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/****************************************************************************
* arch/arm/src/tiva/tm4c129_syscontrol.c
*
* Copyright (C) 2014 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 <assert.h>
#include <debug.h>
#include <nuttx/init.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "up_internal.h"
#include "chip.h"
#include "tiva_syscontrol.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define FAST_OSCDELAY (512*1024)
#define SLOW_OSCDELAY (4*1024)
#define PLLLOCK_DELAY (32*1024)
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: tiva_delay
*
* Description:
* Wait for the newly selected oscillator(s) to settle. This is tricky
* because the time that we wait can be significant and is determined by
* the previous clock setting, not the one that we are configuring.
*
****************************************************************************/
static inline void tiva_delay(uint32_t delay)
{
__asm__ __volatile__("1:\n"
"\tsubs %0, #1\n"
"\tbne 1b\n"
: "=r"(delay) : "r"(delay));
}
/****************************************************************************
* Name: tiva_oscdelay
*
* Description:
* Wait for the newly selected oscillator(s) to settle. This is tricky because
* the time that we wait can be significant and is determined by the previous
* clock setting, not the one that we are configuring.
*
****************************************************************************/
static inline void tiva_oscdelay(uint32_t rcc, uint32_t rcc2)
{
/* Wait for the oscillator to stabilize. A smaller delay is used if the
* current clock rate is very slow.
*/
uint32_t delay = FAST_OSCDELAY;
#warning Missing logic
/* Then delay that number of loops */
tiva_delay(delay);
}
/****************************************************************************
* Name: tiva_pll_lock
*
* Description:
* The new RCC values have been selected... wait for the PLL to lock on
*
****************************************************************************/
static inline void tiva_pll_lock(void)
{
volatile uint32_t delay;
/* Loop until the lock is achieved or until a timeout occurs */
for (delay = PLLLOCK_DELAY; delay > 0; delay--)
{
/* Check if the PLL is locked on */
if ((getreg32(TIVA_SYSCON_RIS) & SYSCON_RIS_PLLLRIS) != 0)
{
/* Yes.. return now */
return;
}
}
/* If we get here, then PLL lock was not achieved */
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tiva_clockconfig
*
* Description:
* Called to change to new clock based on desired pllfreq0, pllfreq1, and
* sysdiv settings. This is use to set up the initial clocking but can be
* used later to support slow clocked, low power consumption modes.
*
* The pllfreq0 and pllfreq1 settings derive from the PLL M, N, and Q
* values to generate Fvco like:
*
* Fin = Fxtal / (Q + 1 )(N + 1) -OR- Fpiosc / (Q + 1)(N + 1)
* Mdiv = Mint + (MFrac / 1024)
* Fvco = Fin * Mdiv
*
* When the PLL is active, the system clock frequency (SysClk) is calculated
* using the following equation:
*
* SysClk = Fvco/ (sysdiv + 1)
*
* See the helper macros M2PLLFREQ0(mint,mfrac) and QN2PLLFREQ1(q,n).
*
* NOTE: The input clock to the PLL may be either the external crystal
* (Fxtal) or PIOSC (Fpiosc). This logic supports only the external
* crystal as the PLL source clock.
*
****************************************************************************/
void tiva_clockconfig(uint32_t pllfreq0, uint32_t pllfreq1, uint32_t sysdiv)
{
#warning Missing logic
}
/****************************************************************************
* Name: up_clockconfig
*
* Description:
* Called early in the boot sequence (before .data and .bss are available)
* in order to configure initial clocking.
*
****************************************************************************/
void up_clockconfig(void)
{
uint32_t pllfreq0;
uint32_t pllfreq1;
/* Set the clocking to run with the default settings provided in the board.h
* header file
*/
pllfreq0 = M2PLLFREQ0(BOARD_PLL_MINT, BOARD_PLL_MFRAC);
pllfreq1 = QN2PLLFREQ1(BOARD_PLL_Q, BOARD_PLL_N);
tiva_clockconfig(pllfreq0, pllfreq1, BOARD_PLL_SYSDIV);
}
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