/**************************************************************************** * arch/arm/src/sam34/sam_rtt.c * * Copyright (C) 2014 Gregory Nutt. All rights reserved. * Authors: Gregory Nutt * Bob Dioron * * 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 #include #include #include #include #include #include #include #include "up_arch.h" #include "sam_rtt.h" #include "sam_periphclks.h" #if defined(CONFIG_TIMER) && (defined(CONFIG_SAM34_RTT)) /**************************************************************************** * Pre-Processor Definitions ****************************************************************************/ /* Clocking *****************************************************************/ #if defined(CONFIG_RTC_HIRES) && defined (CONFIG_SAM34_RTC) # define RTT_PRES (32768/CONFIG_RTC_FREQUENCY) #else /* TODO: Allow prescaler selection. */ # define RTT_PRES 1 #endif #define RTT_FCLK (BOARD_SCLK_FREQUENCY/RTT_PRES) #define RTT_MAXTIMEOUT ((1000000ULL * (0x100000000ULL)) / RTT_FCLK) /* Configuration ************************************************************/ /* Debug ********************************************************************/ /* Non-standard debug that may be enabled just for testing the timer * driver. NOTE: that only lldbg types are used so that the output is * immediately available. */ #ifdef CONFIG_DEBUG_RTT # define rttdbg lldbg # define rttvdbg llvdbg #else # define rttdbg(x...) # define rttvdbg(x...) #endif /**************************************************************************** * Private Types ****************************************************************************/ /* This structure provides the private representation of the "lower-half" * driver state structure. This structure must be cast-compatible with the * timer_lowerhalf_s structure. */ struct sam34_lowerhalf_s { FAR const struct timer_ops_s *ops; /* Lower half operations */ /* Private data */ tccb_t handler; /* Current user interrupt handler */ uint32_t timeout; /* The current timeout value (us) */ uint32_t clkticks; /* actual clock ticks for current interval */ uint32_t val; /* rtt value of current timeout */ uint32_t adjustment; /* time lost due to clock resolution truncation (us) */ bool started; /* The timer has been started */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Register operations ******************************************************/ #if defined(CONFIG_SAM34_RTT_REGDEBUG) && defined(CONFIG_DEBUG) static uint32_t sam34_getreg(uint32_t addr); static void sam34_putreg(uint32_t val, uint32_t addr); #else # define sam34_getreg(addr) getreg32(addr) # define sam34_putreg(val,addr) putreg32(val,addr) #endif /* Interrupt handling *******************************************************/ static int sam34_interrupt(int irq, FAR void *context); /* "Lower half" driver methods **********************************************/ static int sam34_start(FAR struct timer_lowerhalf_s *lower); static int sam34_stop(FAR struct timer_lowerhalf_s *lower); 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 tccb_t sam34_sethandler(FAR struct timer_lowerhalf_s *lower, tccb_t handler); static int sam34_ioctl(FAR struct timer_lowerhalf_s *lower, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ /* "Lower half" driver methods */ static const struct timer_ops_s g_tcops = { .start = sam34_start, .stop = sam34_stop, .getstatus = sam34_getstatus, .settimeout = sam34_settimeout, .sethandler = sam34_sethandler, .ioctl = sam34_ioctl, }; /* "Lower half" driver state */ static struct sam34_lowerhalf_s g_tcdev; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: sam34_readvr * * Description: * Get the contents of the value register. * ****************************************************************************/ static inline uint32_t sam34_readvr(void) { register uint32_t v; /* Async counter, read until two consecutive reads match */ do { v = getreg32(SAM_RTT_VR); } while(v != getreg32(SAM_RTT_VR)); return v; } /**************************************************************************** * Name: sam34_getreg * * Description: * Get the contents of a register * ****************************************************************************/ #if defined(CONFIG_SAM34_RTT_REGDEBUG) && defined(CONFIG_DEBUG) static uint32_t sam34_getreg(uint32_t addr) { static uint32_t prevaddr = 0; static uint32_t count = 0; static uint32_t preval = 0; /* Read the value from the register */ uint32_t val = getreg32(addr); /* Is this the same value that we read from the same registe last time? Are * we polling the register? If so, suppress some of the output. */ if (addr == prevaddr && val == preval) { if (count == 0xffffffff || ++count > 3) { if (count == 4) { lldbg("...