arch/sh/kernel/cpu/sh4/sq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/kernel/cpu/sh4/sq.c
   4  *
   5  * General management API for SH-4 integrated Store Queues
   6  *
   7  * Copyright (C) 2001 - 2006  Paul Mundt
   8  * Copyright (C) 2001, 2002  M. R. Brown
   9  */
  10 #include <linux/init.h>
  11 #include <linux/cpu.h>
  12 #include <linux/bitmap.h>
  13 #include <linux/device.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/mm.h>
  19 #include <linux/io.h>
  20 #include <linux/prefetch.h>
  21 #include <asm/page.h>
  22 #include <asm/cacheflush.h>
  23 #include <cpu/sq.h>
  24
  25 struct sq_mapping;
  26
  27 struct sq_mapping {
  28         const char *name;
  29
  30         unsigned long sq_addr;
  31         unsigned long addr;
  32         unsigned int size;
  33
  34         struct sq_mapping *next;
  35 };
  36
  37 static struct sq_mapping *sq_mapping_list;
  38 static DEFINE_SPINLOCK(sq_mapping_lock);
  39 static struct kmem_cache *sq_cache;
  40 static unsigned long *sq_bitmap;
  41
  42 #define store_queue_barrier()                   \
  43 do {                                            \
  44         (void)__raw_readl(P4SEG_STORE_QUE);     \
  45         __raw_writel(0, P4SEG_STORE_QUE + 0);   \
  46         __raw_writel(0, P4SEG_STORE_QUE + 8);   \
  47 } while (0);
  48
  49 /**
  50  * sq_flush_range - Flush (prefetch) a specific SQ range
  51  * @start: the store queue address to start flushing from
  52  * @len: the length to flush
  53  *
  54  * Flushes the store queue cache from @start to @start + @len in a
  55  * linear fashion.
  56  */
  57 void sq_flush_range(unsigned long start, unsigned int len)
  58 {
  59         unsigned long *sq = (unsigned long *)start;
  60
  61         /* Flush the queues */
  62         for (len >>= 5; len--; sq += 8)
  63                 prefetchw(sq);
  64
  65         /* Wait for completion */
  66         store_queue_barrier();
  67 }
  68 EXPORT_SYMBOL(sq_flush_range);
  69
  70 static inline void sq_mapping_list_add(struct sq_mapping *map)
  71 {
  72         struct sq_mapping **p, *tmp;
  73
  74         spin_lock_irq(&sq_mapping_lock);
  75
  76         p = &sq_mapping_list;
  77         while ((tmp = *p) != NULL)
  78                 p = &tmp->next;
  79
  80         map->next = tmp;
  81         *p = map;
  82
  83         spin_unlock_irq(&sq_mapping_lock);
  84 }
  85
  86 static inline void sq_mapping_list_del(struct sq_mapping *map)
  87 {
  88         struct sq_mapping **p, *tmp;
  89
  90         spin_lock_irq(&sq_mapping_lock);
  91
  92         for (p = &sq_mapping_list; (tmp = *p); p = &tmp->next)
  93                 if (tmp == map) {
  94                         *p = tmp->next;
  95                         break;
  96                 }
  97
  98         spin_unlock_irq(&sq_mapping_lock);
  99 }
 100
 101 static int __sq_remap(struct sq_mapping *map, pgprot_t prot)
 102 {
 103 #if defined(CONFIG_MMU)
 104         struct vm_struct *vma;
 105
 106         vma = __get_vm_area_caller(map->size, VM_IOREMAP, map->sq_addr,
 107                         SQ_ADDRMAX, __builtin_return_address(0));
 108         if (!vma)
 109                 return -ENOMEM;
 110
 111         vma->phys_addr = map->addr;
 112
 113         if (ioremap_page_range((unsigned long)vma->addr,
 114                                (unsigned long)vma->addr + map->size,
 115                                vma->phys_addr, prot)) {
 116                 vunmap(vma->addr);
 117                 return -EAGAIN;
 118         }
 119 #else
 120         /*
 121          * Without an MMU (or with it turned off), this is much more
 122          * straightforward, as we can just load up each queue's QACR with
 123          * the physical address appropriately masked.
 124          */
 125         __raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
 126         __raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
 127 #endif
 128
 129         return 0;
 130 }
 131
 132 /**
 133  * sq_remap - Map a physical address through the Store Queues
 134  * @phys: Physical address of mapping.
