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

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