\n"); } return val; } } /* No this is a new address or value */ else { /* Did we print "..." for the previous value? */ if (count > 3) { /* Yes.. then show how many times the value repeated */ lldbg("[repeats %d more times]\n", count-3); } /* Save the new address, value, and count */ prevaddr = addr; preval = val; count = 1; } /* Show the register value read */ lldbg("%08lx->%08lx\n", addr, val); return val; } #endif /**************************************************************************** * Name: sam34_putreg * * Description: * Set the contents of an SAM34 register to a value * ****************************************************************************/ #if defined(CONFIG_SAM34_RTT_REGDEBUG) && defined(CONFIG_DEBUG) static void sam34_putreg(uint32_t val, uint32_t addr) { /* Show the register value being written */ lldbg("%08lx<-%08lx\n", addr, val); /* Write the value */ putreg32(val, addr); } #endif /**************************************************************************** * Name: sam34_interrupt * * Description: * TC interrupt * * Input Parameters: * Usual interrupt handler arguments. * * Returned Values: * Always returns OK. * ****************************************************************************/ static int sam34_interrupt(int irq, FAR void *context) { FAR struct sam34_lowerhalf_s *priv = &g_tcdev; rttvdbg("Entry\n"); DEBUGASSERT(irq == SAM_IRQ_RTT); /* Check if the interrupt is really pending */ if ((sam34_getreg(SAM_RTT_SR) & RTT_SR_ALMS) != 0) { uint32_t timeout; uint32_t mrval; uint32_t vr; uint32_t lateticks; /* Is there a registered handler? */ if (priv->handler && priv->handler(&priv->timeout)) { /* Disable int before writing new alarm */ mrval = sam34_getreg(SAM_RTT_MR); sam34_putreg(mrval & ~RTT_MR_ALMIEN, SAM_RTT_MR); /* Calculate new ticks / dither adjustment */ vr = sam34_readvr(); priv->clkticks = ((uint64_t)(priv->adjustment + priv->timeout)) * RTT_FCLK / 1000000; /* Subtract off how late we are, but only up to half an interval. * TODO calculate lost ticks? */ lateticks = vr - priv->val; if (lateticks <= (priv->clkticks>>1)) { priv->clkticks -= lateticks; } /* Set next interval interval. */ priv->val = vr + priv->clkticks; sam34_putreg(priv->val-1, SAM_RTT_AR); /* Re-enable alarm */ sam34_putreg(mrval, SAM_RTT_MR); /* Truncated timeout */ timeout = (1000000ULL * priv->clkticks) / RTT_FCLK; /* Truncated time to be added to next interval (dither) */ priv->adjustment = (priv->adjustment + priv->timeout) - timeout; } else /* stop */ { sam34_stop((FAR struct timer_lowerhalf_s *)priv); } /* RTT_SR_ALMS is cleared by reading SAM_RTT_SR */ } return OK; } /**************************************************************************** * Name: sam34_start * * Description: * Start the timer, resetting the time to the current timeout, * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int sam34_start(FAR struct timer_lowerhalf_s *lower) { FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower; uint32_t mr; uint32_t vr; rttvdbg("Entry\n"); DEBUGASSERT(priv); if (priv->started) { return -EINVAL; } #if defined(CONFIG_RTC_HIRES) && defined (CONFIG_SAM34_RTC) /* RTT is started with the RTC and always on */ mr = sam34_getreg(SAM_RTT_MR) & ~RTT_MR_ALMIEN; sam34_putreg(mr, SAM_RTT_MR); vr = sam34_readvr(); #else sam_rtt_enableclk(); /* Enable peripheral clock */ mr = RTT_MR_RTPRES(RTT_PRES); sam34_putreg(mr, SAM_RTT_MR); /* Set prescaler, disable ints */ vr = 0; /* we're going to reset the counter */ #endif priv->val = vr + priv->clkticks; /* value at end of interval */ sam34_putreg(priv->val-1, SAM_RTT_AR); /* Set interval */ if (priv->handler) { /* Clear status and enable interrupt */ sam34_getreg(SAM_RTT_SR); mr |= RTT_MR_ALMIEN; sam34_putreg(mr, SAM_RTT_MR); } #if !(defined(CONFIG_RTC_HIRES) && defined (CONFIG_SAM34_RTC)) sam34_putreg(mr | RTT_MR_RTTRST, SAM_RTT_MR); /* Start counter */ #endif /* !(CONFIG_RTC_HIRES && CONFIG_SAM34_RTC) */ priv->started = true; return OK; } /**************************************************************************** * Name: sam34_stop * * Description: * Stop the timer * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int sam34_stop(FAR struct timer_lowerhalf_s *lower) { FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower; rttvdbg("Entry\n"); DEBUGASSERT(priv); if(!priv->started) { return -EINVAL; } #if !