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nuttx/arch/arm/src/samv7/sam_wdt.c

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/****************************************************************************
* arch/arm/src/samv7/sam_wdg.c
*
* Copyright (C) 2015-2016 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <stdint.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/timers/watchdog.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "sam_wdt.h"
#if defined(CONFIG_WATCHDOG) && defined(CONFIG_SAMV7_WDT)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* The Watchdog Timer uses the Slow Clock divided by 128 to establish the
* maximum Watchdog period to be 16 seconds (with a typical Slow Clock of
* 32768 kHz).
*/
#ifndef BOARD_SCLK_FREQUENCY
# define BOARD_SCLK_FREQUENCY 32768
#endif
#define WDT_FREQUENCY (BOARD_SCLK_FREQUENCY / 128)
/* At 32768Hz, the maximum timeout value will be:
*
* 4096 / WDT_FREQUENCY = 256 seconds or 16,000 milliseconds
*
* And the minimum (non-zero) timeout would be:
*
* 1 / WDT_FREQUENCY = 3.9 milliseconds
*/
#define WDT_MINTIMEOUT ((1000 + WDT_FREQUENCY - 1) / WDT_FREQUENCY)
#define WDT_MAXTIMEOUT ((4096 * 1000) / WDT_FREQUENCY)
/* Debug ********************************************************************/
/* Non-standard debug that may be enabled just for testing the watchdog
* driver. NOTE: that only lldbg types are used so that the output is
* immediately available.
*/
#ifdef CONFIG_DEBUG_WATCHDOG
# define wddbg lldbg
# define wdvdbg llvdbg
#else
# define wddbg(x...)
# define wdvdbg(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
* well-known watchdog_lowerhalf_s structure.
*/
struct sam_lowerhalf_s
{
FAR const struct watchdog_ops_s *ops; /* Lower half operations */
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
xcpt_t handler; /* Current WDT interrupt handler */
#endif
uint32_t timeout; /* The actual timeout value (milliseconds) */
uint16_t reload; /* The 12-bit watchdog reload value */
bool started; /* The timer has been started */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Register operations ******************************************************/
#if defined(CONFIG_SAMV7_WDT_REGDEBUG) && defined(CONFIG_DEBUG)
static uint32_t sam_getreg(uintptr_t regaddr);
static void sam_putreg(uint32_t regval, uintptr_t regaddr);
#else
# define sam_getreg(regaddr) getreg32(regaddr)
# define sam_putreg(regval,regaddr) putreg32(regval,regaddr)
#endif
/* Interrupt hanlding *******************************************************/
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
static int sam_interrupt(int irq, FAR void *context);
#endif
/* "Lower half" driver methods **********************************************/
static int sam_start(FAR struct watchdog_lowerhalf_s *lower);
static int sam_stop(FAR struct watchdog_lowerhalf_s *lower);
static int sam_keepalive(FAR struct watchdog_lowerhalf_s *lower);
static int sam_getstatus(FAR struct watchdog_lowerhalf_s *lower,
FAR struct watchdog_status_s *status);
static int sam_settimeout(FAR struct watchdog_lowerhalf_s *lower,
uint32_t timeout);
static xcpt_t sam_capture(FAR struct watchdog_lowerhalf_s *lower,
xcpt_t handler);
static int sam_ioctl(FAR struct watchdog_lowerhalf_s *lower, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
/* "Lower half" driver methods */
static const struct watchdog_ops_s g_wdgops =
{
.start = sam_start,
.stop = sam_stop,
.keepalive = sam_keepalive,
.getstatus = sam_getstatus,
.settimeout = sam_settimeout,
.capture = sam_capture,
.ioctl = sam_ioctl,
};
/* "Lower half" driver state */
static struct sam_lowerhalf_s g_wdtdev;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sam_getreg
*
* Description:
* Get the contents of an SAMV7 register
*
****************************************************************************/
#if defined(CONFIG_SAMV7_WDT_REGDEBUG) && defined(CONFIG_DEBUG)
static uint32_t sam_getreg(uintptr_t regaddr)
{
