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

DEFINITIONS

1. sq_flush_range
2. sq_mapping_list_add
3. sq_mapping_list_del
4. __sq_remap
5. sq_remap
6. sq_unmap
7. sq_sysfs_show
8. sq_sysfs_store
9. mapping_show
10. mapping_store
11. sq_dev_add
12. sq_dev_remove
13. sq_api_init
14. sq_api_exit

   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(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
 107         if (!vma)
 108                 return -ENOMEM;
 109 
 110         vma->phys_addr = map->addr;
 111 
 112         if (ioremap_page_range((unsigned long)vma->addr,
 113                                (unsigned long)vma->addr + map->size,
 114                                vma->phys_addr, prot)) {
 115                 vunmap(vma->addr);
 116                 return -EAGAIN;
 117         }
 118 #else
 119         /*
 120          * Without an MMU (or with it turned off), this is much more
 121          * straightforward, as we can just load up each queue's QACR with
 122          * the physical address appropriately masked.
 123          */
 124         __raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
 125         __raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
 126 #endif
 127 
 128         return 0;
 129 }
 130 
 131 /**
 132  * sq_remap - Map a physical address through the Store Queues
 133  * @phys: Physical address of mapping.
 134  * @size: Length of mapping.
 135  * @name: User invoking mapping.
 136  * @prot: Protection bits.
 137  *
 138  * Remaps the physical address @phys through the next available store queue
 139  * address of @size length. @name is logged at boot time as well as through
 140  * the sysfs interface.
 141  */
 142 unsigned long sq_remap(unsigned long phys, unsigned int size,
 143                        const char *name, pgprot_t prot)
 144 {
 145         struct sq_mapping *map;
 146         unsigned long end;
 147         unsigned int psz;
 148         int ret, page;
 149 
 150         /* Don't allow wraparound or zero size */
 151         end = phys + size - 1;
 152         if (unlikely(!size || end < phys))
 153                 return -EINVAL;
 154         /* Don't allow anyone to remap normal memory.. */
 155         if (unlikely(phys < virt_to_phys(high_memory)))
 156                 return -EINVAL;
 157 
 158         phys &= PAGE_MASK;
 159         size = PAGE_ALIGN(end + 1) - phys;
 160 
 161         map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
 162         if (unlikely(!map))
 163                 return -ENOMEM;
 164 
 165         map->addr = phys;
 166         map->size = size;
 167         map->name = name;
 168 
 169         page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
 170                                        get_order(map->size));
 171         if (unlikely(page < 0)) {
 172                 ret = -ENOSPC;
 173                 goto out;
 174         }
 175 
 176         map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
 177 
 178         ret = __sq_remap(map, prot);
 179         if (unlikely(ret != 0))
 180                 goto out;
 181 
 182         psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
 183         pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
 184                 likely(map->name) ? map->name : "???",
 185                 psz, psz == 1 ? " " : "s",
 186                 map->sq_addr, map->addr);
 187 
 188         sq_mapping_list_add(map);
 189 
 190         return map->sq_addr;
 191 
 192 out:
 193         kmem_cache_free(sq_cache, map);
 194         return ret;
 195 }
 196 EXPORT_SYMBOL(sq_remap);
 197 
 198 /**
 199  * sq_unmap - Unmap a Store Queue allocation
 200  * @vaddr: Pre-allocated Store Queue mapping.
 201  *
 202  * Unmaps the store queue allocation @map that was previously created by
 203  * sq_remap(). Also frees up the pte that was previously inserted into
 204  * the kernel page table and discards the UTLB translation.
 205  */
 206 void sq_unmap(unsigned long vaddr)
 207 {
 208         struct sq_mapping **p, *map;
 209         int page;
 210 
 211         for (p = &sq_mapping_list; (map = *p); p = &map->next)
 212                 if (map->sq_addr == vaddr)
 213                         break;
 214 
 215         if (unlikely(!map)) {
 216                 printk("%s: bad store queue address 0x%08lx\n",
 217                        __func__, vaddr);
 218                 return;
 219         }
 220 
 221         page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
 222         bitmap_release_region(sq_bitmap, page, get_order(map->size));
 223 
 224 #ifdef CONFIG_MMU
 225         {
 226                 /*
 227                  * Tear down the VMA in the MMU case.
 228                  */
 229                 struct vm_struct *vma;
 230 
 231                 vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
 232                 if (!vma) {
 233                         printk(KERN_ERR "%s: bad address 0x%08lx\n",
 234                                __func__, map->sq_addr);
 235                         return;
 236                 }
 237         }
 238 #endif
 239 
 240         sq_mapping_list_del(map);
 241 
 242         kmem_cache_free(sq_cache, map);
 243 }
 244 EXPORT_SYMBOL(sq_unmap);
 245 
 246 /*
 247  * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
