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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2021 Intel Corporation
4  * Author: Johannes Berg <johannes@sipsolutions.net>
5  */
6 #include <linux/types.h>
7 #include <linux/slab.h>
8 #include <linux/logic_iomem.h>
9 #include <asm/io.h>
10 
11 struct logic_iomem_region {
12 	const struct resource *res;
13 	const struct logic_iomem_region_ops *ops;
14 	struct list_head list;
15 };
16 
17 struct logic_iomem_area {
18 	const struct logic_iomem_ops *ops;
19 	void *priv;
20 };
21 
22 #define AREA_SHIFT	24
23 #define MAX_AREA_SIZE	(1 << AREA_SHIFT)
24 #define MAX_AREAS	((1U << 31) / MAX_AREA_SIZE)
25 #define AREA_BITS	((MAX_AREAS - 1) << AREA_SHIFT)
26 #define AREA_MASK	(MAX_AREA_SIZE - 1)
27 #ifdef CONFIG_64BIT
28 #define IOREMAP_BIAS	0xDEAD000000000000UL
29 #define IOREMAP_MASK	0xFFFFFFFF00000000UL
30 #else
31 #define IOREMAP_BIAS	0x80000000UL
32 #define IOREMAP_MASK	0x80000000UL
33 #endif
34 
35 static DEFINE_MUTEX(regions_mtx);
36 static LIST_HEAD(regions_list);
37 static struct logic_iomem_area mapped_areas[MAX_AREAS];
38 
logic_iomem_add_region(struct resource * resource,const struct logic_iomem_region_ops * ops)39 int logic_iomem_add_region(struct resource *resource,
40 			   const struct logic_iomem_region_ops *ops)
41 {
42 	struct logic_iomem_region *rreg;
43 	int err;
44 
45 	if (WARN_ON(!resource || !ops))
46 		return -EINVAL;
47 
48 	if (WARN_ON((resource->flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM))
49 		return -EINVAL;
50 
51 	rreg = kzalloc(sizeof(*rreg), GFP_KERNEL);
52 	if (!rreg)
53 		return -ENOMEM;
54 
55 	err = request_resource(&iomem_resource, resource);
56 	if (err) {
57 		kfree(rreg);
58 		return -ENOMEM;
59 	}
60 
61 	mutex_lock(&regions_mtx);
62 	rreg->res = resource;
63 	rreg->ops = ops;
64 	list_add_tail(&rreg->list, &regions_list);
65 	mutex_unlock(&regions_mtx);
66 
67 	return 0;
68 }
69 EXPORT_SYMBOL(logic_iomem_add_region);
70 
71 #ifndef CONFIG_INDIRECT_IOMEM_FALLBACK
real_ioremap(phys_addr_t offset,size_t size)72 static void __iomem *real_ioremap(phys_addr_t offset, size_t size)
73 {
74 	WARN(1, "invalid ioremap(0x%llx, 0x%zx)\n",
75 	     (unsigned long long)offset, size);
76 	return NULL;
77 }
78 
real_iounmap(void __iomem * addr)79 static void real_iounmap(void __iomem *addr)
80 {
81 	WARN(1, "invalid iounmap for addr 0x%llx\n",
82 	     (unsigned long long)(uintptr_t __force)addr);
83 }
84 #endif /* CONFIG_INDIRECT_IOMEM_FALLBACK */
85 
ioremap(phys_addr_t offset,size_t size)86 void __iomem *ioremap(phys_addr_t offset, size_t size)
87 {
88 	void __iomem *ret = NULL;
89 	struct logic_iomem_region *rreg, *found = NULL;
90 	int i;
91 
92 	mutex_lock(&regions_mtx);
93 	list_for_each_entry(rreg, &regions_list, list) {
94 		if (rreg->res->start > offset)
95 			continue;
96 		if (rreg->res->end < offset + size - 1)
97 			continue;
98 		found = rreg;
99 		break;
100 	}
101 
102 	if (!found)
103 		goto out;
104 
105 	for (i = 0; i < MAX_AREAS; i++) {
106 		long offs;
107 
108 		if (mapped_areas[i].ops)
109 			continue;
110 
111 		offs = rreg->ops->map(offset - found->res->start,