 135  * @size: Length of mapping.
 136  * @name: User invoking mapping.
 137  * @prot: Protection bits.
 138  *
 139  * Remaps the physical address @phys through the next available store queue
 140  * address of @size length. @name is logged at boot time as well as through
 141  * the sysfs interface.
 142  */
 143 unsigned long sq_remap(unsigned long phys, unsigned int size,
 144                        const char *name, pgprot_t prot)
 145 {
 146         struct sq_mapping *map;
 147         unsigned long end;
 148         unsigned int psz;
 149         int ret, page;
 150
 151         /* Don't allow wraparound or zero size */
 152         end = phys + size - 1;
 153         if (unlikely(!size || end < phys))
 154                 return -EINVAL;
 155         /* Don't allow anyone to remap normal memory.. */
 156         if (unlikely(phys < virt_to_phys(high_memory)))
 157                 return -EINVAL;
 158
 159         phys &= PAGE_MASK;
 160         size = PAGE_ALIGN(end + 1) - phys;
 161
 162         map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
 163         if (unlikely(!map))
 164                 return -ENOMEM;
 165
 166         map->addr = phys;
 167         map->size = size;
 168         map->name = name;
 169
 170         page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
 171                                        get_order(map->size));
 172         if (unlikely(page < 0)) {
 173                 ret = -ENOSPC;
 174                 goto out;
 175         }
 176
 177         map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
 178
 179         ret = __sq_remap(map, prot);
 180         if (unlikely(ret != 0))
 181                 goto out;
 182
 183         psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 184         pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
 185                 likely(map->name) ? map->name : "???",
 186                 psz, psz == 1 ? " " : "s",
 187                 map->sq_addr, map->addr);
 188
 189         sq_mapping_list_add(map);
 190
 191         return map->sq_addr;
 192
 193 out:
 194         kmem_cache_free(sq_cache, map);
 195         return ret;
 196 }
 197 EXPORT_SYMBOL(sq_remap);
 198
 199 /**
 200  * sq_unmap - Unmap a Store Queue allocation
 201  * @vaddr: Pre-allocated Store Queue mapping.
 202  *
 203  * Unmaps the store queue allocation @map that was previously created by
 204  * sq_remap(). Also frees up the pte that was previously inserted into
 205  * the kernel page table and discards the UTLB translation.
 206  */
 207 void sq_unmap(unsigned long vaddr)
 208 {
 209         struct sq_mapping **p, *map;
 210         int page;
 211
 212         for (p = &sq_mapping_list; (map = *p); p = &map->next)
 213                 if (map->sq_addr == vaddr)
 214                         break;
 215
 216         if (unlikely(!map)) {
 217                 printk("%s: bad store queue address 0x%08lx\n",
 218                        __func__, vaddr);
 219                 return;
 220         }
 221
 222         page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
 223         bitmap_release_region(sq_bitmap, page, get_order(map->size));
 224
 225 #ifdef CONFIG_MMU
 226         {
 227                 /*
 228                  * Tear down the VMA in the MMU case.
 229                  */
 230                 struct vm_struct *vma;
 231
 232                 vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
 233                 if (!vma) {
 234                         printk(KERN_ERR "%s: bad address 0x%08lx\n",
 235                                __func__, map->sq_addr);
 236                         return;
 237                 }
 238         }
 239 #endif
 240
 241         sq_mapping_list_del(map);
 242
 243         kmem_cache_free(sq_cache, map);
 244 }
 245 EXPORT_SYMBOL(sq_unmap);
 246
 247 /*
 248  * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
 249  * there is any other easy way to add things on a per-cpu basis without
 250  * putting the directory entries somewhere stupid and having to create
 251  * links in sysfs by hand back in to the per-cpu directories.
 252  *
 253  * Some day we may want to have an additional abstraction per store
 254  * queue, but considering the kobject hell we already have to deal with,
 255  * it's simply not worth the trouble.
