SAMA5: When booting from SDRAM, don't copy vectors to ISRAM. Instread just set the VBAR register to add address of the vectors in SDRAM

4 files changed, 75 insertions, 57 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 6683cad09..7773572a8 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -7122,3 +7122,10 @@
 	* arch/arm/src/sama5/sam_irq.c:  After we modify the AXI MATRIX, make
 	  sure to invalidate all caches and TLBs (probably un-necessary)
 	  (2014-4-2).
+	* arch/arm/src/sama5/sam_irq.c: Set the VBAR register to zero.  If
+	  were started by a bootloader (vs. a RESET), then the VBAR register
+	  may not be in its reset state (zero, 2014-4-3).
+	* arch/arm/src/sama5/sam_boot.c, sam_irq.c, and chip/sama5d3x_memorymap.h:
+	  When booting from SDRAM, don't relocated vectors to ISRAM.  Instead,
+	  just set the VBAR register to address of the vectors in SDRAM.
+
diff --git a/nuttx/arch/arm/src/sama5/chip/sama5d3x_memorymap.h b/nuttx/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
index fe2e02672..310111fd7 100644
--- a/nuttx/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
+++ b/nuttx/arch/arm/src/sama5/chip/sama5d3x_memorymap.h
@@ -620,21 +620,7 @@
 #      error CONFIG_BOOT_SDRAM_DATA not suupported in this configuration
 #    endif
 
-#  elif defined(CONFIG_SAMA5_BOOT_SDRAM) && defined(CONFIG_ARCH_LOWVECTORS)
-
-  /* In this case, vectors must lie in ISRAM, followed by the page table,*/
-
-#    define PGTABLE_BASE_PADDR    (SAM_ISRAM0_PADDR + 0x00004000)
-#    ifndef CONFIG_PAGING
-#      define PGTABLE_BASE_VADDR  (SAM_ISRAM0_VADDR + 0x00004000)
-#    endif
-#    define PGTABLE_IN_LOWSRAM    1
-
-#    ifdef CONFIG_BOOT_SDRAM_DATA
-#      error CONFIG_BOOT_SDRAM_DATA not suupported in this configuration
-#    endif
-
-#  else /* CONFIG_SAMA5_BOOT_SDRAM && CONFIG_ARCH_LOWVECTORS */
+#  else /* CONFIG_SAMA5_BOOT_ISRAM && CONFIG_ARCH_LOWVECTORS */
 
   /* Otherwise, the vectors lie at another location (perhaps in NOR FLASH, perhaps
    * elsewhere in internal SRAM).  The page table will then be positioned at
diff --git a/nuttx/arch/arm/src/sama5/sam_boot.c b/nuttx/arch/arm/src/sama5/sam_boot.c
index 8493c3bf1..e41a38238 100644
--- a/nuttx/arch/arm/src/sama5/sam_boot.c
+++ b/nuttx/arch/arm/src/sama5/sam_boot.c
@@ -106,19 +106,6 @@
 #  define NEED_SDRAM_REMAPPING 1
 #endif
 
-/* We need to copy vectors under two conditions:
- *
- * 1. If vectors lie in high memory because CONFIG_ARCH_LOWVECTORS=n, or
- * 2. If vectors lie in low memory and we are executing from SDRAM.
- */
-
-#undef NEED_VECTOR_COPY
-#if !defined(CONFIG_ARCH_LOWVECTORS)
-#  define NEED_VECTOR_COPY 1
-#elif defined(CONFIG_SAMA5_BOOT_SDRAM)
-#  define NEED_VECTOR_COPY 1
-#endif
-
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -146,28 +133,26 @@ static const struct section_mapping_s section_mapping[] =
   /* SAMA5 Internal Memories */
 
