lib/logic_iomem.c

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