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pmb.c

/*
 * arch/sh/mm/pmb.c
 *
 * Privileged Space Mapping Buffer (PMB) Support.
 *
 * Copyright (C) 2005, 2006, 2007 Paul Mundt
 *
 * P1/P2 Section mapping definitions from map32.h, which was:
 *
 *    Copyright 2003 (c) Lineo Solutions,Inc.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/io.h>

#define NR_PMB_ENTRIES  16

static struct kmem_cache *pmb_cache;
static unsigned long pmb_map;

static struct pmb_entry pmb_init_map[] = {
      /* vpn         ppn         flags (ub/sz/c/wt) */

      /* P1 Section Mappings */
      { 0x80000000, 0x00000000, PMB_SZ_64M  | PMB_C, },
      { 0x84000000, 0x04000000, PMB_SZ_64M  | PMB_C, },
      { 0x88000000, 0x08000000, PMB_SZ_128M | PMB_C, },
      { 0x90000000, 0x10000000, PMB_SZ_64M  | PMB_C, },
      { 0x94000000, 0x14000000, PMB_SZ_64M  | PMB_C, },
      { 0x98000000, 0x18000000, PMB_SZ_64M  | PMB_C, },

      /* P2 Section Mappings */
      { 0xa0000000, 0x00000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
      { 0xa4000000, 0x04000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
      { 0xa8000000, 0x08000000, PMB_UB | PMB_SZ_128M | PMB_WT, },
      { 0xb0000000, 0x10000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
      { 0xb4000000, 0x14000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
      { 0xb8000000, 0x18000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
};

static inline unsigned long mk_pmb_entry(unsigned int entry)
{
      return (entry & PMB_E_MASK) << PMB_E_SHIFT;
}

static inline unsigned long mk_pmb_addr(unsigned int entry)
{
      return mk_pmb_entry(entry) | PMB_ADDR;
}

static inline unsigned long mk_pmb_data(unsigned int entry)
{
      return mk_pmb_entry(entry) | PMB_DATA;
}

static DEFINE_SPINLOCK(pmb_list_lock);
static struct pmb_entry *pmb_list;

static inline void pmb_list_add(struct pmb_entry *pmbe)
{
      struct pmb_entry **p, *tmp;

      p = &pmb_list;
      while ((tmp = *p) != NULL)
            p = &tmp->next;

      pmbe->next = tmp;
      *p = pmbe;
}

static inline void pmb_list_del(struct pmb_entry *pmbe)
{
      struct pmb_entry **p, *tmp;

      for (p = &pmb_list; (tmp = *p); p = &tmp->next)
            if (tmp == pmbe) {
                  *p = tmp->next;
                  return;
            }
}

struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
                      unsigned long flags)
{
      struct pmb_entry *pmbe;

      pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
      if (!pmbe)
            return ERR_PTR(-ENOMEM);

      pmbe->vpn   = vpn;
      pmbe->ppn   = ppn;
      pmbe->flags = flags;

      spin_lock_irq(&pmb_list_lock);
      pmb_list_add(pmbe);
      spin_unlock_irq(&pmb_list_lock);

      return pmbe;
}

void pmb_free(struct pmb_entry *pmbe)
{
      spin_lock_irq(&pmb_list_lock);
      pmb_list_del(pmbe);
      spin_unlock_irq(&pmb_list_lock);

      kmem_cache_free(pmb_cache, pmbe);
}

/*
 * Must be in P2 for __set_pmb_entry()
 */
int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
                unsigned long flags, int *entry)
{
      unsigned int pos = *entry;

      if (unlikely(pos == PMB_NO_ENTRY))
            pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);

repeat:
      if (unlikely(pos > NR_PMB_ENTRIES))
            return -ENOSPC;

      if (test_and_set_bit(pos, &pmb_map)) {
            pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
            goto repeat;
      }

      ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));

#ifdef CONFIG_CACHE_WRITETHROUGH
      /*
       * When we are in 32-bit address extended mode, CCR.CB becomes
       * invalid, so care must be taken to manually adjust cacheable
       * translations.
       */
      if (likely(flags & PMB_C))
            flags |= PMB_WT;
#endif

      ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));

      *entry = pos;

      return 0;
}

int set_pmb_entry(struct pmb_entry *pmbe)
{
      int ret;

      jump_to_P2();
      ret = __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &pmbe->entry);
      back_to_P1();

      return ret;
}

void clear_pmb_entry(struct pmb_entry *pmbe)
{
      unsigned int entry = pmbe->entry;
      unsigned long addr;

      /*
       * Don't allow clearing of wired init entries, P1 or P2 access
       * without a corresponding mapping in the PMB will lead to reset
       * by the TLB.
       */
      if (unlikely(entry < ARRAY_SIZE(pmb_init_map) ||
                 entry >= NR_PMB_ENTRIES))
            return;

      jump_to_P2();

