arch/sh/mm/pmb.c

   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
  36 static void __pmb_unmap(struct pmb_entry *);
  37
  38 static struct kmem_cache *pmb_cache;
  39 static unsigned long pmb_map;
  40
  41 static 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
  61 static inline unsigned long mk_pmb_entry(unsigned int entry)
  62 {
  63         return (entry & PMB_E_MASK) << PMB_E_SHIFT;
  64 }
  65
  66 static inline unsigned long mk_pmb_addr(unsigned int entry)
  67 {
  68         return mk_pmb_entry(entry) | PMB_ADDR;
  69 }
  70
  71 static inline unsigned long mk_pmb_data(unsigned int entry)
  72 {
  73         return mk_pmb_entry(entry) | PMB_DATA;
  74 }
  75
  76 static DEFINE_SPINLOCK(pmb_list_lock);
  77 static struct pmb_entry *pmb_list;
  78
  79 static 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
  91 static 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
 102 static int pmb_alloc_entry(void)
 103 {
 104         unsigned int pos;
 105
 106 repeat:
 107         pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
 108
 109         if (unlikely(pos > NR_PMB_ENTRIES))
 110                 return -ENOSPC;
 111
 112         if (test_and_set_bit(pos, &pmb_map))
 113                 goto repeat;
 114
 115         return pos;
 116 }
 117
 118 struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
 119                             unsigned long flags)
 120 {
 121         struct pmb_entry *pmbe;
 122         int pos;
 123
 124         pos = pmb_alloc_entry();
 125         if (pos < 0)
 126                 return ERR_PTR(pos);
 127
 128         pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
 129         if (!pmbe)
 130                 return ERR_PTR(-ENOMEM);
 131
 132         pmbe->vpn       = vpn;
 133         pmbe->ppn       = ppn;
 134         pmbe->flags     = flags;
 135         pmbe->entry     = pos;
 136
 137         spin_lock_irq(&pmb_list_lock);
 138         pmb_list_add(pmbe);
 139         spin_unlock_irq(&pmb_list_lock);
 140
 141         return pmbe;
 142 }
 143
 144 void pmb_free(struct pmb_entry *pmbe)
 145 {
 146         spin_lock_irq(&pmb_list_lock);
 147         pmb_list_del(pmbe);
 148         spin_unlock_irq(&pmb_list_lock);
 149
 150         kmem_cache_free(pmb_cache, pmbe);
 151 }
 152
 153 /*
 154  * Must be in P2 for __set_pmb_entry()
 155  */
 156 void __set_pmb_entry(unsigned long vpn, unsigned long ppn,
 157                     unsigned long flags, int pos)
 158 {
 159         ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
 160
 161 #ifdef CONFIG_CACHE_WRITETHROUGH
 162         /*
 163          * When we are in 32-bit address extended mode, CCR.CB becomes
 164          * invalid, so care must be taken to manually adjust cacheable
 165          * translations.
 166          */
 167         if (likely(flags & PMB_C))
 168                 flags |= PMB_WT;
 169 #endif
 170
 171         ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
 172 }
 173
 174 void __uses_jump_to_uncached set_pmb_entry(struct pmb_entry *pmbe)
 175 {
 176         jump_to_uncached();
 177         __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, pmbe->entry);
 178         back_to_cached();
 179 }
 180
 181 void __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
 210 static 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
 220 long 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
 240 again:
 241         for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
 242                 if (size < pmb_sizes[i].size)
 243                         continue;
 244
 245                 pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag);
 246                 if (IS_ERR(pmbe)) {
 247                         err = PTR_ERR(pmbe);
 248                         goto out;
 249                 }
 250
 251                 set_pmb_entry(pmbe);
 252
 253                 phys    += pmb_sizes[i].size;
 254                 vaddr   += pmb_sizes[i].size;
 255                 size    -= pmb_sizes[i].size;
 256
 257                 /*
 258                  * Link adjacent entries that span multiple PMB entries
 259                  * for easier tear-down.
 260                  */
 261                 if (likely(pmbp))
 262                         pmbp->link = pmbe;
 263
 264                 pmbp = pmbe;
 265
 266                 /*
 267                  * Instead of trying smaller sizes on every iteration
 268                  * (even if we succeed in allocating space), try using
 269                  * pmb_sizes[i].size again.
 270                  */
 271                 i--;
 272         }
 273
 274         if (size >= 0x1000000)
 275                 goto again;
 276
 277         return wanted - size;
 278
 279 out:
 280         if (pmbp)
 281                 __pmb_unmap(pmbp);
 282
 283         return err;
 284 }
 285
 286 void pmb_unmap(unsigned long addr)
 287 {
 288         struct pmb_entry **p, *pmbe;
 289
 290         for (p = &pmb_list; (pmbe = *p); p = &pmbe->next)
 291                 if (pmbe->vpn == addr)
 292                         break;
 293
 294         if (unlikely(!pmbe))
 295                 return;
 296
 297         __pmb_unmap(pmbe);
 298 }
 299
 300 static void __pmb_unmap(struct pmb_entry *pmbe)
 301 {
 302         WARN_ON(!test_bit(pmbe->entry, &pmb_map));
 303
 304         do {
 305                 struct pmb_entry *pmblink = pmbe;
 306
 307                 /*
 308                  * We may be called before this pmb_entry has been
 309                  * entered into the PMB table via set_pmb_entry(), but
 310                  * that's OK because we've allocated a unique slot for
 311                  * this entry in pmb_alloc() (even if we haven't filled
 312                  * it yet).
