tinySA/os/hal/platforms/AT91SAM7/hal_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012,2013 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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.

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

/**
 * @file    AT91SAM7/hal_lld.c
 * @brief   AT91SAM7 HAL subsystem low level driver source.
 *
 * @addtogroup HAL
 * @{
 */

#include "ch.h"
#include "hal.h"

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

static CH_IRQ_HANDLER(spurious_handler) {

  CH_IRQ_PROLOGUE();

  AT91SAM7_SPURIOUS_HANDLER_HOOK();

  AT91C_BASE_AIC->AIC_EOICR = 0;

  CH_IRQ_EPILOGUE();
}

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level HAL driver initialization.
 *
 * @notapi
 */
void hal_lld_init(void) {
  unsigned i;

  /* FIQ Handler weak symbol defined in vectors.s.*/
  void FiqHandler(void);

  /* Default AIC setup, the device drivers will modify it as needed.*/
  AT91C_BASE_AIC->AIC_ICCR = 0xFFFFFFFF;
  AT91C_BASE_AIC->AIC_IDCR = 0xFFFFFFFF;
  AT91C_BASE_AIC->AIC_SVR[0] = (AT91_REG)FiqHandler;
  for (i = 1; i < 31; i++) {
    AT91C_BASE_AIC->AIC_SVR[i] = (AT91_REG)NULL;
    AT91C_BASE_AIC->AIC_EOICR = (AT91_REG)i;
  }
  AT91C_BASE_AIC->AIC_SPU  = (AT91_REG)spurious_handler;

}

/**
 * @brief   AT91SAM7 clocks and PLL initialization.
 * @note    All the involved constants come from the file @p board.h.
 * @note    This function must be invoked only after the system reset.
 *
 * @special
 */
void at91sam7_clock_init(void) {

  /* wait for reset */
  while((AT91C_BASE_RSTC->RSTC_RSR & (AT91C_RSTC_SRCMP | AT91C_RSTC_NRSTL)) != AT91C_RSTC_NRSTL)
    ;
  /* enable reset */
  AT91C_BASE_RSTC->RSTC_RMR = ((0xA5 << 24) | AT91C_RSTC_URSTEN);

  /* Flash Memory: 1 wait state, about 50 cycles in a microsecond.*/
#if SAM7_PLATFORM == SAM7X512
  AT91C_BASE_MC->MC0_FMR = (AT91C_MC_FMCN & (50 << 16)) | AT91C_MC_FWS_1FWS;
  AT91C_BASE_MC->MC1_FMR = (AT91C_MC_FMCN & (50 << 16)) | AT91C_MC_FWS_1FWS;
#else
  AT91C_BASE_MC->MC_FMR = (AT91C_MC_FMCN & (50 << 16)) | AT91C_MC_FWS_1FWS;
#endif

  /* Enables the main oscillator and waits 56 slow cycles as startup time.*/
  AT91C_BASE_PMC->PMC_MOR = (AT91C_CKGR_OSCOUNT & (7 << 8)) | AT91C_CKGR_MOSCEN;
  while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS))
    ;

  /* PLL setup: DIV = 14, MUL = 72, PLLCOUNT = 10
     PLLfreq = 96109714 Hz (rounded).*/
  AT91C_BASE_PMC->PMC_PLLR = (AT91C_CKGR_DIV & 14) |
                             (AT91C_CKGR_PLLCOUNT & (10 << 8)) |
                             (AT91SAM7_USBDIV) |
                             (AT91C_CKGR_MUL & (72 << 16));
  while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK))
    ;

  /* Master clock = PLLfreq / 2 = 48054858 Hz (rounded).*/
  AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;
  while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY))
    ;

  AT91C_BASE_PMC->PMC_MCKR |= AT91C_PMC_CSS_PLL_CLK;
  while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY))
    ;
}

/** @} */