src/main/drivers/memprot_hal.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <string.h>
  22
  23 #include "platform.h"
  24
  25 #include "memprot.h"
  26
  27 static void memProtConfigError(void)
  28 {
  29     for (;;) {}
  30 }
  31
  32 void memProtConfigure(mpuRegion_t *regions, unsigned regionCount)
  33 {
  34     MPU_Region_InitTypeDef MPU_InitStruct;
  35
  36     if (regionCount > MAX_MPU_REGIONS) {
  37         memProtConfigError();
  38     }
  39
  40     HAL_MPU_Disable();
  41
  42     // Setup common members
  43     MPU_InitStruct.Enable           = MPU_REGION_ENABLE;
  44     MPU_InitStruct.SubRegionDisable = 0x00;
  45     MPU_InitStruct.TypeExtField     = MPU_TEX_LEVEL0;
  46
  47     for (unsigned number = 0; number < regionCount; number++) {
  48         mpuRegion_t *region = &regions[number];
  49
  50         if (region->end == 0 && region->size == 0) {
  51             memProtConfigError();
  52         }
  53
  54         MPU_InitStruct.Number      = number;
  55         MPU_InitStruct.BaseAddress = region->start;
  56
  57         if (region->size) {
  58             MPU_InitStruct.Size = region->size;
  59         } else {
  60             // Adjust start of the region to align with cache line size.
  61             uint32_t start = region->start & ~0x1F;
  62             uint32_t length = region->end - start;
  63
  64             if (length < 32) {
  65                 // This will also prevent flsl from returning negative (case length == 0)
  66                 length = 32;
  67             }
  68
  69             int msbpos = flsl(length) - 1;
  70
  71             if (length != (1U << msbpos)) {
  72                 msbpos += 1;
  73             }
  74
  75             MPU_InitStruct.Size = msbpos;
  76         }
  77
  78         // Copy per region attributes
  79         MPU_InitStruct.AccessPermission = region->perm;
  80         MPU_InitStruct.DisableExec      = region->exec;
  81         MPU_InitStruct.IsShareable      = region->shareable;
  82         MPU_InitStruct.IsCacheable      = region->cacheable;
  83         MPU_InitStruct.IsBufferable     = region->bufferable;
  84
  85         HAL_MPU_ConfigRegion(&MPU_InitStruct);
  86     }
  87
  88     HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
  89 }
  90
  91 void memProtReset(void)
  92 {
  93     MPU_Region_InitTypeDef MPU_InitStruct;
  94
  95     /* Disable the MPU */
  96     HAL_MPU_Disable();
  97
  98     // Disable existing regions
  99
 100     for (uint8_t region = 0; region <= MAX_MPU_REGIONS; region++) {
 101         MPU_InitStruct.Enable = MPU_REGION_DISABLE;
 102         MPU_InitStruct.Number = region;
 103         HAL_MPU_ConfigRegion(&MPU_InitStruct);
 104     }
 105
 106     HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
 107 }