linux/arch/sh/kernel/cpu/sh4/sq.c
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   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
  28struct sq_mapping;
  29
  30struct 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
  40static struct sq_mapping *sq_mapping_list;
  41static DEFINE_SPINLOCK(sq_mapping_lock);
  42static struct kmem_cache *sq_cache;
  43static unsigned long *sq_bitmap;
  44
  45#define store_queue_barrier()                   \
  46do {                                            \
  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 */
  60void 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}
  71EXPORT_SYMBOL(sq_flush_range);
  72
  73static 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
  89static 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
 104static 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 */
 145unsigned 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
 195out:
 196        kmem_cache_free(sq_cache, map);
 197        return ret;
 198}
 199EXPORT_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 */
 209void 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}
 247EXPORT_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 */
 259static struct kobject *sq_kobject[NR_CPUS];
 260
 261struct 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
 269static 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
 280static 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
 291static 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
 304static 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
 322static struct sq_sysfs_attr mapping_attr =
 323        __ATTR(mapping, 0644, mapping_show, mapping_store);
 324
 325static struct attribute *sq_sysfs_attrs[] = {
 326        &mapping_attr.attr,
 327        NULL,
 328};
 329
 330static const struct sysfs_ops sq_sysfs_ops = {
 331        .show   = sq_sysfs_show,
 332        .store  = sq_sysfs_store,
 333};
 334
 335static struct kobj_type ktype_percpu_entry = {
 336        .sysfs_ops      = &sq_sysfs_ops,
 337        .default_attrs  = sq_sysfs_attrs,
 338};
 339
 340static 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
 358static 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
 367static 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
 374static 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
 397out:
 398        kfree(sq_bitmap);
 399        kmem_cache_destroy(sq_cache);
 400
 401        return ret;
 402}
 403
 404static 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
 411module_init(sq_api_init);
 412module_exit(sq_api_exit);
 413
 414MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
 415MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
 416MODULE_LICENSE("GPL");
 417