/****************************************************************************
* arch/arm/src/stm32/stm32_wwdg.c
*
* Copyright (C) 2012 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/watchdog.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "chip/stm32_dbgmcu.h"
#include "stm32_wdg.h"
#if defined(CONFIG_WATCHDOG) && defined(CONFIG_STM32_WWDG)
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/* Clocking *****************************************************************/
/* The minimum frequency of the WWDG clock is:
*
* Fmin = PCLK1 / 4096 / 8
*
* So the maximum delay (in milliseconds) is then:
*
* 1000 * (WWDG_CR_T_MAX+1) / Fmin
*
* For example, if PCLK1 = 42MHz, then the maximum delay is:
*
* Fmin = 1281.74
* 1000 * 64 / Fmin = 49.93 msec
*/
#define WWDG_FMIN (STM32_PCLK1_FREQUENCY / 4096 / 8)
#define WWDG_MAXTIMEOUT (1000 * (WWDG_CR_T_MAX+1) / WWDG_FMIN)
/* Configuration ************************************************************/
#ifndef CONFIG_STM32_WWDG_DEFTIMOUT
# define CONFIG_STM32_WWDG_DEFTIMOUT WWDG_MAXTIMEOUT
#endif
/* 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 stm32_lowerhalf_s
{
FAR const struct watchdog_ops_s *ops; /* Lower half operations */
xcpt_t handler; /* Current EWI interrupt handler */
uint32_t timeout; /* The actual timeout value */
uint32_t fwwdg; /* WWDG clock frequency */
bool started; /* The timer has been started */
uint8_t reload; /* The 7-bit reload field reset value */
uint8_t window; /* The 7-bit window (W) field value */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Register operations ******************************************************/
#if defined(CONFIG_STM32_WWDG_REGDEBUG) && defined(CONFIG_DEBUG)
static uint16_t stm32_getreg(uint32_t addr);
static void stm32_putreg(uint16_t val, uint32_t addr);
#else
# define stm32_getreg(addr) getreg32(addr)
# define stm32_putreg(val,addr) putreg32(val,addr)
#endif
static void stm32_setwindow(FAR struct stm32_lowerhalf_s *priv,
uint8_t window);
/* Interrupt hanlding *******************************************************/
static int stm32_interrupt(int irq, FAR void *context);
/* "Lower half" driver methods **********************************************/
static int stm32_start(FAR struct watchdog_lowerhalf_s *lower);
static int stm32_stop(FAR struct watchdog_lowerhalf_s *lower);
static int stm32_keepalive(FAR struct watchdog_lowerhalf_s *lower);
static int stm32_getstatus(FAR struct watchdog_lowerhalf_s *lower,
FAR struct watchdog_status_s *status);
static int stm32_settimeout(FAR struct watchdog_lowerhalf_s *lower,
uint32_t timeout);
static xcpt_t stm32_capture(FAR struct watchdog_lowerhalf_s *lower,
xcpt_t handler);
static int stm32_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 = stm32_start,
.stop = stm32_stop,
.keepalive = stm32_keepalive,
.getstatus = stm32_getstatus,
.settimeout = stm32_settimeout,
.capture = stm32_capture,
.ioctl = stm32_ioctl,
};
/* "Lower half" driver state */
static struct stm32_lowerhalf_s g_wdgdev;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_getreg
*
* Description:
* Get the contents of an STM32 register
*
****************************************************************************/
#if defined(CONFIG_STM32_WWDG_REGDEBUG) && defined(CONFIG_DEBUG)
static uint16_t stm32_getreg(uint32_t addr)
{
static uint32_t prevaddr = 0;
static uint32_t count = 0;
static uint16_t preval = 0;
/* Read the value from the register */
uint16_t val = getreg16(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("%08x->%04x\n", addr, val);
return val;
}
#endif
/****************************************************************************
* Name: stm32_putreg
*
* Description:
* Set the contents of an STM32 register to a value
*
****************************************************************************/
#if defined(CONFIG_STM32_WWDG_REGDEBUG) && defined(CONFIG_DEBUG)
static void stm32_putreg(uint16_t val, uint32_t addr)
{
/* Show the register value being written */
lldbg("%08x<-%04x\n", addr, val);
/* Write the value */
putreg16(val, addr);
}
#endif
/****************************************************************************
* Name: stm32_setwindow
*
* Description:
* Set the CFR window value. The window value is compared to the down-
* counter when the counter is updated. The WWDG counter should be updated
* only when the counter is below this window value (and greater than 64)
* otherwise a reset will be generated
*
****************************************************************************/
static void stm32_setwindow(FAR struct stm32_lowerhalf_s *priv, uint8_t window)
{
uint16_t regval;
/* Set W[6:0] bits according to selected window value */
regval = stm32_getreg(STM32_WWDG_CFR);
regval &= ~WWDG_CFR_W_MASK;
regval |= window << WWDG_CFR_W_SHIFT;
stm32_putreg(regval, STM32_WWDG_CFR);
/* Remember the window setting */
priv->window = window;
}
/****************************************************************************
* Name: stm32_interrupt
*
* Description:
* WWDG early warning interrupt
*
* Input Parameters:
* Usual interrupt handler arguments.
