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/* PIO IRQ Implementation for OpenPCD
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* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
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* (C) 2007 Henryk Plötz <henryk@ploetzli.ch>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "FreeRTOS.h"
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#include <errno.h>
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#include <sys/types.h>
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#include <lib_AT91SAM7.h>
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#include <string.h>
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#include "pio_irq.h"
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#include "dbgu.h"
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//#include <os/req_ctx.h>
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#include "openpicc.h"
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#include "board.h"
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#include "led.h"
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#include <FreeRTOS.h>
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#include <task.h>
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struct pioirq_state {
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irq_handler_t *handlers[NR_PIO];
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u_int32_t usbmask;
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u_int32_t usb_throttled; /* atomic? */
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};
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static struct pioirq_state pirqs;
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static unsigned long count = 0;
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/* This FIQ implementation of pio data change works in close cooperation with function fiq_handler
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* in os/boot/boot.s
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* This code uses fast forcing for the PIOA irq so that each PIOA data change triggers
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* a FIQ. The FreeRTOS code has been modified to not mask FIQ ever. This means that the FIQ
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* code will run asynchronously with regards to the other code and especially might invade critical
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* sections. The actual FIQ code must therefore be as short as possible and may not call into the
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* FreeRTOS API (or parts of the application that call into the FreeRTOS API).
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* Instead a trick will be attempted: The PIOA IRQ will be set to fast forcing with my_fiq_handler
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* as handler and the FIQ handler then does the absolutely time critical tasks without calling any
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* other code. Additionally a second, normal IRQ handler is set up for a reserved IRQ on the AIC
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* that is not connected to any peripherals (see #define of PIO_SECONDARY_IRQ). After handling
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* the time critical tasks the FIQ handler will then manually assert this IRQ which will then
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* be handled by the AIC and priority controller and also execute synchronized with regards to
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* critical sections.
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* Potential problem: look for race conditions between PIO data change FIQ and handling
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* of PIO_SECONDARY_IRQ.
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*
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* Note: Originally I wanted to use 15 for the PIO_SECONDARY_IRQ but it turns out that that
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* won't work (the identifier is marked as reserved). Use 31 (external IRQ1) instead. Another
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* candidate would be 7 (USART1).
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*/
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#define USE_FIQ
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#define PIO_SECONDARY_IRQ 31
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extern void fiq_handler(void);
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/* Will be used in pio_irq_demux_secondary below and contains the PIO_ISR value
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* from when the FIQ was raised */
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volatile u_int32_t pio_irq_isr_value;
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/* low-level handler, used by Cstartup_app.S PIOA fast forcing and
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* by regular interrupt handler below */
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portBASE_TYPE __ramfunc __pio_irq_demux(u_int32_t pio, portBASE_TYPE xTaskWoken)
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{
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u_int8_t send_usb = 0;
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int i;
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count++;
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DEBUGPCRF("PIO_ISR_STATUS = 0x%08x", pio);
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for (i = 0; i < NR_PIO; i++) {
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if (pio & (1 << i) && pirqs.handlers[i])
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xTaskWoken = pirqs.handlers[i](i, xTaskWoken);
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if (pirqs.usbmask & (1 << i))
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send_usb = 1;
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}
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AT91F_AIC_AcknowledgeIt();
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//AT91F_AIC_ClearIt(AT91C_ID_PIOA);
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return xTaskWoken;
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}
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/* regular interrupt handler, in case fast forcing for PIOA disabled */
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static void pio_irq_demux(void) __attribute__ ((naked));
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static void pio_irq_demux(void)
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{
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portENTER_SWITCHING_ISR();
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portBASE_TYPE xTaskWoken = pdFALSE;
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u_int32_t pio = AT91F_PIO_GetInterruptStatus(AT91C_BASE_PIOA);
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xTaskWoken = __pio_irq_demux(pio, xTaskWoken);
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portEXIT_SWITCHING_ISR(xTaskWoken);
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}
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/* nearly regular interrupt handler, in case fast forcing for PIOA is enabled and the secondary irq hack used */
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static void pio_irq_demux_secondary(void) __attribute__ ((naked));
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static void pio_irq_demux_secondary(void)
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{
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portENTER_SWITCHING_ISR();
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portBASE_TYPE xTaskWoken = pdFALSE;
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xTaskWoken = __pio_irq_demux(pio_irq_isr_value, xTaskWoken);
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AT91F_AIC_ClearIt(PIO_SECONDARY_IRQ);
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portEXIT_SWITCHING_ISR(xTaskWoken);
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}
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void pio_irq_enable(u_int32_t pio)
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{
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AT91F_PIO_InterruptEnable(AT91C_BASE_PIOA, pio);
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}
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void pio_irq_disable(u_int32_t pio)
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{
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AT91F_PIO_InterruptDisable(AT91C_BASE_PIOA, pio);
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}
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/* Return the number of PIO IRQs received */
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long pio_irq_get_count(void)
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{
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return count;
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}
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int pio_irq_register(u_int32_t pio, irq_handler_t *handler)
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{
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u_int8_t num = ffs(pio);
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if (num == 0)
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return -EINVAL;
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num--;
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if (pirqs.handlers[num])
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return -EBUSY;
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pio_irq_disable(pio);
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AT91F_PIO_CfgInput(AT91C_BASE_PIOA, pio);
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pirqs.handlers[num] = handler;
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DEBUGPCRF("registering handler %p for PIOA %u", handler, num);
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return 0;
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}
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void pio_irq_unregister(u_int32_t pio)
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{
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u_int8_t num = ffs(pio);
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if (num == 0)
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return;
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num--;
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pio_irq_disable(pio);
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pirqs.handlers[num] = NULL;
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}
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static int initialized = 0;
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void pio_irq_init_once(void)
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{
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if(!initialized) pio_irq_init();
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}
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void pio_irq_init(void)
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{
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initialized = 1;
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AT91F_PIOA_CfgPMC();
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#ifdef USE_FIQ
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/* This code is not necessary anymore, because fiq_handler is directly part of
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the vector table, so no jump will happen.
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AT91F_AIC_ConfigureIt(AT91C_ID_FIQ,
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//0, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &cdsync_cb);
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0, AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &fiq_handler);
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*/
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/* enable fast forcing for PIOA interrupt */
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*AT91C_AIC_FFER = (1 << AT91C_ID_PIOA);
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/* Set up a regular IRQ handler to be triggered from within the FIQ */
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AT91F_AIC_ConfigureIt(PIO_SECONDARY_IRQ,
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OPENPICC_IRQ_PRIO_PIO,
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AT91C_AIC_SRCTYPE_INT_POSITIVE_EDGE, &pio_irq_demux_secondary);
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AT91F_AIC_ClearIt(PIO_SECONDARY_IRQ);
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AT91F_AIC_EnableIt(PIO_SECONDARY_IRQ);
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#else
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AT91F_AIC_ConfigureIt(AT91C_ID_PIOA,
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OPENPICC_IRQ_PRIO_PIO,
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AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL, &pio_irq_demux);
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#endif
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AT91F_AIC_EnableIt(AT91C_ID_PIOA);
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(void)pio_irq_demux; // FIXME NO IRQ
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}
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