nuttx/arch/arm/src/armv7-a/arm_mmu.c

/****************************************************************************
 * arch/arm/src/armv7-a/arm_mmu.c
 *
 *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>

#include "cache.h"
#include "mmu.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: mmu_l1_setentry
 *
 * Description:
 *   Set a one level 1 translation table entry.  Only a single L1 page table
 *   is supported.
 *
 * Input Paramters:
 *   paddr - The physical address to be mapped.  Must be aligned to a 1MB
 *     address boundary
 *   vaddr - The virtual address to be mapped.  Must be aligned to a 1MB
 *     address boundary
 *   mmuflags - The MMU flags to use in the mapping.
 *
 ****************************************************************************/

#ifndef CONFIG_ARCH_ROMPGTABLE
void mmu_l1_setentry(uint32_t paddr, uint32_t vaddr, uint32_t mmuflags)
{
  uint32_t *l1table = (uint32_t*)PGTABLE_BASE_VADDR;
  uint32_t  index   = vaddr >> 20;

  /* Save the page table entry */

  l1table[index]  = (paddr | mmuflags);

  /* Flush the data cache entry.  Make sure that the modified contents
   * of the page table are flushed into physical memory.
   */

  cp15_clean_dcache_bymva((uint32_t)&l1table[index]);

  /* Invalidate the TLB cache associated with virtual address range */

  mmu_invalidate_region(vaddr, 1024*1024);
}
#endif

/****************************************************************************
 * Name: mmu_l2_setentry
 *
 * Description:
 *   Set one small (4096B) entry in a level2 translation table.
 *
 * Input Parameters:
 *   l2vaddr - the virtual address of the beginning of the L2 translation
 *     table.
 *   paddr - The physical address to be mapped.  Must be aligned to a 4KB
 *     address boundary
 *   vaddr - The virtual address to be mapped.  Must be aligned to a 4KB
 *     address boundary
 *   mmuflags - The MMU flags to use in the mapping.
 *
 ****************************************************************************/

#ifndef CONFIG_ARCH_ROMPGTABLE
void mmu_l2_setentry(uint32_t l2vaddr, uint32_t paddr, uint32_t vaddr,
                     uint32_t mmuflags)
{
  uint32_t *l2table  = (uint32_t*)l2vaddr;
  uint32_t  index;

  /* The table divides a 1Mb address space up into 256 entries, each
   * corresponding to 4Kb of address space.  The page table index is
   * related to the offset from the beginning of 1Mb region.
   */

  index = (vaddr & 0x000ff000) >> 12;

  /* Save the table entry */

  l2table[index] = (paddr | mmuflags);

  /* Flush the data cache entry.  Make sure that the modified contents
   * of the page table are flushed into physical memory.
   */

  cp15_clean_dcache_bymva((uint32_t)&l2table[index]);

  /* Invalidate the TLB cache associated with virtual address range */

  cp15_invalidate_tlb_bymva(vaddr);
}
#endif

/****************************************************************************
 * Name: mmu_l1_map_region
 *
 * Description:
 *   Set multiple level 1 translation table entries in order to map a
 *   region of memory.
 *
 * Input Parameters:
 *   mapping - Describes the mapping to be performed.
 *
 ****************************************************************************/

#ifndef CONFIG_ARCH_ROMPGTABLE
void mmu_l1_map_region(const struct section_mapping_s *mapping)
{
  uint32_t paddr    = mapping->physbase;
  uint32_t vaddr    = mapping->virtbase;
  uint32_t mmuflags = mapping->mmuflags;
  int i;

  /* Loop, writing each mapping into the L1 page table */

  for (i = 0; i < mapping->nsections; i++)
    {
      mmu_l1_setentry(paddr, vaddr, mmuflags);
      paddr += SECTION_SIZE;
      vaddr += SECTION_SIZE;
    }
}
#endif

/****************************************************************************
 * Name: mmu_invalidate_region
 *
 * Description:
 *   Invalidate TLBs for a range of addresses (all 4KB aligned).
 *
 * Input Parameters:
 *   vaddr - The beginning of the region to invalidate.
 *   size  - The size of the region in bytes to be invalidated.
 *
 ****************************************************************************/

#ifndef CONFIG_ARCH_ROMPGTABLE
void mmu_invalidate_region(uint32_t vstart, size_t size)
{
  uint32_t vaddr = vstart & 0xfffff000;
  uint32_t vend  = vaddr + size;

  /* Loop, invalidating regions */

  while (vaddr < vend)
    {
      cp15_invalidate_tlb_bymva(vaddr);
      vaddr += 4096;
    }
}
#endif