1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/unicore32/mm/ioremap.c
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Copyright (C) 2001-2010 GUAN Xue-tao
8 *
9 * Re-map IO memory to kernel address space so that we can access it.
10 *
11 * This allows a driver to remap an arbitrary region of bus memory into
12 * virtual space. One should *only* use readl, writel, memcpy_toio and
13 * so on with such remapped areas.
14 *
15 * Because UniCore only has a 32-bit address space we can't address the
16 * whole of the (physical) PCI space at once. PCI huge-mode addressing
17 * allows us to circumvent this restriction by splitting PCI space into
18 * two 2GB chunks and mapping only one at a time into processor memory.
19 * We use MMU protection domains to trap any attempt to access the bank
20 * that is not currently mapped. (This isn't fully implemented yet.)
21 */
22 #include <linux/module.h>
23 #include <linux/errno.h>
24 #include <linux/mm.h>
25 #include <linux/vmalloc.h>
26 #include <linux/io.h>
27
28 #include <asm/cputype.h>
29 #include <asm/cacheflush.h>
30 #include <asm/mmu_context.h>
31 #include <asm/pgalloc.h>
32 #include <asm/tlbflush.h>
33 #include <linux/sizes.h>
34
35 #include <mach/map.h>
36 #include "mm.h"
37
38 /*
39 * Used by ioremap() and iounmap() code to mark (super)section-mapped
40 * I/O regions in vm_struct->flags field.
41 */
42 #define VM_UNICORE_SECTION_MAPPING 0x80000000
43
ioremap_page(unsigned long virt,unsigned long phys,const struct mem_type * mtype)44 int ioremap_page(unsigned long virt, unsigned long phys,
45 const struct mem_type *mtype)
46 {
47 return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
48 __pgprot(mtype->prot_pte));
49 }
50 EXPORT_SYMBOL(ioremap_page);
51
52 /*
53 * Section support is unsafe on SMP - If you iounmap and ioremap a region,
54 * the other CPUs will not see this change until their next context switch.
55 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
56 * which requires the new ioremap'd region to be referenced, the CPU will
57 * reference the _old_ region.
58 *
59 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
60 * mask the size back to 4MB aligned or we will overflow in the loop below.
61 */
unmap_area_sections(unsigned long virt,unsigned long size)62 static void unmap_area_sections(unsigned long virt, unsigned long size)
63 {
64 unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
65 pgd_t *pgd;
66
67 flush_cache_vunmap(addr, end);
68 pgd = pgd_offset_k(addr);
69 do {
70 pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);
71
72 pmd = *pmdp;
73 if (!pmd_none(pmd)) {
74 /*
75 * Clear the PMD from the page table, and
76 * increment the kvm sequence so others
77 * notice this change.
78 *
79 * Note: this is still racy on SMP machines.
80 */
81 pmd_clear(pmdp);
82
83 /*
84 * Free the page table, if there was one.
85 */
86 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
87 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
88 }
89
90 addr += PGDIR_SIZE;
91 pgd++;
92 } while (addr < end);
93
94 flush_tlb_kernel_range(virt, end);
95 }
96
97 static int
remap_area_sections(unsigned long virt,unsigned long pfn,size_t size,const struct mem_type * type)98 remap_area_sections(unsigned long virt, unsigned long pfn,
99 size_t size, const struct mem_type *type)
100 {
101 unsigned long addr = virt, end = virt + size;
102 pgd_t *pgd;
103
104 /*
105 * Remove and free any PTE-based mapping, and
106 * sync the current kernel mapping.
