SAMA5 free-running timer: Add support for a free-running timer wrapper around the low-level timer/counter logic.

arch/arm/src/sama5/Kconfig

@@ -3552,6 +3552,34 @@ config SAMA5_ONESHOT
 		Enable a wrapper around the low level timer/counter functions to
 		support one-shot timer.
 
+config SAMA5_FREERUN
+	bool "TC free-running wrapper"
+	default n if !SCHED_TICKLESS
+	default y if SCHED_TICKLESS
+	---help---
+		Enable a wrapper around the low level timer/counter functions to
+		support a free-running timer.
+
+if SCHED_TICKLESS
+
+config SAMA5_TICKLESS_ONESHOT
+	int "Tickless one-shot timer channel"
+	range 0 8
+	default 0
+	---help---
+		If the Tickless OS feature is enabled, the one clock must be
+		assigned to provided the one-shot timer needed by the OS.
+
+config SAMA5_TICKLESS_FREERUN
+	int "Tickless free-running timer channel"
+	range 0 8
+	default 0
+	---help---
+		If the Tickless OS feature is enabled, the one clock must be
+		assigned to provided the free-running timer needed by the OS.
+
+endif
+
 config SAMA5_TC_DEBUG
 	bool "TC debug"
 	depends on DEBUG

arch/arm/src/sama5/Make.defs

@@ -255,6 +255,9 @@ CHIP_CSRCS += sam_tc.c
 ifeq ($(CONFIG_SAMA5_ONESHOT),y)
 CHIP_CSRCS += sam_oneshot.c
 endif
+ifeq ($(CONFIG_SAMA5_FREERUN),y)
+CHIP_CSRCS += sam_freerun.c
+endif
 endif
 
 ifeq ($(CONFIG_SAMA5_EBICS0_NAND),y)

