tspdrv: add helper functions for high resolution timers

Signed-off-by: Humberto Borba <humberos@gmail.com>
Signed-off-by: Chirayu Desai <chirayudesai1@gmail.com>
Change-Id: Ie2a0977003224044e766ec64838a1f8fcab301b9

2 files changed, 241 insertions, 0 deletions

diff --git a/drivers/misc/tspdrv/VibeOSKernelLinuxHRTime.c b/drivers/misc/tspdrv/VibeOSKernelLinuxHRTime.c
new file mode 100644
index 0000000..bbd2fad
--- /dev/null
+++ b/drivers/misc/tspdrv/VibeOSKernelLinuxHRTime.c
@@ -0,0 +1,237 @@
+/*
+** =========================================================================
+** File:
+**     VibeOSKernelLinuxHRTime.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.
+*/
+
+/*
+#ifndef CONFIG_HIGH_RES_TIMERS
+#warning "The Kernel does not have high resolution timers enabled. Either provide a non hr-timer implementation of VibeOSKernelLinuxTime.c or re-compile your kernel with CONFIG_HIGH_RES_TIMERS=y"
+#endif
+*/
+
+#include <linux/hrtimer.h>
+#include <linux/mutex.h>
+
+#define WATCHDOG_TIMEOUT    10  /* 10 timer cycles = 50ms */
+
+/* Global variables */
+static bool g_bTimerStarted = false;
+static struct hrtimer g_tspTimer;
+static ktime_t g_ktFiveMs;
+static int g_nWatchdogCounter = 0;
+
+DEFINE_SEMAPHORE(g_hMutex);
+
+/* Forward declarations */
+static void VibeOSKernelLinuxStartTimer(void);
+static void VibeOSKernelLinuxStopTimer(void);
+static int VibeOSKernelProcessData(void* data);
+#define VIBEOSKERNELPROCESSDATA
+
+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)
+    {
+        if (VibeSemIsLocked(&g_hMutex))
+		up(&g_hMutex);
+    }
+
+    return HRTIMER_RESTART;
+}
+
+static int VibeOSKernelProcessData(void* data)
+{
+    int i;
+    int nActuatorNotPlaying = 0;
+
+    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))
+            {
+                VibeInt8 cZero[1] = {0};
+
+                /* Nothing to play for all actuators, turn off the timer when we reach the watchdog tick count limit */
+                ImmVibeSPI_ForceOut_SetSamples(i, 8, 1, cZero);
+                ImmVibeSPI_ForceOut_AmpDisable(i);
+                VibeOSKernelLinuxStopTimer();
+
+                /* Reset watchdog counter */
+                g_nWatchdogCounter = 0;
+            }
+        }
+        else
+        {
+            /* Play the current buffer */
+            if (VIBE_E_FAIL == ImmVibeSPI_ForceOut_SetSamples(
+                pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nActuatorIndex,
+                pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBitDepth,
+                pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize,
+                pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].dataBuffer))
+            {
+                /* VIBE_E_FAIL means NAK has been handled. Schedule timer to restart 5 ms from now */
+                hrtimer_forward_now(&g_tspTimer, g_ktFiveMs);
+            }
+
+            pCurrentActuatorSample->nIndexOutputValue += pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize;
+
+            if (pCurrentActuatorSample->nIndexOutputValue >= pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize)
+            {
+                /* Reach the end of the current buffer */
+                pCurrentActuatorSample->actuatorSamples[(int)pCurrentActuatorSample->nIndexPlayingBuffer].nBufferSize = 0;
+
+                /* Switch buffer */
+                (pCurrentActuatorSample->nIndexPlayingBuffer) ^= 1;
+                pCurrentActuatorSample->nIndexOutputValue = 0;
+
+                /* Finished playing, disable amp for actuator (i) */
+                if (g_bStopRequested)
+                {
+                    pCurrentActuatorSample->nIndexPlayingBuffer = -1;
+
+                    ImmVibeSPI_ForceOut_AmpDisable(i);
+                }
+            }
+        }
+    }
+
+    /* If finished playing, stop timer */
+    if (g_bStopRequested)
+    {
+        VibeOSKernelLinuxStopTimer();
+
+        /* Reset watchdog counter */
+        g_nWatchdogCounter = 0;
+
+        if (VibeSemIsLocked(&g_hMutex)) up(&g_hMutex);
+        return 1;   /* tell the caller this is the last iteration */
+    }
+
+    return 0;
+}
+
+static void VibeOSKernelLinuxInitTimer(void)
+{
+    /* Get a 5,000,000ns = 5ms time value */
+    g_ktFiveMs = ktime_set(0, 5000000);
+
+    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;
+            }
+        }
+    }
+
+    if (0 != VibeOSKernelProcessData(NULL)) 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();
+    if (VibeSemIsLocked(&g_hMutex)) up(&g_hMutex);
+}
diff --git a/drivers/misc/tspdrv/tspdrv.c b/drivers/misc/tspdrv/tspdrv.c
index cf8cd24..c1bfe83 100644
--- a/drivers/misc/tspdrv/tspdrv.c
+++ b/drivers/misc/tspdrv/tspdrv.c
@@ -86,7 +86,11 @@ static VibeInt8 g_nForceLog[FORCE_LOG_BUFFER_SIZE];
 #endif
 
 /* Needs to be included after the global variables because it uses them */
+#ifdef CONFIG_HIGH_RES_TIMERS
+#include "VibeOSKernelLinuxHRTime.c"
+#else
 #include "VibeOSKernelLinuxTime.c"
+#endif
 
 /* timed_output */
 #if defined(CONFIG_PHONE_P1_GSM)