[PATCH rtems v2 3/7] cpu/armv7m: Add table based init for ARMV7M_MPU

Christian Mauderer christian.mauderer at embedded-brains.de
Wed Nov 18 14:45:15 UTC 2020


Modify the MPU functions of the stm32h7 BSP to be table based and
available for all ARMV7M BSPs.

Update #4180
---
 bsps/arm/stm32h7/start/bspstarthooks.c        | 168 ++++++------------
 .../cpu/arm/include/rtems/score/armv7m.h      | 100 +++++++++++
 2 files changed, 150 insertions(+), 118 deletions(-)

diff --git a/bsps/arm/stm32h7/start/bspstarthooks.c b/bsps/arm/stm32h7/start/bspstarthooks.c
index 565bd6876a..41c510aa4c 100644
--- a/bsps/arm/stm32h7/start/bspstarthooks.c
+++ b/bsps/arm/stm32h7/start/bspstarthooks.c
@@ -35,6 +35,52 @@
 
 #include <string.h>
 
+const ARMV7M_MPU_Region_Config
+  stm32h7_start_config_mpu_region [] = {
+    {
+      .begin = stm32h7_memory_sram_axi_begin,
+      .end = stm32h7_memory_sram_axi_end,
+      .flags = ARMV7M_MPU_RASR_XN
+        | ARMV7M_MPU_RASR_AP(0x3)
+        | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
+        | ARMV7M_MPU_RASR_ENABLE,
+    }, {
+      .begin = stm32h7_memory_sdram_1_begin,
+      .end = stm32h7_memory_sdram_1_end,
+      .flags = ARMV7M_MPU_RASR_XN
+        | ARMV7M_MPU_RASR_AP(0x3)
+        | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
+        | ARMV7M_MPU_RASR_ENABLE,
+    }, {
+      .begin = bsp_section_start_begin,
+      .end = bsp_section_text_end,
+      .flags = ARMV7M_MPU_RASR_AP(0x5)
+        | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
+        | ARMV7M_MPU_RASR_ENABLE,
+    }, {
+      .begin = bsp_section_rodata_begin,
+      .end = bsp_section_rodata_end,
+      .flags = ARMV7M_MPU_RASR_XN
+        | ARMV7M_MPU_RASR_AP(0x5)
+        | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
+        | ARMV7M_MPU_RASR_ENABLE,
+    }, {
+      .begin = bsp_section_nocache_begin,
+      .end = bsp_section_nocachenoload_end,
+      .flags = ARMV7M_MPU_RASR_XN
+        | ARMV7M_MPU_RASR_AP(0x3)
+        | ARMV7M_MPU_RASR_TEX(0x2)
+        | ARMV7M_MPU_RASR_ENABLE,
+    }, {
+      .begin = stm32h7_memory_null_begin,
+      .end = stm32h7_memory_null_end,
+      .flags = ARMV7M_MPU_RASR_XN | ARMV7M_MPU_RASR_ENABLE,
+    }
+  };
+
+const size_t stm32h7_start_config_mpu_region_count =
+  RTEMS_ARRAY_SIZE(stm32h7_start_config_mpu_region);
+
 void HAL_MspInit(void)
 {
   __HAL_RCC_SYSCFG_CLK_ENABLE();
@@ -83,123 +129,6 @@ static void init_peripheral_clocks(void)
   }
 }
 
