linux/arch/sh/mm/pmb.c
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   1/*
   2 * arch/sh/mm/pmb.c
   3 *
   4 * Privileged Space Mapping Buffer (PMB) Support.
   5 *
   6 * Copyright (C) 2005, 2006, 2007 Paul Mundt
   7 *
   8 * P1/P2 Section mapping definitions from map32.h, which was:
   9 *
  10 *      Copyright 2003 (c) Lineo Solutions,Inc.
  11 *
  12 * This file is subject to the terms and conditions of the GNU General Public
  13 * License.  See the file "COPYING" in the main directory of this archive
  14 * for more details.
  15 */
  16#include <linux/init.h>
  17#include <linux/kernel.h>
  18#include <linux/sysdev.h>
  19#include <linux/cpu.h>
  20#include <linux/module.h>
  21#include <linux/slab.h>
  22#include <linux/bitops.h>
  23#include <linux/debugfs.h>
  24#include <linux/fs.h>
  25#include <linux/seq_file.h>
  26#include <linux/err.h>
  27#include <asm/system.h>
  28#include <asm/uaccess.h>
  29#include <asm/pgtable.h>
  30#include <asm/mmu.h>
  31#include <asm/io.h>
  32#include <asm/mmu_context.h>
  33
  34#define NR_PMB_ENTRIES  16
  35
  36static void __pmb_unmap(struct pmb_entry *);
  37
  38static struct kmem_cache *pmb_cache;
  39static unsigned long pmb_map;
  40
  41static struct pmb_entry pmb_init_map[] = {
  42        /* vpn         ppn         flags (ub/sz/c/wt) */
  43
  44        /* P1 Section Mappings */
  45        { 0x80000000, 0x00000000, PMB_SZ_64M  | PMB_C, },
  46        { 0x84000000, 0x04000000, PMB_SZ_64M  | PMB_C, },
  47        { 0x88000000, 0x08000000, PMB_SZ_128M | PMB_C, },
  48        { 0x90000000, 0x10000000, PMB_SZ_64M  | PMB_C, },
  49        { 0x94000000, 0x14000000, PMB_SZ_64M  | PMB_C, },
  50        { 0x98000000, 0x18000000, PMB_SZ_64M  | PMB_C, },
  51
  52        /* P2 Section Mappings */
  53        { 0xa0000000, 0x00000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
  54        { 0xa4000000, 0x04000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
  55        { 0xa8000000, 0x08000000, PMB_UB | PMB_SZ_128M | PMB_WT, },
  56        { 0xb0000000, 0x10000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
  57        { 0xb4000000, 0x14000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
  58        { 0xb8000000, 0x18000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
  59};
  60
  61static inline unsigned long mk_pmb_entry(unsigned int entry)
  62{
  63        return (entry & PMB_E_MASK) << PMB_E_SHIFT;
  64}
  65
  66static inline unsigned long mk_pmb_addr(unsigned int entry)
  67{
  68        return mk_pmb_entry(entry) | PMB_ADDR;
  69}
  70
  71static inline unsigned long mk_pmb_data(unsigned int entry)
  72{
  73        return mk_pmb_entry(entry) | PMB_DATA;
  74}
  75
  76static DEFINE_SPINLOCK(pmb_list_lock);
  77static struct pmb_entry *pmb_list;
  78
  79static inline void pmb_list_add(struct pmb_entry *pmbe)
  80{
  81        struct pmb_entry **p, *tmp;
  82
  83        p = &pmb_list;
  84        while ((tmp = *p) != NULL)
  85                p = &tmp->next;
  86
  87        pmbe->next = tmp;
  88        *p = pmbe;
  89}
  90
  91static inline void pmb_list_del(struct pmb_entry *pmbe)
  92{
  93        struct pmb_entry **p, *tmp;
  94
  95        for (p = &pmb_list; (tmp = *p); p = &tmp->next)
  96                if (tmp == pmbe) {
  97                        *p = tmp->next;
  98                        return;
  99                }
 100}
 101
 102struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
 103                            unsigned long flags)
 104{
 105        struct pmb_entry *pmbe;
 106
 107        pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
 108        if (!pmbe)
 109                return ERR_PTR(-ENOMEM);
 110
 111        pmbe->vpn       = vpn;
 112        pmbe->ppn       = ppn;
 113        pmbe->flags     = flags;
 114
 115        spin_lock_irq(&pmb_list_lock);
 116        pmb_list_add(pmbe);
 117        spin_unlock_irq(&pmb_list_lock);
 118
 119        return pmbe;
 120}
 121
 122void pmb_free(struct pmb_entry *pmbe)
 123{
 124        spin_lock_irq(&pmb_list_lock);
 125        pmb_list_del(pmbe);
 126        spin_unlock_irq(&pmb_list_lock);
 127
 128        kmem_cache_free(pmb_cache, pmbe);
 129}
 130
 131/*
 132 * Must be in P2 for __set_pmb_entry()
 133 */
 134int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
 135                    unsigned long flags, int *entry)
 136{
 137        unsigned int pos = *entry;
 138
 139        if (unlikely(pos == PMB_NO_ENTRY))
 140                pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
 141
 142repeat:
 143        if (unlikely(pos > NR_PMB_ENTRIES))
 144                return -ENOSPC;
 145
 146        if (test_and_set_bit(pos, &pmb_map)) {
 147                pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
 148                goto repeat;
 149        }
 150
 151        ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
 152
 153#ifdef CONFIG_CACHE_WRITETHROUGH
 154        /*
 155         * When we are in 32-bit address extended mode, CCR.CB becomes
 156         * invalid, so care must be taken to manually adjust cacheable
 157         * translations.
