diff options
Diffstat (limited to 'nuttx/arch/arm/src/tiva/tiva_timerlow.c')
| -rw-r--r-- | nuttx/arch/arm/src/tiva/tiva_timerlow.c | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/tiva/tiva_timerlow.c b/nuttx/arch/arm/src/tiva/tiva_timerlow.c new file mode 100644 index 000000000..9959d80fe --- /dev/null +++ b/nuttx/arch/arm/src/tiva/tiva_timerlow.c @@ -0,0 +1,583 @@ +/**************************************************************************** + * arch/arm/src/tiva/tiva_timerlow.c + * + * Copyright (C) 2015 Gregory Nutt. All rights reserved. + * Authors: 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 <sys/types.h> + +#include <stdint.h> +#include <errno.h> +#include <assert.h> +#include <debug.h> + +#include <nuttx/kmalloc.h> +#include <nuttx/timer.h> + +#include <arch/board/board.h> + +#include "tiva_timer.h" + +#if defined(CONFIG_TIMER) && defined(CONFIG_TIVA_TIMER) + +/**************************************************************************** + * Pre-Processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * 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 tiva_lowerhalf_s +{ + const struct timer_ops_s *ops; /* Lower half operations */ + struct tiva_gptm32config_s config; /* Persistent timer configuration */ + TIMER_HANDLE handle; /* Contained timer handle */ + tccb_t handler; /* Current user interrupt handler */ + uint32_t clkin; /* Input clock frequency */ + uint32_t timeout; /* The current timeout value (us) */ + uint32_t clkticks; /* Actual clock ticks for current interval */ + uint32_t adjustment; /* Time lost due to clock resolution truncation (us) */ + bool started; /* True: Timer has been started */ +}; + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ +/* Helper functions *********************************************************/ + +static uint32_t tiva_usec2ticks(struct tiva_lowerhalf_s *priv, uint32_t usecs); +static uint32_t tiva_ticks2usec(struct tiva_lowerhalf_s *priv, uint32_t ticks); + +/* Interrupt handling *******************************************************/ + +static void tiva_handler(TIMER_HANDLE handle, + const struct tiva_gptm32config_s *config, uint32_t status); + +/* "Lower half" driver methods **********************************************/ + +static int tiva_start(struct timer_lowerhalf_s *lower); +static int tiva_stop(struct timer_lowerhalf_s *lower); +static int tiva_getstatus(struct timer_lowerhalf_s *lower, + struct timer_status_s *status); +static int tiva_settimeout(struct timer_lowerhalf_s *lower, + uint32_t timeout); +static tccb_t tiva_sethandler(struct timer_lowerhalf_s *lower, + tccb_t handler); +static int tiva_ioctl(struct timer_lowerhalf_s *lower, int cmd, + unsigned long arg); + +/**************************************************************************** + * Private Data + ****************************************************************************/ +/* "Lower half" driver methods */ + +static const struct timer_ops_s g_timer_ops = +{ + .start = tiva_start, + .stop = tiva_stop, + .getstatus = tiva_getstatus, + .settimeout = tiva_settimeout, + .sethandler = tiva_sethandler, + .ioctl = tiva_ioctl, +}; + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: tiva_usec2ticks + * + * Description: + * Convert microseconds to timer clock ticks. + * + * Input Parameters: + * priv - A pointer to a private timer driver lower half instance + * usecs - The number of usecs to convert + * + * Returned Values: + * The time converted to clock ticks. + * + ****************************************************************************/ + +static uint32_t tiva_usec2ticks(struct tiva_lowerhalf_s *priv, uint32_t usecs) +{ + uint64_t bigticks; + + bigticks = ((uint64_t)usecs * (uint64_t)priv->clkin) / 1000000; + if (bigticks > UINT32_MAX) + { + return UINT32_MAX; + } + + return (uint32_t)bigticks; +} + +/**************************************************************************** + * Name: tiva_ticks2usec + * + * Description: + * Convert timer clock ticks to microseconds. + * + * Input Parameters: + * priv - A pointer to a private timer driver lower half instance + * usecs - The number of ticks to convert + * + * Returned Values: + * The time converted to microseconds. + * + ****************************************************************************/ + +static uint32_t tiva_ticks2usec(struct tiva_lowerhalf_s *priv, uint32_t ticks) +{ + uint64_t bigusec; + + bigusec = (1000000ull * (uint64_t)ticks) / priv->clkin; + if (bigusec > UINT32_MAX) + { + return UINT32_MAX; + } + + return (uint32_t)bigusec; +} + +/**************************************************************************** + * Name: tiva_handler + * + * Description: + * 32-bit timer interrupt handler + * + * Input Parameters: + * Usual 32-bit timer interrupt handler arguments. + * + * Returned Values: + * None + * + ****************************************************************************/ + +static void tiva_handler(TIMER_HANDLE handle, + const struct tiva_gptm32config_s *config, + uint32_t status) +{ + struct tiva_lowerhalf_s *priv; + + timvdbg("Entry\n"); + + /* Check if the timeout interrupt is pending */ +#warning Missing logic + { + uint32_t timeout; + + /* Is there a registered handler? */ + + if (priv->handler && priv->handler(&priv->timeout)) + { + /* Calculate new ticks / dither adjustment */ + + priv->clkticks = tiva_usec2ticks(priv, priv->adjustment + priv->timeout); + + /* Set next interval interval. TODO: make sure the interval is not + * so soon it will be missed! + */ +#warning Missing logic + + /* Calculate the next adjustment */ + + timeout = tiva_ticks2usec(priv, priv->clkticks); + priv->adjustment = (priv->adjustment + priv->timeout) - timeout; + } + else /* stop */ + { + tiva_timer32_stop(priv->handle); + } + } +} + +/**************************************************************************** + * Name: tiva_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 tiva_start(struct timer_lowerhalf_s *lower) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + + timvdbg("Entry: started %d\n", priv->started); + + /* Has the timer already been started? */ + + if (!priv->started) + { + /* Start the timer */ + + tiva_timer32_start(priv->handle); + priv->started = true; + return OK; + } + + /* Return EBUSY to indicate that the timer was already running */ + + return -EBUSY; +} + +/**************************************************************************** + * Name: tiva_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 tiva_stop(struct timer_lowerhalf_s *lower) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + + timvdbg("Entry: started %d\n", priv->started); + + /* Has the timer already been started? */ + + if (priv->started) + { + /* Stop the timer */ + + tiva_timer32_stop(priv->handle); + priv->started = false; + return OK; + } + + /* Return ENODEV to indicate that the timer was not running */ + + return -ENODEV; +} + +/**************************************************************************** + * Name: tiva_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 tiva_getstatus(struct timer_lowerhalf_s *lower, + struct timer_status_s *status) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + uint32_t elapsed; + + timvdbg("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 in microseconds */ + + status->timeout = priv->timeout; + + /* Get the time remaining until the timer expires (in microseconds) */ + + //elapsed = ; + status->timeleft = ((uint64_t)priv->timeout * elapsed) / (priv->clkticks + 1); /* TODO - check on this +1 */ + + timvdbg(" flags : %08x\n", status->flags); + timvdbg(" timeout : %d\n", status->timeout); + timvdbg(" timeleft : %d\n", status->timeleft); + return OK; +} + +/**************************************************************************** + * Name: tiva_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 microseconds. + * + * Returned Values: + * Zero on success; a negated errno value on failure. + * + ****************************************************************************/ + +static int tiva_settimeout(struct timer_lowerhalf_s *lower, + uint32_t timeout) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + + DEBUGASSERT(priv); + + if (priv->started) + { + return -EPERM; + } + + timvdbg("Entry: timeout=%d\n", timeout); + + /* Save the desired timeout value */ + + priv->timeout = timeout; + + /* Calculate the actual timeout value in clock ticks */ + + priv->clkticks = tiva_usec2ticks(priv, timeout); + + /* Calculate an adjustment due to truncation in timer resolution */ + + timeout = tiva_ticks2usec(priv, priv->clkticks); + priv->adjustment = priv->timeout - timeout; + + timvdbg("clkin=%d clkticks=%d timout=%d, adjustment=%d\n", + priv->clkin, priv->clkticks, priv->timeout, priv->adjustment); + + /* Reset the timer interval */ + + tiva_timer32_setinterval(priv->handle, priv->clkticks); + return OK; +} + +/**************************************************************************** + * Name: tiva_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 tiva_sethandler(struct timer_lowerhalf_s *lower, + tccb_t handler) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + irqstate_t flags; + tccb_t oldhandler; + + flags = irqsave(); + + DEBUGASSERT(priv); + timvdbg("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: tiva_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 tiva_ioctl(struct timer_lowerhalf_s *lower, int cmd, + unsigned long arg) +{ + struct tiva_lowerhalf_s *priv = (struct tiva_lowerhalf_s *)lower; + int ret = -ENOTTY; + + DEBUGASSERT(priv); + timvdbg("Entry: cmd=%d arg=%ld\n", cmd, arg); + + return ret; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: tiva_timer_register + * + * Description: + * Bind the configuration timer to a timer lower half instance and + * register the timer drivers at 'devpath' + * + * NOTE: Only 32-bit periodic timers are supported. + * + * Input Parameters: + * devpath - The full path to the timer device. This should be of the form + * /dev/timer0 + * gptm - General purpose timer number + * timeout - Timeout interval in microseconds. Set to a non-zero value + * to enable timeout interrupts + * altlck - True: Use alternate clock source. + * + * Returned Values: + * Zero (OK) is returned on success; A negated errno value is returned + * to indicate the nature of any failure. + * + ****************************************************************************/ + +int tiva_timer_register(const char *devpath, int gptm, uint32_t timeout, + bool altclk) +{ + struct tiva_lowerhalf_s *priv; + struct tiva_gptm32config_s *config; + void *rethandle; + + DEBUGASSERT(devpath); + timvdbg("Entry: devpath=%s\n", devpath); + + /* Allocate an instance of the lower half state structure */ + + priv = (struct tiva_lowerhalf_s *)kmm_zalloc(sizeof(struct tiva_lowerhalf_s)); + if (!priv) + { + timdbg("ERROR: Failed to allocate driver structure\n"); + return -ENOMEM; + } + + /* Initialize the non-zero elements of lower half state structure */ + + priv->ops = &g_timer_ops; + priv->clkin = altclk ? ALTCLK_FREQUENCY : SYSCLK_FREQUENCY; + priv->timeout = timeout; + + config = &priv->config; + config->cmn.gptm = gptm; + config->cmn.mode = TIMER32_MODE_PERIODIC; + config->cmn.alternate = altclk; + config->config.flags = TIMER_FLAG_COUNTUP; + config->config.handler = tiva_handler; + config->config.u.periodic.interval = tiva_usec2ticks(priv, timeout); + + /* Create the timer handle */ + + priv->handle = tiva_gptm_configure((const struct tiva_gptmconfig_s *)&priv->config); + if (!priv->handle) + { + timdbg("ERROR: Failed to create timer handle\n"); + return -EINVAL; + } + + /* Register the timer driver as /dev/timerX. The returned value from + * timer_register is a handle that could be used with timer_unregister(). + * REVISIT: The returned handle is discard here. + */ + + rethandle = timer_register(devpath, (struct timer_lowerhalf_s *)priv); + if (!rethandle) + { + /* Free the allocated state structure */ + + kmm_free(priv); + + /* The actual cause of the failure may have been a failure to allocate + * perhaps a failure to register the timer driver (such as if the + * 'depath' were not unique). We know here but we return EEXIST to + * indicate the failure (implying the non-unique devpath). + */ + + return -EEXIST; + } + + return OK; +} + +#endif /* CONFIG_TIMER && CONFIG_TIVA_TIMER */ |