Import of z80 target

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@455 42af7a65-404d-4744-a932-0658087f49c3

6 files changed, 796 insertions, 0 deletions

diff --git a/nuttx/configs/z80sim/src/Makefile b/nuttx/configs/z80sim/src/Makefile
new file mode 100644
index 000000000..24226f2f9
--- /dev/null
+++ b/nuttx/configs/z80sim/src/Makefile
@@ -0,0 +1,79 @@
+############################################################
+# Makefile
+#
+#   Copyright (C) 2007 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 Gregory Nutt 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.
+#
+############################################################
+
+-include $(TOPDIR)/Make.defs
+
+MKDEP 		= $(TOPDIR)/tools/mkdeps.sh
+CFLAGS		+= -I$(TOPDIR)/sched
+
+ASRCS		= z80_lowputc$(ASMEXT) 
+AOBJS		= $(ASRCS:$(ASMEXT)=$(OBJEXT))
+CSRCS		= z80_decodeirq.c z80_irq.c z80_serial.c z80_timerisr.c
+COBJS		= $(CSRCS:.c=$(OBJEXT))
+
+SRCS		= $(ASRCS) $(CSRCS)
+OBJS		= $(AOBJS) $(COBJS)
+
+CFLAGS		+= -I $(TOPDIR)/arch/$(CONFIG_ARCH)/src
+
+all: libboard$(LIBEXT)
+
+$(AOBJS): %$(OBJEXT): %$(ASMEXT)
+	$(CC) -c $(CFLAGS) -D__ASSEMBLY__ $< -o $@
+
+$(COBJS) $(LINKOBJS): %$(OBJEXT): %.c
+	$(CC) -c $(CFLAGS) $< -o $@
+
+libboard$(LIBEXT): $(OBJS)
+	( for obj in $(OBJS) ; do \
+		$(AR) $@ $${obj} || \
+			{ echo "$(AR) $@ $obj FAILED!" ; exit 1 ; } ; \
+	done ; )
+
+.depend: Makefile $(SRCS)
+	$(MKDEP) $(CC) -- $(CFLAGS) -- $(SRCS) >Make.dep
+	touch $@
+
+depend: .depend
+
+clean:
+	rm -f libboard$(LIBEXT)
+	rm -f *.asm *.rel *.lst *.rst *.sym *.adb *.lnk *.map *.mem *.ihx *.hex *~
+	if [ ! -z "$(OBJEXT)" ]; then rm -f *$(OBJEXT); fi
+
+distclean: clean
+	rm -f Make.dep .depend
+
+-include Make.dep
diff --git a/nuttx/configs/z80sim/src/README.txt b/nuttx/configs/z80sim/src/README.txt
new file mode 100644
index 000000000..13c1e3e58
--- /dev/null
+++ b/nuttx/configs/z80sim/src/README.txt
@@ -0,0 +1 @@
+This directory contains drivers unique to the z80 simulation
diff --git a/nuttx/configs/z80sim/src/z80_decodeirq.c b/nuttx/configs/z80sim/src/z80_decodeirq.c
new file mode 100644
index 000000000..d4faf0f89
--- /dev/null
+++ b/nuttx/configs/z80sim/src/z80_decodeirq.c
@@ -0,0 +1,119 @@
+/********************************************************************************
+ * z80/z80_decodeirq.c
+ *
+ *   Copyright (C) 2007, 2008 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 <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <assert.h>
+#include <debug.h>
+#include "up_arch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+/********************************************************************************
+ * Definitions
+ ********************************************************************************/
+
+/********************************************************************************
+ * Public Data
+ ********************************************************************************/
+
+/********************************************************************************
+ * Private Data
+ ********************************************************************************/
+
+/********************************************************************************
+ * Private Functions
+ ********************************************************************************/
+
+/********************************************************************************
+ * Public Funtions
+ ********************************************************************************/
+
+void up_decodeirq(uint16* regs)
+{
+#ifdef CONFIG_SUPPRESS_INTERRUPTS
+  lib_lowprintf("Unexpected IRQ\n");
+  current_regs = regs;
+  PANIC(OSERR_ERREXCEPTION);
+#else
+  /* Decode the interrupt.  First, fetch the interrupt id register. */
+
+  uint16 irqentry = getreg16(DM320_INTC_IRQENTRY0);
+
+  /* The irqentry value is an offset into a table.  Zero means no interrupt. */
+
+  if (irqentry != 0)
+    {
+      /* If non-zero, then we can map the table offset into an IRQ number */
+
+      int irq = (irqentry >> 2) - 1;
+
+      /* Verify that the resulting IRQ number is valie */
+
+      if ((unsigned)irq < NR_IRQS)
+        {
+          /* Mask and acknowledge the interrupt */
+
+          up_maskack_irq(irq);
+
+          /* Current regs non-zero indicates that we are processing an interrupt;
+           * current_regs is also used to manage interrupt level context switches.
