/**
 ******************************************************************************
 * @addtogroup OpenPilotModules OpenPilot Modules
 * @{ 
 * @addtogroup TelemetryModule Telemetry Module
 * @brief Main telemetry module
 * Starts three tasks (RX, TX, and priority TX) that watch event queues
 * and handle all the telemetry of the UAVobjects
 * @{ 
 *
 * @file       telemetry.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      Telemetry module, handles telemetry and UAVObject updates
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * 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 3 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 "openpilot.h"
#include "overosync.h"
#include "overosyncstats.h"
#include "systemstats.h"

// Private constants
#define OVEROSYNC_PACKET_SIZE 1024
#define MAX_QUEUE_SIZE   10
#define STACK_SIZE_BYTES 4096
#define TASK_PRIORITY (tskIDLE_PRIORITY + 0)

// Private types

// Private variables
static xQueueHandle queue;
static UAVTalkConnection uavTalkCon;
static xTaskHandle overoSyncTaskHandle;
volatile bool buffer_swap_failed;
volatile uint32_t buffer_swap_timeval;

// Private functions
static void overoSyncTask(void *parameters);
static int32_t packData(uint8_t * data, int32_t length);
static int32_t transmitData();
static void transmitDataDone(bool crc_ok, uint8_t crc_val);
static void registerObject(UAVObjHandle obj);

// External variables
extern int32_t pios_spi_overo_id;

struct dma_transaction {
	uint8_t tx_buffer[OVEROSYNC_PACKET_SIZE] __attribute__ ((aligned(4)));
	uint8_t rx_buffer[OVEROSYNC_PACKET_SIZE] __attribute__ ((aligned(4)));
};

struct overosync {
	struct dma_transaction transactions[2];
	uint32_t active_transaction_id;
	uint32_t loading_transaction_id;
	xSemaphoreHandle transaction_lock;
	xSemaphoreHandle buffer_lock;
	volatile bool transaction_done;
	uint32_t sent_bytes;
	uint32_t write_pointer;
	uint32_t sent_objects;
	uint32_t failed_objects;
	uint32_t received_objects;
	uint32_t framesync_error;
};

struct overosync *overosync;

static void PIOS_OVERO_IRQHandler();

static const struct pios_exti_cfg pios_exti_overo_cfg __exti_config = {
	.vector = PIOS_OVERO_IRQHandler,
	.line = EXTI_Line15,
	.pin = {
		.gpio = GPIOA,
		.init = {
			.GPIO_Pin = GPIO_Pin_15,
			.GPIO_Speed = GPIO_Speed_100MHz,
			.GPIO_Mode = GPIO_Mode_IN,
			.GPIO_OType = GPIO_OType_OD,
			.GPIO_PuPd = GPIO_PuPd_NOPULL,
		},
	},
	.irq = {
		.init = {
			.NVIC_IRQChannel = EXTI15_10_IRQn,
			.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID,
			.NVIC_IRQChannelSubPriority = 0,
			.NVIC_IRQChannelCmd = ENABLE,
		},
	},
	.exti = {
		.init = {
			.EXTI_Line = EXTI_Line15, // matches above GPIO pin
			.EXTI_Mode = EXTI_Mode_Interrupt,
			.EXTI_Trigger = EXTI_Trigger_Rising,
			.EXTI_LineCmd = ENABLE,
		},
	},
};

/**
 * On the rising edge of NSS schedule a new transaction.  This cannot be
 * done by the DMA complete because there is 150 us between that and the
 * Overo deasserting the CS line.  We don't want to spin that long in an
 * isr
 */
void PIOS_OVERO_IRQHandler()
{
	// transmitData must not block to get semaphore for when we get out of
	// frame and transaction is still running here.  -1 indicates the transaction
	// semaphore is blocked and we are still in a transaction, thus a framesync
	// error occurred.  This shouldn't happen.  Race condition?
	if(transmitData() == -1)
		overosync->framesync_error++;
}

/**
 * Initialise the telemetry module
 * \return -1 if initialisation failed
 * \return 0 on success
 */
int32_t OveroSyncInitialize(void)
{
	if(pios_spi_overo_id == 0)
		return -1;
	
	OveroSyncStatsInitialize();

