/* Copyright (C) 2004 David Decotigny
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#include <sos/assert.h>
#include <sos/klibc.h>
#include <hwcore/irq.h>
#include <sos/list.h>
#include "time.h"
/**
* Number of nanoseconds in 1 second
*/
#define NS_IN_SEC 1000000000UL
/**
* The list of timeout actions waiting for a timeout. The timeout
* actions are stored in the list in increasing initial timeout
* order. Actually, the "timeout" field won't reflect this initial
* timeout: for each element in the list, it stores the timeout
* _difference_ between the timeout action and the previous in the
* list.
*/
static struct sos_timeout_action *timeout_action_list;
/**
* Current resolution of a time tick
*/
static struct sos_time tick_resolution;
/**
* Time elapsed between boot and last timer tick
*
* @note No 'volatile' here because the tick value is NEVER modified
* while in any of the functions below: it is modified only out of
* these functions by the IRQ timer handler because these functions
* are protected against timer IRQ and are "one shot" (no busy waiting
* for a change in the tick's value).
*/
static struct sos_time last_tick_time;
sos_ret_t sos_time_inc(struct sos_time *dest,
const struct sos_time *to_add)
{
/* nanosec is always < 1e9 so that their sum is always < 2e9, which
is smaller than 2^32-1 */
sos_ui32_t sigma_ns = dest->nanosec + to_add->nanosec;
dest->sec += to_add->sec;
dest->sec += sigma_ns / NS_IN_SEC;
dest->nanosec = sigma_ns % NS_IN_SEC;
return SOS_OK;
}
sos_ret_t sos_time_dec(struct sos_time *dest,
const struct sos_time *to_dec)
{
/* nanosec is always < 1e9 so that their difference is always in
(-1e9, 1e9), which is compatible with the (-2^31, 2^31 - 1)
cpacity of a signed dword */
sos_si32_t diff_ns = ((sos_si32_t)dest->nanosec)
- ((sos_si32_t)to_dec->nanosec);
/* Make sure substraction is possible */
SOS_ASSERT_FATAL(dest->sec >= to_dec->sec);
if (dest->sec == to_dec->sec)
SOS_ASSERT_FATAL(dest->nanosec >= to_dec->nanosec);
dest->sec -= to_dec->sec;
if (diff_ns > 0)
dest->sec += diff_ns / NS_IN_SEC;
else
dest->sec -= ((-diff_ns) / NS_IN_SEC);
dest->nanosec = (NS_IN_SEC + diff_ns) % NS_IN_SEC;
if (diff_ns < 0)
dest->sec --;
return SOS_OK;
}
int sos_time_cmp(const struct sos_time *t1,
const struct sos_time *t2)
{
/* Compare seconds */
if (t1->sec < t2->sec)
return -1;
else if (t1->sec > t2->sec)
return 1;
/* seconds are equal => compare nanoseconds */
else if (t1->nanosec < t2->nanosec)
return -1;
else if (t1->nanosec > t2->nanosec)
return 1;
/* else: sec and nanosecs are equal */
return 0;
}
sos_bool_t sos_time_is_zero(const struct sos_time *tm)
{
return ( (0 == tm->sec) && (0 == tm->nanosec) );
}
sos_ret_t sos_time_subsysem_setup(const struct sos_time *initial_resolution)
{
timeout_action_list = NULL;
last_tick_time = (struct sos_time) { .sec = 0, .nanosec = 0 };
memcpy(& tick_resolution, initial_resolution, sizeof(struct sos_time));
return SOS_OK;
}
sos_ret_t sos_time_get_tick_resolution(struct sos_time *resolution)
{
sos_ui32_t flags;
sos_disable_IRQs(flags);
memcpy(resolution, & tick_resolution, sizeof(struct sos_time));
sos_restore_IRQs(flags);
return SOS_OK;
}
sos_ret_t sos_time_set_tick_resolution(const struct sos_time *resolution)
{
sos_ui32_t flags;
sos_disable_IRQs(flags);
memcpy(& tick_resolution, resolution, sizeof(struct sos_time));
sos_restore_IRQs(flags);
return SOS_OK;
}
sos_ret_t sos_time_get_now(struct sos_time *now)
{
sos_ui32_t flags;
sos_disable_IRQs(flags);
memcpy(now, & last_tick_time, sizeof(struct sos_time));
sos_restore_IRQs(flags);
return SOS_OK;
}
/**
* Helper routine to add the action in the list. MUST be called with
* interrupts disabled !