arch/arm/src/sama5/sam_freerun.c

@@ -0,0 +1,333 @@
+/****************************************************************************
+ * arch/arm/src/sama5/sam_freerun.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * References:
+ *
+ *   SAMA5D3 Series Data Sheet
+ *   Atmel NoOS sample code.
+ *
+ * The Atmel sample code has a BSD compatible license that requires this
+ * copyright notice:
+ *
+ *   Copyright (c) 2011, Atmel Corporation
+ *
+ * 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 names NuttX nor Atmel 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 <stdint.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+
+#include "sam_freerun.h"
+
+#ifdef CONFIG_SAMA5_ONESHOT
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_SAMA5_TC_DEBUG
+#  define tcdbg  dbg
+#  define tcvdbg vdbg
+#else
+#  define tcdbg(x...)
+#  define tcvdbg(x...)
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+/****************************************************************************
+ * Name: sam_freerun_handler
+ *
+ * Description:
+ *   Timer interrupt callback.  When the freerun timer counter overflows,
+ *   this interrupt will occur.  We will just increment an overflow count.
+ *
+ * Input Parameters:
+ *   handle - The handle that represents the timer state
+ *   arg    - An opaque argument provided when the interrupt was registered
+ *   sr     - The value of the timer interrupt status register at the time
+ *            that the interrupt occurred.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void sam_freerun_handler(TC_HANDLE handle, void *arg, uint32_t sr)
+{
+  struct sam_freerun_s *freerun = (struct sam_freerun_s *)arg;
+  DEBUGASSERT(freerun && freerun->overflow < UINT16_MAX);
+  freerun->overflow++;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sam_freerun_initialize
+ *
+ * Description:
+ *   Initialize the freerun timer wrapper
+ *
+ * Input Parameters:
+ *   freerun    Caller allocated instance of the freerun state structure
+ *   chan       Timer counter channel to be used.  See the TC_CHAN*
+ *              definitions in arch/arm/src/sama5/sam_tc.h.
+ *   resolution The required resolution of the timer in units of
+ *              microseconds.  NOTE that the range is restricted to the
+ *              range of uint16_t (excluding zero).
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_initialize(struct sam_freerun_s *freerun, int chan,
+                           uint16_t resolution)
+{
+  uint32_t frequency;
+  uint32_t divisor;
+  uint32_t cmr;
+  int ret;
+
+  tcvdbg("chan=%d resolution=%d usec\n", chan, resolution);
+  DEBUGASSERT(freerun && resolution > 0);
+
+  /* Get the TC frequency the corresponds to the requested resolution */
+
+  frequency = 1000000 / (uint32_t)resolution;
+
+  /* The pre-calculate values to use when we start the timer */
+
+  ret = sam_tc_divisor(frequency, &divisor, &cmr);
+  if (ret < 0)
+    {
+      tcdbg("ERROR: sam_tc_divisor failed: %d\n", ret);
+      return ret;
+    }
+
+  tcvdbg("frequency=%lu, divisor=%u, cmr=%08lx\n",
+         (unsigned long)frequency, (unsigned long)divisor,
+         (unsigned long)cmr);
+
+  /* Allocate the timer/counter and select its mode of operation
+   *
+   *   CMR_TCCLKS          - Returned by sam_tc_divisor
+   *   TC_CMR_CLKI=0       - Not inverted
+   *   TC_CMR_BURST_NONE   - Not gated by an external signal
+   *   TC_CMR_CPCSTOP=0    - Don't stop the clock on an RC compare event
+   *   TC_CMR_CPCDIS=0     - Don't disable the clock on an RC compare event
+   *   TC_CMR_EEVTEDG_NONE - No external events (and, hence, no edges
+   *   TC_CMR_EEVT_TIOB    - ???? REVISIT
+   *   TC_CMR_ENET=0       - External event trigger disabled
+   *   TC_CMR_WAVSEL_UP    - TC_CV is incremented from 0 to 0xffffffff
+   *   TC_CMR_WAVE         - Waveform mode
+   *   TC_CMR_ACPA_NONE    - RA compare has no effect on TIOA
+   *   TC_CMR_ACPC_NONE    - RC compare has no effect on TIOA
+   *   TC_CMR_AEEVT_NONE   - No external event effect on TIOA
+   *   TC_CMR_ASWTRG_NONE  - No software trigger effect on TIOA
+   *   TC_CMR_BCPB_NONE    - RB compare has no effect on TIOB
+   *   TC_CMR_BCPC_NONE    - RC compare has no effect on TIOB
+   *   TC_CMR_BEEVT_NONE   - No external event effect on TIOB
+   *   TC_CMR_BSWTRG_NONE  - No software trigger effect on TIOB
+   */
+
+  cmr |= (TC_CMR_BURST_NONE  | TC_CMR_EEVTEDG_NONE | TC_CMR_EEVT_TIOB   |
+          TC_CMR_WAVSEL_UP   | TC_CMR_WAVE         | TC_CMR_ACPA_NONE   |
+          TC_CMR_ACPC_NONE   | TC_CMR_AEEVT_NONE   | TC_CMR_ASWTRG_NONE |
+          TC_CMR_BCPB_NONE   | TC_CMR_BCPC_NONE    | TC_CMR_BEEVT_NONE  |
+          TC_CMR_BSWTRG_NONE);
+
+  freerun->handle = sam_tc_allocate(chan, cmr);
+  if (!freerun->handle)
+    {
+      tcdbg("ERROR: Failed to allocate timer channel %d\n", chan);
+      return -EBUSY;
+    }
+
+  /* Initialize the remaining fields in the state structure and return
+   * success.
+   */
+
+  freerun->chan       = chan;
+  freerun->running    = false;
+  freerun->resolution = resolution;
+
+  /* Set up to receive the callback when the counter overflow occurs */
+
+  (void)sam_tc_attach(freerun->handle, sam_freerun_handler, freerun,
+                      TC_INT_COVFS);
+
+  /* Start the counter */
+
+  sam_tc_start(freerun->handle);
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: sam_freerun_counter
+ *
+ * Description:
+ *   Read the counter register of the free-running timer.
+ *
+ * Input Parameters:
+ *   freerun Caller allocated instance of the freerun state structure.  This
+ *           structure must have been previously initialized via a call to
+ *           sam_freerun_initialize();
+ *   ts      The location in which to return the time from the free-running
+ *           timer.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_counter(struct sam_freerun_s *freerun, struct timespec *ts)
+{
+  uint64_t usec;
+  uint32_t counter;
+  uint32_t verify;
+  uint32_t sr;
+  uint32_t overflow;
+  uint32_t sec;
+  irqstate_t flags;
+
+  /* Temporarily disable the overflow counter */
+
+  flags    = irqsave();
+  overflow = freerun->overflow;
+  counter  = sam_tc_getcounter(freerun->handle);
+  sr       = sam_tc_getpending(freerun->handle);
+  verify   = sam_tc_getcounter(freerun->handle);
+  irqrestore(flags);
+
+  tcvdbg("counter=%lu (%lu) overflow=%lu, sr=%08lx\n",
+         (unsigned long)counter,  (unsigned long)verify,
+         (unsigned long)overflow, (unsigned long)sr);
+
+  /* If an interrupt was pending before we re-enabled interrupts,
+   * then our value of overflow needs to be incremented.
+   */
+
+  if ((sr & TC_INT_COVFS) != 0)
+    {
+      /* Increment the overflow count and use the value of the
+       * guaranteed to be AFTER the overflow occurred.
+       */
+
+      overflow++;
+      counter = verify;
+
+      tcvdbg("counter=%lu overflow=%lu\n",
+             (unsigned long)counter, (unsigned long)overflow);
+    }
+
+  /* Convert the whole thing to units of microseconds */
+
+  usec = (((uint64_t)overflow << 32) + (uint64_t)counter) *
+         freerun->resolution;
+
+  /* And return the value of the timer */
+
+  sec = (uint32_t)(usec / 1000000);
+  ts->tv_sec  = sec;
+  ts->tv_nsec = (usec - (sec * 1000000)) * 1000;
+
+  tcvdbg("usec=%016llx ts=(%lu, %lu)\n",
+          usec, (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec);
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: sam_freerun_uninitialize
+ *
+ * Description:
+ *   Stop the free-running timer and release all resources that it uses.
+ *
+ * Input Parameters:
+ *   freerun Caller allocated instance of the freerun state structure.  This
+ *           structure must have been previously initialized via a call to
+ *           sam_freerun_initialize();
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_uninitialize(struct sam_freerun_s *freerun)
+{
+  irqstate_t flags;
+
+  /* Now we can disable the timer interrupt and disable the timer. */
+
+  sam_tc_attach(freerun->handle, NULL, NULL, 0);
+  sam_tc_stop(freerun->handle);
+
+  /* Free the timer */
+
+  sam_tc_free(freerun->handle);
+  irqrestore(flags);
+  return OK;
+}
+
+#endif /* CONFIG_SAMA5_ONESHOT */