	PIOS_EXTI_Init(&pios_exti_overo_cfg);
	// Create object queues
	queue = xQueueCreate(MAX_QUEUE_SIZE, sizeof(UAVObjEvent));

	// Initialise UAVTalk
	uavTalkCon = UAVTalkInitialize(&packData);

	return 0;
}

/**
 * Initialise the telemetry module
 * \return -1 if initialisation failed
 * \return 0 on success
 */
int32_t OveroSyncStart(void)
{
	if(pios_spi_overo_id == 0)
		return -1;

	overosync = (struct overosync *) pvPortMalloc(sizeof(*overosync));
	if(overosync == NULL)
		return -1;

	overosync->transaction_lock = xSemaphoreCreateMutex();
	if(overosync->transaction_lock == NULL)
		return -1;

	overosync->buffer_lock = xSemaphoreCreateMutex();
	if(overosync->buffer_lock == NULL)
		return -1;

	overosync->active_transaction_id = 0;
	overosync->loading_transaction_id = 0;
	overosync->write_pointer = 0;
	overosync->sent_bytes = 0;
	overosync->framesync_error = 0;

	// Process all registered objects and connect queue for updates
	UAVObjIterate(&registerObject);
	
	// Start telemetry tasks
	xTaskCreate(overoSyncTask, (signed char *)"OveroSync", STACK_SIZE_BYTES/4, NULL, TASK_PRIORITY, &overoSyncTaskHandle);
	
	TaskMonitorAdd(TASKINFO_RUNNING_OVEROSYNC, overoSyncTaskHandle);
	
	return 0;
}

MODULE_INITCALL(OveroSyncInitialize, OveroSyncStart)

/**
 * Register a new object, adds object to local list and connects the queue depending on the object's
 * telemetry settings.
 * \param[in] obj Object to connect
 */
static void registerObject(UAVObjHandle obj)
{
	int32_t eventMask;
	eventMask = EV_UPDATED | EV_UPDATED_MANUAL | EV_UPDATE_REQ;
	if (UAVObjIsMetaobject(obj)) {
		eventMask |= EV_UNPACKED;	// we also need to act on remote updates (unpack events)
	}
	UAVObjConnectQueue(obj, queue, eventMask);
}

/**
 * Telemetry transmit task, regular priority
 *
 * Logic: We need to double buffer the DMA transfers.  Pack the buffer until either
 * 1) it is full (and then we should record the number of missed events then)
 * 2) the current transaction is done (we should immediately schedule since we are slave)
 * when done packing the buffer we should call PIOS_SPI_TransferBlock, change the active buffer
 * and then take the semaphrore
 */
static void overoSyncTask(void *parameters)
{
	UAVObjEvent ev;

	// Kick off SPI transfers (once one is completed another will automatically transmit)
	overosync->transaction_done = true;
	overosync->sent_objects = 0;
	overosync->failed_objects = 0;
	overosync->received_objects = 0;
	
	portTickType lastUpdateTime = xTaskGetTickCount();
	portTickType updateTime;
	
	// Loop forever
	while (1) {
		// Wait for queue message
		if (xQueueReceive(queue, &ev, portMAX_DELAY) == pdTRUE) {
			// Process event.  This calls transmitData
			UAVTalkSendObject(uavTalkCon, ev.obj, ev.instId, false, 0);

			updateTime = xTaskGetTickCount();
			if(((portTickType) (updateTime - lastUpdateTime)) > 1000) {
				// Update stats.  This will trigger a local send event too
				OveroSyncStatsData syncStats;
				syncStats.Send = overosync->sent_bytes;
				syncStats.Received = 0;
				syncStats.Connected = syncStats.Send > 500 ? OVEROSYNCSTATS_CONNECTED_TRUE : OVEROSYNCSTATS_CONNECTED_FALSE;
				syncStats.DroppedUpdates = overosync->failed_objects;
				OveroSyncStatsSet(&syncStats);
				overosync->failed_objects = 0;
				overosync->sent_bytes = 0;
				lastUpdateTime = updateTime;
			}
		}
	}
}

static void transmitDataDone(bool crc_ok, uint8_t crc_val)
{
	uint8_t *rx_buffer;
	static signed portBASE_TYPE xHigherPriorityTaskWoken;

	rx_buffer = overosync->transactions[overosync->active_transaction_id].rx_buffer;