*/
static sos_ret_t _add_action(struct sos_timeout_action *act,
const struct sos_time *due_date,
sos_bool_t is_relative_due_date,
sos_timeout_routine_t *routine,
void *routine_data)
{
struct sos_timeout_action *other, *insert_before;
int nb_act;
/* Delay must be specified */
if (due_date == NULL)
return -SOS_EINVAL;
/* Action container MUST be specified */
if (act == NULL)
return -SOS_EINVAL;
/* Refuse to add an empty action */
if (NULL == routine)
return -SOS_EINVAL;
/* Refuse to add the action if it is already added */
if (NULL != act->tmo_next)
return -SOS_EBUSY;
/* Compute action absolute due date */
if (is_relative_due_date)
{
/* The provided due_date is relative to the current time */
memcpy(& act->timeout, & last_tick_time, sizeof(struct sos_time));
sos_time_inc(& act->timeout, due_date);
}
else
{
/* The provided due_date is absolute (ie relative to the system
boot instant) */
if (sos_time_cmp(due_date, & last_tick_time) < 0)
/* Refuse to add a past action ! */
return -SOS_EINVAL;
memcpy(& act->timeout, due_date, sizeof(struct sos_time));
}
/* Prepare the action data structure */
act->routine = routine;
act->routine_data = routine_data;
/* Find the right place in the list of the timeout action. */
insert_before = NULL;
list_foreach_forward_named(timeout_action_list,
other, nb_act,
tmo_prev, tmo_next)
{
if (sos_time_cmp(& act->timeout, & other->timeout) < 0)
{
insert_before = other;
break;
}
/* Loop over to next timeout */
}
/* Now insert the action in the list */
if (insert_before != NULL)
list_insert_before_named(timeout_action_list, insert_before, act,
tmo_prev, tmo_next);
else
list_add_tail_named(timeout_action_list, act,
tmo_prev, tmo_next);
return SOS_OK;
}
sos_ret_t
sos_time_register_action_relative(struct sos_timeout_action *act,
const struct sos_time *delay,
sos_timeout_routine_t *routine,
void *routine_data)
{
sos_ui32_t flags;
sos_ret_t retval;
sos_disable_IRQs(flags);
retval = _add_action(act, delay, TRUE, routine, routine_data);
sos_restore_IRQs(flags);
return retval;
}
sos_ret_t
sos_time_register_action_absolute(struct sos_timeout_action *act,
const struct sos_time *date,
sos_timeout_routine_t *routine,
void *routine_data)
{
sos_ui32_t flags;
sos_ret_t retval;
sos_disable_IRQs(flags);
retval = _add_action(act, date, FALSE, routine, routine_data);
sos_restore_IRQs(flags);
return retval;
}
/**
* Helper routine to remove the action from the list. MUST be called
* with interrupts disabled !
*/
static sos_ret_t _remove_action(struct sos_timeout_action *act)
{
/* Don't do anything if action is not in timeout list */
if (NULL == act->tmo_next)
return -SOS_EINVAL;
/* Update the action's remaining timeout */
if (sos_time_cmp(& act->timeout, & last_tick_time) <= 0)
act->timeout = (struct sos_time){ .sec=0, .nanosec=0 };
else
sos_time_dec(& act->timeout, & last_tick_time);
/* Actually remove the action from the list */
list_delete_named(timeout_action_list, act,
tmo_prev, tmo_next);
act->tmo_prev = act->tmo_next = NULL;
return SOS_OK;
}
sos_ret_t sos_time_unregister_action(struct sos_timeout_action *act)
{
sos_ret_t retval;
sos_ui32_t flags;
sos_disable_IRQs(flags);
retval = _remove_action(act);
sos_restore_IRQs(flags);
return SOS_OK;
}
sos_ret_t sos_time_do_tick()
{
sos_ui32_t flags;
sos_disable_IRQs(flags);
/* Update kernel time */
sos_time_inc(& last_tick_time, & tick_resolution);
while (! list_is_empty_named(timeout_action_list, tmo_prev, tmo_next))
{
struct sos_timeout_action *act;
act = list_get_head_named(timeout_action_list, tmo_prev, tmo_next);
/* Did we go too far in the actions' list ? */
if (sos_time_cmp(& last_tick_time, & act->timeout) < 0)
{
/* Yes: No need to look further. */
break;
}
/* Remove the action from the list */
_remove_action(act);
/* Call the action's routine */
act->routine(act);
}
sos_restore_IRQs(flags);
return SOS_OK;
}