   /* If CONFIG_ARCH_LOWVECTORS is defined, then the vectors located at the
-   * beginning of the .text region must appear at address zero.  There are
-   * three ways to accomplish this:
+   * beginning of the .text region must appear at address at the address
+   * specified in the VBAR.  There are three ways to accomplish this:
    *
    *   1. By explicitly mapping the beginning of .text region with a page
    *      table entry so that the virtual address zero maps to the beginning
-   *      of the .text region.
+   *      of the .text region.  VBAR == 0x0000:0000.
    *
    *   2. A second way is to map the use the AXI MATRIX remap register to
    *      map physical address zero to the beginning of the text region,
    *      either internal SRAM or EBI CS 0.  Then we can set an identity
    *      mapping to map the boot region at 0x0000:0000 to virtual address
-   *      0x0000:00000
+   *      0x0000:00000.   VBAR == 0x0000:0000.
    *
-   *      This method is used when booting from NORFLASH.  In that case,
-   *      vectors must lie at the beginning of NOFR FLASH.
+   *      This method is used when booting from ISRAM or NOR FLASH.  In
+   &      that case, vectors must lie at the beginning of NOFR FLASH.
    *
-   *   3. Set the AXI MATRIX remap register so that SRAM appears at address
-   *      zero, mapping the boot region to address 0, then copying the
-   *      vectors to address zero.
+   *   3. Set the Cortex-A5 VBAR register so that the vector table address
+   *      is moved to a location other than 0x0000:0000.
    *
-   *      This is the method used when booting from either SDRAM or
-   *      SRAM.
+   *      This is the method used when booting from SDRAM.
    *
    * - When executing from NOR FLASH, the first level bootloader is supposed
    *   to provide the AXI MATRIX mapping for us at boot time base on the state
@@ -181,21 +166,16 @@ static const struct section_mapping_s section_mapping[] =
    *   probably copied us into ISRAM and set the AXI REMAP bit for us.
    *
    * - If we are executing from external SDRAM, then a secondary bootloader must
-   *   have loaded us into SDRAM.  In this case, we will may the BOOT memory,
-   *   set the AXI matrix to locate the ISRAM in boot memory, and copy the vector
-   *   table ISRAM.
+   *   have loaded us into SDRAM.  In this case, simply set the VBAR register
+   *   to the address of the vector table (not necessary at the beginning
+   *   or SDRAM).
    */
 
-#if defined(CONFIG_ARCH_LOWVECTORS) && !defined(CONFIG_SAMA5_BOOT_ISRAM)
-#  if defined(CONFIG_SAMA5_BOOT_SDRAM)
-  { SAM_ISRAM_PSECTION,    0x00000000,
-    MMU_ROMFLAGS,          1
-  },
-#  else
+#if defined(CONFIG_ARCH_LOWVECTORS) && !defined(CONFIG_SAMA5_BOOT_ISRAM) && \
+    !defined(CONFIG_SAMA5_BOOT_SDRAM)
   { CONFIG_FLASH_START,    0x00000000,
     MMU_ROMFLAGS,          1
   },
-#  endif
 #else
   { SAM_BOOTMEM_PSECTION,  SAM_BOOTMEM_VSECTION,
     SAM_BOOTMEM_MMUFLAGS,  SAM_BOOTMEM_NSECTIONS
@@ -512,7 +492,7 @@ static void sam_vectormapping(void)
  *
  ****************************************************************************/
 
-#ifdef NEED_VECTOR_COPY
+#if !defined(CONFIG_ARCH_LOWVECTORS)
 static void sam_copyvectorblock(void)
 {
   uint32_t *src;
diff --git a/nuttx/arch/arm/src/sama5/sam_irq.c b/nuttx/arch/arm/src/sama5/sam_irq.c
index 0da4b5a0e..13f3d2028 100644
--- a/nuttx/arch/arm/src/sama5/sam_irq.c
+++ b/nuttx/arch/arm/src/sama5/sam_irq.c
@@ -237,7 +237,9 @@ static uint32_t *sam_fiqhandler(int irq, uint32_t *regs)
 
 void up_irqinitialize(void)
 {
+#if defined(CONFIG_SAMA5_BOOT_ISRAM) || defined(CONFIG_SAMA5_BOOT_CS0FLASH)
   size_t vectorsize;
+#endif
   int i;
 
   /* The following operations need to be atomic, but since this function is
@@ -309,7 +311,44 @@ void up_irqinitialize(void)
   putreg32(AIC_WPMR_WPKEY | AIC_WPMR_WPEN, SAM_AIC_WPMR);
 
