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/*
** =========================================================================
** File:
** VibeOSKernelLinuxTime.c
**
** Description:
** High Resolution Time helper functions for Linux.
**
** Portions Copyright (c) 2010 Immersion Corporation. All Rights Reserved.
**
** P1 Compat Author: Humberto Borba <kernel@humberos.com.br>
**
** This file contains Original Code and/or Modifications of Original Code
** as defined in and that are subject to the GNU Public License v2 -
** (the 'License'). You may not use this file except in compliance with the
** License. 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.,
** 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or contact
** TouchSenseSales@immersion.com.
**
** The Original Code and all software distributed under the License are
** distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
** EXPRESS OR IMPLIED, AND IMMERSION HEREBY DISCLAIMS ALL SUCH WARRANTIES,
** INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
** FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see
** the License for the specific language governing rights and limitations
** under the License.
** =========================================================================
*/
/*
** Kernel high-resolution software timer is used as an example but another type
** of timer (such as HW timer or standard software timer) might be used to achieve
** the 5ms required rate.
*/
#include <linux/hrtimer.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#define WATCHDOG_TIMEOUT 10 /* 10 timer cycles = 50ms */
/* Global variables */
static bool g_bTimerThreadStarted = false;
static bool g_bTimerStarted = false;
static struct hrtimer g_tspTimer;
static ktime_t g_ktFiveMs;
struct task_struct *g_pTspThread;
static int g_nWatchdogCounter = 0;
DECLARE_COMPLETION(g_tspCompletion);
DEFINE_SEMAPHORE(g_hMutex);
/* Forward declarations */
static void VibeOSKernelLinuxStartTimer(void);
static void VibeOSKernelLinuxStopTimer(void);
/**
* VibeSemIsLocked - is the semaphore locked
* @lock: the semaphore to be queried
*
* Returns 1 if the semaphore is locked, 0 if unlocked.
*/
static inline int VibeSemIsLocked(struct semaphore *lock)
{
#if ((LINUX_VERSION_CODE & 0xFFFFFF) < KERNEL_VERSION(2,6,27))
return atomic_read(&lock->count) != 1;
#else
return (lock->count) != 1;
#endif
}
static enum hrtimer_restart tsp_timer_interrupt(struct hrtimer *timer)
{
/* Scheduling next timeout value right away */
hrtimer_forward_now(timer, g_ktFiveMs);
if (g_bTimerStarted) {
/* Notifying the handler of this timer of the tick */
/* This allows us to perform operations that are usually */
/* not allowed inside interrupt context, such as locking */
/* a mutex, etc. */
complete(&g_tspCompletion);
}
return HRTIMER_RESTART;
}
static int VibeOSKernelTimerProc(void* data)
{
int nActuatorNotPlaying;
int i;
int bReachEndBuffer = 0;
while (!kthread_should_stop()) {
if (g_bTimerThreadStarted) {
/* Block until we get woken up by timer tick */
/* . only do this if we're not exiting entirely */
wait_for_completion(&g_tspCompletion);
/* Reinitialized completion so it isn't free by default */
init_completion(&g_tspCompletion);
}
nActuatorNotPlaying = 0;
/* Return right away if timer is not supposed to run */
if (g_bTimerStarted) {
for (i = 0; i < NUM_ACTUATORS; i++) {
actuator_samples_buffer *pCurrentActuatorSample = &(g_SamplesBuffer[i]);
if (-1 == pCurrentActuatorSample->nIndexPlayingBuffer) {
nActuatorNotPlaying++;
if ((NUM_ACTUATORS == nActuatorNotPlaying) && ((++g_nWatchdogCounter) > WATCHDOG_TIMEOUT)) {
/*
Nothing to play for all actuators,
turn off the timer when we reach the watchdog tick count limit