-static uint32_t get_region_size(uintptr_t size)
-{
-  if ((size & (size - 1)) == 0) {
-    return ARMV7M_MPU_RASR_SIZE(30 - __builtin_clz(size));
-  } else {
-    return ARMV7M_MPU_RASR_SIZE(31 - __builtin_clz(size));
-  }
-}
-
-static void set_region(
-  volatile ARMV7M_MPU *mpu,
-  uint32_t region,
-  uint32_t rasr,
-  const void *begin,
-  const void *end
-)
-{
-  uintptr_t size;
-  uint32_t rbar;
-
-  RTEMS_OBFUSCATE_VARIABLE(begin);
-  RTEMS_OBFUSCATE_VARIABLE(end);
-  size = (uintptr_t) end - (uintptr_t) begin;
-
-  if ( size > 0 ) {
-    rbar = (uintptr_t) begin | region | ARMV7M_MPU_RBAR_VALID;
-    rasr |= get_region_size(size);
-  } else {
-    rbar = region;
-    rasr = 0;
-  }
-
-  mpu->rbar = rbar;
-  mpu->rasr = rasr;
-}
-
-static void init_mpu(void)
-{
-  volatile ARMV7M_MPU *mpu;
-  volatile ARMV7M_SCB *scb;
-  uint32_t region_count;
-  uint32_t region;
-
-  mpu = _ARMV7M_MPU;
-  scb = _ARMV7M_SCB;
-
-  region_count = ARMV7M_MPU_TYPE_DREGION_GET(mpu->type);
-
-  for (region = 0; region < region_count; ++region) {
-    mpu->rbar = ARMV7M_MPU_RBAR_VALID | region;
-    mpu->rasr = 0;
-  }
-
-  set_region(
-    mpu,
-    0,
-    ARMV7M_MPU_RASR_XN
-      | ARMV7M_MPU_RASR_AP(0x3)
-      | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
-      | ARMV7M_MPU_RASR_ENABLE,
-    stm32h7_memory_sram_axi_begin,
-    stm32h7_memory_sram_axi_end
-  );
-  set_region(
-    mpu,
-    1,
-    ARMV7M_MPU_RASR_XN
-      | ARMV7M_MPU_RASR_AP(0x3)
-      | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
-      | ARMV7M_MPU_RASR_ENABLE,
-    stm32h7_memory_sdram_1_begin,
-    stm32h7_memory_sdram_1_end
-  );
-  set_region(
-    mpu,
-    2,
-    ARMV7M_MPU_RASR_AP(0x5)
-      | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
-      | ARMV7M_MPU_RASR_ENABLE,
-    bsp_section_start_begin,
-    bsp_section_text_end
-  );
-  set_region(
-    mpu,
-    3,
-    ARMV7M_MPU_RASR_XN
-      | ARMV7M_MPU_RASR_AP(0x5)
-      | ARMV7M_MPU_RASR_TEX(0x1) | ARMV7M_MPU_RASR_C | ARMV7M_MPU_RASR_B
-      | ARMV7M_MPU_RASR_ENABLE,
-    bsp_section_rodata_begin,
-    bsp_section_rodata_end
-  );
-  set_region(
-    mpu,
-    4,
-    ARMV7M_MPU_RASR_XN
-      | ARMV7M_MPU_RASR_AP(0x3)
-      | ARMV7M_MPU_RASR_TEX(0x2)
-      | ARMV7M_MPU_RASR_ENABLE,
-    bsp_section_nocache_begin,
-    bsp_section_nocachenoload_end
-  );
-  set_region(
-    mpu,
-    region - 1,
-    ARMV7M_MPU_RASR_XN | ARMV7M_MPU_RASR_ENABLE,
-    stm32h7_memory_null_begin,
-    stm32h7_memory_null_end
-  );
-
-  mpu->ctrl = ARMV7M_MPU_CTRL_ENABLE | ARMV7M_MPU_CTRL_PRIVDEFENA;
-  scb->shcsr |= ARMV7M_SCB_SHCSR_MEMFAULTENA;
-
-  _ARM_Data_synchronization_barrier();
-  _ARM_Instruction_synchronization_barrier();
-}
-
 void bsp_start_hook_0(void)
 {
   if ((RCC->AHB3ENR & RCC_AHB3ENR_FMCEN) == 0) {
@@ -226,7 +155,10 @@ void bsp_start_hook_0(void)
     SCB_EnableDCache();
   }
 
-  init_mpu();
+  _ARMV7M_MPU_setup_from_config_and_enable(
+    stm32h7_start_config_mpu_region,
+    stm32h7_start_config_mpu_region_count
+  );
 }
 
 void bsp_start_hook_1(void)
diff --git a/cpukit/score/cpu/arm/include/rtems/score/armv7m.h b/cpukit/score/cpu/arm/include/rtems/score/armv7m.h
index c701e1037c..212fbfe44c 100644
--- a/cpukit/score/cpu/arm/include/rtems/score/armv7m.h
+++ b/cpukit/score/cpu/arm/include/rtems/score/armv7m.h
@@ -22,6 +22,9 @@
 #define RTEMS_SCORE_ARMV7M_H
 