+           */
+
+          current_regs = regs;
+
+          /* Deliver the IRQ */
+
+          irq_dispatch(irq, regs);
+
+          /* Indicate that we are no long in an interrupt handler */
+
+          current_regs = NULL;
+
+          /* Unmask the last interrupt (global interrupts are still
+           * disabled.
+           */
+
+          up_enable_irq(irq);
+        }
+    }
+#endif
+}
diff --git a/nuttx/configs/z80sim/src/z80_irq.c b/nuttx/configs/z80sim/src/z80_irq.c
new file mode 100644
index 000000000..3c3443663
--- /dev/null
+++ b/nuttx/configs/z80sim/src/z80_irq.c
@@ -0,0 +1,110 @@
+/****************************************************************************
+ * z80/z80_irq.c
+ *
+ *   Copyright (C) 2007 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 Gregory Nutt 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 <nuttx/irq.h>
+#include "up_arch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+uint32 *current_regs;
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Funtions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_irqinitialize
+ ****************************************************************************/
+
+void up_irqinitialize(void)
+{
+  /* currents_regs is non-NULL only while processing an interrupt */
+
+  current_regs = NULL;
+
+  /* And finally, enable interrupts */
+
+#ifndef CONFIG_SUPPRESS_INTERRUPTS
+  irqrestore(TRUE);
+#endif
+}
+
+/****************************************************************************
+ * Name: up_disable_irq
+ *
+ * Description:
+ *   Disable the IRQ specified by 'irq'
+ *
+ ****************************************************************************/
+
+void up_disable_irq(int irq)
+{
+  irqrestore(FALSE);
+}
+
+/****************************************************************************
+ * Name: up_enable_irq
+ *
+ * Description:
+ *   Enable the IRQ specified by 'irq'
+ *
+ ****************************************************************************/
+
+void up_enable_irq(int irq)
+{
+ irqrestore(TRUE);
+}
diff --git a/nuttx/configs/z80sim/src/z80_serial.c b/nuttx/configs/z80sim/src/z80_serial.c
new file mode 100644
index 000000000..73bba4932
--- /dev/null
+++ b/nuttx/configs/z80sim/src/z80_serial.c
@@ -0,0 +1,334 @@
+/****************************************************************************
+ * z80/z80_serial.c
+ *
+ *   Copyright (C) 2007, 2008 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 <unistd.h>
+#include <semaphore.h>
+#include <string.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+#include <nuttx/serial.h>
+#include <arch/serial.h>
+
+#include "up_arch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int     up_setup(struct uart_dev_s *dev);
+static void    up_shutdown(struct uart_dev_s *dev);
+static int     up_interrupt(int irq, void *context);
+static int     up_ioctl(struct file *filep, int cmd, unsigned long arg);
+static int     up_receive(struct uart_dev_s *dev, uint32 *status);
+static void    up_rxint(struct uart_dev_s *dev, boolean enable);
+static boolean up_rxfifonotempty(struct uart_dev_s *dev);
+static void    up_send(struct uart_dev_s *dev, int ch);
+static void    up_txint(struct uart_dev_s *dev, boolean enable);
+static boolean up_txfifonotfull(struct uart_dev_s *dev);
+static boolean up_txfifoempty(struct uart_dev_s *dev);
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+struct uart_ops_s g_uart_ops =
+{
+  .setup          = up_setup,
+  .shutdown       = up_shutdown,
+  .handler        = up_interrupt,
+  .ioctl          = up_ioctl,
+  .receive        = up_receive,
+  .rxint          = up_rxint,
+  .rxfifonotempty = up_rxfifonotempty,
+  .send           = up_send,
+  .txint          = up_txint,
+  .txfifonotfull  = up_txfifonotfull,
+  .txfifoempty    = up_txfifoempty,
+};
+
+/* I/O buffers */
+
+static char g_uartrxbuffer[CONFIG_UART0_RXBUFSIZE];
+static char g_uarttxbuffer[CONFIG_UART0_TXBUFSIZE];
+
+/* This describes the state of the fake UART port. */
+
+static uart_dev_t g_uartport =
+{
+  .irq      = DM320_IRQ_UART0,
+  .recv     =
+  {
+    .size   = CONFIG_UART0_RXBUFSIZE,
+    .buffer = g_uart0rxbuffer,
+  },
+  .xmit     =
+  {
+    .size   = CONFIG_UART0_TXBUFSIZE,
+    .buffer = g_uart0txbuffer,
+  },
+  .ops      = &g_uart_ops,
+  .priv     = NULL,
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_setup
+ *
+ * Description:
+ *   Configure the UART baud, bits, parity, fifos, etc. This
+ *   method is called the first time that the serial port is
+ *   opened.