(defined(CONFIG_RTC_HIRES) && defined (CONFIG_SAM34_RTC)) #if defined(RTT_MR_RTTDIS) sam34_putreg(RTT_MR_RTTDIS, SAM_RTT_MR); /* Disable RTT */ #endif sam_rtt_disableclk(); /* Disable peripheral clock */ #endif priv->started = false; return OK; } /**************************************************************************** * Name: sam34_getstatus * * Description: * Get the current timer status * * Input Parameters: * 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. * ****************************************************************************/ static int sam34_getstatus(FAR struct timer_lowerhalf_s *lower, FAR struct timer_status_s *status) { FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower; rttvdbg("Entry\n"); DEBUGASSERT(priv); /* Return the status bit */ status->flags = 0; if (priv->started) { status->flags |= TCFLAGS_ACTIVE; } if (priv->handler) { status->flags |= TCFLAGS_HANDLER; } /* Return the actual timeout is milliseconds */ status->timeout = priv->timeout; /* Get the time remaining until the timer expires (in microseconds) */ status->timeleft = 1000000ULL*(sam34_getreg(SAM_RTT_AR) - sam34_readvr())/RTT_FCLK; rttvdbg(" flags : %08x\n", status->flags); rttvdbg(" timeout : %d\n", status->timeout); rttvdbg(" timeleft : %d\n", status->timeleft); return OK; } /**************************************************************************** * Name: sam34_settimeout * * Description: * Set a new timeout value (and reset the timer) * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * timeout - The new timeout value in milliseconds. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ 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; DEBUGASSERT(priv); rttvdbg("Entry: timeout=%d\n", timeout); if(priv->started) return -EPERM; /* Can this timeout be represented? */ if (timeout < 1 || timeout > RTT_MAXTIMEOUT) { rttdbg("Cannot represent timeout=%lu > %lu\n", timeout, RTT_MAXTIMEOUT); return -ERANGE; } priv->timeout = timeout; /* Intended timeout */ priv->clkticks = (((uint64_t)timeout * RTT_FCLK) / 1000000); /* Actual clock ticks */ timeout = (1000000ULL * priv->clkticks) / RTT_FCLK; /* Truncated timeout */ priv->adjustment = priv->timeout - timeout; /* Truncated time to be added to next interval (dither) */ rttvdbg("fclk=%d clkticks=%d timout=%d, adjustment=%d\n", RTT_FCLK, priv->clkticks, priv->timeout, priv->adjustment); return OK; } /**************************************************************************** * Name: sam34_sethandler * * Description: * Call this user provided timeout handler. * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * newhandler - The new timer expiration function pointer. If this * function pointer is NULL, then the reset-on-expiration * behavior is restored, * * Returned Values: * The previous timer expiration function pointer or NULL is there was * no previous function pointer. * ****************************************************************************/ static tccb_t sam34_sethandler(FAR struct timer_lowerhalf_s *lower, tccb_t handler) { FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower; irqstate_t flags; tccb_t oldhandler; flags = irqsave(); DEBUGASSERT(priv); rttvdbg("Entry: handler=%p\n", handler); /* Get the old handler return value */ oldhandler = priv->handler; /* Save the new handler */ priv->handler = handler; irqrestore(flags); return oldhandler; } /**************************************************************************** * Name: sam34_ioctl * * Description: * Any ioctl commands that are not recognized by the "upper-half" driver * are forwarded to the lower half driver through this method. * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * cmd - The ioctl command value * arg - The optional argument that accompanies the 'cmd'. The * interpretation of this argument depends on the particular * command. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int sam34_ioctl(FAR struct timer_lowerhalf_s *lower, int cmd, unsigned long arg) { FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower; int ret = -ENOTTY; DEBUGASSERT(priv); rttvdbg("Entry: cmd=%d arg=%ld\n", cmd, arg); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: sam_rttinitialize * * Description: * Initialize the timer. The timer is initialized and registers as * 'devpath'. * * Input Parameters: * devpath - The full path to the timer. This should be of the form * /dev/rtt0 * * Returned Values: * None * ****************************************************************************/ void sam_rttinitialize(FAR const char *devpath) { FAR struct sam34_lowerhalf_s *priv = &g_tcdev; rttvdbg("Entry: devpath=%s\n", devpath); /* Initialize the driver state structure. Here we assume: (1) the state * structure lies in .bss and was zeroed at reset time. (2) This function * is only called once so it is never necessary to re-zero the structure. */ priv->ops = &g_tcops; (void)irq_attach(SAM_IRQ_RTT, sam34_interrupt); /* Enable NVIC interrupt. */ up_enable_irq(SAM_IRQ_RTT); /* Register the timer driver as /dev/timerX */ (void)timer_register(devpath, (FAR struct timer_lowerhalf_s *)priv); } #endif /* CONFIG_TIMER && CONFIG_SAM34_TCx */