Fix clearing of SRAM when clocks reset

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2923 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/arm/arm.h

@@ -254,6 +254,9 @@
 
 /* Default MMU flags for RAM memory, IO, vector region */
 
+#define MMU_ROMFLAGS \
+  (PMD_TYPE_SECT|PMD_BIT4|PMD_SECT_AP_READ)
+
 #define MMU_MEMFLAGS \
   (PMD_TYPE_SECT|PMD_SECT_WB|PMD_BIT4|PMD_SECT_AP_WRITE|PMD_SECT_AP_READ)
 
@@ -282,6 +285,47 @@
 
 #ifndef __ASSEMBLY__
 
+/* Get the current value of the CP15 C1 control register */
+
+static inline unsigned int get_cp15c1(void)
+{
+  unsigned int retval;
+  __asm__ __volatile__
+    (
+	 "\tmrc	p15, 0, %0, c1, c0"
+     : "=r" (retval)
+     :
+     : "memory");
+  return retval;
+}
+
+/* Get the current value of the CP15 C2 page table pointer register */
+
+static inline unsigned int get_cp15c2(void)
+{
+  unsigned int retval;
+  __asm__ __volatile__
+    (
+	 "\tmrc	p15, 0, %0, c2, c0"
+     : "=r" (retval)
+     :
+     : "memory");
+  return retval;
+}
+/* Get the current value of the CP15 C3 domain access register */
+
+static inline unsigned int get_cp15c3(void)
+{
+  unsigned int retval;
+  __asm__ __volatile__
+    (
+	 "\tmrc	p15, 0, %0, c3, c0"
+     : "=r" (retval)
+     :
+     : "memory");
+  return retval;
+}
+
 /* ARMv4/ARMv5 operation: Invalidate TLB
  * ARM926EJ-S operation:  Invalidate set-associative
  * Data:                  Should be zero

arch/arm/src/lpc313x/lpc313x_boot.c

@@ -285,6 +285,18 @@ static void up_vectormapping(void)
 
 static void up_copyvectorblock(void)
 {
+  uint32_t *src;
+  uint32_t *end;
+  uint32_t *dest;
+
+  /* If we are using vectors in low memory but RAM in that area has been marked
+   * read only, then temparily mark the mapping write-able (non-buffered).
+   */
+
+#if !defined(CONFIG_ARCH_ROMPGTABLE) && defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
+  up_vectorpermissions(MMU_L2_VECTRWFLAGS);
+#endif
+
   /* Copy the vectors into ISRAM at the address that will be mapped to the vector
    * address:
    *
@@ -293,15 +305,21 @@ static void up_copyvectorblock(void)
    *   LPC313X_VECTOR_VADDR - Virtual address of vector table (0x00000000 or 0xffff0000)
    */
 
-  uint32_t *src  = (uint32_t*)&_vector_start;
+  src  = (uint32_t*)&_vector_start;
-  uint32_t *end  = (uint32_t*)&_vector_end;
+  end  = (uint32_t*)&_vector_end;
-  uint32_t *dest = (uint32_t*)LPC313X_VECTOR_VSRAM;
+  dest = (uint32_t*)LPC313X_VECTOR_VSRAM;
 
   while (src < end)
     {
       *dest++ = *src++;
     }
 
+  /* Make the vectors read-only, cacheable again */
+
+#if !defined(CONFIG_ARCH_ROMPGTABLE) && defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
+  up_vectorpermissions(MMU_L2_VECTROFLAGS);
+#endif
+
   /* Then set the LPC313x shadow register, LPC313X_SYSCREG_ARM926SHADOWPTR, so that
    * the vector table is mapped to address 0x0000:0000 - NOTE: that there is not yet
    * full support for the vector table at address 0xffff0000.
@@ -331,14 +349,6 @@ void up_boot(void)
 #ifndef CONFIG_ARCH_ROMPGTABLE
   up_setupmappings();
 
-  /* If we are using vectors in low memory but RAM in that area has been marked
-   * read only, then temparily mark the mapping write-able (non-buffered).
-   */
-
-#if defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
-  up_vectorpermissions(MMU_L2_VECTRWFLAGS);
-#endif
-
   /* Provide a special mapping for the IRAM interrupt vector positioned in high
    * memory.
    */
@@ -354,12 +364,6 @@ void up_boot(void)
 
   up_copyvectorblock();
 
-  /* Make the vectors read-only, cacheable again */
-
-#if !defined(CONFIG_ARCH_ROMPGTABLE) && defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
-  up_vectorpermissions(MMU_L2_VECTROFLAGS);
-#endif
-
   /* Reset all clocks */
 
   lpc313x_resetclks();
@@ -381,6 +385,16 @@ void up_boot(void)
 
   lpc313x_lowsetup();
 
+  /* NOTE:  Something in the operation of lpc313x_resetclks() causes the first
+   * 6 words of memory to be zeroed, wiping out the interrupt vectors.  However,
+   * moving the vector initialization until after the clock setup seems to hang
+   * the system (and I can't step though the clock setup to find why without
+   * losing my JTAG connection).  So, the simplest work-around is to simply
+   * initialize the vectors twice.
+   */
+
+  up_copyvectorblock();
+
   /* Perform early serial initialization if we are going to use the serial driver */
 
 #ifdef CONFIG_USE_EARLYSERIALINIT

arch/arm/src/lpc313x/lpc313x_lowputc.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/lpc313x/lpc313x_lowputc.c
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009-2010 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -339,10 +339,6 @@ void lpc313x_lowsetup(void)
 #endif
 }
 
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
 /****************************************************************************
  * Name: up_lowputc
  *

arch/arm/src/lpc313x/lpc313x_memorymap.h

@@ -183,7 +183,7 @@
 
 /* Section MMU Flags */
 
-#define LPC313X_SHADOWSPACE_MMUFLAGS   MMU_MEMFLAGS
+#define LPC313X_SHADOWSPACE_MMUFLAGS   MMU_ROMFLAGS
 #define LPC313X_INTSRAM_MMUFLAGS       MMU_MEMFLAGS
 #define LPC313X_INTSROM_MMUFLAGS       MMU_MEMFLAGS
 #define LPC313X_APB01_MMUFLAGS         MMU_IOFLAGS