struct mem_type *type)
105 unsigned long addr = virt, end = virt + size;
106 pgd_t *pgd;
109 * Remove and free any PTE-based mapping, and
110 * sync the current kernel mapping.
112 unmap_area_sections(virt, size);
114 pgd = pgd_offset_k(addr);
115 do {
116 pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
118 set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
119 pfn += SZ_4M >> PAGE_SHIFT;
120 flush_pmd_entry(pmd);
122 addr += PGDIR_SIZE;
123 pgd++;
124 } while (addr < end);
126 return 0;
129 void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
130 unsigned long offset, size_t size, unsigned int mtype, void *caller)
132 const struct mem_type *type;
133 int err;
134 unsigned long addr;
135 struct vm_struct *area;
138 * High mappings must be section aligned
140 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
141 return NULL;
144 * Don't allow RAM to be mapped
146 if (pfn_valid(pfn)) {
147 printk(KERN_WARNING "BUG: Your driver calls ioremap() on\n"
148 "system memory. This leads to architecturally\n"
149 "unpredictable behaviour, and ioremap() will fail in\n"
150 "the next kernel release. Please fix your driver.\n");
151 WARN_ON(1);
154 type = get_mem_type(mtype);
155 if (!type)
156 return NULL;
159 * Page align the mapping size, taking account of any offset.
161 size = PAGE_ALIGN(offset + size);
163 area = get_vm_area_caller(size, VM_IOREMAP, caller);
164 if (!area)
165 return NULL;
166 addr = (unsigned long)area->addr;
168 if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
169 area->flags |= VM_UNICORE_SECTION_MAPPING;
170 err = remap_area_sections(addr, pfn, size, type);
171 } else
172 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
173 __pgprot(type->prot_pte));
175 if (err) {
176 vunmap((void *)addr);
177 return NULL;
180 flush_cache_vmap(addr, addr + size);
181 return (void __iomem *) (offset + addr);
184 void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
185 unsigned int mtype, void *caller)
187 unsigned long last_addr;
188 unsigned long offset = phys_addr & ~PAGE_MASK;
189 unsigned long pfn = __phys_to_pfn(phys_addr);
192 * Don't allow wraparound or zero size
194 last_addr = phys_addr + size - 1;
195 if (!size || last_addr < phys_addr)
196 return NULL;
198 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
202 * Remap an arbitrary physical address space into the kernel virtual
203 * address space. Needed when the kernel wants to access high addresses
204 * directly.
206 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
207 * have to convert them into an offset in a page-aligned mapping, but the
208 * caller shouldn't need to know that small detail.
210 void __iomem *
211 __uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
212 unsigned int mtype)
214 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
215 __builtin_return_address(0));
217 EXPORT_SYMBOL(__uc32_ioremap_pfn);
219 void __iomem *
220 __uc32_ioremap(unsigned long phys_addr, size_t size)
222 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
223 __builtin_return_address(0));
225 EXPORT_SYMBOL(__uc32_ioremap);
227 void __iomem *
228 __uc32_ioremap_cached(unsigned long phys_addr, size_t size)
230 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED,
231 __builtin_return_address(0));
233 EXPORT_SYMBOL(__uc32_ioremap_cached);
235 void __uc32_iounmap(volatile void __iomem *io_addr)
237 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
238 struct vm_struct **p, *tmp;
241 * If this is a section based mapping we need to handle it
242 * specially as the VM subsystem does not know how to handle
243 * such a beast. We need the lock here b/c we need to clear
244 * all the mappings before the area can be reclaimed
245 * by someone else.
247 write_lock(&vmlist_lock);
248 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
249 if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
250 if (tmp->flags & VM_UNICORE_SECTION_MAPPING) {
251 unmap_area_sections((unsigned long)tmp->addr,
252 tmp->size);
254 break;
257 write_unlock(&vmlist_lock);
259 vunmap(addr);
261 EXPORT_SYMBOL(__uc32_iounmap);