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