Add SAM3U clock and systick init logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2511 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 162 insertions, 0 deletions

diff --git a/nuttx/arch/arm/src/sam3u/sam3u_timerisr.c b/nuttx/arch/arm/src/sam3u/sam3u_timerisr.c
new file mode 100755
index 000000000..225af25f6
--- /dev/null
+++ b/nuttx/arch/arm/src/sam3u/sam3u_timerisr.c
@@ -0,0 +1,162 @@
+/****************************************************************************
+ * arch/arm/src/sam3u/sam3u_timerisr.c
+ *
+ *   Copyright (C) 2010 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 <stdint.h>
+#include <time.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "nvic.h"
+#include "clock_internal.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+#include "chip.h"
+#include "sam3u_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* The desired timer interrupt frequency is provided by the definition
+ * CLK_TCK (see include/time.h).  CLK_TCK defines the desired number of
+ * system clock ticks per second.  That value is a user configurable setting
+ * that defaults to 100 (100 ticks per second = 10 MS interval).
+ *
+ * The SAM3U feeds the Cortex System Timer (SysTick) with the MCK clock or
+ * the MCK clock divided by 8, configurable with the CLKSOURCE bit in the
+ * SysTick Control and Status register.
+ */
+
+#undef CONFIG_SAM3U_SYSTICK_HCLKd8 /* Power up default is MCK, not MCK/8 */
+
+#if CONFIG_SAM3U_SYSTICK_HCLKd8
+#  define SYSTICK_RELOAD ((SAM3U_MCK_FREQUENCY / 8 / CLK_TCK) - 1)
+#else
+#  define SYSTICK_RELOAD ((SAM3U_MCK_FREQUENCY / CLK_TCK) - 1)
+#endif
+
+/* The size of the reload field is 24 bits.  Verify that the reload value
+ * will fit in the reload register.
+ */
+
+#if SYSTICK_RELOAD > 0x00ffffff
+#  error SYSTICK_RELOAD exceeds the range of the RELOAD register
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  up_timerisr
+ *
+ * Description:
+ *   The timer ISR will perform a variety of services for various portions
+ *   of the systems.
+ *
+ ****************************************************************************/
+
+int up_timerisr(int irq, uint32_t *regs)
+{
+   /* Process timer interrupt */
+
+   sched_process_timer();
+   return 0;
+}
+
+/****************************************************************************
+ * Function:  up_timerinit
+ *
+ * Description:
+ *   This function is called during start-up to initialize
+ *   the timer interrupt.
+ *
+ ****************************************************************************/
+
+void up_timerinit(void)
+{
+  uint32_t regval;
+
+  /* Set the SysTick interrupt to the default priority */
+
+  regval = getreg32(NVIC_SYSH12_15_PRIORITY);
+  regval &= ~NVIC_SYSH_PRIORITY_PR15_MASK;
+  regval |= (NVIC_SYSH_PRIORITY_DEFAULT << NVIC_SYSH_PRIORITY_PR15_SHIFT);
+  putreg32(regval, NVIC_SYSH12_15_PRIORITY);
+
+  /* Make sure that the SYSTICK clock source is set correctly */
+
+#if 0 /* Does not work.  Comes up with HCLK source and I can't change it */
+  regval = getreg32(NVIC_SYSTICK_CTRL);
+#if CONFIG_SAM3U_SYSTICK_HCLKd8
+  regval &= ~NVIC_SYSTICK_CTRL_CLKSOURCE;
+#else
+  regval |= NVIC_SYSTICK_CTRL_CLKSOURCE;
+#endif
+  putreg32(regval, NVIC_SYSTICK_CTRL);
+#endif
+
+  /* Configure SysTick to interrupt at the requested rate */
+
+  putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD);
+
+  /* Attach the timer interrupt vector */
+
+  (void)irq_attach(SAM3U_IRQ_SYSTICK, (xcpt_t)up_timerisr);
+
+  /* Enable SysTick interrupts */
+
+  putreg32((NVIC_SYSTICK_CTRL_CLKSOURCE|NVIC_SYSTICK_CTRL_TICKINT|NVIC_SYSTICK_CTRL_ENABLE), NVIC_SYSTICK_CTRL);
+
+  /* And enable the timer interrupt */
+
+  up_enable_irq(SAM3U_IRQ_SYSTICK);
+}