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 
early_ioremap_debug_setup(char * str)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 
early_memremap_pgprot_adjust(resource_size_t phys_addr,unsigned long size,pgprot_t prot)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 
early_ioremap_shutdown(void)41 void __init __weak early_ioremap_shutdown(void)
42 {
43 }
44 
early_ioremap_reset(void)45 void __init early_ioremap_reset(void)
46 {
47 	early_ioremap_shutdown();
48 	after_paging_init = 1;
49 }
50 
51 /*
52  * Generally, ioremap() is available after paging_init() has been called.
53  * Architectures wanting to allow early_ioremap after paging_init() can
54  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
55  */
56 #ifndef __late_set_fixmap
__late_set_fixmap(enum fixed_addresses idx,phys_addr_t phys,pgprot_t prot)57 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
58 					    phys_addr_t phys, pgprot_t prot)
59 {
60 	BUG();
61 }
62 #endif
63 
64 #ifndef __late_clear_fixmap
__late_clear_fixmap(enum fixed_addresses idx)65 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
66 {
67 	BUG();
68 }
69 #endif
70 
71 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
72 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
73 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
74 
early_ioremap_setup(void)75 void __init early_ioremap_setup(void)
76 {
77 	int i;
78 
79 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
80 		if (WARN_ON(prev_map[i]))
81 			break;
82 
83 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
84 		slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
85 }
86 
check_early_ioremap_leak(void)87 static int __init check_early_ioremap_leak(void)
88 {
89 	int count = 0;
90 	int i;
91 
92 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
93 		if (prev_map[i])
94 			count++;
95 
96 	if (WARN(count, KERN_WARNING
97 		 "Debug warning: early ioremap leak of %d areas detected.\n"
98 		 "please boot with early_ioremap_debug and report the dmesg.\n",
99 		 count))
100 		return 1;
101 	return 0;
102 }
103 late_initcall(check_early_ioremap_leak);
104 
105 static void __init __iomem *
__early_ioremap(resource_size_t phys_addr,unsigned long size,pgprot_t prot)106 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
107 {
108 	unsigned long offset;
109 	resource_size_t last_addr;
110 	unsigned int nrpages;
111 	enum fixed_addresses idx;
112 	int i, slot;
113 
114 	WARN_ON(system_state >= SYSTEM_RUNNING);
115 
116 	slot = -1;
117 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
118 		if (!prev_map[i]) {
119 			slot = i;
120 			break;
121 		}
122 	}
123 
124 	if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
125 		 __func__, (u64)phys_addr, size))
126 		return NULL;
127 
128 	/* Don't allow wraparound or zero size */
129 	last_addr = phys_addr + size - 1;
130 	if (WARN_ON(!size || last_addr < phys_addr))
131 		return NULL;
132 
133 	prev_size[slot] = size;
134 	/*
135 	 * Mappings have to be page-aligned
136 	 */
137 	offset = offset_in_page(phys_addr);
138 	phys_addr &= PAGE_MASK;
139 	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
140 
141 	/*
142 	 * Mappings have to fit in the FIX_BTMAP area.
143 	 */
144 	nrpages = size >> PAGE_SHIFT;
145 	if (WARN_ON(nrpages > NR_FIX_BTMAPS))
146 		return NULL;
147 
148 	/*
149 	 * Ok, go for it..
