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/******************************************************************************

**

** (C) Copyright 2017 DFC Design, s.r.o., Brno, Czech Republic

** Author: Marek Kvas (m.kvas@dspfpga.com)

**

****************************************************************************

**

** This file is part of Xenia Ethernet Example project.

**

** Xenia Ethernet Example project is free software: you can

** redistribute it and/or modify it under the terms of

** the GNU Lesser General Public License as published by the Free

** Software Foundation, either version 3 of the License, or

** (at your option) any later version.

**

** Xenia Ethernet Example project 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 Lesser General Public License

** for more details.

**

** You should have received a copy of the GNU Lesser General Public

** License along with Xenia Ethernet Example project.  If not,

** see <http://www.gnu.org/licenses/>.

****************************************************************************

*/

#include "timers.h"

#define PERIODIC_TIMER_NO       0

#define ONE_SHOT_TIMER_NO   1

#define PERIODIC_TIMER_RST_VAL (0xffffffff - (TIMER_FREQ/1000)) /* ms */

/* internal clock with millisecond step */

static volatile u32 ms_time = 0;

static volatile int one_shot_flag = 0;

static XTmrCtr* TmrCtrInst;

u32 timers_ms_now()

{

        return ms_time;

}

u32 Timers_ms_elapsed(u32 start)

{

        u32 now;

        now = timers_ms_now();

        return timers_ms_diff(start, now);

}

u32 timers_ms_diff(u32 start, u32 stop)

{

        u32 elapsed;

        if (stop >= start)

                elapsed = (stop - start);

        else

                elapsed = 0xffffffff - (start - stop);

        return elapsed;

}

u32 timers_ms_elapsed_update(u32 *start)

{

        u32 now;

        u32 elapsed;

        now = timers_ms_now();

        elapsed = timers_ms_diff(now, *start);

        *start = now;

        return elapsed;

}

/* Timers handler */

void timers_Handler(void *CallBackRef, u8 TmrCtrNumber)

{

        XTmrCtr *InstancePtr = (XTmrCtr *)CallBackRef;

        /* service the periodic counter */

        if (XTmrCtr_IsExpired(InstancePtr, PERIODIC_TIMER_NO)) {

                ms_time++;

        }

}

/* Initialize timers (interrupts are already set */

int timers_init(XTmrCtr* TmrCtrInstancePtr, u16 DeviceId)

{

        int Status;

        TmrCtrInst = TmrCtrInstancePtr;

        /*

         * Initialize the timer counter so that it's ready to use,

         * specify the device ID that is generated in xparameters.h

         */

        Status = XTmrCtr_Initialize(TmrCtrInst, DeviceId);

        if (Status != XST_SUCCESS) {

                return XST_FAILURE;

        }

        /*

         * Setup the handler for both halfs of timer

         */

        XTmrCtr_SetHandler(TmrCtrInst, timers_Handler,

                        TmrCtrInst);

        /*

         * Enable the interrupt

         */

        /* Set up periodic counter */

        XTmrCtr_SetOptions(TmrCtrInst, PERIODIC_TIMER_NO,

                                XTC_INT_MODE_OPTION | XTC_AUTO_RELOAD_OPTION);

        /* Set reset value determining timer period */

        XTmrCtr_SetResetValue(TmrCtrInst, PERIODIC_TIMER_NO, PERIODIC_TIMER_RST_VAL);

        /* Set up one-shot counter */

        XTmrCtr_SetOptions(TmrCtrInst, ONE_SHOT_TIMER_NO,

                        XTC_DOWN_COUNT_OPTION/*XTC_INT_MODE_OPTION*/);

        /*

         * Start the timer counter such that it's incrementing by default

         */

        XTmrCtr_Start(TmrCtrInst, PERIODIC_TIMER_NO);

        return XST_SUCCESS;

}

void timers_udelay(u32 usDelay)

{

        u32 timer_preset;

        /* calculate preset value */

        timer_preset = (TIMER_FREQ/1000000) * usDelay; /* us */

        /* Set counter initial value */

        XTmrCtr_SetResetValue(TmrCtrInst, ONE_SHOT_TIMER_NO, timer_preset);

        /* Start timer */

        XTmrCtr_Start(TmrCtrInst, ONE_SHOT_TIMER_NO);

        /* Wait for timer to elapse */

        while (XTmrCtr_GetValue(TmrCtrInst, ONE_SHOT_TIMER_NO));

}