xref: /openbmc/linux/arch/arm/mm/ioremap.c (revision b34e08d5)
1 /*
2  *  linux/arch/arm/mm/ioremap.c
3  *
4  * Re-map IO memory to kernel address space so that we can access it.
5  *
6  * (C) Copyright 1995 1996 Linus Torvalds
7  *
8  * Hacked for ARM by Phil Blundell <philb@gnu.org>
9  * Hacked to allow all architectures to build, and various cleanups
10  * by Russell King
11  *
12  * This allows a driver to remap an arbitrary region of bus memory into
13  * virtual space.  One should *only* use readl, writel, memcpy_toio and
14  * so on with such remapped areas.
15  *
16  * Because the ARM only has a 32-bit address space we can't address the
17  * whole of the (physical) PCI space at once.  PCI huge-mode addressing
18  * allows us to circumvent this restriction by splitting PCI space into
19  * two 2GB chunks and mapping only one at a time into processor memory.
20  * We use MMU protection domains to trap any attempt to access the bank
21  * that is not currently mapped.  (This isn't fully implemented yet.)
22  */
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/mm.h>
26 #include <linux/vmalloc.h>
27 #include <linux/io.h>
28 #include <linux/sizes.h>
29 
30 #include <asm/cp15.h>
31 #include <asm/cputype.h>
32 #include <asm/cacheflush.h>
33 #include <asm/mmu_context.h>
34 #include <asm/pgalloc.h>
35 #include <asm/tlbflush.h>
36 #include <asm/system_info.h>
37 
38 #include <asm/mach/map.h>
39 #include <asm/mach/pci.h>
40 #include "mm.h"
41 
42 
43 LIST_HEAD(static_vmlist);
44 
45 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
46 			size_t size, unsigned int mtype)
47 {
48 	struct static_vm *svm;
49 	struct vm_struct *vm;
50 
51 	list_for_each_entry(svm, &static_vmlist, list) {
52 		vm = &svm->vm;
53 		if (!(vm->flags & VM_ARM_STATIC_MAPPING))
54 			continue;
55 		if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
56 			continue;
57 
58 		if (vm->phys_addr > paddr ||
59 			paddr + size - 1 > vm->phys_addr + vm->size - 1)
60 			continue;
61 
62 		return svm;
63 	}
64 
65 	return NULL;
66 }
67 
68 struct static_vm *find_static_vm_vaddr(void *vaddr)
69 {
70 	struct static_vm *svm;
71 	struct vm_struct *vm;
72 
73 	list_for_each_entry(svm, &static_vmlist, list) {
74 		vm = &svm->vm;
75 
76 		/* static_vmlist is ascending order */
77 		if (vm->addr > vaddr)
78 			break;
79 
80 		if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
81 			return svm;
82 	}
83 
84 	return NULL;
85 }
86 
87 void __init add_static_vm_early(struct static_vm *svm)
88 {
89 	struct static_vm *curr_svm;
90 	struct vm_struct *vm;
91 	void *vaddr;
92 
93 	vm = &svm->vm;
94 	vm_area_add_early(vm);
95 	vaddr = vm->addr;
96 
97 	list_for_each_entry(curr_svm, &static_vmlist, list) {
98 		vm = &curr_svm->vm;
99 
100 		if (vm->addr > vaddr)
101 			break;
102 	}
103 	list_add_tail(&svm->list, &curr_svm->list);
104 }
105 
106 int ioremap_page(unsigned long virt, unsigned long phys,
107 		 const struct mem_type *mtype)
108 {
109 	return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
110 				  __pgprot(mtype->prot_pte));
111 }
112 EXPORT_SYMBOL(ioremap_page);
113 
114 void __check_vmalloc_seq(struct mm_struct *mm)
115 {
116 	unsigned int seq;
117 
118 	do {
119 		seq = init_mm.context.vmalloc_seq;
120 		memcpy(pgd_offset(mm, VMALLOC_START),
121 		       pgd_offset_k(VMALLOC_START),
122 		       sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
123 					pgd_index(VMALLOC_START)));
124 		mm->context.vmalloc_seq = seq;
125 	} while (seq != init_mm.context.vmalloc_seq);
126 }
127 
128 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
129 /*
130  * Section support is unsafe on SMP - If you iounmap and ioremap a region,
131  * the other CPUs will not see this change until their next context switch.
132  * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
133  * which requires the new ioremap'd region to be referenced, the CPU will
134  * reference the _old_ region.
135  *
136  * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
137  * mask the size back to 1MB aligned or we will overflow in the loop below.