*
* Returned Values:
* Always returns OK.
*
****************************************************************************/
static int stm32_interrupt(int irq, FAR void *context)
{
FAR struct stm32_lowerhalf_s *priv = &g_wdgdev;
uint16_t regval;
/* Check if the EWI interrupt is really pending */
regval = stm32_getreg(STM32_WWDG_SR);
if ((regval & WWDG_SR_EWIF) != 0)
{
/* Is there a registered handler? */
if (priv->handler)
{
/* Yes... NOTE: This interrupt service routine (ISR) must reload
* the WWDG counter to prevent the reset. Otherwise, we will reset
* upon return.
*/
priv->handler(irq, context);
}
/* The EWI interrupt is cleared by writing '0' to the EWIF bit in the
* WWDG_SR register.
*/
regval &= ~WWDG_SR_EWIF;
stm32_putreg(regval, STM32_WWDG_SR);
}
return OK;
}
/****************************************************************************
* Name: stm32_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 stm32_start(FAR struct watchdog_lowerhalf_s *lower)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
wdvdbg("Entry\n");
DEBUGASSERT(priv);
/* The watchdog is always disabled after a reset. It is enabled by setting
* the WDGA bit in the WWDG_CR register, then it cannot be disabled again
* except by a reset.
*/
stm32_putreg(WWDG_CR_WDGA | WWDG_CR_T_RESET | priv->reload, STM32_WWDG_CR);
priv->started = true;
return OK;
}
/****************************************************************************
* Name: stm32_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 stm32_stop(FAR struct watchdog_lowerhalf_s *lower)
{
/* The watchdog is always disabled after a reset. It is enabled by setting
* the WDGA bit in the WWDG_CR register, then it cannot be disabled again
* except by a reset.
*/
wdvdbg("Entry\n");
return -ENOSYS;
}
/****************************************************************************
* Name: stm32_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".
*
* The application program must write in the WWDG_CR register at regular
* intervals during normal operation to prevent an MCU reset. This operation
* must occur only when the counter value is lower than the window register
* value. The value to be stored in the WWDG_CR register must be between
* 0xff and 0xC0:
*
* 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 stm32_keepalive(FAR struct watchdog_lowerhalf_s *lower)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
wdvdbg("Entry\n");
DEBUGASSERT(priv);
/* Write to T[6:0] bits to configure the counter value, no need to do
* a read-modify-write; writing a 0 to WDGA bit does nothing.