static uint32_t prevaddr = 0;
static uint32_t count = 0;
static uint32_t preval = 0;
/* Read the value from the register */
uint32_t regval = getreg32(regaddr);
/* 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 (regaddr == prevaddr && regval == preval)
{
if (count == 0xffffffff || ++count > 3)
{
if (count == 4)
{
lldbg("...\n");
}
return regval;
}
}
/* 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 = regaddr;
preval = regval;
count = 1;
}
/* Show the register value read */
lldbg("%08x->%048\n", regaddr, regval);
return regval;
}
#endif
/****************************************************************************
* Name: sam_putreg
*
* Description:
* Set the contents of an SAMV7 register to a value
*
****************************************************************************/
#if defined(CONFIG_SAMV7_WDT_REGDEBUG) && defined(CONFIG_DEBUG)
static void sam_putreg(uint32_t regval, uintptr_t regaddr)
{
/* Show the register value being written */
lldbg("%08x<-%08x\n", regaddr, regval);
/* Write the value */
putreg32(regval, regaddr);
}
#endif
/****************************************************************************
* Name: sam_interrupt
*
* Description:
* WDT early warning interrupt
*
* Input Parameters:
* Usual interrupt handler arguments.
*
* Returned Values:
* Always returns OK.
*
****************************************************************************/
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
static int sam_interrupt(int irq, FAR void *context)
{
FAR struct sam_lowerhalf_s *priv = &g_wdtdev;
/* Is there a registered handler? */
if (priv->handler)
{
/* Yes... NOTE: This interrupt service routine (ISR) must reload
* the WDT counter to prevent the reset. Otherwise, we will reset
* upon return.
*/
priv->handler(irq, context);
}
return OK;
}
#endif
/****************************************************************************
* Name: sam_start
*
* Description:
* Start the watchdog 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 sam_start(FAR struct watchdog_lowerhalf_s *lower)
{
FAR struct sam_lowerhalf_s *priv = (FAR struct sam_lowerhalf_s *)lower;
/* The watchdog timer is enabled or disabled by writing to the MR register.
*
* NOTE: The Watchdog Mode Register (WDT_MR) can be written only once. Only
* a processor reset resets it. Writing the WDT_MR register reloads the
* timer with the newly programmed mode parameters.
*/
wdvdbg("Entry\n");
return priv->started ? OK : -ENOSYS;
}
/****************************************************************************
* Name: sam_stop
*
* Description:
* Stop the watchdog 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 sam_stop(FAR struct watchdog_lowerhalf_s *lower)
{
/* The watchdog timer is enabled or disabled by writing to the MR register.
*
* NOTE: The Watchdog Mode Register (WDT_MR) can be written only once. Only
* a processor reset resets it. Writing the WDT_MR register reloads the
* timer with the newly programmed mode parameters.
*/
wdvdbg("Entry\n");
return -ENOSYS;
}
/****************************************************************************
* Name: sam_keepalive
*
* Description:
* Reset the watchdog timer to the current timeout value, prevent any
* imminent watchdog timeouts. This is sometimes referred as "pinging"
* the atchdog timer or "petting the dog".
*
* 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 sam_keepalive(FAR struct watchdog_lowerhalf_s *lower)
{
wdvdbg("Entry\n");
/* Write WDT_CR_WDRSTT to the WDT CR regiser (along with the KEY value)
* will restart the watchdog timer.
*/
sam_putreg(WDT_CR_WDRSTT | WDT_CR_KEY, SAM_WDT_CR);
return OK;
}
/****************************************************************************
* Name: sam_getstatus
*
* Description:
* Get the current watchdog timer status
*
* Input Parameters:
* lower - A pointer the publicly visible representation of the "lower-half"
* driver state structure.
* stawtus - The location to return the watchdog status information.
