xref: /openbmc/linux/mm/early_ioremap.c (revision 0ad53fe3) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Provide common bits of early_ioremap() support for architectures needing
4  * temporary mappings during boot before ioremap() is available.
5  *
6  * This is mostly a direct copy of the x86 early_ioremap implementation.
7  *
8  * (C) Copyright 1995 1996, 2014 Linus Torvalds
9  *
10  */
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/mm.h>
17 #include <linux/vmalloc.h>
18 #include <asm/fixmap.h>
19 #include <asm/early_ioremap.h>
20 
21 #ifdef CONFIG_MMU
22 static int early_ioremap_debug __initdata;
23 
24 static int __init early_ioremap_debug_setup(char *str)
25 {
26 	early_ioremap_debug = 1;
27 
28 	return 0;
29 }
30 early_param("early_ioremap_debug", early_ioremap_debug_setup);
31 
32 static int after_paging_init __initdata;
33 
34 pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
35 						    unsigned long size,
36 						    pgprot_t prot)
37 {
38 	return prot;
39 }
40 
41 void __init early_ioremap_reset(void)
42 {
43 	after_paging_init = 1;
44 }
45 
46 /*
47  * Generally, ioremap() is available after paging_init() has been called.
48  * Architectures wanting to allow early_ioremap after paging_init() can
49  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
50  */
51 #ifndef __late_set_fixmap
52 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
53 					    phys_addr_t phys, pgprot_t prot)
54 {
55 	BUG();
56 }
57 #endif
58 
59 #ifndef __late_clear_fixmap
60 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
61 {
62 	BUG();
63 }
64 #endif
65 
66 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
67 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
68 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
69 
70 void __init early_ioremap_setup(void)
71 {
72 	int i;
73 
74 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
75 		if (WARN_ON(prev_map[i]))
76 			break;
77 
78 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
79 		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
80 }
81 
82 static int __init check_early_ioremap_leak(void)
83 {
84 	int count = 0;
85 	int i;
86 
87 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
88 		if (prev_map[i])
89 			count++;
90 
91 	if (WARN(count, KERN_WARNING
92 		 "Debug warning: early ioremap leak of %d areas detected.\n"
93 		 "please boot with early_ioremap_debug and report the dmesg.\n",
94 		 count))
95 		return 1;
96 	return 0;
97 }
98 late_initcall(check_early_ioremap_leak);
99 
100 static void __init __iomem *
101 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
102 {
103 	unsigned long offset;
104 	resource_size_t last_addr;
105 	unsigned int nrpages;
106 	enum fixed_addresses idx;
107 	int i, slot;
108 
109 	WARN_ON(system_state >= SYSTEM_RUNNING);
110 
111 	slot = -1;
112 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
113 		if (!prev_map[i]) {
114 			slot = i;
115 			break;
116 		}
117 	}
118 
119 	if (WARN(slot < 0, "%s(%pa, %08lx) not found slot\n",
120 		 __func__, &phys_addr, size))
121 		return NULL;
122 
123 	/* Don't allow wraparound or zero size */
124 	last_addr = phys_addr + size - 1;
125 	if (WARN_ON(!size || last_addr < phys_addr))
126 		return NULL;
127 
128 	prev_size[slot] = size;
129 	/*
130 	 * Mappings have to be page-aligned
131 	 */
132 	offset = offset_in_page(phys_addr);
133 	phys_addr &= PAGE_MASK;
134 	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
135 
136 	/*
137 	 * Mappings have to fit in the FIX_BTMAP area.
138 	 */
139 	nrpages = size >> PAGE_SHIFT;
140 	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
141 		return NULL;
142 
143 	/*
144 	 * Ok, go for it..
