SAM3/4: Enhanced timer/counter driver from Bob Doiron

2 files changed, 96 insertions, 89 deletions

diff --git a/nuttx/arch/arm/src/sam34/Kconfig b/nuttx/arch/arm/src/sam34/Kconfig
index ad076de88..62ddf0743 100644
--- a/nuttx/arch/arm/src/sam34/Kconfig
+++ b/nuttx/arch/arm/src/sam34/Kconfig
@@ -475,45 +475,54 @@ config SAM34_SSC
 config SAM34_TC0
 	bool "Timer/Counter 0 (TC0)"
 	default n
+	select SAM34_TC
 
 config SAM34_TC1
 	bool "Timer/Counter 1 (TC1)"
 	default n
+	select SAM34_TC
 
 config SAM34_TC2
 	bool "Timer/Counter 2 (TC2)"
 	default n
 	depends on ARCH_CHIP_SAM3U || ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4S || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC3
 	bool "Timer/Counter 3 (TC3)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4S || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC4
 	bool "Timer/Counter 4 (TC4)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4S || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC5
 	bool "Timer/Counter 5 (TC5)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4S || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC6
 	bool "Timer/Counter 6 (TC6)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC7
 	bool "Timer/Counter 7 (TC7)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TC8
 	bool "Timer/Counter 6 (TC8)"
 	default n
 	depends on ARCH_CHIP_SAM3X || ARCH_CHIP_SAM3A || ARCH_CHIP_SAM4E
+	select SAM34_TC
 
 config SAM34_TRNG
 	bool "True Random Number Generator (TRNG)"
@@ -1177,8 +1186,8 @@ config SAM34_HSMCI_CMDDEBUG
 endmenu # HSMCI device driver options
 endif # SAM34_HSMCI
 
-if SAM34_UDP
 menu "AT91SAM3/4 USB Full Speed Device Controller driver (DCD) options"
+	depends on SAM34_UDP
 
 config SAM34_UDP_REGDEBUG
 	bool "Enable low-level UDP register debug"
@@ -1186,10 +1195,23 @@ config SAM34_UDP_REGDEBUG
 	depends on DEBUG
 
 endmenu # USB Full Speed Device Controller driver (DCD) options
-endif # SAM34_UDP
 
-if SAM34_WDT
+config SAM34_TC
+	bool
+	default n
+
+menu "AT91SAM3/4 Timer/Counter options"
+	depends on SAM34_TC
+
+config SAM34_TC_REGDEBUG
+	bool "Enable low-level timer/counter register debug"
+	default n
+	depends on DEBUG
+
+endmenu # USB Full Speed Device Controller driver (DCD) options
+
 menu "AT91SAM3/4 Watchdog Configuration"
+	depends on SAM34_WDT
 
 config WDT_ENABLED_ON_RESET
 	bool "Watchdog Enabled on reset"
@@ -1248,6 +1270,6 @@ config WDT_THREAD_PRIORITY
 config WDT_THREAD_STACKSIZE
 	int "Watchdog Thread Stacksize"
 	default 1024
+
 endif # WDT_THREAD
 endmenu #"AT91SAM3/4 Watchdog device driver options"
-endif # SAM34_WDT
diff --git a/nuttx/arch/arm/src/sam34/sam_tc.c b/nuttx/arch/arm/src/sam34/sam_tc.c
index 99fbce646..cb48f84b6 100644
--- a/nuttx/arch/arm/src/sam34/sam_tc.c
+++ b/nuttx/arch/arm/src/sam34/sam_tc.c
@@ -54,8 +54,6 @@
 #include "sam_tc.h"
 #include "sam_periphclks.h"
 
-//#define CONFIG_SAM34_TC_REGDEBUG
-
 #if defined(CONFIG_TIMER) && (defined(CONFIG_SAM34_TC0) || \
     defined(CONFIG_SAM34_TC1) || defined(CONFIG_SAM34_TC2) || \
     defined(CONFIG_SAM34_TC3) || defined(CONFIG_SAM34_TC4) || \
@@ -98,10 +96,15 @@
 struct sam34_lowerhalf_s
 {
   FAR const struct timer_ops_s  *ops;  /* Lower half operations */
-  xcpt_t   handler;  /* Current user interrupt handler */
-  uint32_t timeout;  /* The actual timeout value (us) */
-  bool     started;  /* The timer has been started */
-  uint16_t reload;   /* The 12-bit reload field reset value (WDV) */
+
+  /* Private data */
+
+  uint32_t base;            /* Base address of the timer */
+  tccb_t   handler;         /* Current user interrupt handler */
+  uint32_t timeout;         /* The current timeout value (us) */
+  uint32_t adjustment;      /* time lost due to clock resolution truncation (us) */
+  uint32_t clkticks;        /* actual clock ticks for current interval */
+  bool     started;         /* The timer has been started */
   uint16_t debug;
 };
 
@@ -118,7 +121,7 @@ static void     sam34_putreg(uint32_t val, uint32_t addr);
 # define        sam34_putreg(val,addr) putreg32(val,addr)
 #endif
 
