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 pmb_entry pmb_entry_list[NR_PMB_ENTRIES];
  39 static unsigned long pmb_map;
  40
  41 static inline unsigned long mk_pmb_entry(unsigned int entry)
  42 {
  43         return (entry & PMB_E_MASK) << PMB_E_SHIFT;
  44 }
  45
  46 static inline unsigned long mk_pmb_addr(unsigned int entry)
  47 {
  48         return mk_pmb_entry(entry) | PMB_ADDR;
  49 }
  50
  51 static inline unsigned long mk_pmb_data(unsigned int entry)
  52 {
  53         return mk_pmb_entry(entry) | PMB_DATA;
  54 }
  55
  56 static int pmb_alloc_entry(void)
  57 {
  58         unsigned int pos;
  59
  60 repeat:
  61         pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
  62
  63         if (unlikely(pos > NR_PMB_ENTRIES))
  64                 return -ENOSPC;
  65
  66         if (test_and_set_bit(pos, &pmb_map))
  67                 goto repeat;
  68
  69         return pos;
  70 }
  71
  72 static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
  73                                    unsigned long flags, int entry)
  74 {
  75         struct pmb_entry *pmbe;
  76         int pos;
  77
  78         if (entry == PMB_NO_ENTRY) {
  79                 pos = pmb_alloc_entry();
  80                 if (pos < 0)
  81                         return ERR_PTR(pos);
  82         } else {
  83                 if (test_bit(entry, &pmb_map))
  84                         return ERR_PTR(-ENOSPC);
  85                 pos = entry;
  86         }
  87
  88         pmbe = &pmb_entry_list[pos];
  89         if (!pmbe)
  90                 return ERR_PTR(-ENOMEM);
  91
  92         pmbe->vpn       = vpn;
  93         pmbe->ppn       = ppn;
  94         pmbe->flags     = flags;
  95         pmbe->entry     = pos;
  96
  97         return pmbe;
  98 }
  99
 100 static void pmb_free(struct pmb_entry *pmbe)
 101 {
 102         int pos = pmbe->entry;
 103
 104         pmbe->vpn       = 0;
 105         pmbe->ppn       = 0;
 106         pmbe->flags     = 0;
 107         pmbe->entry     = 0;
 108
 109         clear_bit(pos, &pmb_map);
 110 }
 111
 112 /*
 113  * Must be in P2 for __set_pmb_entry()
 114  */
 115 static void __set_pmb_entry(unsigned long vpn, unsigned long ppn,
 116                             unsigned long flags, int pos)
 117 {
 118         ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
 119
 120 #ifdef CONFIG_CACHE_WRITETHROUGH
 121         /*
 122          * When we are in 32-bit address extended mode, CCR.CB becomes
 123          * invalid, so care must be taken to manually adjust cacheable
 124          * translations.
 125          */
 126         if (likely(flags & PMB_C))
 127                 flags |= PMB_WT;
 128 #endif
 129
 130         ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
 131 }
 132
 133 static void __uses_jump_to_uncached set_pmb_entry(struct pmb_entry *pmbe)
 134 {
 135         jump_to_uncached();
 136         __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, pmbe->entry);
 137         back_to_cached();
 138 }
 139
 140 static void __uses_jump_to_uncached clear_pmb_entry(struct pmb_entry *pmbe)
 141 {
 142         unsigned int entry = pmbe->entry;
 143         unsigned long addr;
 144
 145         if (unlikely(entry >= NR_PMB_ENTRIES))
 146                 return;
 147
 148         jump_to_uncached();
 149
 150         /* Clear V-bit */
 151         addr = mk_pmb_addr(entry);
 152         ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
 153
 154         addr = mk_pmb_data(entry);
 155         ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
 156
 157         back_to_cached();
 158 }
 159
 160
 161 static struct {
 162         unsigned long size;
 163         int flag;
 164 } pmb_sizes[] = {
 165         { .size = 0x20000000, .flag = PMB_SZ_512M, },
 166         { .size = 0x08000000, .flag = PMB_SZ_128M, },
 167         { .size = 0x04000000, .flag = PMB_SZ_64M,  },
 168         { .size = 0x01000000, .flag = PMB_SZ_16M,  },
 169 };
 170
 171 long pmb_remap(unsigned long vaddr, unsigned long phys,
 172                unsigned long size, unsigned long flags)
 173 {
 174         struct pmb_entry *pmbp, *pmbe;
 175         unsigned long wanted;
 176         int pmb_flags, i;
 177         long err;
 178
 179         /* Convert typical pgprot value to the PMB equivalent */
 180         if (flags & _PAGE_CACHABLE) {
 181                 if (flags & _PAGE_WT)
 182                         pmb_flags = PMB_WT;
 183                 else
 184                         pmb_flags = PMB_C;
 185         } else
 186                 pmb_flags = PMB_WT | PMB_UB;
 187
 188         pmbp = NULL;
 189         wanted = size;
 190
 191 again:
 192         for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
 193                 if (size < pmb_sizes[i].size)
 194                         continue;
 195
 196                 pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag,
 197                                  PMB_NO_ENTRY);
 198                 if (IS_ERR(pmbe)) {
 199                         err = PTR_ERR(pmbe);
 200                         goto out;
 201                 }
 202
 203                 set_pmb_entry(pmbe);
 204
 205                 phys    += pmb_sizes[i].size;
 206                 vaddr   += pmb_sizes[i].size;
 207                 size    -= pmb_sizes[i].size;
 208
 209                 /*
 210                  * Link adjacent entries that span multiple PMB entries
 211                  * for easier tear-down.