*/
stm32_putreg((WWDG_CR_T_RESET | priv->reload), STM32_WWDG_CR);
return OK;
}
/****************************************************************************
* Name: stm32_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 stm32_getstatus(FAR struct watchdog_lowerhalf_s *lower,
FAR struct watchdog_status_s *status)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
uint32_t elapsed;
uint16_t reload;
wdvdbg("Entry\n");
DEBUGASSERT(priv);
/* Return the status bit */
status->flags = WDFLAGS_RESET;
if (priv->started)
{
status->flags |= WDFLAGS_ACTIVE;
}
if (priv->handler)
{
status->flags |= WDFLAGS_CAPTURE;
}
/* Return the actual timeout is milliseconds */
status->timeout = priv->timeout;
/* Get the time remaining until the watchdog expires (in milliseconds) */
reload = (stm32_getreg(STM32_WWDG_CR) >> WWDG_CR_T_SHIFT) & 0x7f;
elapsed = priv->reload - reload;
status->timeleft = (priv->timeout * elapsed) / (priv->reload + 1);
wdvdbg("Status :\n");
wdvdbg(" flags : %08x\n", status->flags);
wdvdbg(" timeout : %d\n", status->timeout);
wdvdbg(" timeleft : %d\n", status->flags);
return OK;
}
/****************************************************************************
* Name: stm32_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 stm32_settimeout(FAR struct watchdog_lowerhalf_s *lower,
uint32_t timeout)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
uint32_t fwwdg;
uint32_t reload;
uint16_t regval;
int wdgtb;
DEBUGASSERT(priv);
wdvdbg("Entry: timeout=%d\n", timeout);
/* Can this timeout be represented? */
if (timeout < 1 || timeout > WWDG_MAXTIMEOUT)
{
wddbg("Cannot represent timeout=%d > %d\n",
timeout, WWDG_MAXTIMEOUT);
return -ERANGE;
}
/* Determine prescaler value.
*
* Fwwdg = PCLK1/4096/prescaler.
*
* Where
* Fwwwdg is the frequency of the WWDG clock
* wdgtb is one of {1, 2, 4, or 8}
*/
/* Select the smallest prescaler that will result in a reload field value that is
* less than the maximum.
*/
for (wdgtb = 0; ; wdgtb++)
{
/* WDGTB = 0 -> Divider = 1 = 1 << 0
* WDGTB = 1 -> Divider = 2 = 1 << 1
* WDGTB = 2 -> Divider = 4 = 1 << 2
* WDGTB = 3 -> Divider = 8 = 1 << 3
*/
/* Get the WWDG counter frequency in Hz. */
fwwdg = (STM32_PCLK1_FREQUENCY/4096) >> wdgtb;
/* The formula to calculate the timeout value is given by:
*
* timeout = 1000 * (reload + 1) / Fwwdg, OR
* reload = timeout * Fwwdg / 1000 - 1
*
* Where
* timeout is the desired timout in milliseconds
* reload is the contents of T{5:0]
* Fwwdg is the frequency of the WWDG clock
*/
reload = timeout * fwwdg / 1000 - 1;
/* If this reload valid is less than the maximum or we are not ready
* at the prescaler value, then break out of the loop to use these
* settings.
*/
#if 0
wdvdbg("wdgtb=%d fwwdg=%d reload=%d timout=%d\n",
wdgtb, fwwdg, reload, 1000 * (reload + 1) / fwwdg);
#endif
if (reload <= WWDG_CR_T_MAX || wdgtb == 3)
{
/* Note that we explicity break out of the loop rather than using
* the 'for' loop termination logic because we do not want the
* value of wdgtb to be incremented.
*/
break;
}
}
/* Make sure that the final reload value is within range */
if (reload > WWDG_CR_T_MAX)
{
reload = WWDG_CR_T_MAX;
}
/* Calculate and save the actual timeout value in milliseconds:
*
* timeout = 1000 * (reload + 1) / Fwwdg
*/
priv->timeout = 1000 * (reload + 1) / fwwdg;
/* Remember the selected values */
priv->fwwdg = fwwdg;
priv->reload = reload;
wdvdbg("wdgtb=%d fwwdg=%d reload=%d timout=%d\n",
wdgtb, fwwdg, reload, priv->timeout);
/* Set WDGTB[1:0] bits according to calculated value */
regval = stm32_getreg(STM32_WWDG_CFR);
regval &= ~WWDG_CFR_WDGTB_MASK;
regval |= (uint16_t)wdgtb << WWDG_CFR_WDGTB_SHIFT;
stm32_putreg(regval, STM32_WWDG_CFR);
/* Reset the 7-bit window value to the maximum value.. essentially disabling
* the lower limit of the watchdog reset time.
