Add basic context switching logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1777 42af7a65-404d-4744-a932-0658087f49c3

6 files changed, 287 insertions, 13 deletions

diff --git a/nuttx/arch/arm/src/lm3s/Make.defs b/nuttx/arch/arm/src/lm3s/Make.defs
index b312d330c..0684a35e7 100644
--- a/nuttx/arch/arm/src/lm3s/Make.defs
+++ b/nuttx/arch/arm/src/lm3s/Make.defs
@@ -45,9 +45,9 @@ CMN_CSRCS	= up_allocateheap.c up_assert.c up_blocktask.c up_copystate.c \
 		  up_sigdeliver.c up_syscall.c up_unblocktask.c \
 		  up_undefinedinsn.c up_usestack.c
 
-CHIP_ASRCS	= 
-CHIP_CSRCS	= lm3s_start.c lm3s_syscontrol.c lm3s_irq.c lm3s_timerisr.c \
-		  lm3s_lowputc.c lm3s_serial.c
+CHIP_ASRCS	= lm3s_context.S
+CHIP_CSRCS	= lm3s_start.c lm3s_syscontrol.c lm3s_irq.c lm3s_pendsv.c \
+		  lm3s_timerisr.c lm3s_lowputc.c lm3s_serial.c
 
 ifdef CONFIG_NET
 CHIP_CSRCS	+= lm3s_ethernet.c
diff --git a/nuttx/arch/arm/src/lm3s/lm3s_context.S b/nuttx/arch/arm/src/lm3s/lm3s_context.S
new file mode 100644
index 000000000..a0a75fea4
--- /dev/null
+++ b/nuttx/arch/arm/src/lm3s/lm3s_context.S
@@ -0,0 +1,145 @@
+/************************************************************************************

+ * arch/arm/src/lm3s/lm3s_context.S

+ * arch/arm/src/chip/lm3s_context.S

+ *

+ *   Copyright (C) 2009 Gregory Nutt. All rights reserved.

+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>

+ *

+ * Redistribution and use in source and binary forms, with or without

+ * modification, are permitted provided that the following conditions

+ * are met:

+ *

+ * 1. Redistributions of source code must retain the above copyright

+ *    notice, this list of conditions and the following disclaimer.

+ * 2. Redistributions in binary form must reproduce the above copyright

+ *    notice, this list of conditions and the following disclaimer in

+ *    the documentation and/or other materials provided with the

+ *    distribution.

+ * 3. Neither the name NuttX nor the names of its contributors may be

+ *    used to endorse or promote products derived from this software

+ *    without specific prior written permission.

+ *

+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE

+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,

+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,

+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS

+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN

+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

+ * POSSIBILITY OF SUCH DAMAGE.

+ *

+ ************************************************************************************/

+

+/************************************************************************************

+ * Included Files

+ ************************************************************************************/

+

+#include <nuttx/config.h>

+#include <arch/irq.h>

+#include "cortexm3_nvic.h"

+

+/************************************************************************************

+ * Preprocessor Definitions

+ ************************************************************************************/

+

+/************************************************************************************

+ * Global Symbols

+ ************************************************************************************/

+

+	.syntax		unified

+	.thumb

+	.file		"lm3s_context.S"

+

+/************************************************************************************

+ * Macros

+ ************************************************************************************/

+

+/************************************************************************************

+ * Public Functions

+ ************************************************************************************/

+

+/**************************************************************************

+ * Name: up_saveusercontext

+ *

+ * Description:

+ *   Save the current thread context.  Full prototype is:

+ *

+ *   int  up_saveusercontext(uint32 *regs);

+ *

+ * Return:

+ *   0: Normal return

+ *   1: Context switch return

+ *

+ **************************************************************************/

+

+	.text

+	.thumb_func

+	.globl		up_saveusercontext

+	.type		up_saveusercontext, function

+up_saveusercontext:

+

+	/* Perform the System call with R0=0 and R1=regs */

+

+	ldr	r2, nvic_intctrl	/* R2: Address NVIC INTCTRL registers */

+	ldr	r3, [r2, #0]		/* R3: Contentx of NVIC INCTRL */

+	orr	r3, r3, #NVIC_INTCTRL_PENDSVSET

+	mov	r1, r0			/* R1: regs */

+	mov	r0, #0			/* R0: 0 means save context (also return value) */

+	str     r3, [r2, #0]		/* Force Pend SV */

+

+	/* There are two return conditions.  On the first return, R0 (the

+	 * return value will be zero.  On the second return we need to

+	 * force R0 to be 1.