138  */
139 static void unmap_area_sections(unsigned long virt, unsigned long size)
140 {
141 	unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
142 	pgd_t *pgd;
143 	pud_t *pud;
144 	pmd_t *pmdp;
145 
146 	flush_cache_vunmap(addr, end);
147 	pgd = pgd_offset_k(addr);
148 	pud = pud_offset(pgd, addr);
149 	pmdp = pmd_offset(pud, addr);
150 	do {
151 		pmd_t pmd = *pmdp;
152 
153 		if (!pmd_none(pmd)) {
154 			/*
155 			 * Clear the PMD from the page table, and
156 			 * increment the vmalloc sequence so others
157 			 * notice this change.
158 			 *
159 			 * Note: this is still racy on SMP machines.
160 			 */
161 			pmd_clear(pmdp);
162 			init_mm.context.vmalloc_seq++;
163 
164 			/*
165 			 * Free the page table, if there was one.
166 			 */
167 			if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
168 				pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
169 		}
170 
171 		addr += PMD_SIZE;
172 		pmdp += 2;
173 	} while (addr < end);
174 
175 	/*
176 	 * Ensure that the active_mm is up to date - we want to
177 	 * catch any use-after-iounmap cases.
178 	 */
179 	if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)
180 		__check_vmalloc_seq(current->active_mm);
181 
182 	flush_tlb_kernel_range(virt, end);
183 }
184 
185 static int
186 remap_area_sections(unsigned long virt, unsigned long pfn,
187 		    size_t size, const struct mem_type *type)
188 {
189 	unsigned long addr = virt, end = virt + size;
190 	pgd_t *pgd;
191 	pud_t *pud;
192 	pmd_t *pmd;
193 
194 	/*
195 	 * Remove and free any PTE-based mapping, and
196 	 * sync the current kernel mapping.
197 	 */
198 	unmap_area_sections(virt, size);
199 
200 	pgd = pgd_offset_k(addr);
201 	pud = pud_offset(pgd, addr);
202 	pmd = pmd_offset(pud, addr);
203 	do {
204 		pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
205 		pfn += SZ_1M >> PAGE_SHIFT;
206 		pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
207 		pfn += SZ_1M >> PAGE_SHIFT;
208 		flush_pmd_entry(pmd);
209 
210 		addr += PMD_SIZE;
211 		pmd += 2;
212 	} while (addr < end);
213 
214 	return 0;
215 }
216 
217 static int
218 remap_area_supersections(unsigned long virt, unsigned long pfn,
219 			 size_t size, const struct mem_type *type)
220 {
221 	unsigned long addr = virt, end = virt + size;
222 	pgd_t *pgd;
223 	pud_t *pud;
224 	pmd_t *pmd;
225 
226 	/*
227 	 * Remove and free any PTE-based mapping, and
228 	 * sync the current kernel mapping.
229 	 */
230 	unmap_area_sections(virt, size);
231 
232 	pgd = pgd_offset_k(virt);
233 	pud = pud_offset(pgd, addr);
234 	pmd = pmd_offset(pud, addr);
235 	do {
236 		unsigned long super_pmd_val, i;
237 
238 		super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
239 				PMD_SECT_SUPER;
240 		super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
241 
242 		for (i = 0; i < 8; i++) {
243 			pmd[0] = __pmd(super_pmd_val);
244 			pmd[1] = __pmd(super_pmd_val);
245 			flush_pmd_entry(pmd);
246 
247 			addr += PMD_SIZE;
248 			pmd += 2;
249 		}
250 
251 		pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
252 	} while (addr < end);
253 
254 	return 0;
255 }
256 #endif
257 
258 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
259 	unsigned long offset, size_t size, unsigned int mtype, void *caller)
260 {
261 	const struct mem_type *type;
262 	int err;
263 	unsigned long addr;
264 	struct vm_struct *area;
265 	phys_addr_t paddr = __pfn_to_phys(pfn);
266 
267 #ifndef CONFIG_ARM_LPAE
268 	/*
269 	 * High mappings must be supersection aligned
270 	 */
271 	if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
272 		return NULL;
273 #endif
274 
275 	type = get_mem_type(mtype);
276 	if (!type)
277 		return NULL;
278 
279 	/*
280 	 * Page align the mapping size, taking account of any offset.
281 	 */
282 	size = PAGE_ALIGN(offset + size);
283 
284 	/*
285 	 * Try to reuse one of the static mapping whenever possible.