 212                  */
 213                 if (likely(pmbp))
 214                         pmbp->link = pmbe;
 215
 216                 pmbp = pmbe;
 217
 218                 /*
 219                  * Instead of trying smaller sizes on every iteration
 220                  * (even if we succeed in allocating space), try using
 221                  * pmb_sizes[i].size again.
 222                  */
 223                 i--;
 224         }
 225
 226         if (size >= 0x1000000)
 227                 goto again;
 228
 229         return wanted - size;
 230
 231 out:
 232         if (pmbp)
 233                 __pmb_unmap(pmbp);
 234
 235         return err;
 236 }
 237
 238 void pmb_unmap(unsigned long addr)
 239 {
 240         struct pmb_entry *pmbe = NULL;
 241         int i;
 242
 243         for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
 244                 if (test_bit(i, &pmb_map)) {
 245                         pmbe = &pmb_entry_list[i];
 246                         if (pmbe->vpn == addr)
 247                                 break;
 248                 }
 249         }
 250
 251         if (unlikely(!pmbe))
 252                 return;
 253
 254         __pmb_unmap(pmbe);
 255 }
 256
 257 static void __pmb_unmap(struct pmb_entry *pmbe)
 258 {
 259         BUG_ON(!test_bit(pmbe->entry, &pmb_map));
 260
 261         do {
 262                 struct pmb_entry *pmblink = pmbe;
 263
 264                 /*
 265                  * We may be called before this pmb_entry has been
 266                  * entered into the PMB table via set_pmb_entry(), but
 267                  * that's OK because we've allocated a unique slot for
 268                  * this entry in pmb_alloc() (even if we haven't filled
 269                  * it yet).
 270                  *
 271                  * Therefore, calling clear_pmb_entry() is safe as no
 272                  * other mapping can be using that slot.
 273                  */
 274                 clear_pmb_entry(pmbe);
 275
 276                 pmbe = pmblink->link;
 277
 278                 pmb_free(pmblink);
 279         } while (pmbe);
 280 }
 281
 282 #ifdef CONFIG_PMB
 283 int __uses_jump_to_uncached pmb_init(void)
 284 {
 285         unsigned int i;
 286         long size, ret;
 287
 288         jump_to_uncached();
 289
 290         /*
 291          * Insert PMB entries for the P1 and P2 areas so that, after
 292          * we've switched the MMU to 32-bit mode, the semantics of P1
 293          * and P2 are the same as in 29-bit mode, e.g.