+	 */

+

+	add	r2, r1, #(4*REG_R0)

+	mov	r3, #1

+	str	r3, [r2, #0]

+	bx	lr			/* "normal" return with r0=0 or

+					 * context switch with r0=1 */

+	.size		up_saveusercontext, .-up_saveusercontext

+

+

+/**************************************************************************

+ * Name: up_fullcontextrestore

+ *

+ * Description:

+ *   Restore the current thread context.  Full prototype is:

+ *

+ *   void up_fullcontextrestore(uint32 *regs) __attribute__ ((noreturn));

+ *

+ * Return:

+ *   None

+ *

+ **************************************************************************/

+

+	.thumb_func

+	.globl		up_fullcontextrestore

+	.type		up_fullcontextrestore, function

+up_fullcontextrestore:

+

+	/* Perform the System call with R0=1 and R1=regs */

+

+	ldr	r2, nvic_intctrl	/* R2: Address NVIC INTCTRL registers */

+	ldr	r3, [r2, #0]		/* R3: Contentx of NVIC INCTRL */

+	orr	r3, r3, #NVIC_INTCTRL_PENDSVSET

+	mov	r1, r0			/* R1: regs */

+	mov	r0, #1			/* R0: 1 means restore context */

+	str     r3, [r2, #0]		/* Force Pend SV */

+

+	/* These call should not return */

+

+	bx	lr			/* Unnecessary ... will not return */

+	.size		up_fullcontextrestore, .-up_fullcontextrestore

+

+        .align  2

+	.type		nvic_intctrl, object

+nvic_intctrl:

+        .word   NVIC_INTCTRL

+	.size		nvic_intctrl, .-nvic_intctrl

+        .end

+

diff --git a/nuttx/arch/arm/src/lm3s/lm3s_internal.h b/nuttx/arch/arm/src/lm3s/lm3s_internal.h
index 349a3461e..3f8540dd5 100644
--- a/nuttx/arch/arm/src/lm3s/lm3s_internal.h
+++ b/nuttx/arch/arm/src/lm3s/lm3s_internal.h
@@ -43,6 +43,10 @@
 #include <nuttx/config.h>
 #include <sys/types.h>
 
+#include "up_internal.h"
+#include "lm3s_memorymap.h"
+#include "lm3s_gpio.h"
+
 /************************************************************************************
  * Definitions
  ************************************************************************************/
@@ -247,6 +251,15 @@ EXTERN void up_clockconfig(void);
 
 EXTERN int lm3s_configgpio(uint32 bitset);
 
+/****************************************************************************
+ * Name: lm3s_pendsv
+ *
+ * Description:
+ *   This is PendSV exception handler that performs context switching
+ *
+ ****************************************************************************/
+
+EXTERN int lm3s_pendsv(int irq, FAR void *context);
 
 #undef EXTERN
 #if defined(__cplusplus)
diff --git a/nuttx/arch/arm/src/lm3s/lm3s_irq.c b/nuttx/arch/arm/src/lm3s/lm3s_irq.c
index 04110e3cf..4b3c404e0 100644
--- a/nuttx/arch/arm/src/lm3s/lm3s_irq.c
+++ b/nuttx/arch/arm/src/lm3s/lm3s_irq.c
@@ -173,6 +173,12 @@ void up_irqinitialize(void)
 
   current_regs = NULL;
 
