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SAMA5: Add functions to calculate PLLACK, PCK, and MCK frequencies given the main clock frequency

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This commit is contained in:
Gregory Nutt 2014-03-29 15:54:10 -06:00
parent 8bc70e38ab
commit 1b6ae2ccbb
5 changed files with 361 additions and 5 deletions
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5
ChangeLog
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@ -7065,4 +7065,7 @@
for the Atmel SAMA5D3 Xplaiend board. The initial check in is not
finished. For example, it still builds to run out of NOR FLASH but
the SAMA5D Xlpained has no NOR FLASH (2013-4-28).
* arch/arm/src/sama5/sam_pmc.c and .h: Add functions to calculate
PLLACK, PCK, and MCK frequencies given the main clock frequency
(2014-3-29).

4
arch/arm/src/sama5/Make.defs
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@ -94,8 +94,8 @@ CHIP_ASRCS =
# SAMA5-specific C source files
CHIP_CSRCS = sam_allocateheap.c sam_boot.c sam_clockconfig.c sam_irq.c
CHIP_CSRCS += sam_lowputc.c sam_memories.c sam_pck.c sam_pio.c sam_serial.c
CHIP_CSRCS += sam_timerisr.c
CHIP_CSRCS += sam_lowputc.c sam_memories.c sam_pck.c sam_pio.c sam_pmc.c
CHIP_CSRCS += sam_serial.c sam_timerisr.c
# Configuration dependent C and assembly language files

4
arch/arm/src/sama5/sam_can.c
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@ -1,4 +1,4 @@
/************************************************************************************
/****************************************************************************
* arch/arm/src/sama5/sam_can.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
@ -41,7 +41,7 @@
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
****************************************************************************/
/****************************************************************************
* Included Files

238
arch/arm/src/sama5/sam_pmc.c Executable file
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@ -0,0 +1,238 @@
/****************************************************************************
* arch/arm/src/sama5/sam_pmc.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References:
*
* SAMA5D3 Series Data Sheet
*
* 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 <arch/board/board.h>
#include "up_arch.h"
#include "chip.h"
#include "chip/sam_pmc.h"
#include "sam_pmc.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_pllack_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the PPA output clock, PLLACK
*
* Assumptions:
* PLLA is enabled. If the PLL is is disabled, either at the input divider
* or the output multiplier, the value zero is returned.
*
****************************************************************************/
uint32_t sam_pllack_frequency(uint32_t mainclk)
{
uint32_t regval;
uint32_t diva;
uint32_t mula;
uint32_t pllack;
/* Get the PLLA divider (DIVA) and multiplier (MULA) */
regval = getreg32(SAM_PMC_CKGR_PLLAR);
/* DIVA = 0: Divider output is 0
* DIVA = 1: Divider is bypassed
* DIVA = 2-255: Divider output is the selected clock divided by DIVA
*/
diva = (regval & PMC_CKGR_PLLAR_DIV_MASK) >> PMC_CKGR_PLLAR_DIV_SHIFT;
pllack = mainclk;
if (diva > 1)
{
pllack /= diva;
}
else if (diva < 1)
{
return 0;
}
/* MULA = 0: PLLA is deactivated
* MULA > 0: The PLLA Clock frequency is the PLLA input frequency
* multiplied by MULA + 1.
*/
mula = (regval & PMC_CKGR_PLLAR_MUL_MASK) >> PMC_CKGR_PLLAR_MUL_SHIFT;
if (mula > 1)
{
pllack *= (mula + 1);
}
else if (diva < 1)
{
return 0;
}
return pllack;
}
/****************************************************************************
* Name: sam_pck_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the processor clock (PCK).
*
* Assumptions:
* PLLA is enabled and the either the main clock or the PLLA output clock
* (PLLACK) provides the input to the MCK prescaler.
*
****************************************************************************/
uint32_t sam_pck_frequency(uint32_t mainclk)
{
uint32_t regval;
uint32_t pres;
uint32_t pck;
/* Get the input source selection to the master/processor clock divider */
regval = getreg32(SAM_PMC_MCKR);
switch (regval & PMC_MCKR_CSS_MASK)
{
case PMC_MCKR_CSS_MAIN: /* Main Clock */
/* Use the Main Clock frequency */
pck = mainclk;
break;
case PMC_MCKR_CSS_PLLA: /* PLLA Clock */
/* Use the PLLA output clock */
pck = sam_pllack_frequency(mainclk);
if (pck == 0)
{
return 0;
}
/* Check if the PLLACK output is divided by 2 */
if ((regval & PMC_MCKR_PLLADIV2) != 0)
{
pck >>= 1;
}
break;
case PMC_MCKR_CSS_SLOW: /* Slow Clock */
case PMC_MCKR_CSS_UPLL: /* UPLL Clock */
default:
return 0;
}
/* Get the PCK frequency which is given by the selected input clock
* divided by a power-of-two prescaler.
*
* PRES = 0: Selected clock
* PRES = n > 0: Selected clock divided by 2**n
*/
pres = (regval & PMC_MCKR_PRES_MASK) >> PMC_MCKR_PRES_SHIFT;
return pck >> pres;
}
/****************************************************************************
* Name: sam_mck_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the PPA output clock, PLLACK
*
* Assumptions:
* PLLA is enabled and the either the main clock or the PLLA output clock
* (PLLACK) provides the input to the MCK prescaler.
*
****************************************************************************/
uint32_t sam_mck_frequency(uint32_t mainclk)
{
uint32_t regval;
uint32_t mdiv;
uint32_t mck;
/* The MCK frequency is equivalent to the PCK clock frequency with an
* additional divider.
*/
mck = sam_pck_frequency(mainclk);
if (mck == 0)
{
return 0;
}
/* MDIV = n: Master Clock is Prescaler Output Clock divided by (n + 1) */
regval = getreg32(SAM_PMC_MCKR);
mdiv = (regval & PMC_MCKR_MDIV_MASK) >> PMC_MCKR_MDIV_SHIFT;
if (mdiv > 0)
{
mck /= (mdiv + 1);
}
return mck;
}

115
arch/arm/src/sama5/sam_pmc.h Normal file
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@ -0,0 +1,115 @@
/****************************************************************************
* arch/arm/src/sama5/sam_pmc.h
*
* 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.
*
****************************************************************************/
#ifndef __ARCH_ARM_SRC_SAMA5_SAM_PMC_H
#define __ARCH_ARM_SRC_SAMA5_SAM_PMC_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef __ASSEMBLY__
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_pllack_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the PPA output clock, PLLACK
*
* Assumptions:
* PLLA is enabled. If the PLL is is disabled, either at the input divider
* or the output multiplier, the value zero is returned.
*
****************************************************************************/
uint32_t sam_pllack_frequency(uint32_t mainclk);
/****************************************************************************
* Name: sam_pck_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the processor clock (PCK).
*
* Assumptions:
* PLLA is enabled and the either the main clock or the PLLA output clock
* (PLLACK) provides the input to the MCK prescaler.
*
****************************************************************************/
uint32_t sam_pck_frequency(uint32_t mainclk);
/****************************************************************************
* Name: sam_mck_frequency
*
* Description:
* Given the Main Clock frequency that provides the input to PLLA, return
* the frequency of the PPA output clock, PLLACK
*
* Assumptions:
* PLLA is enabled and the either the main clock or the PLLA output clock
* (PLLACK) provides the input to the MCK prescaler.
*
****************************************************************************/
uint32_t sam_mck_frequency(uint32_t mainclk);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __ASSEMBLY__ */
#endif /* __ARCH_ARM_SRC_SAMA5_SAM_PMC_H */