 294          *
 295          *      P1 - provides a cached window onto physical memory
 296          *      P2 - provides an uncached window onto physical memory
 297          */
 298         size = __MEMORY_START + __MEMORY_SIZE;
 299
 300         ret = pmb_remap(P1SEG, 0x00000000, size, PMB_C);
 301         BUG_ON(ret != size);
 302
 303         ret = pmb_remap(P2SEG, 0x00000000, size, PMB_WT | PMB_UB);
 304         BUG_ON(ret != size);
 305
 306         ctrl_outl(0, PMB_IRMCR);
 307
 308         /* PMB.SE and UB[7] */
 309         ctrl_outl(PASCR_SE | (1 << 7), PMB_PASCR);
 310
 311         /* Flush out the TLB */
 312         i =  ctrl_inl(MMUCR);
 313         i |= MMUCR_TI;
 314         ctrl_outl(i, MMUCR);
 315
 316         back_to_cached();
 317
 318         return 0;
 319 }
 320 #else
 321 int __uses_jump_to_uncached pmb_init(void)
 322 {
 323         int i;
 324         unsigned long addr, data;
 325
 326         jump_to_uncached();
 327
 328         for (i = 0; i < PMB_ENTRY_MAX; i++) {
 329                 struct pmb_entry *pmbe;
 330                 unsigned long vpn, ppn, flags;
 331
 332                 addr = PMB_DATA + (i << PMB_E_SHIFT);
 333                 data = ctrl_inl(addr);
 334                 if (!(data & PMB_V))
 335                         continue;
 336
 337                 if (data & PMB_C) {
 338 #if defined(CONFIG_CACHE_WRITETHROUGH)
 339                         data |= PMB_WT;
 340 #elif defined(CONFIG_CACHE_WRITEBACK)
 341                         data &= ~PMB_WT;
 342 #else
 343                         data &= ~(PMB_C | PMB_WT);
 344 #endif
 345                 }
 346                 ctrl_outl(data, addr);
 347
 348                 ppn = data & PMB_PFN_MASK;
 349
 350                 flags = data & (PMB_C | PMB_WT | PMB_UB);
 351                 flags |= data & PMB_SZ_MASK;
 352
 353                 addr = PMB_ADDR + (i << PMB_E_SHIFT);
 354                 data = ctrl_inl(addr);
 355
 356                 vpn = data & PMB_PFN_MASK;
 357
 358                 pmbe = pmb_alloc(vpn, ppn, flags, i);
 359                 WARN_ON(IS_ERR(pmbe));
 360         }
 361
 362         back_to_cached();
 363
 364         return 0;
 365 }
 366 #endif /* CONFIG_PMB */
 367
 368 static int pmb_seq_show(struct seq_file *file, void *iter)
 369 {
 370         int i;
 371
 372         seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
 373                          "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
 374         seq_printf(file, "ety   vpn  ppn  size   flags\n");
 375
 376         for (i = 0; i < NR_PMB_ENTRIES; i++) {
 377                 unsigned long addr, data;
 378                 unsigned int size;
 379                 char *sz_str = NULL;
 380
 381                 addr = ctrl_inl(mk_pmb_addr(i));
 382                 data = ctrl_inl(mk_pmb_data(i));
 383
 384                 size = data & PMB_SZ_MASK;
 385                 sz_str = (size == PMB_SZ_16M)  ? " 16MB":
 386                          (size == PMB_SZ_64M)  ? " 64MB":
 387                          (size == PMB_SZ_128M) ? "128MB":
 388                                                  "512MB";
 389
 390                 /* 02: V 0x88 0x08 128MB C CB  B */
 391                 seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
 392                            i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
 393                            (addr >> 24) & 0xff, (data >> 24) & 0xff,
 394                            sz_str, (data & PMB_C) ? 'C' : ' ',
 395                            (data & PMB_WT) ? "WT" : "CB",
 396                            (data & PMB_UB) ? "UB" : " B");
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int pmb_debugfs_open(struct inode *inode, struct file *file)
 403 {
 404         return single_open(file, pmb_seq_show, NULL);
 405 }
 406
 407 static const struct file_operations pmb_debugfs_fops = {
 408         .owner          = THIS_MODULE,
 409         .open           = pmb_debugfs_open,
 410         .read           = seq_read,
 411         .llseek         = seq_lseek,
 412         .release        = single_release,
 413 };
 414
 415 static int __init pmb_debugfs_init(void)
 416 {
 417         struct dentry *dentry;
 418
 419         dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
 420                                      sh_debugfs_root, NULL, &pmb_debugfs_fops);
 421         if (!dentry)
 422                 return -ENOMEM;
 423         if (IS_ERR(dentry))
 424                 return PTR_ERR(dentry);
 425
 426         return 0;
 427 }
 428 postcore_initcall(pmb_debugfs_init);
 429
 430 #ifdef CONFIG_PM
 431 static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 432 {
 433         static pm_message_t prev_state;
 434         int i;
 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                 for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
 441                         if (test_bit(i, &pmb_map)) {
 442                                 pmbe = &pmb_entry_list[i];
 443                                 set_pmb_entry(pmbe);
 444                         }
 445                 }
 446         }
 447         prev_state = state;
 448         return 0;
 449 }
 450
 451 static int pmb_sysdev_resume(struct sys_device *dev)
 452 {
 453         return pmb_sysdev_suspend(dev, PMSG_ON);
 454 }
 455
 456 static struct sysdev_driver pmb_sysdev_driver = {
 457         .suspend = pmb_sysdev_suspend,
 458         .resume = pmb_sysdev_resume,
 459 };
 460
 461 static int __init pmb_sysdev_init(void)
 462 {
 463         return sysdev_driver_register(&cpu_sysdev_class, &pmb_sysdev_driver);
 464 }
 465
 466 subsys_initcall(pmb_sysdev_init);
 467 #endif