      /* Clear V-bit */
      addr = mk_pmb_addr(entry);
      ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);

      addr = mk_pmb_data(entry);
      ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);

      back_to_P1();

      clear_bit(entry, &pmb_map);
}


static struct {
      unsigned long size;
      int flag;
} pmb_sizes[] = {
      { .size     = 0x20000000, .flag = PMB_SZ_512M, },
      { .size = 0x08000000, .flag = PMB_SZ_128M, },
      { .size = 0x04000000, .flag = PMB_SZ_64M,  },
      { .size = 0x01000000, .flag = PMB_SZ_16M,  },
};

long pmb_remap(unsigned long vaddr, unsigned long phys,
             unsigned long size, unsigned long flags)
{
      struct pmb_entry *pmbp;
      unsigned long wanted;
      int pmb_flags, i;

      /* Convert typical pgprot value to the PMB equivalent */
      if (flags & _PAGE_CACHABLE) {
            if (flags & _PAGE_WT)
                  pmb_flags = PMB_WT;
            else
                  pmb_flags = PMB_C;
      } else
            pmb_flags = PMB_WT | PMB_UB;

      pmbp = NULL;
      wanted = size;

again:
      for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
            struct pmb_entry *pmbe;
            int ret;

            if (size < pmb_sizes[i].size)
                  continue;

            pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag);
            if (IS_ERR(pmbe))
                  return PTR_ERR(pmbe);

            ret = set_pmb_entry(pmbe);
            if (ret != 0) {
                  pmb_free(pmbe);
                  return -EBUSY;
            }

            phys  += pmb_sizes[i].size;
            vaddr += pmb_sizes[i].size;
            size  -= pmb_sizes[i].size;

            /*
             * Link adjacent entries that span multiple PMB entries
             * for easier tear-down.
             */
            if (likely(pmbp))
                  pmbp->link = pmbe;

            pmbp = pmbe;
      }

      if (size >= 0x1000000)
            goto again;

      return wanted - size;
}

void pmb_unmap(unsigned long addr)
{
      struct pmb_entry **p, *pmbe;

      for (p = &pmb_list; (pmbe = *p); p = &pmbe->next)
            if (pmbe->vpn == addr)
                  break;

      if (unlikely(!pmbe))
            return;

      WARN_ON(!test_bit(pmbe->entry, &pmb_map));

      do {
            struct pmb_entry *pmblink = pmbe;

            clear_pmb_entry(pmbe);
            pmbe = pmblink->link;

            pmb_free(pmblink);
      } while (pmbe);
}

static void pmb_cache_ctor(struct kmem_cache *cachep, void *pmb)
{
      struct pmb_entry *pmbe = pmb;

      memset(pmb, 0, sizeof(struct pmb_entry));

      pmbe->entry = PMB_NO_ENTRY;
}

static int __init pmb_init(void)
{
      unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
      unsigned int entry;

      BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));

      pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
                              SLAB_PANIC, pmb_cache_ctor);

      jump_to_P2();

      /*
       * Ordering is important, P2 must be mapped in the PMB before we
       * can set PMB.SE, and P1 must be mapped before we jump back to
       * P1 space.
       */
      for (entry = 0; entry < nr_entries; entry++) {
            struct pmb_entry *pmbe = pmb_init_map + entry;

            __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &entry);
      }

      ctrl_outl(0, PMB_IRMCR);

      /* PMB.SE and UB[7] */
      ctrl_outl((1 << 31) | (1 << 7), PMB_PASCR);

      back_to_P1();

      return 0;
}
arch_initcall(pmb_init);

static int pmb_seq_show(struct seq_file *file, void *iter)
{
      int i;

      seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
                   "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
      seq_printf(file, "ety   vpn  ppn  size   flags\n");

      for (i = 0; i < NR_PMB_ENTRIES; i++) {
            unsigned long addr, data;
            unsigned int size;
            char *sz_str = NULL;

            addr = ctrl_inl(mk_pmb_addr(i));
            data = ctrl_inl(mk_pmb_data(i));

            size = data & PMB_SZ_MASK;
            sz_str = (size == PMB_SZ_16M)  ? " 16MB":
                   (size == PMB_SZ_64M)  ? " 64MB":
                   (size == PMB_SZ_128M) ? "128MB":
                                       "512MB";

            /* 02: V 0x88 0x08 128MB C CB  B */
            seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
                     i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
                     (addr >> 24) & 0xff, (data >> 24) & 0xff,
                     sz_str, (data & PMB_C) ? 'C' : ' ',
                     (data & PMB_WT) ? "WT" : "CB",
                     (data & PMB_UB) ? "UB" : " B");
      }

      return 0;
}

static int pmb_debugfs_open(struct inode *inode, struct file *file)
{
      return single_open(file, pmb_seq_show, NULL);
}

static const struct file_operations pmb_debugfs_fops = {
      .owner            = THIS_MODULE,
      .open       = pmb_debugfs_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init pmb_debugfs_init(void)
{
      struct dentry *dentry;

      dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
                             NULL, NULL, &pmb_debugfs_fops);
      if (IS_ERR(dentry))
            return PTR_ERR(dentry);

      return 0;
}
postcore_initcall(pmb_debugfs_init);

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