/****************************************************************************
* arch/arm/src/sam34/sam_rtt.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Authors: Gregory Nutt <gnutt@nuttx.org>
* 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 <nuttx/config.h>
#include <nuttx/arch.h>
#include <sys/types.h>
#include <stdint.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/timers/timer.h>
#include <arch/board/board.h>
#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);
UNUSED(priv);
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 */