*
* Returned Values:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int sam_getstatus(FAR struct watchdog_lowerhalf_s *lower,
FAR struct watchdog_status_s *status)
{
FAR struct sam_lowerhalf_s *priv = (FAR struct sam_lowerhalf_s *)lower;
wdvdbg("Entry\n");
DEBUGASSERT(priv);
/* Return the status bit */
status->flags = WDFLAGS_RESET;
if (priv->started)
{
status->flags |= WDFLAGS_ACTIVE;
}
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
if (priv->handler)
{
status->flags |= WDFLAGS_CAPTURE;
}
#endif
/* Return the actual timeout is milliseconds */
status->timeout = priv->timeout;
/* Get the time remaining until the watchdog expires (in milliseconds)
*
* REVISIT: I think this that this information is available.
*/
status->timeleft = 0;
wdvdbg("Status :\n");
wdvdbg(" flags : %08x\n", status->flags);
wdvdbg(" timeout : %d\n", status->timeout);
wdvdbg(" timeleft : %d\n", status->timeleft);
return OK;
}
/****************************************************************************
* Name: sam_settimeout
*
* Description:
* Set a new timeout value (and reset the watchdog timer)
*
* Input Parameters:
* lower - A pointer the publicly visible representation of the "lower-half"
* driver state structure.
* timeout - The new timeout value in millisecnds.
*
* Returned Values:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int sam_settimeout(FAR struct watchdog_lowerhalf_s *lower,
uint32_t timeout)
{
FAR struct sam_lowerhalf_s *priv = (FAR struct sam_lowerhalf_s *)lower;
uint32_t reload;
uint32_t regval;
DEBUGASSERT(priv);
wdvdbg("Entry: timeout=%d\n", timeout);
/* Can this timeout be represented? */
if (timeout < WDT_MINTIMEOUT || timeout >= WDT_MAXTIMEOUT)
{
wddbg("Cannot represent timeout: %d < %d > %d\n",
WDT_MINTIMEOUT, timeout, WDT_MAXTIMEOUT);
return -ERANGE;
}
/* Calculate the reload value to achiee this (appoximate) timeout.
*
* Examples with WDT_FREQUENCY = 32768 / 128 = 256:
* timeout = 4 -> reload = 1
* timeout = 16000 -> reload = 4096
*/
reload = (timeout * WDT_FREQUENCY + 500) / 1000;
if (reload < 1)
{
reload = 1;
}
else if (reload > 4095)
{
reload = 4095;
}
/* Calculate and save the actual timeout value in milliseconds:
*
* timeout = 1000 * (reload + 1) / Fwwdg
*/
priv->timeout = (1000 * reload + WDT_FREQUENCY/2) / WDT_FREQUENCY;
/* Remember the selected values */
priv->reload = reload;
wdvdbg("reload=%d timout: %d->%d\n",
reload, timeout, priv->timeout);
/* Set the WDT_MR according to calculated value
*
* NOTE: The Watchdog Mode Register (WDT_MR) can be written only once. Only
* a processor reset resets it. Writing the WDT_MR register reloads the
* timer with the newly programmed mode parameters.
*/
regval = WDT_MR_WDV(reload) | WDT_MR_WDD(reload);
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
/* Generate an interrupt whent he watchdog timer expires */
regval |= WDT_MR_WDFIEN;
#else
/* Reset (everything) if the watchdog timer expires.
*
* REVISIT: Set WDT_MR_WDRPROC so that only the processor is reset?
*/
regval |= WDT_MR_WDRSTEN;
#endif
#ifdef CONFIG_SAMV7_WDT_DEBUGHALT
/* Halt the watchdog in the debug state */
regval |= WDT_MR_WDDBGHLT;
#endif
#ifdef CONFIG_SAMV7_WDT_IDLEHALT
/* Halt the watchdog in the IDLE mode */
regval |= WDT_MR_WDIDLEHLT;
#endif
sam_putreg(regval, SAM_WDT_MR);
/* NOTE: We had to start the watchdog here (because we cannot re-write the
* MR register). So sam_start will not be able to do anything.