 158         */
 159        if (likely(flags & PMB_C))
 160                flags |= PMB_WT;
 161#endif
 162
 163        ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
 164
 165        *entry = pos;
 166
 167        return 0;
 168}
 169
 170int __uses_jump_to_uncached set_pmb_entry(struct pmb_entry *pmbe)
 171{
 172        int ret;
 173
 174        jump_to_uncached();
 175        ret = __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &pmbe->entry);
 176        back_to_cached();
 177
 178        return ret;
 179}
 180
 181void __uses_jump_to_uncached clear_pmb_entry(struct pmb_entry *pmbe)
 182{
 183        unsigned int entry = pmbe->entry;
 184        unsigned long addr;
 185
 186        /*
 187         * Don't allow clearing of wired init entries, P1 or P2 access
 188         * without a corresponding mapping in the PMB will lead to reset
 189         * by the TLB.
 190         */
 191        if (unlikely(entry < ARRAY_SIZE(pmb_init_map) ||
 192                     entry >= NR_PMB_ENTRIES))
 193                return;
 194
 195        jump_to_uncached();
 196
 197        /* Clear V-bit */
 198        addr = mk_pmb_addr(entry);
 199        ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
 200
 201        addr = mk_pmb_data(entry);
 202        ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
 203
 204        back_to_cached();
 205
 206        clear_bit(entry, &pmb_map);
 207}
 208
 209
 210static struct {
 211        unsigned long size;
 212        int flag;
 213} pmb_sizes[] = {
 214        { .size = 0x20000000, .flag = PMB_SZ_512M, },
 215        { .size = 0x08000000, .flag = PMB_SZ_128M, },
 216        { .size = 0x04000000, .flag = PMB_SZ_64M,  },
 217        { .size = 0x01000000, .flag = PMB_SZ_16M,  },
 218};
 219
 220long pmb_remap(unsigned long vaddr, unsigned long phys,
 221               unsigned long size, unsigned long flags)
 222{
 223        struct pmb_entry *pmbp, *pmbe;
 224        unsigned long wanted;
 225        int pmb_flags, i;
 226        long err;
 227
 228        /* Convert typical pgprot value to the PMB equivalent */
 229        if (flags & _PAGE_CACHABLE) {
 230                if (flags & _PAGE_WT)
 231                        pmb_flags = PMB_WT;
 232                else
 233                        pmb_flags = PMB_C;
 234        } else
 235                pmb_flags = PMB_WT | PMB_UB;
 236
 237        pmbp = NULL;
 238        wanted = size;
 239
 240again:
 241        for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
 242                int ret;
 243
 244                if (size < pmb_sizes[i].size)
 245                        continue;
 246
 247                pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag);
 248                if (IS_ERR(pmbe)) {
 249                        err = PTR_ERR(pmbe);
 250                        goto out;
 251                }
 252
 253                ret = set_pmb_entry(pmbe);
 254                if (ret != 0) {
 255                        pmb_free(pmbe);
 256                        err = -EBUSY;
 257                        goto out;
 258                }
 259
 260                phys    += pmb_sizes[i].size;
 261                vaddr   += pmb_sizes[i].size;
 262                size    -= pmb_sizes[i].size;
 263
 264                /*
 265                 * Link adjacent entries that span multiple PMB entries
 266                 * for easier tear-down.
 267                 */
 268                if (likely(pmbp))
 269                        pmbp->link = pmbe;
 270
 271                pmbp = pmbe;
 272
 273                /*
 274                 * Instead of trying smaller sizes on every iteration
 275                 * (even if we succeed in allocating space), try using
 276                 * pmb_sizes[i].size again.
 277                 */
 278                i--;
 279        }
 280
 281        if (size >= 0x1000000)
 282                goto again;
 283
 284        return wanted - size;
 285
 286out:
 287        if (pmbp)
 288                __pmb_unmap(pmbp);
 289
 290        return err;
 291}
 292
 293void pmb_unmap(unsigned long addr)
 294{
 295        struct pmb_entry **p, *pmbe;
 296
 297        for (p = &pmb_list; (pmbe = *p); p = &pmbe->next)
 298                if (pmbe->vpn == addr)
 299                        break;
 300
 301        if (unlikely(!pmbe))
 302                return;
 303
 304        __pmb_unmap(pmbe);
 305}
 306
 307static void __pmb_unmap(struct pmb_entry *pmbe)
 308{
 309        WARN_ON(!test_bit(pmbe->entry, &pmb_map));
 310
 311        do {
 312                struct pmb_entry *pmblink = pmbe;
 313
 314                if (pmbe->entry != PMB_NO_ENTRY)
 315                        clear_pmb_entry(pmbe);
 316
 317                pmbe = pmblink->link;
 318
 319                pmb_free(pmblink);
 320        } while (pmbe);
 321}
 322
 323static void pmb_cache_ctor(void *pmb)
 324{
 325        struct pmb_entry *pmbe = pmb;
 326
 327        memset(pmb, 0, sizeof(struct pmb_entry));
 328
 329        pmbe->entry = PMB_NO_ENTRY;
 330}
 331
 332static int __uses_jump_to_uncached pmb_init(void)
 333{
 334        unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
 335        unsigned int entry, i;
 336
 337        BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
 338
 339        pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
 340                                      SLAB_PANIC, pmb_cache_ctor);
 341
 342        jump_to_uncached();
 343
 344        /*
 345         * Ordering is important, P2 must be mapped in the PMB before we
 346         * can set PMB.SE, and P1 must be mapped before we jump back to
 347         * P1 space.
