Changes to ARMv7-A boot logic to handle the case where we execute out of NOR FLASH

configs/sama5d3x-ek/Kconfig

@@ -11,6 +11,18 @@ config SAMA5_NOR_MAIN
 	depends on SAMA5_BOOT_ISRAM
 	---help---
 		nor_main is a tiny program that runs in ISRAM.  nor_main will enable
-		NOR flash then jump to the program in NOR flash
+		NOR flash then either (1) jump to the program in NOR flash or (2)
+		wait for you to break in with GDB to debug the NOR program.
+
+config SAMA5_NOR_START
+	bool "Start NOR program"
+	default n
+	depends on SAMA5_NOR_MAIN
+	---help---
+		The default behavior of the NOR boot program is to initialize the
+		NOR FLASH at CS0, then patiently wait for you to break into the
+		program with GDB.  An alternative behvior is enabled with this
+		option:  If SAMA5_NOR_START is defined, then it will not wait but
+		will, instead, immediately start the program in NOR FLASH.
 
 endif

configs/sama5d3x-ek/README.txt

@@ -699,6 +699,20 @@ Configurations
     STATUS:
       2013-7-28:  This configuration was verified functional.
 
+  norboot:
+    This is a little program to help debug of code in NOR flash.  It
+    does the following:
+
+    - It enables and configures NOR FLASH, then
+    - Waits for you to break in with GDB.
+
+    At that point, you can set the PC and begin executing from NOR FLASH
+    under debug control.
+
+    NOTES:
+    1. This program derives from the hello configuration.  All of the
+       notes there apply to this configuration as well.
+
   ostest:
     This configuration directory, performs a simple OS test using
     examples/ostest.

configs/sama5d3x-ek/ostest/defconfig

@@ -228,8 +228,8 @@ CONFIG_BOOT_RUNFROMFLASH=y
 CONFIG_RAM_START=0x00304000
 CONFIG_RAM_VSTART=0x00304000
 CONFIG_RAM_SIZE=114688
-CONFIG_FLASH_START=0x1000000
-CONFIG_FLASH_VSTART=0x1000000
+CONFIG_FLASH_START=0x10000000
+CONFIG_FLASH_VSTART=0x10000000
 CONFIG_FLASH_SIZE=134217728
 
 #

configs/sama5d3x-ek/src/Makefile

@@ -73,11 +73,11 @@ ARCH_SRCDIR = $(TOPDIR)/arch/$(CONFIG_ARCH)/src
 ifeq ($(WINTOOL),y)
   CFLAGS += -I "${shell cygpath -w $(ARCH_SRCDIR)/chip}"
   CFLAGS += -I "${shell cygpath -w $(ARCH_SRCDIR)/common}"
-  CFLAGS += -I "${shell cygpath -w $(ARCH_SRCDIR)/armv7-m}"
+  CFLAGS += -I "${shell cygpath -w $(ARCH_SRCDIR)/armv7-a}"
 else
   CFLAGS += -I$(ARCH_SRCDIR)/chip
   CFLAGS += -I$(ARCH_SRCDIR)/common
-  CFLAGS += -I$(ARCH_SRCDIR)/armv7-m
+  CFLAGS += -I$(ARCH_SRCDIR)/armv7-a
 endif
 
 all: libboard$(LIBEXT)

configs/sama5d3x-ek/src/nor_main.c

@@ -43,6 +43,7 @@
 #include <debug.h>
 
 #include "up_arch.h"
+#include "sctlr.h"
 #include "sam_periphclks.h"
 #include "chip/sam_hsmc.h"
 
@@ -114,18 +115,33 @@ int nor_main(int argc, char *argv)
            HSMC_MODE_TDFCYCLES(1);
   putreg32(regval, SAM_HSMC_MODE(HSMC_CS0));
 
+  /* Disable the caches and the MMU.  Disabling the MMU should be safe here
+   * because there is a 1-to-1 identity mapping between the physical and
+   * virtual addressing.
+   */
+
+#if 0 /* Causes a crash */
+  printf("Disabling the caches and the MMU\n");
+  regval  = cp15_rdsctlr();
+  regval &= ~(SCTLR_M | SCTLR_C | SCTLR_I);
+  cp15_wrsctlr(regval);
+#endif
+
+#ifdef SAMA5_NOR_START
   /* Then jump into NOR flash */
 
-#if 1
-  printf("Waiting for GDB halt\n");
-  fflush(stdout);
-  for (;;);
-#else
   printf("Jumping to NOR flash on CS0\n");
   fflush(stdout);
   usleep(500*1000);
 
   NOR_ENTRY();
+#else
+  /* Or just wait patiently for the user to break in with GDB. */
+
+  printf("Waiting for GDB halt\n");
+  fflush(stdout);
+  for (;;);
 #endif
+
   return 0; /* NOR_ENTRY() should not return */
 }