*/
priv->started = true;
wdvdbg("Setup: CR: %08x MR: %08x SR: %08x\n",
sam_getreg(SAM_WDT_CR), sam_getreg(SAM_WDT_MR),
sam_getreg(SAM_WDT_SR));
return OK;
}
/****************************************************************************
* Name: sam_capture
*
* Description:
* Don't reset on watchdog timer timeout; instead, call this user provider
* timeout handler. NOTE: Providing handler==NULL will restore the reset
* behavior.
*
* Input Parameters:
* lower - A pointer the publicly visible representation of the "lower-half"
* driver state structure.
* newhandler - The new watchdog expiration function pointer. If this
* function pointer is NULL, then the reset-on-expiration
* behavior is restored,
*
* Returned Values:
* The previous watchdog expiration function pointer or NULL is there was
* no previous function pointer, i.e., if the previous behavior was
* reset-on-expiration (NULL is also returned if an error occurs).
*
****************************************************************************/
static xcpt_t sam_capture(FAR struct watchdog_lowerhalf_s *lower,
xcpt_t handler)
{
#ifndef CONFIG_SAMV7_WDT_INTERRUPT
wddbg("ERROR: Not configured for this mode\n");
return NULL;
#else
FAR struct sam_lowerhalf_s *priv = (FAR struct sam_lowerhalf_s *)lower;
irqstate_t flags;
xcpt_t oldhandler;
DEBUGASSERT(priv);
wdvdbg("Entry: handler=%p\n", handler);
/* Get the old handler return value */
flags = enter_critical_section();
oldhandler = priv->handler;
/* Save the new handler */
priv->handler = handler;
/* Are we attaching or detaching the handler? */
if (handler)
{
/* Attaching... Enable the WDT interrupt */
up_enable_irq(SAM_IRQ_WDT);
}
else
{
/* Detaching... Disable the WDT interrupt */
up_disable_irq(SAM_IRQ_WDT);
}
leave_critical_section(flags);
return oldhandler;
#endif
}
/****************************************************************************
* Name: sam_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 ioctol 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 sam_ioctl(FAR struct watchdog_lowerhalf_s *lower, int cmd,
unsigned long arg)
{
wdvdbg("cmd=%d arg=%ld\n", cmd, arg);
/* No ioctls are supported */
return -ENOTTY;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_wdt_initialize
*
* Description:
* Initialize the WDT watchdog time. The watchdog timer is initialized and
* registered as 'devpath. The initial state of the watchdog time is
* disabled.
*
* Input Parameters:
* None
*
* Returned Values:
* None
*
****************************************************************************/
int sam_wdt_initialize(void)
{
FAR struct sam_lowerhalf_s *priv = &g_wdtdev;
wdvdbg("Entry: CR: %08x MR: %08x SR: %08x\n",
sam_getreg(SAM_WDT_CR), sam_getreg(SAM_WDT_MR),
sam_getreg(SAM_WDT_SR));
/* Check if some previous logic was disabled the watchdog timer. Since the
* MR can be written only one time, we are out of business if that is the
* case.
*/
DEBUGASSERT((sam_getreg(SAM_WDT_MR) & WDT_MR_WDDIS) == 0);
/* No clock setup is required. The Watchdog Timer uses the Slow Clock
* divided by 128 to establish the maximum Watchdog period to be 16 seconds
* (with a typical Slow Clock of 32768 kHz).
*/
/* 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_wdgops;
#ifdef CONFIG_SAMV7_WDT_INTERRUPT
/* Attach our WDT interrupt handler (But don't enable it yet) */
(void)irq_attach(SAM_IRQ_WDT, sam_interrupt);
#endif
/* Register the watchdog driver as /dev/wdt */
(void)watchdog_register("/dev/wdt",
(FAR struct watchdog_lowerhalf_s *)priv);
return OK;
}
#endif /* CONFIG_WATCHDOG && CONFIG_SAMV7_WDT */
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