145 	 */
146 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
147 	while (nrpages > 0) {
148 		if (after_paging_init)
149 			__late_set_fixmap(idx, phys_addr, prot);
150 		else
151 			__early_set_fixmap(idx, phys_addr, prot);
152 		phys_addr += PAGE_SIZE;
153 		--idx;
154 		--nrpages;
155 	}
156 	WARN(early_ioremap_debug, "%s(%pa, %08lx) [%d] => %08lx + %08lx\n",
157 	     __func__, &phys_addr, size, slot, offset, slot_virt[slot]);
158 
159 	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
160 	return prev_map[slot];
161 }
162 
163 void __init early_iounmap(void __iomem *addr, unsigned long size)
164 {
165 	unsigned long virt_addr;
166 	unsigned long offset;
167 	unsigned int nrpages;
168 	enum fixed_addresses idx;
169 	int i, slot;
170 
171 	slot = -1;
172 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
173 		if (prev_map[i] == addr) {
174 			slot = i;
175 			break;
176 		}
177 	}
178 
179 	if (WARN(slot < 0, "%s(%p, %08lx) not found slot\n",
180 		  __func__, addr, size))
181 		return;
182 
183 	if (WARN(prev_size[slot] != size,
184 		 "%s(%p, %08lx) [%d] size not consistent %08lx\n",
185 		  __func__, addr, size, slot, prev_size[slot]))
186 		return;
187 
188 	WARN(early_ioremap_debug, "%s(%p, %08lx) [%d]\n",
189 	      __func__, addr, size, slot);
190 
191 	virt_addr = (unsigned long)addr;
192 	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
193 		return;
194 
195 	offset = offset_in_page(virt_addr);
196 	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
197 
198 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
199 	while (nrpages > 0) {
200 		if (after_paging_init)
201 			__late_clear_fixmap(idx);
202 		else
203 			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
204 		--idx;
205 		--nrpages;
206 	}
207 	prev_map[slot] = NULL;
208 }
209 
210 /* Remap an IO device */
211 void __init __iomem *
212 early_ioremap(resource_size_t phys_addr, unsigned long size)
213 {
214 	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
215 }
216 
217 /* Remap memory */
218 void __init *
219 early_memremap(resource_size_t phys_addr, unsigned long size)
220 {
221 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
222 						     FIXMAP_PAGE_NORMAL);
223 
224 	return (__force void *)__early_ioremap(phys_addr, size, prot);
225 }
226 #ifdef FIXMAP_PAGE_RO
227 void __init *
228 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
229 {
230 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
231 						     FIXMAP_PAGE_RO);
232 
233 	return (__force void *)__early_ioremap(phys_addr, size, prot);
234 }
235 #endif
236 
237 #ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
238 void __init *
239 early_memremap_prot(resource_size_t phys_addr, unsigned long size,
240 		    unsigned long prot_val)
241 {
242 	return (__force void *)__early_ioremap(phys_addr, size,
243 					       __pgprot(prot_val));
244 }
245 #endif
246 
247 #define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
248 
249 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
250 {
251 	unsigned long slop, clen;
252 	char *p;
253 
254 	while (size) {
255 		slop = offset_in_page(src);
256 		clen = size;
257 		if (clen > MAX_MAP_CHUNK - slop)
258 			clen = MAX_MAP_CHUNK - slop;
259 		p = early_memremap(src & PAGE_MASK, clen + slop);
260 		memcpy(dest, p + slop, clen);
261 		early_memunmap(p, clen + slop);
262 		dest += clen;
263 		src += clen;
264 		size -= clen;
265 	}
266 }
267 
268 #else /* CONFIG_MMU */
269 
270 void __init __iomem *
271 early_ioremap(resource_size_t phys_addr, unsigned long size)
272 {
273 	return (__force void __iomem *)phys_addr;
274 }
275 
276 /* Remap memory */
277 void __init *
278 early_memremap(resource_size_t phys_addr, unsigned long size)
279 {
280 	return (void *)phys_addr;
281 }
282 void __init *
283 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
284 {
285 	return (void *)phys_addr;
286 }
287 
288 void __init early_iounmap(void __iomem *addr, unsigned long size)
289 {
290 }
291 
292 #endif /* CONFIG_MMU */
293 
294 
295 void __init early_memunmap(void *addr, unsigned long size)
296 {
297 	early_iounmap((__force void __iomem *)addr, size);
298 }
299