 313                  *
 314                  * Therefore, calling clear_pmb_entry() is safe as no
 315                  * other mapping can be using that slot.
 316                  */
 317                 clear_pmb_entry(pmbe);
 318
 319                 pmbe = pmblink->link;
 320
 321                 pmb_free(pmblink);
 322         } while (pmbe);
 323 }
 324
 325 static void pmb_cache_ctor(void *pmb)
 326 {
 327         memset(pmb, 0, sizeof(struct pmb_entry));
 328 }
 329
 330 static int __uses_jump_to_uncached pmb_init(void)
 331 {
 332         unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
 333         unsigned int entry, i;
 334
 335         BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
 336
 337         pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
 338                                       SLAB_PANIC, pmb_cache_ctor);
 339
 340         jump_to_uncached();
 341
 342         /*
 343          * Ordering is important, P2 must be mapped in the PMB before we
 344          * can set PMB.SE, and P1 must be mapped before we jump back to
 345          * P1 space.
 346          */
 347         for (entry = 0; entry < nr_entries; entry++) {
 348                 struct pmb_entry *pmbe = pmb_init_map + entry;
 349
 350                 __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, entry);
 351         }
 352
 353         ctrl_outl(0, PMB_IRMCR);
 354
 355         /* PMB.SE and UB[7] */
 356         ctrl_outl((1 << 31) | (1 << 7), PMB_PASCR);
 357
 358         /* Flush out the TLB */
 359         i =  ctrl_inl(MMUCR);
 360         i |= MMUCR_TI;
 361         ctrl_outl(i, MMUCR);
 362
 363         back_to_cached();
 364
 365         return 0;
 366 }
 367 arch_initcall(pmb_init);
 368
 369 static int pmb_seq_show(struct seq_file *file, void *iter)
 370 {
 371         int i;
 372
 373         seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
 374                          "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
 375         seq_printf(file, "ety   vpn  ppn  size   flags\n");
 376
 377         for (i = 0; i < NR_PMB_ENTRIES; i++) {
 378                 unsigned long addr, data;
 379                 unsigned int size;
 380                 char *sz_str = NULL;
 381
 382                 addr = ctrl_inl(mk_pmb_addr(i));
 383                 data = ctrl_inl(mk_pmb_data(i));
 384
 385                 size = data & PMB_SZ_MASK;
 386                 sz_str = (size == PMB_SZ_16M)  ? " 16MB":
 387                          (size == PMB_SZ_64M)  ? " 64MB":
 388                          (size == PMB_SZ_128M) ? "128MB":
 389                                                  "512MB";
 390
 391                 /* 02: V 0x88 0x08 128MB C CB  B */
 392                 seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
 393                            i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
 394                            (addr >> 24) & 0xff, (data >> 24) & 0xff,
 395                            sz_str, (data & PMB_C) ? 'C' : ' ',
 396                            (data & PMB_WT) ? "WT" : "CB",
 397                            (data & PMB_UB) ? "UB" : " B");
 398         }
 399
 400         return 0;
 401 }
 402
 403 static int pmb_debugfs_open(struct inode *inode, struct file *file)
 404 {
 405         return single_open(file, pmb_seq_show, NULL);
 406 }
 407
 408 static const struct file_operations pmb_debugfs_fops = {
 409         .owner          = THIS_MODULE,
 410         .open           = pmb_debugfs_open,
 411         .read           = seq_read,
 412         .llseek         = seq_lseek,
 413         .release        = single_release,
 414 };
 415
 416 static int __init pmb_debugfs_init(void)
 417 {
 418         struct dentry *dentry;
 419
 420         dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
 421                                      sh_debugfs_root, NULL, &pmb_debugfs_fops);
 422         if (!dentry)
 423                 return -ENOMEM;
 424         if (IS_ERR(dentry))
 425                 return PTR_ERR(dentry);
 426
 427         return 0;
 428 }
 429 postcore_initcall(pmb_debugfs_init);
 430
 431 #ifdef CONFIG_PM
 432 static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 433 {
 434         static pm_message_t prev_state;
 435
 436         /* Restore the PMB after a resume from hibernation */
 437         if (state.event == PM_EVENT_ON &&
 438             prev_state.event == PM_EVENT_FREEZE) {
 439                 struct pmb_entry *pmbe;
 440                 spin_lock_irq(&pmb_list_lock);
 441                 for (pmbe = pmb_list; pmbe; pmbe = pmbe->next)
 442                         set_pmb_entry(pmbe);
 443                 spin_unlock_irq(&pmb_list_lock);
 444         }
 445         prev_state = state;
 446         return 0;
 447 }
 448
 449 static int pmb_sysdev_resume(struct sys_device *dev)
 450 {
 451         return pmb_sysdev_suspend(dev, PMSG_ON);
 452 }
 453
 454 static struct sysdev_driver pmb_sysdev_driver = {
 455         .suspend = pmb_sysdev_suspend,
 456         .resume = pmb_sysdev_resume,
 457 };
 458
 459 static int __init pmb_sysdev_init(void)
 460 {
 461         return sysdev_driver_register(&cpu_sysdev_class, &pmb_sysdev_driver);
 462 }
 463
 464 subsys_initcall(pmb_sysdev_init);
 465 #endif