xref: /openbmc/linux/mm/early_ioremap.c (revision f77d1a49) 
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 #include "internal.h"
21 
22 #ifdef CONFIG_MMU
23 static int early_ioremap_debug __initdata;
24 
25 static int __init early_ioremap_debug_setup(char *str)
26 {
27 	early_ioremap_debug = 1;
28 
29 	return 0;
30 }
31 early_param("early_ioremap_debug", early_ioremap_debug_setup);
32 
33 static int after_paging_init __initdata;
34 
35 pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
36 						    unsigned long size,
37 						    pgprot_t prot)
38 {
39 	return prot;
40 }
41 
42 void __init early_ioremap_reset(void)
43 {
44 	after_paging_init = 1;
45 }
46 
47 /*
48  * Generally, ioremap() is available after paging_init() has been called.
49  * Architectures wanting to allow early_ioremap after paging_init() can
50  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
51  */
52 #ifndef __late_set_fixmap
53 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
54 					    phys_addr_t phys, pgprot_t prot)
55 {
56 	BUG();
57 }
58 #endif
59 
60 #ifndef __late_clear_fixmap
61 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
62 {
63 	BUG();
64 }
65 #endif
66 
67 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
68 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
69 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
70 
71 void __init early_ioremap_setup(void)
72 {
73 	int i;
74 
75 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
76 		WARN_ON_ONCE(prev_map[i]);
77 		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
78 	}
79 }
80 
81 static int __init check_early_ioremap_leak(void)
82 {
83 	int count = 0;
84 	int i;
85 
86 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
87 		if (prev_map[i])
88 			count++;
89 
90 	if (WARN(count, KERN_WARNING
91 		 "Debug warning: early ioremap leak of %d areas detected.\n"
92 		 "please boot with early_ioremap_debug and report the dmesg.\n",
93 		 count))
94 		return 1;
95 	return 0;
96 }
97 late_initcall(check_early_ioremap_leak);
98 
99 static void __init __iomem *
100 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
101 {
102 	unsigned long offset;
103 	resource_size_t last_addr;
104 	unsigned int nrpages;
105 	enum fixed_addresses idx;
106 	int i, slot;
107 
108 	WARN_ON(system_state >= SYSTEM_RUNNING);
109 
110 	slot = -1;
111 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
112 		if (!prev_map[i]) {
113 			slot = i;
114 			break;
115 		}
116 	}
117 
118 	if (WARN(slot < 0, "%s(%pa, %08lx) not found slot\n",
119 		 __func__, &phys_addr, size))
120 		return NULL;
121 
122 	/* Don't allow wraparound or zero size */
123 	last_addr = phys_addr + size - 1;
124 	if (WARN_ON(!size || last_addr < phys_addr))
125 		return NULL;
126 
127 	prev_size[slot] = size;
128 	/*
129 	 * Mappings have to be page-aligned
130 	 */
131 	offset = offset_in_page(phys_addr);
132 	phys_addr &= PAGE_MASK;
133 	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
134 
135 	/*
136 	 * Mappings have to fit in the FIX_BTMAP area.
137 	 */
138 	nrpages = size >> PAGE_SHIFT;
139 	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
140 		return NULL;
141 
142 	/*
143 	 * Ok, go for it..
144 	 */
145 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
146 	while (nrpages > 0) {
147 		if (after_paging_init)
148 			__late_set_fixmap(idx, phys_addr, prot);
149 		else
150 			__early_set_fixmap(idx, phys_addr, prot);
151 		phys_addr += PAGE_SIZE;
152 		--idx;
153 		--nrpages;
154 	}
155 	WARN(early_ioremap_debug, "%s(%pa, %08lx) [%d] => %08lx + %08lx\n",
156 	     __func__, &phys_addr, size, slot, offset, slot_virt[slot]);
157 
158 	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
159 	return prev_map[slot];
160 }
161 
162 void __init early_iounmap(void __iomem *addr, unsigned long size)
163 {
164 	unsigned long virt_addr;
165 	unsigned long offset;
166 	unsigned int nrpages;
167 	enum fixed_addresses idx;
168 	int i, slot;
169 
170 	slot = -1;
171 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
172 		if (prev_map[i] == addr) {
173 			slot = i;
174 			break;
175 		}
176 	}
177 
178 	if (WARN(slot < 0, "%s(%p, %08lx) not found slot\n",
179 		  __func__, addr, size))
180 		return;
181 
182 	if (WARN(prev_size[slot] != size,
183 		 "%s(%p, %08lx) [%d] size not consistent %08lx\n",
184 		  __func__, addr, size, slot, prev_size[slot]))
185 		return;
186 
187 	WARN(early_ioremap_debug, "%s(%p, %08lx) [%d]\n",
188 	      __func__, addr, size, slot);
189 
190 	virt_addr = (unsigned long)addr;
191 	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
192 		return;
193 
194 	offset = offset_in_page(virt_addr);
195 	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
196 
197 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
198 	while (nrpages > 0) {
199 		if (after_paging_init)
200 			__late_clear_fixmap(idx);
201 		else
202 			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
203 		--idx;
204 		--nrpages;
205 	}
206 	prev_map[slot] = NULL;
207 }
208 
209 /* Remap an IO device */
210 void __init __iomem *
211 early_ioremap(resource_size_t phys_addr, unsigned long size)
212 {
213 	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
214 }
215 
216 /* Remap memory */
217 void __init *
218 early_memremap(resource_size_t phys_addr, unsigned long size)
219 {
220 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
221 						     FIXMAP_PAGE_NORMAL);
222 
223 	return (__force void *)__early_ioremap(phys_addr, size, prot);
224 }
225 #ifdef FIXMAP_PAGE_RO
226 void __init *
227 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
228 {
229 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
230 						     FIXMAP_PAGE_RO);
231 
232 	return (__force void *)__early_ioremap(phys_addr, size, prot);
233 }
234 #endif
235 
236 #ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
237 void __init *
238 early_memremap_prot(resource_size_t phys_addr, unsigned long size,
239 		    unsigned long prot_val)
240 {
241 	return (__force void *)__early_ioremap(phys_addr, size,
242 					       __pgprot(prot_val));
243 }
244 #endif
245 
246 #define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
247 
248 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
249 {
250 	unsigned long slop, clen;
251 	char *p;
252 
253 	while (size) {
254 		slop = offset_in_page(src);
255 		clen = size;
256 		if (clen > MAX_MAP_CHUNK - slop)
257 			clen = MAX_MAP_CHUNK - slop;
258 		p = early_memremap(src & PAGE_MASK, clen + slop);
259 		memcpy(dest, p + slop, clen);
260 		early_memunmap(p, clen + slop);
261 		dest += clen;
262 		src += clen;
263 		size -= clen;
264 	}
265 }
266 
267 #else /* CONFIG_MMU */
268 
269 void __init __iomem *
270 early_ioremap(resource_size_t phys_addr, unsigned long size)
271 {
272 	return (__force void __iomem *)phys_addr;
273 }
274 
275 /* Remap memory */
276 void __init *
277 early_memremap(resource_size_t phys_addr, unsigned long size)
278 {
279 	return (void *)phys_addr;
280 }
281 void __init *
282 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
283 {
284 	return (void *)phys_addr;
285 }
286 
287 void __init early_iounmap(void __iomem *addr, unsigned long size)
288 {
289 }
290 
291 #endif /* CONFIG_MMU */
292 
293 
294 void __init early_memunmap(void *addr, unsigned long size)
295 {
296 	early_iounmap((__force void __iomem *)addr, size);
297 }
298