107 */
108 unmap_area_sections(virt, size);
109
110 pgd = pgd_offset_k(addr);
111 do {
112 pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
113
114 set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
115 pfn += SZ_4M >> PAGE_SHIFT;
116 flush_pmd_entry(pmd);
117
118 addr += PGDIR_SIZE;
119 pgd++;
120 } while (addr < end);
121
122 return 0;
123 }
124
__uc32_ioremap_pfn_caller(unsigned long pfn,unsigned long offset,size_t size,unsigned int mtype,void * caller)125 void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
126 unsigned long offset, size_t size, unsigned int mtype, void *caller)
127 {
128 const struct mem_type *type;
129 int err;
130 unsigned long addr;
131 struct vm_struct *area;
132
133 /*
134 * High mappings must be section aligned
135 */
136 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
137 return NULL;
138
139 /*
140 * Don't allow RAM to be mapped
141 */
142 if (pfn_valid(pfn)) {
143 WARN(1, "BUG: Your driver calls ioremap() on\n"
144 "system memory. This leads to architecturally\n"
145 "unpredictable behaviour, and ioremap() will fail in\n"
146 "the next kernel release. Please fix your driver.\n");
147 return NULL;
148 }
149
150 type = get_mem_type(mtype);
151 if (!type)
152 return NULL;
153
154 /*
155 * Page align the mapping size, taking account of any offset.
156 */
157 size = PAGE_ALIGN(offset + size);
158
159 area = get_vm_area_caller(size, VM_IOREMAP, caller);
160 if (!area)
161 return NULL;
162 addr = (unsigned long)area->addr;
163
164 if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
165 area->flags |= VM_UNICORE_SECTION_MAPPING;
166 err = remap_area_sections(addr, pfn, size, type);
167 } else
168 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
169 __pgprot(type->prot_pte));
170
171 if (err) {
172 vunmap((void *)addr);
173 return NULL;
174 }
175
176 flush_cache_vmap(addr, addr + size);
177 return (void __iomem *) (offset + addr);
178 }
179
__uc32_ioremap_caller(unsigned long phys_addr,size_t size,unsigned int mtype,void * caller)180 void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
181 unsigned int mtype, void *caller)
182 {
183 unsigned long last_addr;
184 unsigned long offset = phys_addr & ~PAGE_MASK;
185 unsigned long pfn = __phys_to_pfn(phys_addr);
186
187 /*
188 * Don't allow wraparound or zero size
189 */
190 last_addr = phys_addr + size - 1;
191 if (!size || last_addr < phys_addr)
192 return NULL;
193
194 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
195 }
196
197 /*
198 * Remap an arbitrary physical address space into the kernel virtual
199 * address space. Needed when the kernel wants to access high addresses
200 * directly.
201 *
202 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
203 * have to convert them into an offset in a page-aligned mapping, but the
204 * caller shouldn't need to know that small detail.
205 */
206 void __iomem *
__uc32_ioremap_pfn(unsigned long pfn,unsigned long offset,size_t size,unsigned int mtype)207 __uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
208 unsigned int mtype)
209 {
210 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
211 __builtin_return_address(0));
212 }
213 EXPORT_SYMBOL(__uc32_ioremap_pfn);
214
215 void __iomem *
__uc32_ioremap(unsigned long phys_addr,size_t size)216 __uc32_ioremap(unsigned long phys_addr, size_t size)
217 {
218 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
219 __builtin_return_address(0));
220 }
221 EXPORT_SYMBOL(__uc32_ioremap);
222
223 void __iomem *
__uc32_ioremap_cached(unsigned long phys_addr,size_t size)224 __uc32_ioremap_cached(unsigned long phys_addr, size_t size)
225 {
226 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED,
227 __builtin_return_address(0));
228 }
229 EXPORT_SYMBOL(__uc32_ioremap_cached);
230
__uc32_iounmap(volatile void __iomem * io_addr)231 void __uc32_iounmap(volatile void __iomem *io_addr)
232 {
233 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
234 struct vm_struct *vm;
235
236 /*
237 * If this is a section based mapping we need to handle it
238 * specially as the VM subsystem does not know how to handle
239 * such a beast. We need the lock here b/c we need to clear
240 * all the mappings before the area can be reclaimed
241 * by someone else.
242 */
243 vm = find_vm_area(addr);
244 if (vm && (vm->flags & VM_IOREMAP) &&
245 (vm->flags & VM_UNICORE_SECTION_MAPPING))
246 unmap_area_sections((unsigned long)vm->addr, vm->size);
247
248 vunmap(addr);
249 }
250 EXPORT_SYMBOL(__uc32_iounmap);
251