*/
stm32_setwindow(priv, 0x7f);
return OK;
}
/****************************************************************************
* Name: stm32_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 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 stm32_capture(FAR struct watchdog_lowerhalf_s *lower,
xcpt_t handler)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
irqstate_t flags;
xcpt_t oldhandler;
uint16_t regval;
DEBUGASSERT(priv);
wdvdbg("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 = stm32_getreg(STM32_WWDG_CFR);
if (handler)
{
/* Attaching... Enable the EWI interrupt */
regval |= WWDG_CFR_EWI;
stm32_putreg(regval, STM32_WWDG_CFR);
up_enable_irq(STM32_IRQ_WWDG);
}
else
{
/* Detaching... Disable the EWI interrupt */
regval &= ~WWDG_CFR_EWI;
stm32_putreg(regval, STM32_WWDG_CFR);
up_disable_irq(STM32_IRQ_WWDG);
}
irqrestore(flags);
return oldhandler;
}
/****************************************************************************
* Name: stm32_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 stm32_ioctl(FAR struct watchdog_lowerhalf_s *lower, int cmd,
unsigned long arg)
{
FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower;
int ret = -ENOTTY;
DEBUGASSERT(priv);
wdvdbg("Entry: cmd=%d arg=%ld\n", cmd, arg);
/* WDIOC_MINTIME: Set the minimum ping time. If two keepalive ioctls
* are received within this time, a reset event will be generated.
* Argument: A 32-bit time value in milliseconds.
*/
if (cmd == WDIOC_MINTIME)
{
uint32_t mintime = (uint32_t)arg;
/* The minimum time should be strictly less than the total delay
* which, in turn, will be less than or equal to WWDG_CR_T_MAX
*/
ret = -EINVAL;
if (mintime < priv->timeout)
{
uint32_t window = (priv->timeout - mintime) * priv->fwwdg / 1000 - 1;
DEBUGASSERT(window < priv->reload);
stm32_setwindow(priv, window | WWDG_CR_T_RESET);
ret = OK;
}
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_wwdginitialize
*
* Description:
* Initialize the WWDG watchdog time. The watchdog timer is intialized and
* registers as 'devpath. The initial state of the watchdog time is
* disabled.
*
* Input Parameters:
* devpath - The full path to the watchdog. This should be of the form
* /dev/watchdog0
*
* Returned Values:
* None
*
****************************************************************************/
void stm32_wwdginitialize(FAR const char *devpath)
{
FAR struct stm32_lowerhalf_s *priv = &g_wdgdev;
wdvdbg("Entry: devpath=%s\n", devpath);
/* NOTE we assume that clocking to the IWDG has already been provided by
* the RCC initialization logic.
*/
/* 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;
/* Attach our EWI interrupt handler (But don't enable it yet) */
(void)irq_attach(STM32_IRQ_WWDG, stm32_interrupt);
/* Select an arbitrary initial timeout value. But don't start the watchdog
* yet. NOTE: If the "Hardware watchdog" feature is enabled through the
* device option bits, the watchdog is automatically enabled at power-on.
*/
stm32_settimeout((FAR struct watchdog_lowerhalf_s *)priv,
CONFIG_STM32_WWDG_DEFTIMOUT);
/* Register the watchdog driver as /dev/watchdog0 */
(void)watchdog_register(devpath, (FAR struct watchdog_lowerhalf_s *)priv);
/* When the microcontroller enters debug mode (Cortex�-M4F core halted),
* the WWDG counter either continues to work normally or stops, depending
* on DBG_WWDG_STOP configuration bit in DBG module.
*/
#if defined(CONFIG_STM32_JTAG_FULL_ENABLE) || \
defined(CONFIG_STM32_JTAG_NOJNTRST_ENABLE) || \
defined(CONFIG_STM32_JTAG_SW_ENABLE)
{
uint32_t cr = getreg32(STM32_DBGMCU_CR);
cr |= DBGMCU_CR_WWDGSTOP;
putreg32(cr, STM32_DBGMCU_CR);
}
#endif
}
#endif /* CONFIG_WATCHDOG && CONFIG_STM32_WWDG */
