path: root/nuttx/arch/arm/src/samv7/sam_clockconfig.c

/****************************************************************************
 * arch/arm/src/samv7/sam_clockconfig.c
 *
 *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <debug.h>

#include <nuttx/arch.h>
#include <arch/board/board.h>

#include "up_arch.h"
#include "up_internal.h"

#include "sam_clockconfig.h"
#include "chip/sam_pmc.h"
#include "chip/sam_eefc.h"
#include "chip/sam_wdt.h"
#include "chip/sam_supc.h"
#include "chip/sam_matrix.h"
#include "chip/sam_utmi.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* Board Settings **********************************************************/
/* PMC register settings based on the board configuration values defined
 * in board.h
 */

#define BOARD_CKGR_MOR      (PMC_CKGR_MOR_MOSCXTEN | PMC_CKGR_MOR_MOSCRCEN | \
                             BOARD_CKGR_MOR_MOSCXTST | PMC_CKGR_MOR_KEY)
#define BOARD_CKGR_PLLAR    (BOARD_CKGR_PLLAR_DIV | BOARD_CKGR_PLLAR_COUNT | \
                             BOARD_CKGR_PLLAR_MUL | PMC_CKGR_PLLAR_ONE)
                             
#define BOARD_PMC_MCKR_FAST (PMC_MCKR_CSS_MAIN | BOARD_PMC_MCKR_PRES | \
                             BOARD_PMC_MCKR_MDIV | BOARD_PMC_MCKR_UPLLDIV2)
#define BOARD_PMC_MCKR      (BOARD_PMC_MCKR_CSS | BOARD_PMC_MCKR_PRES | \
                             BOARD_PMC_MCKR_MDIV | BOARD_PMC_MCKR_UPLLDIV2)

/****************************************************************************
 * Public Data
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: sam_efcsetup
 *
 * Description:
 *   Configure wait states for embedded flash access
 *
 ****************************************************************************/

static inline void sam_efcsetup(void)
{
  uint32_t regval = EEFC_FMR_FWS(BOARD_FWS) | EEFC_FMR_CLOE;
  putreg32(regval, SAM_EEFC_FMR);
}

/****************************************************************************
 * Name: sam_wdtsetup
 *
 * Description:
 *   Disable the watchdog timer
 *
 ****************************************************************************/

static inline void sam_wdtsetup(void)
{
#if !defined(CONFIG_SAMV7_WDT0) || \
    (defined(CONFIG_WDT0_ENABLED_ON_RESET) && defined(CONFIG_WDT0_DISABLE_ON_RESET))
  putreg32(WDT_MR_WDDIS, SAM_WDT0_MR);
#endif

#if !defined(CONFIG_SAMV7_WDT1) || \
    (defined(CONFIG_WDT1_ENABLED_ON_RESET) && defined(CONFIG_WDT1_DISABLE_ON_RESET))
  putreg32(WDT_MR_WDDIS, SAM_WDT1_MR);
#endif
}

/****************************************************************************
 * Name: sam_supcsetup
 *
 * Description:
 *   Select the external slow clock
 *
 ****************************************************************************/

static inline void sam_supcsetup(void)
{
  /* Check if the 32-kHz is already selected */

  if ((getreg32(SAM_SUPC_SR) & SUPC_SR_OSCSEL) == 0)
    {
      uint32_t delay;

      putreg32((SUPC_CR_XTALSEL|SUPR_CR_KEY), SAM_SUPC_CR);
      for (delay = 0;
           (getreg32(SAM_SUPC_SR) & SUPC_SR_OSCSEL) == 0 && delay < UINT32_MAX;
           delay++);
    }
}

/****************************************************************************
 * Name: sam_pmcwait
 *
 * Description:
 *   Wait for the specified PMC status bit to become "1"
 *
 ****************************************************************************/

static void sam_pmcwait(uint32_t bit)
{
  volatile uint32_t delay;

  for (delay = 0;
       (getreg32(SAM_PMC_SR) & bit) == 0 && delay < UINT32_MAX;
       delay++);
}

/****************************************************************************
 * Name: sam_pmcsetup
 *
 * Description:
 *   Initialize clocking
 *
 ****************************************************************************/

static inline void sam_pmcsetup(void)
{
  uint32_t regval;