arch/arm/src/sama5/sam_freerun.h

@@ -0,0 +1,161 @@
+/****************************************************************************
+ * arch/arm/src/sama5/sam_freerun.h
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_ARM_SRC_SAMA5_SAM_FREERUN_H
+#define __ARCH_ARM_SRC_SAMA5_SAM_FREERUN_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <time.h>
+
+#include "sam_tc.h"
+
+#ifdef CONFIG_SAMA5_FREERUN
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* The freerun client must allocate an instance of this structure and called
+ * sam_freerun_initialize() before using the freerun facilities.  The client
+ * should not access the contents of this structure directly since the
+ * contents are subject to change.
+ */
+
+struct sam_freerun_s
+{
+  uint8_t chan;              /* The timer/counter in use */
+  bool running;              /* True: the timer is running */
+  uint16_t resolution;       /* Timer resolution in microseconds */
+  uint16_t overflow;         /* Timer counter overflow */
+  TC_HANDLE handle;          /* Handle returned by sam_tc_initialize() */
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sam_freerun_initialize
+ *
+ * Description:
+ *   Initialize the freerun timer wrapper
+ *
+ * Input Parameters:
+ *   freerun    Caller allocated instance of the freerun state structure
+ *   chan       Timer counter channel to be used.  See the TC_CHAN*
+ *              definitions in arch/arm/src/sama5/sam_tc.h.
+ *   resolution The required resolution of the timer in units of
+ *              microseconds.  NOTE that the range is restricted to the
+ *              range of uint16_t (excluding zero).
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_initialize(struct sam_freerun_s *freerun, int chan,
+                           uint16_t resolution);
+
+/****************************************************************************
+ * Name: sam_freerun_counter
+ *
+ * Description:
+ *   Read the counter register of the free-running timer.
+ *
+ * Input Parameters:
+ *   freerun Caller allocated instance of the freerun state structure.  This
+ *           structure must have been previously initialized via a call to
+ *           sam_freerun_initialize();
+ *   ts      The location in which to return the time remaining on the
+ *           oneshot timer.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_counter(struct sam_freerun_s *freerun, struct timespec *ts);
+
+/****************************************************************************
+ * Name: sam_freerun_uninitialize
+ *
+ * Description:
+ *   Stop the free-running timer and release all resources that it uses.
+ *
+ * Input Parameters:
+ *   freerun Caller allocated instance of the freerun state structure.  This
+ *           structure must have been previously initialized via a call to
+ *           sam_freerun_initialize();
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int sam_freerun_uninitialize(struct sam_freerun_s *freerun);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_SAMA5_FREERUN */
+#endif /* __ARCH_ARM_SRC_SAMA5_SAM_FREERUN_H */