-/* Interrupt hanlding *******************************************************/
+/* Interrupt handling *******************************************************/
 
 static int      sam34_interrupt(int irq, FAR void *context);
 
@@ -130,8 +133,8 @@ static int      sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
                   FAR struct timer_status_s *status);
 static int      sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
                   uint32_t timeout);
-static xcpt_t   sam34_capture(FAR struct timer_lowerhalf_s *lower,
-                  xcpt_t handler);
+static tccb_t   sam34_capture(FAR struct timer_lowerhalf_s *lower,
+                  tccb_t handler);
 static int      sam34_ioctl(FAR struct timer_lowerhalf_s *lower, int cmd,
                   unsigned long arg);
 
@@ -269,12 +272,27 @@ static int sam34_interrupt(int irq, FAR void *context)
   regval = sam34_getreg(SAM_TC0_SR);
   if ((regval & TC_INT_CPCS) != 0)
     {
+      uint32_t timeout;
+
       /* Is there a registered handler? */
 
-      if (priv->handler)
-      {
-        priv->handler(irq, context);
-      }
+      if (priv->handler && priv->handler(&priv->timeout))
+        {
+          /* Calculate new ticks */
+
+          priv->clkticks = ((uint64_t)(priv->adjustment + priv->timeout))*TC_FCLK / 1000000;
+
+          /* Set next interval interval. TODO: make sure the interval is not so soon it will be missed! */
+
+          sam34_putreg(priv->clkticks, SAM_TC0_RC);
+
+          timeout = (1000000ULL * priv->clkticks) / TC_FCLK;    /* trucated timeout */
+          priv->adjustment = (priv->adjustment + priv->timeout) - timeout;  /* truncated time to be added to next interval (dither) */
+        }
+      else /* stop */
+        {
+          sam34_stop((FAR struct timer_lowerhalf_s *)&g_tcdev);
+        }
 
       /* TC_INT_CPCS is cleared by reading SAM_TC0_SR */
     }
@@ -305,9 +323,14 @@ static int sam34_start(FAR struct timer_lowerhalf_s *lower)
   tcvdbg("Entry\n");
   DEBUGASSERT(priv);
 
+  if(priv->started)
+    {
+      return -EINVAL;
+    }
+
   sam_tc0_enableclk();
 
-  sam34_putreg(TC_CCR_CLKDIS, SAM_TC0_CCR); // disable counter
+  sam34_putreg(TC_CCR_CLKDIS, SAM_TC0_CCR); /* Disable counter */
 
   /* TC_CMR_WAVE - waveform mode
    * TC_CMR_WAVSEL_UPAUTO - reset on RC compare (interval timer)
@@ -317,19 +340,17 @@ static int sam34_start(FAR struct timer_lowerhalf_s *lower)
   mr_val |= (TC_CMR_WAVE + TC_CMR_WAVSEL_UPAUTO + TC_CMR_TCCLKS_TIMERCLOCK5);
   sam34_putreg(mr_val, SAM_TC0_CMR);
 
-  sam34_putreg(priv->reload, SAM_TC0_RC); // set interval
+  sam34_putreg(priv->clkticks, SAM_TC0_RC); /* Set interval */
 
-  /* TODO: isr active without user handle for now... */
-//  if (priv->handler)
+  if (priv->handler)
     {
-      /* Clear status */
+      /* Clear status and enable interrupt */
 
       sam34_getreg(SAM_TC0_SR);
-      sam34_putreg(TC_INT_CPCS, SAM_TC0_IMR);
       sam34_putreg(TC_INT_CPCS, SAM_TC0_IER);
     }
 
-  sam34_putreg(TC_CCR_SWTRG + TC_CCR_CLKEN, SAM_TC0_CCR); // start counter
+  sam34_putreg(TC_CCR_SWTRG + TC_CCR_CLKEN, SAM_TC0_CCR); /* Start counter */
 
   priv->started = true;
   return OK;
@@ -352,10 +373,19 @@ static int sam34_start(FAR struct timer_lowerhalf_s *lower)
 
 static int sam34_stop(FAR struct timer_lowerhalf_s *lower)
 {
+  FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
   tcvdbg("Entry\n");
-  sam34_putreg(TC_CCR_CLKDIS, SAM_TC0_CCR); // disable counter
-  sam34_putreg(TC_INT_ALL, SAM_TC0_IDR); // disable all ints
+  DEBUGASSERT(priv);
+
+  if(!priv->started)
+    {
+      return -EINVAL;
+    }
+
+  sam34_putreg(TC_CCR_CLKDIS, SAM_TC0_CCR); /* Disable counter */
+  sam34_putreg(TC_INT_ALL, SAM_TC0_IDR); /* Disable all ints */
   sam_tc0_disableclk();
+  priv->started = false;
 