 #include <rtems/score/cpu.h>
+#ifndef ASM
+#include <rtems/fatal.h>
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -347,6 +350,24 @@ typedef struct {
     0 \
   }
 
+/**
+ * Higher level region configuration.
+ *
+ * Allows to configure with begin and end which is more convenient for
+ * calculating the sizes from linker command file. Note that you still have to
+ * follow the following rules:
+ *
+ * - Begin address has to be aligned to 0x20 (lower 5 bits set to 0)
+ * - Sizes can only be a value of 2^x with a minimum of 32 Byte. If you have an
+ *   end address that is not aligned, the region will get bigger.
+ * - Later regions have higher priority.
+ */
+typedef struct {
+  const void *begin;
+  const void *end;
+  uint32_t flags;
+} ARMV7M_MPU_Region_Config;
+
 typedef struct {
   uint32_t dhcsr;
   uint32_t dcrsr;
@@ -611,6 +632,85 @@ void _ARMV7M_Supervisor_call( void );
 
 void _ARMV7M_Clock_handler( void );
 
+static inline uint32_t _ARMV7M_MPU_get_region_size(uintptr_t size)
+{
+  if ((size & (size - 1)) == 0) {
+    return ARMV7M_MPU_RASR_SIZE(30 - __builtin_clz(size));
+  } else {
+    return ARMV7M_MPU_RASR_SIZE(31 - __builtin_clz(size));
+  }
+}
+
+static inline void _ARMV7M_MPU_set_region(
+  volatile ARMV7M_MPU *mpu,
+  uint32_t region,
+  uint32_t rasr,
+  const void *begin,
+  const void *end
+)
+{
+  uintptr_t size;
+  uint32_t rbar;
+
+  RTEMS_OBFUSCATE_VARIABLE(begin);
+  RTEMS_OBFUSCATE_VARIABLE(end);
+  size = (uintptr_t) end - (uintptr_t) begin;
+
+  if ( size > 0 ) {
+    rbar = (uintptr_t) begin | region | ARMV7M_MPU_RBAR_VALID;
+    rasr |= _ARMV7M_MPU_get_region_size(size);
+  } else {
+    rbar = region;
+    rasr = 0;
+  }
+
+  mpu->rbar = rbar;
+  mpu->rasr = rasr;
+}
+
+static inline void _ARMV7M_MPU_disable_region(
+  volatile ARMV7M_MPU *mpu,
+  uint32_t region
+)
+{
+  mpu->rbar = ARMV7M_MPU_RBAR_VALID | region;
+  mpu->rasr = 0;
+}
+
+static inline void _ARMV7M_MPU_setup_from_config_and_enable(
+  const ARMV7M_MPU_Region_Config *cfg,
+  size_t cfg_count
+)
+{
+  volatile ARMV7M_MPU *mpu;
+  volatile ARMV7M_SCB *scb;
+  uint32_t region_count;
+  uint32_t region;
+
+  mpu = _ARMV7M_MPU;
+  scb = _ARMV7M_SCB;
+
+  region_count = ARMV7M_MPU_TYPE_DREGION_GET(mpu->type);
+
+  if (cfg_count > region_count) {
+    rtems_panic("invalid MPU config");
+  }
+
+  for (region = 0; region < region_count; ++region) {
+    _ARMV7M_MPU_disable_region(mpu, region);
+  }
+
+  for (region = 0; region < cfg_count; ++region) {
+    _ARMV7M_MPU_set_region(mpu, region, cfg->flags, cfg->begin, cfg->end);
+  }
+
+  mpu->ctrl = ARMV7M_MPU_CTRL_ENABLE | ARMV7M_MPU_CTRL_PRIVDEFENA;
+  scb->shcsr |= ARMV7M_SCB_SHCSR_MEMFAULTENA;
+
+  _ARM_Data_synchronization_barrier();
+  _ARM_Instruction_synchronization_barrier();
+}
+
 #endif /* ASM */
 
 #endif /* ARM_MULTILIB_ARCH_V7M */
-- 
2.26.2



More information about the devel mailing list