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
43LIST_HEAD(static_vmlist);
44
45static 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
68struct 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
87void __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
106int 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}
112EXPORT_SYMBOL(ioremap_page);
113
114void __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 */
139static 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
185static int
186remap_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
217static int
218remap_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
258void __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
334void __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 */
361void __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}
368EXPORT_SYMBOL(__arm_ioremap_pfn);
369
370void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
371				      unsigned int, void *) =
372	__arm_ioremap_caller;
373
374void __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}
380EXPORT_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 */
389void __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
403void __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
432void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
433
434void __arm_iounmap(volatile void __iomem *io_addr)
435{
436	arch_iounmap(io_addr);
437}
438EXPORT_SYMBOL(__arm_iounmap);
439
440#ifdef CONFIG_PCI
441static int pci_ioremap_mem_type = MT_DEVICE;
442
443void pci_ioremap_set_mem_type(int mem_type)
444{
445	pci_ioremap_mem_type = mem_type;
446}
447
448int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
449{
450	BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);
451
452	return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
453				  PCI_IO_VIRT_BASE + offset + SZ_64K,
454				  phys_addr,
455				  __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
456}
457EXPORT_SYMBOL_GPL(pci_ioremap_io);
458#endif
459