//*****************************************************************************
//
//! @file am_hal_sysctrl.c
//!
//! @brief Functions for interfacing with the M4F system control registers
//!
//! @addtogroup sysctrl3 SYSCTRL - System Control
//! @ingroup apollo3_hal
//! @{
//
//*****************************************************************************

//*****************************************************************************
//
// Copyright (c) 2024, Ambiq Micro, Inc.
// All rights reserved.
//
// 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 of the copyright holder 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 HOLDER 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.
//
// This is part of revision release_sdk_3_2_0-dd5f40c14b of the AmbiqSuite Development Package.
//
//*****************************************************************************

#include <stdint.h>
#include <stdbool.h>
#include "am_mcu_apollo.h"


//*****************************************************************************
//
//  Globals
//
//*****************************************************************************
uint32_t g_am_hal_sysctrl_sleep_count = 0;

//*****************************************************************************
//
// @brief Place the core into sleep or deepsleep.
//
// @param bSleepDeep - False for Normal or True Deep sleep.
//
// This function puts the MCU to sleep or deepsleep depending on bSleepDeep.
//
// Valid values for bSleepDeep are:
//
//     AM_HAL_SYSCTRL_SLEEP_NORMAL
//     AM_HAL_SYSCTRL_SLEEP_DEEP
//
//*****************************************************************************
void
am_hal_sysctrl_sleep(bool bSleepDeep)
{
    //
    // Disable interrupts and save the previous interrupt state.
    //
    AM_CRITICAL_BEGIN

    g_am_hal_sysctrl_sleep_count++;

    //
    // If the user selected DEEPSLEEP and the TPIU is off, attempt to enter
    // DEEP SLEEP.
    //
    if ( (bSleepDeep == AM_HAL_SYSCTRL_SLEEP_DEEP)    &&
         (MCUCTRL->TPIUCTRL_b.ENABLE == MCUCTRL_TPIUCTRL_ENABLE_DIS) )
    {

        //
        // Retrieve the reset generator status bits
        // This gets reset on Deep Sleep, so we take a snapshot here
        //
        if (!gAmHalResetStatus)
        {
            gAmHalResetStatus = RSTGEN->STAT;
        }

        //
        // save original SIMOBUCK1 value, it will be restored
        //
        uint32_t ui32Simobuck1Backup = MCUCTRL->SIMOBUCK1;

        //
        // increase VDDC by 9 counts
        //
        uint32_t ui32Vddc = _FLD2VAL( MCUCTRL_SIMOBUCK1_MEMACTIVETRIM, ui32Simobuck1Backup );
        ui32Vddc += 9;

        //
        // check for overflow and limit
        //
        ui32Vddc =  ui32Vddc > (MCUCTRL_SIMOBUCK1_MEMACTIVETRIM_Msk>>MCUCTRL_SIMOBUCK1_MEMACTIVETRIM_Pos) ?
                    (MCUCTRL_SIMOBUCK1_MEMACTIVETRIM_Msk>>MCUCTRL_SIMOBUCK1_MEMACTIVETRIM_Pos) :
                    ui32Vddc;

        ui32Vddc = _VAL2FLD(MCUCTRL_SIMOBUCK1_MEMACTIVETRIM, ui32Vddc );

        //
        // increase VDDF by 24 counts
        //
        uint32_t ui32Vddf = _FLD2VAL( MCUCTRL_SIMOBUCK1_COREACTIVETRIM, ui32Simobuck1Backup ) ;
        ui32Vddf += 24 ;

        //
        // check for overflow and limit
        //
        ui32Vddf    = ui32Vddf > (MCUCTRL_SIMOBUCK1_COREACTIVETRIM_Msk >> MCUCTRL_SIMOBUCK1_COREACTIVETRIM_Pos) ?
                      (MCUCTRL_SIMOBUCK1_COREACTIVETRIM_Msk >> MCUCTRL_SIMOBUCK1_COREACTIVETRIM_Pos) :
                      ui32Vddf;
        ui32Vddf = _VAL2FLD(MCUCTRL_SIMOBUCK1_COREACTIVETRIM, ui32Vddf );

        //
        // remove original values of vddc and vddf and replace with modified values
        //
        uint32_t  ui32VddVffMask = MCUCTRL_SIMOBUCK1_MEMACTIVETRIM_Msk | MCUCTRL_SIMOBUCK1_COREACTIVETRIM_Msk;
        uint32_t  ui32SimoBuck1Working =
                      (ui32Simobuck1Backup & ~ui32VddVffMask) | ui32Vddc | ui32Vddf;

        //
        // write updated vddc and vddf to SIMOBUCK1 and wait for 20 microseconds
        //
        MCUCTRL->SIMOBUCK1 = ui32SimoBuck1Working;

        //
        // 20 micosecond delay
        //
        am_hal_flash_delay(FLASH_CYCLES_US(20));

        //
        // just before sleep, restore SIMONBUCK1 to original value
        //
        MCUCTRL->SIMOBUCK1 = ui32Simobuck1Backup;