+ *
+ ****************************************************************************/
+
+static int up_setup(struct uart_dev_s *dev)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: up_shutdown
+ *
+ * Description:
+ *   Disable the UART.  This method is called when the serial
+ *   port is closed
+ *
+ ****************************************************************************/
+
+static void up_shutdown(struct uart_dev_s *dev)
+{
+}
+
+/****************************************************************************
+ * Name: up_interrupt
+ *
+ * Description:
+ *   This is the UART interrupt handler.  It will be invoked
+ *   when an interrupt received on the 'irq'  It should call
+ *   uart_transmitchars or uart_receivechar to perform the
+ *   appropriate data transfers.  The interrupt handling logic\
+ *   must be able to map the 'irq' number into the approprite
+ *   uart_dev_s structure in order to call these functions.
+ *
+ ****************************************************************************/
+
+static int up_interrupt(int irq, void *context)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: up_ioctl
+ *
+ * Description:
+ *   All ioctl calls will be routed through this method
+ *
+ ****************************************************************************/
+
+static int up_ioctl(struct file *filep, int cmd, unsigned long arg)
+{
+  *get_errno_ptr() = ENOTTY;
+  return ERROR;
+}
+
+/****************************************************************************
+ * Name: up_receive
+ *
+ * Description:
+ *   Called (usually) from the interrupt level to receive one
+ *   character from the UART.  Error bits associated with the
+ *   receipt are provided in the the return 'status'.
+ *
+ ****************************************************************************/
+
+static int up_receive(struct uart_dev_s *dev, uint32 *status)
+{
+  uint8 ch = up_lowgetc();
+  *status = 0;
+  return ch;
+}
+
+/****************************************************************************
+ * Name: up_rxint
+ *
+ * Description:
+ *   Call to enable or disable RX interrupts
+ *
+ ****************************************************************************/
+
+static void up_rxint(struct uart_dev_s *dev, boolean enable)
+{
+}
+
+/****************************************************************************
+ * Name: up_rxfifonotempty
+ *
+ * Description:
+ *   Return TRUE if the receive fifo is not empty
+ *
+ ****************************************************************************/
+
+static boolean up_rxfifonotempty(struct uart_dev_s *dev)
+{
+  return TRUE;
+}
+
+/****************************************************************************
+ * Name: up_send
+ *
+ * Description:
+ *   This method will send one byte on the UART
+ *
+ ****************************************************************************/
+
+static void up_send(struct uart_dev_s *dev, int ch)
+{
+  up_lowputc(ch);
+}
+
+/****************************************************************************
+ * Name: up_txint
+ *
+ * Description:
+ *   Call to enable or disable TX interrupts
+ *
+ ****************************************************************************/
+
+static void up_txint(struct uart_dev_s *dev, boolean enable)
+{
+}
+
+/****************************************************************************
+ * Name: up_txfifonotfull
+ *
+ * Description:
+ *   Return TRUE if the tranmsit fifo is not full
+ *
+ ****************************************************************************/
+
+static boolean up_txfifonotfull(struct uart_dev_s *dev)
+{
+  return TRUE;
+}
+
+/****************************************************************************
+ * Name: up_txfifoempty
+ *
+ * Description:
+ *   Return TRUE if the transmit fifo is empty
+ *
+ ****************************************************************************/
+
+static boolean up_txfifoempty(struct uart_dev_s *dev)
+{
+  return FALSE;
+}
+
+/****************************************************************************
+ * Public Funtions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_serialinit
+ *
+ * Description:
+ *   Performs the low level UART initialization early in 
+ *   debug so that the serial console will be available
+ *   during bootup.  This must be called before up_serialinit.