 248  * there is any other easy way to add things on a per-cpu basis without
 249  * putting the directory entries somewhere stupid and having to create
 250  * links in sysfs by hand back in to the per-cpu directories.
 251  *
 252  * Some day we may want to have an additional abstraction per store
 253  * queue, but considering the kobject hell we already have to deal with,
 254  * it's simply not worth the trouble.
 255  */
 256 static struct kobject *sq_kobject[NR_CPUS];
 257 
 258 struct sq_sysfs_attr {
 259         struct attribute attr;
 260         ssize_t (*show)(char *buf);
 261         ssize_t (*store)(const char *buf, size_t count);
 262 };
 263 
 264 #define to_sq_sysfs_attr(a)     container_of(a, struct sq_sysfs_attr, attr)
 265 
 266 static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
 267                              char *buf)
 268 {
 269         struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
 270 
 271         if (likely(sattr->show))
 272                 return sattr->show(buf);
 273 
 274         return -EIO;
 275 }
 276 
 277 static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
 278                               const char *buf, size_t count)
 279 {
 280         struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
 281 
 282         if (likely(sattr->store))
 283                 return sattr->store(buf, count);
 284 
 285         return -EIO;
 286 }
 287 
 288 static ssize_t mapping_show(char *buf)
 289 {
 290         struct sq_mapping **list, *entry;
 291         char *p = buf;
 292 
 293         for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
 294                 p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
 295                              entry->sq_addr, entry->sq_addr + entry->size,
 296                              entry->addr, entry->name);
 297 
 298         return p - buf;
 299 }
 300 
 301 static ssize_t mapping_store(const char *buf, size_t count)
 302 {
 303         unsigned long base = 0, len = 0;
 304 
 305         sscanf(buf, "%lx %lx", &base, &len);
 306         if (!base)
 307                 return -EIO;
 308 
 309         if (likely(len)) {
 310                 int ret = sq_remap(base, len, "Userspace", PAGE_SHARED);
 311                 if (ret < 0)
 312                         return ret;
 313         } else
 314                 sq_unmap(base);
 315 
 316         return count;
 317 }
 318 
 319 static struct sq_sysfs_attr mapping_attr =
 320         __ATTR(mapping, 0644, mapping_show, mapping_store);
 321 
 322 static struct attribute *sq_sysfs_attrs[] = {
 323         &mapping_attr.attr,
 324         NULL,
 325 };
 326 
 327 static const struct sysfs_ops sq_sysfs_ops = {
 328         .show   = sq_sysfs_show,
 329         .store  = sq_sysfs_store,
 330 };
 331 
 332 static struct kobj_type ktype_percpu_entry = {
 333         .sysfs_ops      = &sq_sysfs_ops,
 334         .default_attrs  = sq_sysfs_attrs,
 335 };
 336 
 337 static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
 338 {
 339         unsigned int cpu = dev->id;
 340         struct kobject *kobj;
 341         int error;
 342 
 343         sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
 344         if (unlikely(!sq_kobject[cpu]))
 345                 return -ENOMEM;
 346 
 347         kobj = sq_kobject[cpu];
 348         error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
 349                                      "%s", "sq");
 350         if (!error)
 351                 kobject_uevent(kobj, KOBJ_ADD);
 352         return error;
 353 }
 354 
 355 static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
 356 {
 357         unsigned int cpu = dev->id;
 358         struct kobject *kobj = sq_kobject[cpu];
 359 
 360         kobject_put(kobj);
 361 }
 362 
 363 static struct subsys_interface sq_interface = {
 364         .name           = "sq",
 365         .subsys         = &cpu_subsys,
 366         .add_dev        = sq_dev_add,
 367         .remove_dev     = sq_dev_remove,
 368 };
 369 
 370 static int __init sq_api_init(void)
 371 {
 372         unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
 373         unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
 374         int ret = -ENOMEM;
 375 
 376         printk(KERN_NOTICE "sq: Registering store queue API.\n");
 377 
 378         sq_cache = kmem_cache_create("store_queue_cache",
 379                                 sizeof(struct sq_mapping), 0, 0, NULL);
 380         if (unlikely(!sq_cache))
 381                 return ret;
 382 
 383         sq_bitmap = kzalloc(size, GFP_KERNEL);
 384         if (unlikely(!sq_bitmap))
 385                 goto out;
 386 
 387         ret = subsys_interface_register(&sq_interface);
 388         if (unlikely(ret != 0))
 389                 goto out;
 390 
 391         return 0;
 392 
 393 out:
 394         kfree(sq_bitmap);
 395         kmem_cache_destroy(sq_cache);
 396 
 397         return ret;
 398 }
 399 
 400 static void __exit sq_api_exit(void)
 401 {
 402         subsys_interface_unregister(&sq_interface);
 403         kfree(sq_bitmap);
 404         kmem_cache_destroy(sq_cache);
 405 }
 406 
 407 module_init(sq_api_init);
 408 module_exit(sq_api_exit);
 409 
 410 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
 411 MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
 412 MODULE_LICENSE("GPL");