        //
        // Prepare the core for deepsleep (write 1 to the DEEPSLEEP bit).
        //
        SCB->SCR |= _VAL2FLD(SCB_SCR_SLEEPDEEP, 1);
    }
    else
    {
        //
        // Prepare the core for normal sleep (write 0 to the DEEPSLEEP bit).
        //
        SCB->SCR &= ~_VAL2FLD(SCB_SCR_SLEEPDEEP, 1);
    }

    //
    // Before executing WFI, flush any buffered core and peripheral writes.
    //
    __DSB();
    am_hal_sysctrl_bus_write_flush();

    //
    // Execute the sleep instruction.
    //
    __WFI();

    //
    // Upon wake, execute the Instruction Sync Barrier instruction.
    //
    __ISB();

    //
    // Restore the interrupt state.
    //
    AM_CRITICAL_END
}

//*****************************************************************************
//
// @brief Enable the floating point module.
//
// Call this function to enable the ARM hardware floating point module.
//
//*****************************************************************************
void
am_hal_sysctrl_fpu_enable(void)
{
    //
    // Enable access to the FPU in both privileged and user modes.
    // NOTE: Write 0s to all reserved fields in this register.
    //
    SCB->CPACR = _VAL2FLD(SCB_CPACR_CP11, 0x3) |
                 _VAL2FLD(SCB_CPACR_CP10, 0x3);
}

//*****************************************************************************
//
// @brief Disable the floating point module.
//
// Call this function to disable the ARM hardware floating point module.
//
//*****************************************************************************
void
am_hal_sysctrl_fpu_disable(void)
{
    //
    // Disable access to the FPU in both privileged and user modes.
    // NOTE: Write 0s to all reserved fields in this register.
    //
    SCB->CPACR = 0x00000000                         &
                 ~(_VAL2FLD(SCB_CPACR_CP11, 0x3) |
                   _VAL2FLD(SCB_CPACR_CP10, 0x3));
}

//*****************************************************************************
//
// @brief Enable stacking of FPU registers on exception entry.
//
// @param bLazy - Set to "true" to enable "lazy stacking".
//
// This function allows the core to save floating-point information to the
// stack on exception entry. Setting the bLazy option enables "lazy stacking"
// for interrupt handlers.  Normally, mixing floating-point code and interrupt
// driven routines causes increased interrupt latency, because the core must
// save extra information to the stack upon exception entry. With the lazy
// stacking option enabled, the core will skip the saving of floating-point
// registers when possible, reducing average interrupt latency.
//
// @note At reset of the Cortex M4, the ASPEN and LSPEN bits are set to 1,
// enabling Lazy mode by default. Therefore this function will generally
// only have an affect when setting for full-context save (or when switching
// from full-context to lazy mode).
//
// @note See also:
// infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dai0298a/DAFGGBJD.html
//
// @note Three valid FPU context saving modes are possible.
// 1. Lazy           ASPEN=1 LSPEN=1 am_hal_sysctrl_fpu_stacking_enable(true)
//                                   and default.
// 2. Full-context   ASPEN=1 LSPEN=0 am_hal_sysctrl_fpu_stacking_enable(false)
// 3. No FPU state   ASPEN=0 LSPEN=0 am_hal_sysctrl_fpu_stacking_disable()
// 4. Invalid        ASPEN=0 LSPEN=1
//
//*****************************************************************************
void
am_hal_sysctrl_fpu_stacking_enable(bool bLazy)
{
    uint32_t ui32fpccr;

    //
    // Set the requested FPU stacking mode in ISRs.
    //
    AM_CRITICAL_BEGIN
#define SYSCTRL_FPCCR_LAZY  (FPU_FPCCR_ASPEN_Msk | FPU_FPCCR_LSPEN_Msk)
    ui32fpccr  = FPU->FPCCR;
    ui32fpccr &= ~SYSCTRL_FPCCR_LAZY;
    ui32fpccr |= (bLazy ? SYSCTRL_FPCCR_LAZY : FPU_FPCCR_ASPEN_Msk);
    FPU->FPCCR = ui32fpccr;
    AM_CRITICAL_END
}

//*****************************************************************************
//
// @brief Disable FPU register stacking on exception entry.
//
// This function disables all stacking of floating point registers for
// interrupt handlers.  This mode should only be used when it is absolutely
// known that no FPU instructions will be executed in an ISR.
//
//*****************************************************************************
void
am_hal_sysctrl_fpu_stacking_disable(void)
{
    //
    // Completely disable FPU context save on entry to ISRs.
    //
    AM_CRITICAL_BEGIN
    FPU->FPCCR &= ~SYSCTRL_FPCCR_LAZY;
    AM_CRITICAL_END
}

//*****************************************************************************
//
// @brief Issue a system wide reset using the AIRCR bit in the M4 system ctrl.
//
// This function issues a system wide reset (Apollo POR level reset).
//
//*****************************************************************************
void
am_hal_sysctrl_aircr_reset(void)
{
    //
    // Set the system reset bit in the AIRCR register
    //
    __NVIC_SystemReset();
}

//*****************************************************************************
//
// End Doxygen group.
//! @}
//
//*****************************************************************************