+ *
+ ****************************************************************************/
+
+void up_earlyserialinit(void)
+{
+}
+
+/****************************************************************************
+ * Name: up_serialinit
+ *
+ * Description:
+ *   Register serial console and serial ports.  This assumes
+ *   that up_earlyserialinit was called previously.
+ *
+ ****************************************************************************/
+
+void up_serialinit(void)
+{
+  (void)uart_register("/dev/console", &g_uartport);
+  (void)uart_register("/dev/ttyS0", &g_uartport);
+}
+#endif /* CONFIG_NFILE_DESCRIPTORS > 0 */
+
+/****************************************************************************
+ * Name: up_putc
+ *
+ * Description:
+ *   Provide priority, low-level access to support OS debug
+ *   writes
+ *
+ ****************************************************************************/
+
+int up_putc(int ch)
+{
+  up_lowputc(ch);
+}
+
+
+
+
diff --git a/nuttx/configs/z80sim/src/z80_timerisr.c b/nuttx/configs/z80sim/src/z80_timerisr.c
new file mode 100644
index 000000000..603a66c91
--- /dev/null
+++ b/nuttx/configs/z80sim/src/z80_timerisr.c
@@ -0,0 +1,153 @@
+/************************************************************
+ * dm320/dm320_timerisr.c
+ *
+ *   Copyright (C) 2007 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 Gregory Nutt 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 <debug.h>
+#include <nuttx/arch.h>
+#include "clock_internal.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/* DM320 Timers
+ *
+ * Each of the general-purpose timers can run in one of two modes:  one-
+ * shot mode and free-run mode.  In one-shot mode, an interrupt only 
+ * occurs once and then the timer must be explicitly reset to begin the 
+ * timing operation again.  In free-run mode, when the timer generates an 
+ * interrupt, the timer counter is automatically reloaded to start the count 
+ * operation again.  Use the bit field MODE in TMMDx to configure the 
+ * timer for one-shot more or free-run mode. The bit field MODE in TMMDx
+ * also allows you to stop the timer.
+ * 
+ * Either the ARM clock divided by 2 (CLK_ARM/2) or an external clock 
+ * connected to the M27XI pin can be selected as the clock source of the 
+ * timer.
+ *
+ * The actual clock frequency used in the timer count operation is the input 
+ * clock divided by: 1 plus the value set in the bit field PRSCL of the 
+ * register TMPRSCLx (10 bits).  The timer expires when it reaches the 
+ * value set in the bit field DIV of the register TMDIVx (16 bits) plus 1. 
+ * PRSCL+1 is the source clock frequency divide factor and DIV+1 is the 
+ * timer count value.  The frequency of a timer interrupt is given by the 
+ * following equation:
+ *
+ * Interrupt Frequency = (Source Clock Frequency) / (PRSCL+1) / (DIV+1)
+ */
+
+/* System Timer
+ *
+ * Timer0 is dedicated as the system timer.  The rate of system timer
+ * interrupts is assumed to to 10MS per tick / 100Hz. The following
+ * register settings are used for timer 0
+ *
+ * System clock formula:
+ *   Interrupt Frequency = (Source Clock Frequency) / (PRSCL+1) / (DIV+1)
+ *   Source Clock Frequency = 27MHz  (PLL clock)
+ *   DIV                    = 26,999 (Yields 1Khz timer clock)
+ *   PRSCL                  = 9      (Produces 100Hz interrupts)
+ */
+
+#define DM320_TMR0_MODE  DM320_TMR_MODE_FREERUN /* Free running */
+#define DM320_TMR0_DIV   26999                  /* (see above) */
+#define DM320_TMR0_PRSCL 9                      /* (see above) */
+
+/************************************************************
+ * 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 *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)
+{
+  up_disable_irq(DM320_IRQ_SYSTIMER);
+
+  /* Start timer0 running so that an interrupt is generated at
+   * the rate MSEC_PER_TICK.
+   */
+
+  putreg16(DM320_TMR0_PRSCL, DM320_TIMER0_TMPRSCL); /* Timer 0 Prescalar */
+  putreg16(DM320_TMR0_DIV, DM320_TIMER0_TMDIV);     /* Timer 0 Divisor (count) */
+
+  /* Start the timer */
+
+  putreg16(DM320_TMR0_MODE, DM320_TIMER0_TMMD); /* Timer 0 Mode */
+
+  /* Attach and enable the timer interrupt */
+
+  irq_attach(DM320_IRQ_SYSTIMER, (xcpt_t)up_timerisr);
+  up_enable_irq(DM320_IRQ_SYSTIMER);
+}
+