112 				      size, &mapped_areas[i].ops,
113 				      &mapped_areas[i].priv);
114 		if (offs < 0) {
115 			mapped_areas[i].ops = NULL;
116 			break;
117 		}
118 
119 		if (WARN_ON(!mapped_areas[i].ops)) {
120 			mapped_areas[i].ops = NULL;
121 			break;
122 		}
123 
124 		ret = (void __iomem *)(IOREMAP_BIAS + (i << AREA_SHIFT) + offs);
125 		break;
126 	}
127 out:
128 	mutex_unlock(&regions_mtx);
129 	if (ret)
130 		return ret;
131 	return real_ioremap(offset, size);
132 }
133 EXPORT_SYMBOL(ioremap);
134 
135 static inline struct logic_iomem_area *
get_area(const volatile void __iomem * addr)136 get_area(const volatile void __iomem *addr)
137 {
138 	unsigned long a = (unsigned long)addr;
139 	unsigned int idx;
140 
141 	if (WARN_ON((a & IOREMAP_MASK) != IOREMAP_BIAS))
142 		return NULL;
143 
144 	idx = (a & AREA_BITS) >> AREA_SHIFT;
145 
146 	if (mapped_areas[idx].ops)
147 		return &mapped_areas[idx];
148 
149 	return NULL;
150 }
151 
iounmap(void __iomem * addr)152 void iounmap(void __iomem *addr)
153 {
154 	struct logic_iomem_area *area = get_area(addr);
155 
156 	if (!area) {
157 		real_iounmap(addr);
158 		return;
159 	}
160 
161 	if (area->ops->unmap)
162 		area->ops->unmap(area->priv);
163 
164 	mutex_lock(&regions_mtx);
165 	area->ops = NULL;
166 	area->priv = NULL;
167 	mutex_unlock(&regions_mtx);
168 }
169 EXPORT_SYMBOL(iounmap);
170 
171 #ifndef CONFIG_INDIRECT_IOMEM_FALLBACK
172 #define MAKE_FALLBACK(op, sz) 						\
173 static u##sz real_raw_read ## op(const volatile void __iomem *addr)	\
174 {									\
175 	WARN(1, "Invalid read" #op " at address %llx\n",		\
176 	     (unsigned long long)(uintptr_t __force)addr);		\
177 	return (u ## sz)~0ULL;						\
178 }									\
179 									\
180 static void real_raw_write ## op(u ## sz val,				\
181 				 volatile void __iomem *addr)		\
182 {									\
183 	WARN(1, "Invalid writeq" #op " of 0x%llx at address %llx\n",	\
184 	     (unsigned long long)val,					\
185 	     (unsigned long long)(uintptr_t __force)addr);\
186 }									\
187 
188 MAKE_FALLBACK(b, 8);
189 MAKE_FALLBACK(w, 16);
190 MAKE_FALLBACK(l, 32);
191 #ifdef CONFIG_64BIT
192 MAKE_FALLBACK(q, 64);
193 #endif
194 
real_memset_io(volatile void __iomem * addr,int value,size_t size)195 static void real_memset_io(volatile void __iomem *addr, int value, size_t size)
196 {
197 	WARN(1, "Invalid memset_io at address 0x%llx\n",
198 	     (unsigned long long)(uintptr_t __force)addr);
199 }
200 
real_memcpy_fromio(void * buffer,const volatile void __iomem * addr,size_t size)201 static void real_memcpy_fromio(void *buffer, const volatile void __iomem *addr,
202 			       size_t size)
203 {
204 	WARN(1, "Invalid memcpy_fromio at address 0x%llx\n",
205 	     (unsigned long long)(uintptr_t __force)addr);
206 
207 	memset(buffer, 0xff, size);
208 }
209 
real_memcpy_toio(volatile void __iomem * addr,const void * buffer,size_t size)210 static void real_memcpy_toio(volatile void __iomem *addr, const void *buffer,
211 			     size_t size)
212 {
213 	WARN(1, "Invalid memcpy_toio at address 0x%llx\n",
214 	     (unsigned long long)(uintptr_t __force)addr);