   return OK;
 }
@@ -367,9 +397,9 @@ static int sam34_stop(FAR struct timer_lowerhalf_s *lower)
  *   Get the current timer status
  *
  * Input Parameters:
- *   lower   - A pointer the publicly visible representation of the "lower-half"
- *             driver state structure.
- *   stawtus - The location to return the status information.
+ *   lower  - A pointer the publicly visible representation of the "lower-half"
+ *            driver state structure.
+ *   status - The location to return the status information.
  *
  * Returned Values:
  *   Zero on success; a negated errno value on failure.
@@ -405,7 +435,7 @@ static int sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
   /* Get the time remaining until the timer expires (in microseconds) */
 
   elapsed = sam34_getreg(SAM_TC0_CV);
-  status->timeleft = (priv->timeout * elapsed) / (priv->reload + 1);
+  status->timeleft = (priv->timeout * elapsed) / (priv->clkticks + 1); /* TODO - check on this +1 */
 
   tcvdbg("  flags    : %08x\n", status->flags);
   tcvdbg("  timeout  : %d\n", status->timeout);
@@ -422,7 +452,7 @@ static int sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
  * Input Parameters:
  *   lower   - A pointer the publicly visible representation of the "lower-half"
  *             driver state structure.
- *   timeout - The new timeout value in millisecnds.
+ *   timeout - The new timeout value in milliseconds.
  *
  * Returned Values:
  *   Zero on success; a negated errno value on failure.
@@ -433,7 +463,6 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
                             uint32_t timeout)
 {
   FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
-  uint32_t reload;
 
   DEBUGASSERT(priv);
   tcvdbg("Entry: timeout=%d\n", timeout);
@@ -447,32 +476,13 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
       return -ERANGE;
     }
 
+  priv->timeout = timeout;                                    /* Intended timeout */
+  priv->clkticks = (((uint64_t)timeout * TC_FCLK) / 1000000); /* Actual clock ticks */
+  timeout = (1000000ULL * priv->clkticks) / TC_FCLK;          /* Truncated timeout */
+  priv->adjustment = priv->timeout - timeout;                 /* Truncated time to be added to next interval (dither) */
 
-  /* TODOR: -1 or no? */
-
-  reload = (((uint64_t)timeout * TC_FCLK) / 1000000) - 1;
-
-  /* Make sure that the final reload value is within range */
-  /* TODOR: +1 or no? */
-
-  if (reload > TC_CV_MASK)
-    {
-      reload = TC_CV_MASK;
-    }
-
-  /* Calculate and save the actual timeout value in milliseconds:
-   *
-   * timeout =  1000 * (reload + 1) / Fwdt
-   */
-
-  priv->timeout = 1000 * (reload + 1) / TC_FCLK;
-
-  /* Remember the selected values */
-
-  priv->reload = reload;
-
-  tcvdbg("fwdt=%d reload=%d timout=%d\n",
-         TC_FCLK, reload, priv->timeout);
+  tcvdbg("fwdt=%d reload=%d timout=%d, adjustment=%d\n",
+         TC_FCLK, reload, priv->timeout, priv->adjustment);
 
   /* Don't commit to MR register until started! */
 
@@ -501,53 +511,28 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
  *
  ****************************************************************************/
 
-static xcpt_t sam34_capture(FAR struct timer_lowerhalf_s *lower,
-                            xcpt_t handler)
+static tccb_t sam34_capture(FAR struct timer_lowerhalf_s *lower,
+                            tccb_t handler)
 {
-#if 0 // TODO
   FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
   irqstate_t flags;
-  xcpt_t oldhandler;
-  uint16_t regval;
+  tccb_t oldhandler;
+
+  flags = irqsave();
 
   DEBUGASSERT(priv);
   tcvdbg("Entry: handler=%p\n", handler);
 
   /* Get the old handler return value */
-  flags = irqsave();
+
   oldhandler = priv->handler;
 
   /* Save the new handler */
 
    priv->handler = handler;
 
-  /* Are we attaching or detaching the handler? */
-
-  regval = sam34_getreg(SAM_TC_CFR);
-  if (handler)
-    {
-      /* Attaching... Enable the EWI interrupt */
-
-      regval |= WWDG_CFR_EWI;
-      sam34_putreg(regval, SAM_TC_CFR);
-
-      up_enable_irq(STM32_IRQ_WWDG);
-    }
-  else
-    {
-      /* Detaching... Disable the EWI interrupt */
-
-      regval &= ~WWDG_CFR_EWI;
-      sam34_putreg(regval, SAM_TC_CFR);
-
-      up_disable_irq(STM32_IRQ_WWDG);
-    }
-
   irqrestore(flags);
   return oldhandler;
-#endif
-  ASSERT(0);
-  return NULL;
 }
 
 /****************************************************************************
@@ -560,7 +545,7 @@ static xcpt_t sam34_capture(FAR struct timer_lowerhalf_s *lower,
  * Input Parameters:
  *   lower - A pointer the publicly visible representation of the "lower-half"
  *           driver state structure.
- *   cmd   - The ioctol command value
+ *   cmd   - The ioctl command value
  *   arg   - The optional argument that accompanies the 'cmd'.  The
  *           interpretation of this argument depends on the particular
  *           command.