286 	 */
287 	if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
288 		struct static_vm *svm;
289 
290 		svm = find_static_vm_paddr(paddr, size, mtype);
291 		if (svm) {
292 			addr = (unsigned long)svm->vm.addr;
293 			addr += paddr - svm->vm.phys_addr;
294 			return (void __iomem *) (offset + addr);
295 		}
296 	}
297 
298 	/*
299 	 * Don't allow RAM to be mapped - this causes problems with ARMv6+
300 	 */
301 	if (WARN_ON(pfn_valid(pfn)))
302 		return NULL;
303 
304 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
305  	if (!area)
306  		return NULL;
307  	addr = (unsigned long)area->addr;
308 	area->phys_addr = paddr;
309 
310 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
311 	if (DOMAIN_IO == 0 &&
312 	    (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
313 	       cpu_is_xsc3()) && pfn >= 0x100000 &&
314 	       !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
315 		area->flags |= VM_ARM_SECTION_MAPPING;
316 		err = remap_area_supersections(addr, pfn, size, type);
317 	} else if (!((paddr | size | addr) & ~PMD_MASK)) {
318 		area->flags |= VM_ARM_SECTION_MAPPING;
319 		err = remap_area_sections(addr, pfn, size, type);
320 	} else
321 #endif
322 		err = ioremap_page_range(addr, addr + size, paddr,
323 					 __pgprot(type->prot_pte));
324 
325 	if (err) {
326  		vunmap((void *)addr);
327  		return NULL;
328  	}
329 
330 	flush_cache_vmap(addr, addr + size);
331 	return (void __iomem *) (offset + addr);
332 }
333 
334 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
335 	unsigned int mtype, void *caller)
336 {
337 	phys_addr_t last_addr;
338  	unsigned long offset = phys_addr & ~PAGE_MASK;
339  	unsigned long pfn = __phys_to_pfn(phys_addr);
340 
341  	/*
342  	 * Don't allow wraparound or zero size
343 	 */
344 	last_addr = phys_addr + size - 1;
345 	if (!size || last_addr < phys_addr)
346 		return NULL;
347 
348 	return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
349 			caller);
350 }
351 
352 /*
353  * Remap an arbitrary physical address space into the kernel virtual
354  * address space. Needed when the kernel wants to access high addresses
355  * directly.
356  *
357  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
358  * have to convert them into an offset in a page-aligned mapping, but the
359  * caller shouldn't need to know that small detail.
360  */
361 void __iomem *
362 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
363 		  unsigned int mtype)
364 {
365 	return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
366 			__builtin_return_address(0));
367 }
368 EXPORT_SYMBOL(__arm_ioremap_pfn);
369 
370 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
371 				      unsigned int, void *) =
372 	__arm_ioremap_caller;
373 
374 void __iomem *
375 __arm_ioremap(phys_addr_t phys_addr, size_t size, unsigned int mtype)
376 {
377 	return arch_ioremap_caller(phys_addr, size, mtype,
378 		__builtin_return_address(0));
379 }
380 EXPORT_SYMBOL(__arm_ioremap);
381 
382 /*
383  * Remap an arbitrary physical address space into the kernel virtual
384  * address space as memory. Needed when the kernel wants to execute
385  * code in external memory. This is needed for reprogramming source
386  * clocks that would affect normal memory for example. Please see
387  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
388  */
389 void __iomem *
390 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
391 {
392 	unsigned int mtype;
393 
394 	if (cached)
395 		mtype = MT_MEMORY_RWX;
396 	else
397 		mtype = MT_MEMORY_RWX_NONCACHED;
398 
399 	return __arm_ioremap_caller(phys_addr, size, mtype,
400 			__builtin_return_address(0));
401 }
402 
403 void __iounmap(volatile void __iomem *io_addr)
404 {
405 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
406 	struct static_vm *svm;
407 
408 	/* If this is a static mapping, we must leave it alone */
409 	svm = find_static_vm_vaddr(addr);
410 	if (svm)
411 		return;
412 
413 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
414 	{
415 		struct vm_struct *vm;
416 
417 		vm = find_vm_area(addr);
418 
419 		/*
420 		 * If this is a section based mapping we need to handle it
421 		 * specially as the VM subsystem does not know how to handle
422 		 * such a beast.
423 		 */
424 		if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
425 			unmap_area_sections((unsigned long)vm->addr, vm->size);
426 	}
427 #endif
428 
429 	vunmap(addr);
430 }
431 
432 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
433 
434 void __arm_iounmap(volatile void __iomem *io_addr)
435 {
436 	arch_iounmap(io_addr);
437 }
438 EXPORT_SYMBOL(__arm_iounmap);
439 
440 #ifdef CONFIG_PCI
441 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
442 {
443 	BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);
444 
445 	return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
446 				  PCI_IO_VIRT_BASE + offset + SZ_64K,
447 				  phys_addr,
448 				  __pgprot(get_mem_type(MT_DEVICE)->prot_pte));
449 }
450 EXPORT_SYMBOL_GPL(pci_ioremap_io);
451 #endif
452