 256  */
 257 static struct kobject *sq_kobject[NR_CPUS];
 258
 259 struct sq_sysfs_attr {
 260         struct attribute attr;
 261         ssize_t (*show)(char *buf);
 262         ssize_t (*store)(const char *buf, size_t count);
 263 };
 264
 265 #define to_sq_sysfs_attr(a)     container_of(a, struct sq_sysfs_attr, attr)
 266
 267 static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
 268                              char *buf)
 269 {
 270         struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
 271
 272         if (likely(sattr->show))
 273                 return sattr->show(buf);
 274
 275         return -EIO;
 276 }
 277
 278 static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
 279                               const char *buf, size_t count)
 280 {
 281         struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
 282
 283         if (likely(sattr->store))
 284                 return sattr->store(buf, count);
 285
 286         return -EIO;
 287 }
 288
 289 static ssize_t mapping_show(char *buf)
 290 {
 291         struct sq_mapping **list, *entry;
 292         char *p = buf;
 293
 294         for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
 295                 p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
 296                              entry->sq_addr, entry->sq_addr + entry->size,
 297                              entry->addr, entry->name);
 298
 299         return p - buf;
 300 }
 301
 302 static ssize_t mapping_store(const char *buf, size_t count)
 303 {
 304         unsigned long base = 0, len = 0;
 305
 306         sscanf(buf, "%lx %lx", &base, &len);
 307         if (!base)
 308                 return -EIO;
 309
 310         if (likely(len)) {
 311                 int ret = sq_remap(base, len, "Userspace", PAGE_SHARED);
 312                 if (ret < 0)
 313                         return ret;
 314         } else
 315                 sq_unmap(base);
 316
 317         return count;
 318 }
 319
 320 static struct sq_sysfs_attr mapping_attr =
 321         __ATTR(mapping, 0644, mapping_show, mapping_store);
 322
 323 static struct attribute *sq_sysfs_attrs[] = {
 324         &mapping_attr.attr,
 325         NULL,
 326 };
 327 ATTRIBUTE_GROUPS(sq_sysfs);
 328
 329 static const struct sysfs_ops sq_sysfs_ops = {
 330         .show   = sq_sysfs_show,
 331         .store  = sq_sysfs_store,
 332 };
 333
 334 static struct kobj_type ktype_percpu_entry = {
 335         .sysfs_ops      = &sq_sysfs_ops,
 336         .default_groups = sq_sysfs_groups,
 337 };
 338
 339 static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
 340 {
 341         unsigned int cpu = dev->id;
 342         struct kobject *kobj;
 343         int error;
 344
 345         sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
 346         if (unlikely(!sq_kobject[cpu]))
 347                 return -ENOMEM;
 348
 349         kobj = sq_kobject[cpu];
 350         error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
 351                                      "%s", "sq");
 352         if (!error)
 353                 kobject_uevent(kobj, KOBJ_ADD);
 354         return error;
 355 }
 356
 357 static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
 358 {
 359         unsigned int cpu = dev->id;
 360         struct kobject *kobj = sq_kobject[cpu];
 361
 362         kobject_put(kobj);
 363 }
 364
 365 static struct subsys_interface sq_interface = {
 366         .name           = "sq",
 367         .subsys         = &cpu_subsys,
 368         .add_dev        = sq_dev_add,
 369         .remove_dev     = sq_dev_remove,
 370 };
 371
 372 static int __init sq_api_init(void)
 373 {
 374         unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
 375         int ret = -ENOMEM;
 376
 377         printk(KERN_NOTICE "sq: Registering store queue API.\n");
 378
 379         sq_cache = kmem_cache_create("store_queue_cache",
 380                                 sizeof(struct sq_mapping), 0, 0, NULL);
 381         if (unlikely(!sq_cache))
 382                 return ret;
 383
 384         sq_bitmap = bitmap_zalloc(nr_pages, GFP_KERNEL);
 385         if (unlikely(!sq_bitmap))
 386                 goto out;
 387
 388         ret = subsys_interface_register(&sq_interface);
 389         if (unlikely(ret != 0))
 390                 goto out;
 391
 392         return 0;
 393
 394 out:
 395         bitmap_free(sq_bitmap);
 396         kmem_cache_destroy(sq_cache);
 397
 398         return ret;
 399 }
 400
 401 static void __exit sq_api_exit(void)
 402 {
 403         subsys_interface_unregister(&sq_interface);
 404         bitmap_free(sq_bitmap);
 405         kmem_cache_destroy(sq_cache);
 406 }
 407
 408 module_init(sq_api_init);
 409 module_exit(sq_api_exit);
 410
 411 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
 412 MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
 413 MODULE_LICENSE("GPL");