 348         */
 349        for (entry = 0; entry < nr_entries; entry++) {
 350                struct pmb_entry *pmbe = pmb_init_map + entry;
 351
 352                __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &entry);
 353        }
 354
 355        ctrl_outl(0, PMB_IRMCR);
 356
 357        /* PMB.SE and UB[7] */
 358        ctrl_outl((1 << 31) | (1 << 7), PMB_PASCR);
 359
 360        /* Flush out the TLB */
 361        i =  ctrl_inl(MMUCR);
 362        i |= MMUCR_TI;
 363        ctrl_outl(i, MMUCR);
 364
 365        back_to_cached();
 366
 367        return 0;
 368}
 369arch_initcall(pmb_init);
 370
 371static int pmb_seq_show(struct seq_file *file, void *iter)
 372{
 373        int i;
 374
 375        seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
 376                         "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
 377        seq_printf(file, "ety   vpn  ppn  size   flags\n");
 378
 379        for (i = 0; i < NR_PMB_ENTRIES; i++) {
 380                unsigned long addr, data;
 381                unsigned int size;
 382                char *sz_str = NULL;
 383
 384                addr = ctrl_inl(mk_pmb_addr(i));
 385                data = ctrl_inl(mk_pmb_data(i));
 386
 387                size = data & PMB_SZ_MASK;
 388                sz_str = (size == PMB_SZ_16M)  ? " 16MB":
 389                         (size == PMB_SZ_64M)  ? " 64MB":
 390                         (size == PMB_SZ_128M) ? "128MB":
 391                                                 "512MB";
 392
 393                /* 02: V 0x88 0x08 128MB C CB  B */
 394                seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
 395                           i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
 396                           (addr >> 24) & 0xff, (data >> 24) & 0xff,
 397                           sz_str, (data & PMB_C) ? 'C' : ' ',
 398                           (data & PMB_WT) ? "WT" : "CB",
 399                           (data & PMB_UB) ? "UB" : " B");
 400        }
 401
 402        return 0;
 403}
 404
 405static int pmb_debugfs_open(struct inode *inode, struct file *file)
 406{
 407        return single_open(file, pmb_seq_show, NULL);
 408}
 409
 410static const struct file_operations pmb_debugfs_fops = {
 411        .owner          = THIS_MODULE,
 412        .open           = pmb_debugfs_open,
 413        .read           = seq_read,
 414        .llseek         = seq_lseek,
 415        .release        = single_release,
 416};
 417
 418static int __init pmb_debugfs_init(void)
 419{
 420        struct dentry *dentry;
 421
 422        dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
 423                                     sh_debugfs_root, NULL, &pmb_debugfs_fops);
 424        if (!dentry)
 425                return -ENOMEM;
 426        if (IS_ERR(dentry))
 427                return PTR_ERR(dentry);
 428
 429        return 0;
 430}
 431postcore_initcall(pmb_debugfs_init);
 432
 433#ifdef CONFIG_PM
 434static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 435{
 436        static pm_message_t prev_state;
 437
 438        /* Restore the PMB after a resume from hibernation */
 439        if (state.event == PM_EVENT_ON &&
 440            prev_state.event == PM_EVENT_FREEZE) {
 441                struct pmb_entry *pmbe;
 442                spin_lock_irq(&pmb_list_lock);
 443                for (pmbe = pmb_list; pmbe; pmbe = pmbe->next)
 444                        set_pmb_entry(pmbe);
 445                spin_unlock_irq(&pmb_list_lock);
 446        }
 447        prev_state = state;
 448        return 0;
 449}
 450
 451static int pmb_sysdev_resume(struct sys_device *dev)
 452{
 453        return pmb_sysdev_suspend(dev, PMSG_ON);
 454}
 455
 456static struct sysdev_driver pmb_sysdev_driver = {
 457        .suspend = pmb_sysdev_suspend,
 458        .resume = pmb_sysdev_resume,
 459};
 460
 461static int __init pmb_sysdev_init(void)
 462{
 463        return sysdev_driver_register(&cpu_sysdev_class, &pmb_sysdev_driver);
 464}
 465
 466subsys_initcall(pmb_sysdev_init);
 467#endif
 468