  /* Enable main oscillator (if it has not already been selected) */

  if ((getreg32(SAM_PMC_CKGR_MOR) & PMC_CKGR_MOR_MOSCSEL) == 0)
    {
      /* "When the MOSCXTEN bit and the MOSCXTCNT are written in CKGR_MOR to
       *  enable the main oscillator, the MOSCXTS bit in the Power Management
       *  Controller Status Register (PMC_SR) is cleared and the counter starts
       *  counting down on the slow clock divided by 8 from the MOSCXTCNT
       *  value. ... When the counter reaches 0, the MOSCXTS bit is set,
       *  indicating that the main clock is valid."
       */

      putreg32(BOARD_CKGR_MOR, SAM_PMC_CKGR_MOR);
      sam_pmcwait(PMC_INT_MOSCXTS);
    }

  /* "Switch to the main oscillator.  The selection is made by writing the
   *  MOSCSEL bit in the Main Oscillator Register (CKGR_MOR). The switch of
   *  the Main Clock source is glitch free, so there is no need to run out
   *  of SLCK, PLLACK or UPLLCK in order to change the selection. The MOSCSELS
   *  bit of the power Management Controller Status Register (PMC_SR) allows
   *  knowing when the switch sequence is done."
   *
   *   MOSCSELS: Main Oscillator Selection Status
   *             0 = Selection is done
   *             1 = Selection is in progress
   */

  putreg32((BOARD_CKGR_MOR | PMC_CKGR_MOR_MOSCSEL), SAM_PMC_CKGR_MOR);
  sam_pmcwait(PMC_INT_MOSCSELS);

  /* "Select the master clock. "The Master Clock selection is made by writing
   *  the CSS field (Clock Source Selection) in PMC_MCKR (Master Clock Register).
   *  The prescaler supports the division by a power of 2 of the selected clock
   *  between 1 and 64, and the division by 3. The PRES field in PMC_MCKR programs
   *  the prescaler. Each time PMC_MCKR is written to define a new Master Clock,
   *  the MCKRDY bit is cleared in PMC_SR. It reads 0 until the Master Clock is
   *  established.
   */

  regval  = getreg32(SAM_PMC_MCKR);
  regval &= ~PMC_MCKR_CSS_MASK;
  regval |= PMC_MCKR_CSS_MAIN;
  putreg32(regval, SAM_PMC_MCKR);
  sam_pmcwait(PMC_INT_MCKRDY);

  /* Setup PLLA and wait for LOCKA */

  putreg32(BOARD_CKGR_PLLAR, SAM_PMC_CKGR_PLLAR);
  sam_pmcwait(PMC_INT_LOCKA);

#ifdef CONFIG_USBDEV
  /* UTMI configuration: Enable port0, select 12/16 MHz MAINOSC crystal source */

#if 0 /* REVISIT:  Does this apply only to OHCI? */
  putreg32(UTMI_OHCIICR_RES0, SAM_UTMI_OHCIICR);
#endif

#if BOARD_MAINOSC_FREQUENCY == 12000000
  putreg32(UTMI_CKTRIM_FREQ_XTAL12, SAM_UTMI_CKTRIM);
#elif BOARD_MAINOSC_FREQUENCY == 12000000
  putreg32(UTMI_CKTRIM_FREQ_XTAL16, SAM_UTMI_CKTRIM);
#else
#  error ERROR: Unrecognized MAINSOSC frequency
#endif

  /* Enable UTMI Clocking. The USBHS can work in two modes:
   *
   * - Normal mode where High speed, Full speed and Low speed are available.
   * - Low-power mode where only Full speed and Low speed are available.
   *
   * Only the normal mode is supported by this logic.
   */

#ifdef CONFIG_SAMV7_USBDEVHS_LOWPOWER
  /* UTMI Low-power mode, Full/Low Speed mode
   *
   * Enable the 48MHz FS Clock.
   */

  putreg32(PMC_USBCLK, SAM_PMC_SCER);

#else
  /* UTMI normal mode, High/Full/Low Speed
   *
   * Disable the 48MHz USB FS Clock.  It is not used in this configuration
   */

  putreg32(PMC_USBCLK, SAM_PMC_SCDR);
#endif

  /* Select the UTMI PLL as the USB PLL clock input (480MHz) with divider
   * to get to 48MHz.  UPLL output frequency is determined only by the
   * 12/16MHz crystal selection above.
   */

  regval = PMC_USB_USBS_UPLL;