150 	 */
151 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
152 	while (nrpages > 0) {
153 		if (after_paging_init)
154 			__late_set_fixmap(idx, phys_addr, prot);
155 		else
156 			__early_set_fixmap(idx, phys_addr, prot);
157 		phys_addr += PAGE_SIZE;
158 		--idx;
159 		--nrpages;
160 	}
161 	WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
162 	     __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
163 
164 	prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
165 	return prev_map[slot];
166 }
167 
early_iounmap(void __iomem * addr,unsigned long size)168 void __init early_iounmap(void __iomem *addr, unsigned long size)
169 {
170 	unsigned long virt_addr;
171 	unsigned long offset;
172 	unsigned int nrpages;
173 	enum fixed_addresses idx;
174 	int i, slot;
175 
176 	slot = -1;
177 	for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
178 		if (prev_map[i] == addr) {
179 			slot = i;
180 			break;
181 		}
182 	}
183 
184 	if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
185 		 addr, size))
186 		return;
187 
188 	if (WARN(prev_size[slot] != size,
189 		 "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
190 		 addr, size, slot, prev_size[slot]))
191 		return;
192 
193 	WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
194 	     addr, size, slot);
195 
196 	virt_addr = (unsigned long)addr;
197 	if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
198 		return;
199 
200 	offset = offset_in_page(virt_addr);
201 	nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
202 
203 	idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
204 	while (nrpages > 0) {
205 		if (after_paging_init)
206 			__late_clear_fixmap(idx);
207 		else
208 			__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
209 		--idx;
210 		--nrpages;
211 	}
212 	prev_map[slot] = NULL;
213 }
214 
215 /* Remap an IO device */
216 void __init __iomem *
early_ioremap(resource_size_t phys_addr,unsigned long size)217 early_ioremap(resource_size_t phys_addr, unsigned long size)
218 {
219 	return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
220 }
221 
222 /* Remap memory */
223 void __init *
early_memremap(resource_size_t phys_addr,unsigned long size)224 early_memremap(resource_size_t phys_addr, unsigned long size)
225 {
226 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
227 						     FIXMAP_PAGE_NORMAL);
228 
229 	return (__force void *)__early_ioremap(phys_addr, size, prot);
230 }
231 #ifdef FIXMAP_PAGE_RO
232 void __init *
early_memremap_ro(resource_size_t phys_addr,unsigned long size)233 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
234 {
235 	pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
236 						     FIXMAP_PAGE_RO);
237 
238 	return (__force void *)__early_ioremap(phys_addr, size, prot);
239 }
240 #endif
241 
242 #ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
243 void __init *
early_memremap_prot(resource_size_t phys_addr,unsigned long size,unsigned long prot_val)244 early_memremap_prot(resource_size_t phys_addr, unsigned long size,
245 		    unsigned long prot_val)
246 {
247 	return (__force void *)__early_ioremap(phys_addr, size,
248 					       __pgprot(prot_val));
249 }
250 #endif
251 
252 #define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
253 
copy_from_early_mem(void * dest,phys_addr_t src,unsigned long size)254 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
255 {
256 	unsigned long slop, clen;
257 	char *p;
258 
259 	while (size) {
260 		slop = offset_in_page(src);
261 		clen = size;
262 		if (clen > MAX_MAP_CHUNK - slop)
263 			clen = MAX_MAP_CHUNK - slop;
264 		p = early_memremap(src & PAGE_MASK, clen + slop);
265 		memcpy(dest, p + slop, clen);
266 		early_memunmap(p, clen + slop);
267 		dest += clen;
268 		src += clen;
269 		size -= clen;
270 	}
271 }
272 
273 #else /* CONFIG_MMU */
274 
275 void __init __iomem *
early_ioremap(resource_size_t phys_addr,unsigned long size)276 early_ioremap(resource_size_t phys_addr, unsigned long size)
277 {
278 	return (__force void __iomem *)phys_addr;
279 }
280 
281 /* Remap memory */
282 void __init *
early_memremap(resource_size_t phys_addr,unsigned long size)283 early_memremap(resource_size_t phys_addr, unsigned long size)
284 {
285 	return (void *)phys_addr;
286 }
287 void __init *
early_memremap_ro(resource_size_t phys_addr,unsigned long size)288 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
289 {
290 	return (void *)phys_addr;
291 }
292 
early_iounmap(void __iomem * addr,unsigned long size)293 void __init early_iounmap(void __iomem *addr, unsigned long size)
294 {
295 }
296 
297 #endif /* CONFIG_MMU */
298 
299 
early_memunmap(void * addr,unsigned long size)300 void __init early_memunmap(void *addr, unsigned long size)
301 {
302 	early_iounmap((__force void __iomem *)addr, size);
303 }
304