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/* PIO IRQ Implementation for OpenPCD

 * (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>

 *  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 <sys/types.h>

#include <lib_AT91SAM7.h>

#include <string.h>

#include "pio_irq.h"

#include "dbgu.h"

//#include <os/req_ctx.h>

#include "openpicc.h"

#include "board.h"

#include "led.h"

#include <FreeRTOS.h>

#include <task.h>

struct pioirq_state {

	irq_handler_t *handlers[NR_PIO];

	u_int32_t usbmask;

	u_int32_t usb_throttled; /* atomic? */

};

static struct pioirq_state pirqs;

 * This code uses fast forcing for the PIOA irq so that each PIOA data change triggers

 * a FIQ. The FreeRTOS code has been modified to not mask FIQ ever. This means that the FIQ

 * code will run asynchronously with regards to the other code and especially might invade critical

 * sections. The actual FIQ code must therefore be as short as possible and may not call into the

 * FreeRTOS API (or parts of the application that call into the FreeRTOS API).

 * Instead a trick will be attempted: The PIOA IRQ will be set to fast forcing with my_fiq_handler

 * as handler and the FIQ handler then does the absolutely time critical tasks without calling any

 * other code. Additionally a second, normal IRQ handler is set up for a reserved IRQ on the AIC 

 * that is not connected to any peripherals (see #define of PIO_SECONDARY_IRQ). After handling

 * the time critical tasks the FIQ handler will then manually assert this IRQ which will then

 * be handled by the AIC and priority controller and also execute synchronized with regards to 

 * critical sections. 

 * Potential problem: look for race conditions between PIO data change FIQ and handling 

 * of PIO_SECONDARY_IRQ.

 * 

 * Note: Originally I wanted to use 15 for the PIO_SECONDARY_IRQ but it turns out that that

 * won't work (the identifier is marked as reserved). Use 31 (external IRQ1) instead. Another

 * candidate would be 7 (USART1).

 */

#define USE_FIQ

#define PIO_SECONDARY_IRQ 31

extern void fiq_handler(void);

/* Will be used in pio_irq_demux_secondary below and contains the PIO_ISR value 

 * from when the FIQ was raised */

 * by regular interrupt handler below */

	u_int8_t send_usb = 0;

	int i;

	DEBUGPCRF("PIO_ISR_STATUS = 0x%08x", pio);

	for (i = 0; i < NR_PIO; i++) {

		if (pio & (1 << i) && pirqs.handlers[i])

			send_usb = 1;

	}

	AT91F_AIC_AcknowledgeIt();

	//AT91F_AIC_ClearIt(AT91C_ID_PIOA);

/* regular interrupt handler, in case fast forcing for PIOA disabled */

static void pio_irq_demux(void)

	portBASE_TYPE xTaskWoken = pdFALSE;

	portEXIT_SWITCHING_ISR(xTaskWoken);

static void pio_irq_demux_secondary(void) __attribute__ ((naked));

static void pio_irq_demux_secondary(void)

{

	portBASE_TYPE xTaskWoken = pdFALSE;

	xTaskWoken = __pio_irq_demux(pio_irq_isr_value, xTaskWoken);

{

	AT91F_PIO_InterruptEnable(AT91C_BASE_PIOA, pio);

}

void pio_irq_disable(u_int32_t pio)

{

	AT91F_PIO_InterruptDisable(AT91C_BASE_PIOA, pio);

}

long pio_irq_get_count(void)

{

	return count;

}

{

	u_int8_t num = ffs(pio);

	if (num == 0)

		return -EINVAL;

	num--;

	if (pirqs.handlers[num])

		return -EBUSY;

	pio_irq_disable(pio);

	AT91F_PIO_CfgInput(AT91C_BASE_PIOA, pio);

	pirqs.handlers[num] = handler;

	DEBUGPCRF("registering handler %p for PIOA %u", handler, num);

	return 0;

}

void pio_irq_unregister(u_int32_t pio)

{

	u_int8_t num = ffs(pio);

	if (num == 0)

		return;

	num--;

	pio_irq_disable(pio);

	pirqs.handlers[num] = NULL;

}

void pio_irq_init_once(void)

{

	if(!initialized) pio_irq_init();

}

{

	the vector table, so no jump will happen. 

                              //0, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &cdsync_cb);

*/

        *AT91C_AIC_FFER = (1 << AT91C_ID_PIOA);

        /* Set up a regular IRQ handler to be triggered from within the FIQ */

	AT91F_AIC_ConfigureIt(PIO_SECONDARY_IRQ,

			      OPENPICC_IRQ_PRIO_PIO,

			      AT91C_AIC_SRCTYPE_INT_POSITIVE_EDGE, &pio_irq_demux_secondary);

        AT91F_AIC_ClearIt(PIO_SECONDARY_IRQ);

	AT91F_AIC_EnableIt(PIO_SECONDARY_IRQ);