	// Release the semaphore and start another transaction (which grabs semaphore again but then
	// returns instantly).  Because this is called by the DMA ISR we need to be aware of context
	// switches.
	xSemaphoreGiveFromISR(overosync->transaction_lock, &xHigherPriorityTaskWoken);
	portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);

	overosync->transaction_done = true;
	
	// Parse the data from overo
	for (uint32_t i = 0; rx_buffer[0] != 0 && i < sizeof(rx_buffer) ; i++)
		UAVTalkProcessInputStream(uavTalkCon, rx_buffer[i]);
}

/**
 * Transmit data buffer to the modem or USB port.
 * \param[in] data Data buffer to send
 * \param[in] length Length of buffer
 * \return -1 on failure
 * \return number of bytes transmitted on success
 */
uint32_t too_long = 0;
static int32_t packData(uint8_t * data, int32_t length)
{
	uint8_t *tx_buffer;
	
	portTickType tickTime = xTaskGetTickCount();

	// Get the lock for manipulating the buffer
	xSemaphoreTake(overosync->buffer_lock, portMAX_DELAY);

	// Check this packet will fit
	if ((overosync->write_pointer + length + sizeof(tickTime)) >
		sizeof(overosync->transactions[overosync->loading_transaction_id].tx_buffer)) {
		overosync->failed_objects ++;
		xSemaphoreGive(overosync->buffer_lock);
		return -1;
	}

	// Get offset into buffer and copy contents
	tx_buffer = overosync->transactions[overosync->loading_transaction_id].tx_buffer +
		overosync->write_pointer;
	memcpy(tx_buffer, &tickTime, sizeof(tickTime));
	memcpy(tx_buffer + sizeof(tickTime),data,length);
	overosync->write_pointer += length + sizeof(tickTime);
	overosync->sent_bytes += length;
	overosync->sent_objects++;

	xSemaphoreGive(overosync->buffer_lock);
	
	// When the NSS line rises while we are packing data then a transaction doesn't start
	// because that means we will be here very shortly afterwards (priority of task making that
	// not always perfectly true) schedule the transaction here.
	if (buffer_swap_failed && (PIOS_DELAY_DiffuS(buffer_swap_timeval) < 50)) {
		buffer_swap_failed = false;
		transmitData();
	} else if (buffer_swap_failed) {
		buffer_swap_failed = false;
		too_long++;
	}

	return length;
}

static int32_t transmitData()
{
	uint8_t *tx_buffer, *rx_buffer;
	static signed portBASE_TYPE xHigherPriorityTaskWoken;

	// Get this lock first so we don't swap buffers and then fail
	// to start
	if (xSemaphoreTake(overosync->transaction_lock, 0) == pdFALSE)
		return -1;

	// Get lock to manipulate buffers
	if(xSemaphoreTake(overosync->buffer_lock, 0) == pdFALSE) {
		xSemaphoreGiveFromISR(overosync->transaction_lock, &xHigherPriorityTaskWoken);
		portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);
		buffer_swap_failed = true;
		buffer_swap_timeval = PIOS_DELAY_GetRaw();
		return -2;
	}

	overosync->transaction_done = false;

	// Swap buffers
	overosync->active_transaction_id = overosync->loading_transaction_id;
	overosync->loading_transaction_id = (overosync->loading_transaction_id + 1) % 
		NELEMENTS(overosync->transactions);
		
	tx_buffer = overosync->transactions[overosync->active_transaction_id].tx_buffer;
	rx_buffer = overosync->transactions[overosync->active_transaction_id].rx_buffer;
	
	// Prepare the new loading buffer
	memset(overosync->transactions[overosync->loading_transaction_id].tx_buffer, 0xff, 
		   sizeof(overosync->transactions[overosync->loading_transaction_id].tx_buffer));
	overosync->write_pointer = 0;

	xSemaphoreGiveFromISR(overosync->buffer_lock, &xHigherPriorityTaskWoken);
	portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);

	return PIOS_SPI_TransferBlock(pios_spi_overo_id, (uint8_t *) tx_buffer, (uint8_t *) rx_buffer, sizeof(overosync->transactions[overosync->active_transaction_id].tx_buffer), &transmitDataDone) == 0 ? 0 : -3;
}

/**
  * @}
  * @}
  */