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tlb-sh5.c

/*
 * arch/sh/mm/tlb-sh5.c
 *
 * Copyright (C) 2003  Paul Mundt <lethal@linux-sh.org>
 * Copyright (C) 2003  Richard Curnow <richard.curnow@superh.com>
 *
 * 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/mm.h>
#include <linux/init.h>
#include <asm/page.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>

/**
 * sh64_tlb_init - Perform initial setup for the DTLB and ITLB.
 */
int __init sh64_tlb_init(void)
{
      /* Assign some sane DTLB defaults */
      cpu_data->dtlb.entries  = 64;
      cpu_data->dtlb.step     = 0x10;

      cpu_data->dtlb.first    = DTLB_FIXED | cpu_data->dtlb.step;
      cpu_data->dtlb.next     = cpu_data->dtlb.first;

      cpu_data->dtlb.last     = DTLB_FIXED |
                          ((cpu_data->dtlb.entries - 1) *
                           cpu_data->dtlb.step);

      /* And again for the ITLB */
      cpu_data->itlb.entries  = 64;
      cpu_data->itlb.step     = 0x10;

      cpu_data->itlb.first    = ITLB_FIXED | cpu_data->itlb.step;
      cpu_data->itlb.next     = cpu_data->itlb.first;
      cpu_data->itlb.last     = ITLB_FIXED |
                          ((cpu_data->itlb.entries - 1) *
                           cpu_data->itlb.step);

      return 0;
}

/**
 * sh64_next_free_dtlb_entry - Find the next available DTLB entry
 */
unsigned long long sh64_next_free_dtlb_entry(void)
{
      return cpu_data->dtlb.next;
}

/**
 * sh64_get_wired_dtlb_entry - Allocate a wired (locked-in) entry in the DTLB
 */
unsigned long long sh64_get_wired_dtlb_entry(void)
{
      unsigned long long entry = sh64_next_free_dtlb_entry();

      cpu_data->dtlb.first += cpu_data->dtlb.step;
      cpu_data->dtlb.next  += cpu_data->dtlb.step;

      return entry;
}

/**
 * sh64_put_wired_dtlb_entry - Free a wired (locked-in) entry in the DTLB.
 *
 * @entry:  Address of TLB slot.
 *
 * Works like a stack, last one to allocate must be first one to free.
 */
int sh64_put_wired_dtlb_entry(unsigned long long entry)
{
      __flush_tlb_slot(entry);

      /*
       * We don't do any particularly useful tracking of wired entries,
       * so this approach works like a stack .. last one to be allocated
       * has to be the first one to be freed.
       *
       * We could potentially load wired entries into a list and work on
       * rebalancing the list periodically (which also entails moving the
       * contents of a TLB entry) .. though I have a feeling that this is
       * more trouble than it's worth.
       */

      /*
       * Entry must be valid .. we don't want any ITLB addresses!
       */
      if (entry <= DTLB_FIXED)
            return -EINVAL;

      /*
       * Next, check if we're within range to be freed. (ie, must be the
       * entry beneath the first 'free' entry!
       */
      if (entry < (cpu_data->dtlb.first - cpu_data->dtlb.step))
            return -EINVAL;

      /* If we are, then bring this entry back into the list */
      cpu_data->dtlb.first    -= cpu_data->dtlb.step;
      cpu_data->dtlb.next     = entry;

      return 0;
}

/**
 * sh64_setup_tlb_slot - Load up a translation in a wired slot.
 *
 * @config_addr:  Address of TLB slot.
 * @eaddr:        Virtual address.
 * @asid:         Address Space Identifier.
 * @paddr:        Physical address.
 *
 * Load up a virtual<->physical translation for @eaddr<->@paddr in the
 * pre-allocated TLB slot @config_addr (see sh64_get_wired_dtlb_entry).
 */
inline void sh64_setup_tlb_slot(unsigned long long config_addr,
                        unsigned long eaddr,
                        unsigned long asid,
                        unsigned long paddr)
{
      unsigned long long pteh, ptel;

      /* Sign extension */
#if (NEFF == 32)
      pteh = (unsigned long long)(signed long long)(signed long) eaddr;
#else
#error "Can't sign extend more than 32 bits yet"
#endif
      pteh &= PAGE_MASK;
      pteh |= (asid << PTEH_ASID_SHIFT) | PTEH_VALID;
#if (NEFF == 32)
      ptel = (unsigned long long)(signed long long)(signed long) paddr;
#else
#error "Can't sign extend more than 32 bits yet"
#endif
      ptel &= PAGE_MASK;
      ptel |= (_PAGE_CACHABLE | _PAGE_READ | _PAGE_WRITE);

      asm volatile("putcfg %0, 1, %1\n\t"
                  "putcfg %0, 0, %2\n"
                  : : "r" (config_addr), "r" (ptel), "r" (pteh));
}

/**
 * sh64_teardown_tlb_slot - Teardown a translation.
 *
 * @config_addr:  Address of TLB slot.
 *
 * Teardown any existing mapping in the TLB slot @config_addr.
 */
inline void sh64_teardown_tlb_slot(unsigned long long config_addr)
      __attribute__ ((alias("__flush_tlb_slot")));

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