+  /* Attach the PendSV exception handler.  This is used for performing
+   * context switches.
+   */
+
+  irq_attach(LMSB_IRQ_PENDSV, lm3s_pendsv);
+
   /* Attach all processor exceptions (except reset and sys tick) */
 
 #ifdef CONFIG_DEBUG
@@ -183,7 +189,6 @@ void up_irqinitialize(void)
   irq_attach(LMSB_IRQ_USAGEFAULT, lm3s_usagefault);
   irq_attach(LMSB_IRQ_SVCALL, lm3s_svcall);
   irq_attach(LMSB_IRQ_DBGMONITOR, lm3s_dbgmonitor);
-  irq_attach(LMSB_IRQ_PENDSV, lm3s_pendsv);
   irq_attach(LMSB_IRQ_RESERVED, lm3s_reserved);
 #endif
 
@@ -368,14 +373,6 @@ int lm3s_dbgmonitor(int irq, FAR void *context)
   return 0;
 }
 
-int lm3s_pendsv(int irq, FAR void *context)
-{
-  (void)irqsave();
-  dbg("PANIC!!! PendSV received\n");
-  PANIC(OSERR_UNEXPECTEDISR);
-  return 0;
-}
-
 int lm3s_reserved(int irq, FAR void *context)
 {
   (void)irqsave();
diff --git a/nuttx/arch/arm/src/lm3s/lm3s_pendsv.c b/nuttx/arch/arm/src/lm3s/lm3s_pendsv.c
new file mode 100644
index 000000000..1db255fef
--- /dev/null
+++ b/nuttx/arch/arm/src/lm3s/lm3s_pendsv.c
@@ -0,0 +1,118 @@
+/****************************************************************************
+ * arch/arm/src/lm3s/lm3s_pendsv.c
+ * arch/arm/src/chip/lm3s_pendsv.c
+ *
+ *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+
+#include <string.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+
+#include "os_internal.h"
+#include "lm3s_internal.h"
+
+/****************************************************************************
+ * Private Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lm3xs_pendxv
+ *
+ * Description:
+ *   This is PendSV exception handler that performs context switching
+ *
+ ****************************************************************************/
+
+int lm3s_pendsv(int irq, FAR void *context)
+{
+  uint32 *svregs  = (uint32*)context;
+  uint32 *tcbregs = (uint32*)svregs[REG_R1];
+
+  DEBUGASSERT(svregs && svregs == current_regs && tcbregs);
+
+  /* The PendSV software interrupt is called with R0 = PendSV command and R1 = 
+   * the TCB register save area.
+   */
+
+  switch (svregs[REG_R0])
+    {
+      /* R0=0:  This is a save context command.  In this case, we simply need
+       * to copy the svregs to the tdbregs and return.
+       */
+
+      case 0:
+        memcpy(tcbregs, svregs, XCPTCONTEXT_SIZE);
+        break;
+
+      /* R1=1: This a restore context command.  In this case, we simply need to
+       * set current_regs to tcbrgs.  svregs == current_regs is the normal exception
+       * turn.  By setting current_regs = tcbregs, we force the return through
+       * the saved context.
+       */
+
+      case 1:
+        current_regs = tcbregs;
+        break;
+
+      default:
+        PANIC(OSERR_INTERNAL);
+        break;
+    }
+
+  return OK;
+}
diff --git a/nuttx/arch/arm/src/lm3s/lm3s_vectors.S b/nuttx/arch/arm/src/lm3s/lm3s_vectors.S
index c17a387ae..2873f72e1 100644
--- a/nuttx/arch/arm/src/lm3s/lm3s_vectors.S
+++ b/nuttx/arch/arm/src/lm3s/lm3s_vectors.S
@@ -1,5 +1,6 @@
 /************************************************************************************

- * arch/arm/src/lm3s/lm3slm3s_vectors.S

+ * arch/arm/src/lm3s/lm3s_vectors.S

+ * arch/arm/src/chip/lm3s_vectors.S

  *

  *   Copyright (C) 2009 Gregory Nutt. All rights reserved.

  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>