More context switching logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3016 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/cortexm3/up_switchcontext.S

@@ -1,7 +1,7 @@
 /************************************************************************************
  * arch/arm/src/cortexm3/up_switchcontext.S
  *
- *   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
@@ -51,7 +51,7 @@
 
 	.syntax		unified
 	.thumb
-	.file		"up_context.S"
+	.file		"up_switchcontext.S"
 
 /************************************************************************************
  * Macros

arch/avr/src/at91uc3/Make.defs

@@ -39,7 +39,7 @@ HEAD_ASRC	= up_nommuhead.S
 
 # Common AVR/AVR32 files
 
-CMN_ASRCS	= up_exceptions.S up_fullcontextrestore.S
+CMN_ASRCS	= up_exceptions.S up_fullcontextrestore.S up_switchcontext.S
 CMN_CSRCS	= up_assert.c up_allocateheap.c up_blocktask.c up_copystate.c \
 		  up_createstack.c up_mdelay.c up_udelay.c up_exit.c up_idle.c \
 		  up_initialize.c up_initialstate.c up_interruptcontext.c \

arch/avr/src/at91uc3/at91uc3_irq.c

@@ -292,7 +292,7 @@ int up_prioritize_irq(int irq, int priority)
  *
  ****************************************************************************/
 #warning "Is this safe to call from assembly?"
-unsigned int avr32_int0irqno(unsigned int level)
+unsigned int avr32_intirqno(unsigned int level)
 {
   /* Get the group that caused the interrupt: "ICRn identifies the group with
    * the highest priority that has a pending interrupt of level n. This value

arch/avr/src/avr32/up_exceptions.S

@@ -44,11 +44,12 @@
  * External Symbols
  ****************************************************************************/
 
-	.global		avr32_int0irqno	/* Returns the IRQ number of an INT0 interrupt */
+	.global		avr32_int0irqno			/* Returns the IRQ number of an INT0 interrupt */
-	.global		avr32_int1irqno	/* Returns the IRQ number of an INT1 interrupt */
+	.global		avr32_int1irqno			/* Returns the IRQ number of an INT1 interrupt */
-	.global		avr32_int2irqno	/* Returns the IRQ number of an INT2 interrupt */
+	.global		avr32_int2irqno			/* Returns the IRQ number of an INT2 interrupt */
-	.global		avr32_int3irqno	/* Returns the IRQ number of an INT3 interrupt */
+	.global		avr32_int3irqno			/* Returns the IRQ number of an INT3 interrupt */
-	.global		up_doirq		/* Dispatch an IRQ */
+	.global		up_doirq				/* Dispatch an IRQ */
+	.global		up_fullcontextrestore	/* Restore new task contex */
 
 /****************************************************************************
  * Macros
@@ -219,6 +220,16 @@ avr32_excptcommon:
 /* and call the IRQ dispatching logic.                                      */
 
 avr32_common:
+    /* Disable interrupts in the current SR.  This is necessary because the */
+	/* AVR32 permits nested interrupts (if they are of higher priority).    */
+	/* We can support nested interrupts without some effort because:        */
+	/* - The global variable current_regs permits only one interrupt,       */
+	/* - If CONFIG_ARCH_INTERRUPTSTACK is defined, then there is a single   */
+	/*   interrupt stack, and                                               */
+	/* - Probably other things.                                             */
+
+	ssrf	AVR32_SR_GM_SHIFT
+
 	/* Save the SP (as it was before the interrupt) in the conext save      */
 	/* structure.                                                           */
 	/*     xx xx xx xx xx xx xx xx SP SR PC LR 12 11 10 09 08               */
@@ -245,8 +256,7 @@ avr32_common:
 
 #if CONFIG_ARCH_INTERRUPTSTACK > 3
 	mov		r7, sp
-	mov		sp, up_intstackbase
+	lddpc	sp, .Lup_instackbase
-	movh	sp, (up_intstackbase >> 0)
 #endif
 
 	/* Call up_doirq with r12=IRQ number and r11=register save area         */
@@ -282,12 +292,16 @@ avr32_common:
 	sub		sp, -4
 	rete
 
-	/* Context switch... we need to do a little more work.                  */
+	/* Context switch... jump to up_fullcontestrestor with r12=address of   */
+	/* the task context to restore.                                         */
+
 1:
-#warning "Missing Logic"
+	lddpc	pc, .Lup_fullcontextrestore
 
 .Lup_doirq:
 	.word	up_doirq
+.Lup_fullcontextrestore:
+	.word	up_fullcontextrestore
 
 /************************************************************************************
  *  Name: up_interruptstack
@@ -302,6 +316,9 @@ up_interruptstack:
 	.skip	(CONFIG_ARCH_INTERRUPTSTACK & ~3)
 up_intstackbase:
 	.size	up_interruptstack, .-up_interruptstack
+.Lup_instackbase
+	.word	up_intstackbase
+	.size	.Lup_instackbase, .-.Lup_instackbase
 #endif
 	.end
 

arch/avr/src/avr32/up_fullcontextrestore.S

@@ -44,6 +44,8 @@
  * External Symbols
  ****************************************************************************/
 
+	.file		"up_fullcontextrestore.S"
+
 /****************************************************************************
  * Macros
  ****************************************************************************/
@@ -54,6 +56,9 @@
  * C Prototype:
  *  void up_fullcontextrestore(uint32_t *regs);
  *
+ * Assumptions:
+ *   Interrupts are disabled.
+ *
  ****************************************************************************/
 
 	.text
@@ -96,7 +101,7 @@ up_fullcontextrestore:
 	ldm		r12++, r8-r11
 	
 	/* r12 now points +4 beyond the end of the register save area. Restore  */
-	/* SR.                                                                  */
+	/* SR.  NOTE:  This may enable interrupts!                              */
 	/*     07 06 05 04 03 02 01 00 SP SR PC LR 12 11 10 09  08              */
 	/*                                ^r12-4*8                 ^r12         */
 	

arch/avr/src/avr32/up_nommuhead.S

@@ -47,6 +47,7 @@
  * External Symbols
  ****************************************************************************/
 
+	.file		"up_nommuhead.S"
 	.global		_sbss			/* Start of .bss.  Defined by ld.script */
 	.global		_ebss			/* End of .bss.  Defined by ld.script */
 #ifdef CONFIG_BOOT_RUNFROMFLASH