215 }
216 #endif /* CONFIG_INDIRECT_IOMEM_FALLBACK */
217 
218 #define MAKE_OP(op, sz) 						\
219 u##sz __raw_read ## op(const volatile void __iomem *addr)		\
220 {									\
221 	struct logic_iomem_area *area = get_area(addr);			\
222 									\
223 	if (!area)							\
224 		return real_raw_read ## op(addr);			\
225 									\
226 	return (u ## sz) area->ops->read(area->priv,			\
227 					 (unsigned long)addr & AREA_MASK,\
228 					 sz / 8);			\
229 }									\
230 EXPORT_SYMBOL(__raw_read ## op);					\
231 									\
232 void __raw_write ## op(u ## sz val, volatile void __iomem *addr)	\
233 {									\
234 	struct logic_iomem_area *area = get_area(addr);			\
235 									\
236 	if (!area) {							\
237 		real_raw_write ## op(val, addr);			\
238 		return;							\
239 	}								\
240 									\
241 	area->ops->write(area->priv,					\
242 			 (unsigned long)addr & AREA_MASK,		\
243 			 sz / 8, val);					\
244 }									\
245 EXPORT_SYMBOL(__raw_write ## op)
246 
247 MAKE_OP(b, 8);
248 MAKE_OP(w, 16);
249 MAKE_OP(l, 32);
250 #ifdef CONFIG_64BIT
251 MAKE_OP(q, 64);
252 #endif
253 
memset_io(volatile void __iomem * addr,int value,size_t size)254 void memset_io(volatile void __iomem *addr, int value, size_t size)
255 {
256 	struct logic_iomem_area *area = get_area(addr);
257 	unsigned long offs, start;
258 
259 	if (!area) {
260 		real_memset_io(addr, value, size);
261 		return;
262 	}
263 
264 	start = (unsigned long)addr & AREA_MASK;
265 
266 	if (area->ops->set) {
267 		area->ops->set(area->priv, start, value, size);
268 		return;
269 	}
270 
271 	for (offs = 0; offs < size; offs++)
272 		area->ops->write(area->priv, start + offs, 1, value);
273 }
274 EXPORT_SYMBOL(memset_io);
275 
memcpy_fromio(void * buffer,const volatile void __iomem * addr,size_t size)276 void memcpy_fromio(void *buffer, const volatile void __iomem *addr,
277                    size_t size)
278 {
279 	struct logic_iomem_area *area = get_area(addr);
280 	u8 *buf = buffer;
281 	unsigned long offs, start;
282 
283 	if (!area) {
284 		real_memcpy_fromio(buffer, addr, size);
285 		return;
286 	}
287 
288 	start = (unsigned long)addr & AREA_MASK;
289 
290 	if (area->ops->copy_from) {
291 		area->ops->copy_from(area->priv, buffer, start, size);
292 		return;
293 	}
294 
295 	for (offs = 0; offs < size; offs++)
296 		buf[offs] = area->ops->read(area->priv, start + offs, 1);
297 }
298 EXPORT_SYMBOL(memcpy_fromio);
299 
memcpy_toio(volatile void __iomem * addr,const void * buffer,size_t size)300 void memcpy_toio(volatile void __iomem *addr, const void *buffer, size_t size)
301 {
302 	struct logic_iomem_area *area = get_area(addr);
303 	const u8 *buf = buffer;
304 	unsigned long offs, start;
305 
306 	if (!area) {
307 		real_memcpy_toio(addr, buffer, size);
308 		return;
309 	}
310 
311 	start = (unsigned long)addr & AREA_MASK;
312 
313 	if (area->ops->copy_to) {
314 		area->ops->copy_to(area->priv, start, buffer, size);
315 		return;
316 	}
317 
318 	for (offs = 0; offs < size; offs++)
319 		area->ops->write(area->priv, start + offs, 1, buf[offs]);
320 }
321 EXPORT_SYMBOL(memcpy_toio);
322