#ifdef CONFIG_SAMV7_USBDEVHS_LOWPOWER
  if ((getreg32(SAM_PMC_MCKR) & PMC_MCKR_PLLADIV2) != 0)
    {
      /* Divider = 480 Mhz / 2 / 48 Mhz = 5 */

      regval |=  PMC_USB_USBDIV(4);
    }
  else
    {
      /* Divider = 480 Mhz / 1 / 48 Mhz = 10 */

      regval |=  PMC_USB_USBDIV(9);
    }
#endif

  putreg32(regval, SAM_PMC_USB);

  /* Enable the UTMI PLL with the maximum start-up time */

  regval = PMC_CKGR_UCKR_UPLLEN | PMC_CKGR_UCKR_UPLLCOUNT_MAX;
  putreg32(regval, SAM_PMC_CKGR_UCKR);

  /* Wait for LOCKU */

  sam_pmcwait(PMC_INT_LOCKU);
#endif

  /* Switch to the fast clock and wait for MCKRDY */

  putreg32(BOARD_PMC_MCKR_FAST, SAM_PMC_MCKR);
  sam_pmcwait(PMC_INT_MCKRDY);

  putreg32(BOARD_PMC_MCKR, SAM_PMC_MCKR);
  sam_pmcwait(PMC_INT_MCKRDY);
}

/****************************************************************************
 * Name: sam_enabledefaultmaster and sam_disabledefaultmaster
 *
 * Description:
 *   Enable/disable default master access
 *
 ****************************************************************************/

static inline void sam_enabledefaultmaster(void)
{
#warning REVISIT
#if 0 /* REVISIT -- this is stuff left over from SAM3/4 */
  uint32_t regval;

  /* Set default master: SRAM0 -> Cortex-M7 System */

  regval  = getreg32(SAM_MATRIX_SCFG0);
  regval |= (MATRIX_SCFG0_FIXEDDEFMSTR_ARMS|MATRIX_SCFG_DEFMSTRTYPE_FIXED);
  putreg32(regval, SAM_MATRIX_SCFG0);

  /* Set default master: SRAM1 -> Cortex-M7 System */

  regval  = getreg32(SAM_MATRIX_SCFG1);
  regval |= (MATRIX_SCFG1_FIXEDDEFMSTR_ARMS|MATRIX_SCFG_DEFMSTRTYPE_FIXED);
  putreg32(regval, SAM_MATRIX_SCFG1);

  /* Set default master: Internal flash0 -> Cortex-M7 Instruction/Data */

  regval  = getreg32(SAM_MATRIX_SCFG3);
  regval |= (MATRIX_SCFG3_FIXEDDEFMSTR_ARMC|MATRIX_SCFG_DEFMSTRTYPE_FIXED);
  putreg32(regval, SAM_MATRIX_SCFG3);
#endif
}

#if 0 /* Not used -- this is stuff left over from SAM3/4 */
static inline void sam_disabledefaultmaster(void)
{
  uint32_t regval;

  /* Clear default master: SRAM0 -> Cortex-M7 System */

  regval  = getreg32(SAM_MATRIX_SCFG0);
  regval &= ~MATRIX_SCFG_DEFMSTRTYPE_MASK;
  putreg32(regval, SAM_MATRIX_SCFG0);

  /* Clear default master: SRAM1 -> Cortex-M7 System */

  regval  = getreg32(SAM_MATRIX_SCFG1);
  regval &= ~MATRIX_SCFG_DEFMSTRTYPE_MASK;
  putreg32(regval, SAM_MATRIX_SCFG1);

  /* Clear default master: Internal flash0 -> Cortex-M7 Instruction/Data */

  regval  = getreg32(SAM_MATRIX_SCFG3);
  regval &= ~MATRIX_SCFG_DEFMSTRTYPE_MASK;
  putreg32(regval, SAM_MATRIX_SCFG3);
}
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: sam_clockconfig
 *
 * Description:
 *   Called to initialize the SAMV7.  This does whatever setup is needed
 *   to put the SoC in a usable state.  This includes the initialization of
 *   clocking using the settings in board.h.  (After power-on reset, the
 *   SAMV7 is initially running on a 4MHz internal RC clock).  This function
 *   also performs other low-level chip initialization of the chip including
 *   EFC, master clock, IRQ & watchdog configuration.
 *
 ****************************************************************************/

void sam_clockconfig(void)
{
  /* Configure embedded flash access */

  sam_efcsetup();

  /* Configure the watchdog timer */

  sam_wdtsetup();

  /* Setup the supply controller to use the external slow clock */

  sam_supcsetup();

  /* Initialize clocking */

  sam_pmcsetup();

  /* Optimize CPU setting for speed */

  sam_enabledefaultmaster();
}