 #if defined(CONFIG_ARCH_LOWVECTORS)
-  /* Set the vector base address register to zero */
+  /* If CONFIG_ARCH_LOWVECTORS is defined, then the vectors located at the
+   * beginning of the .text region must appear at address at the address
+   * specified in the VBAR.  There are three ways to accomplish this:
+   *
+   *   1. By explicitly mapping the beginning of .text region with a page
+   *      table entry so that the virtual address zero maps to the beginning
+   *      of the .text region.  VBAR == 0x0000:0000.
+   *
+   *   2. A second way is to map the use the AXI MATRIX remap register to
+   *      map physical address zero to the beginning of the text region,
+   *      either internal SRAM or EBI CS 0.  Then we can set an identity
+   *      mapping to map the boot region at 0x0000:0000 to virtual address
+   *      0x0000:00000.   VBAR == 0x0000:0000.
+   *
+   *      This method is used when booting from ISRAM or NOR FLASH.  In
+   &      that case, vectors must lie at the beginning of NOFR FLASH.
+   *
+   *   3. Set the Cortex-A5 VBAR register so that the vector table address
+   *      is moved to a location other than 0x0000:0000.
+   *
+   *      This is the method used when booting from SDRAM.
+   *
+   * - When executing from NOR FLASH, the first level bootloader is supposed
+   *   to provide the AXI MATRIX mapping for us at boot time base on the state
+   *   of the BMS pin.  However, I have found that in the test environments
+   *   that I use, I cannot always be assured of that physical address mapping.
+   *
+   * - If we are executing out of ISRAM, then the SAMA5 primary bootloader
+   *   probably copied us into ISRAM and set the AXI REMAP bit for us.
+   *
+   * - If we are executing from external SDRAM, then a secondary bootloader
+   *   must have loaded us into SDRAM.  In this case, simply set the VBAR
+   *   register to the address of the vector table (not necessary at the
+   *   beginning or SDRAM).
+   */
+
+#if defined(CONFIG_SAMA5_BOOT_ISRAM) || defined(CONFIG_SAMA5_BOOT_CS0FLASH)
+  /* Set the vector base address register to 0x0000:0000 */
 
   cp15_wrvbar(0);
 
@@ -338,12 +377,12 @@ void up_irqinitialize(void)
    * address 0x0000:0000 in that case anyway.
    */
 
-#if defined(CONFIG_SAMA5_BOOT_ISRAM) || defined(CONFIG_SAMA5_BOOT_SDRAM)
   putreg32(MATRIX_MRCR_RCB0, SAM_MATRIX_MRCR);   /* Enable Cortex-A5 remap */
+
+#if defined(CONFIG_SAMA5_BOOT_ISRAM)
   putreg32(AXIMX_REMAP_REMAP0, SAM_AXIMX_REMAP); /* Remap SRAM */
-#elif defined(CONFIG_SAMA5_BOOT_CS0FLASH)
-  putreg32(MATRIX_MRCR_RCB0, SAM_MATRIX_MRCR);   /* Enable Cortex-A5 remap */
-  putreg32(AXIMX_REMAP_REMAP1, SAM_AXIMX_REMAP); /* Remap NOR FLASH */
+#else /* elif defined(CONFIG_SAMA5_BOOT_CS0FLASH) */
+  putreg32(AXIMX_REMAP_REMAP1, SAM_AXIMX_REMAP); /* Remap NOR FLASH on CS0 */
 #endif
 
   /* Make sure that there is no trace of any previous mapping */
@@ -359,8 +398,14 @@ void up_irqinitialize(void)
   putreg32(MATRIX_WPMR_WPKEY | MATRIX_WPMR_WPEN, SAM_MATRIX_WPMR);
 #endif
 
-  /* It might be wise to flush the instruction cache here */
-#endif
+#elif defined(CONFIG_SAMA5_BOOT_SDRAM)
+  /* Set the VBAR register to the address of the vector table in SDRAM */
+
+  DEBUGASSERT((((uintptr_t)&_vector_start) & ~VBAR_MASK) == 0);
+  cp15_wrvbar((uint32_t)&_vector_start);
+
+#endif /* CONFIG_SAMA5_BOOT_ISRAM || CONFIG_SAMA5_BOOT_CS0FLASH */
+#endif /* CONFIG_ARCH_LOWVECTORS */
 
   /* currents_regs is non-NULL only while processing an interrupt */