*/
ImmVibeSPI_ForceOut_Set(i, 0);
ImmVibeSPI_ForceOut_AmpDisable(i);
VibeOSKernelLinuxStopTimer();
/* Reset watchdog counter */
g_nWatchdogCounter = 0;
}
} else {
/* Play the current buffer */
ImmVibeSPI_ForceOut_Set(i, pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].dataBuffer[(int)(pCurrentActuatorSample->nIndexOutputValue++)]);
if (pCurrentActuatorSample->nIndexOutputValue >= pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize) {
/* We were playing in the last tick */
/* Reach the end of the current buffer */
pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize = 0;
bReachEndBuffer = 1;
/* Check stop request and empty buffer */
if ((g_bStopRequested) || (0 == (pCurrentActuatorSample->actuatorSamples[(int)((pCurrentActuatorSample->nIndexPlayingBuffer) ^ 1)].nBufferSize))) {
pCurrentActuatorSample->nIndexPlayingBuffer = -1;
if (g_bStopRequested) {
/* g_bStopReqested is set, so turn off all actuators */
ImmVibeSPI_ForceOut_Set(i, 0);
ImmVibeSPI_ForceOut_AmpDisable(i);
/* If it's the last actuator, stop the timer */
if (i == (NUM_ACTUATORS-1)) {
VibeOSKernelLinuxStopTimer();
/* Reset watchdog counter */
g_nWatchdogCounter = 0;
}
}
} else { /* The other buffer has data in it */
/* Switch buffer */
(pCurrentActuatorSample->nIndexPlayingBuffer) ^= 1;
pCurrentActuatorSample->nIndexOutputValue = 0;
}
}
}
}
/* Release the mutex if locked */
if (bReachEndBuffer && VibeSemIsLocked(&g_hMutex)) {
up(&g_hMutex);
}
}
}
return 0;
}
static void VibeOSKernelLinuxInitTimer(void)
{
/* Get a 5,000,000ns = 5ms time value */
g_ktFiveMs = ktime_set(0, 5000000);
/* Start the companion thread. It's controlled by the timer, so when that is stopped, we're OK. */
g_bTimerThreadStarted = true;
g_pTspThread = kthread_run(VibeOSKernelTimerProc, NULL, "TouchSense Player Thread");
hrtimer_init(&g_tspTimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
/* Initialize a 5ms-timer with tsp_timer_interrupt as timer callback (interrupt driven)*/
g_tspTimer.function = tsp_timer_interrupt;
}
static void VibeOSKernelLinuxStartTimer(void)
{
int i;
int res;
/* Reset watchdog counter */
g_nWatchdogCounter = 0;
if (!g_bTimerStarted) {
if (!VibeSemIsLocked(&g_hMutex))
res = down_interruptible(&g_hMutex); /* start locked */
g_bTimerStarted = true;
/* Start the timer */
hrtimer_start(&g_tspTimer, g_ktFiveMs, HRTIMER_MODE_REL);
/* Don't block the write() function after the first sample to allow the host sending the next samples with no delay */
for (i = 0; i < NUM_ACTUATORS; i++) {
if ((g_SamplesBuffer[i].actuatorSamples[0].nBufferSize) || (g_SamplesBuffer[i].actuatorSamples[1].nBufferSize)) {
g_SamplesBuffer[i].nIndexOutputValue = 0;
return;
}
}
}
/*
** Use interruptible version of down to be safe
** (try to not being stuck here if the mutex is not freed for any reason)
*/
res = down_interruptible(&g_hMutex); /* wait for the mutex to be freed by the timer */
if (res != 0)
DbgOut((KERN_INFO "VibeOSKernelLinuxStartTimer: down_interruptible interrupted by a signal.\n"));
}
static void VibeOSKernelLinuxStopTimer(void)
{
int i;
if (g_bTimerStarted) {
g_bTimerStarted = false;
hrtimer_cancel(&g_tspTimer);
}
/* Reset samples buffers */
for (i = 0; i < NUM_ACTUATORS; i++) {
g_SamplesBuffer[i].nIndexPlayingBuffer = -1;
g_SamplesBuffer[i].actuatorSamples[0].nBufferSize = 0;
g_SamplesBuffer[i].actuatorSamples[1].nBufferSize = 0;
}
g_bStopRequested = false;
g_bIsPlaying = false;
}
static void VibeOSKernelLinuxTerminateTimer(void)
{
VibeOSKernelLinuxStopTimer();
g_bTimerThreadStarted = false;
complete_all(&g_tspCompletion);
kthread_stop(g_pTspThread);
if (VibeSemIsLocked(&g_hMutex))
up(&g_hMutex);
}
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