path: root/stm-fmc.c

/*
 * stm-fmc.c
 * ---------
 * Functions to set up and use the FMC bus.
 *
 * Copyright (c) 2015, NORDUnet A/S All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the NORDUnet 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.
 */
#include "stm32f4xx_hal.h"
#include "stm-fmc.h"


static SRAM_HandleTypeDef _fmc_fpga_inst;

static void _fmc_init_gpio(void);
static void _fmc_init_params(void);
static int _fmc_nwait_idle(void);


void fmc_init(void)
{
    // configure fmc pins
    _fmc_init_gpio();

    // configure fmc registers
    _fmc_init_params();
}


int fmc_write_32(uint32_t addr, uint32_t *data)
{
    // calculate target fpga address
    uint32_t ptr = FMC_FPGA_BASE_ADDR + (addr & FMC_FPGA_ADDR_MASK);

    // write data to fpga
    HAL_StatusTypeDef ok = HAL_SRAM_Write_32b(&_fmc_fpga_inst, (uint32_t *)ptr, data, 1);

    // check for error
    if (ok != HAL_OK) return -1;

    // wait for transaction to complete
    int wait = _fmc_nwait_idle();

    // check for timeout
    if (wait != 0) return -1;

    // everything went ok
    return 0;
}


int fmc_read_32(uint32_t addr, uint32_t *data)
{
    // calculate target fpga address
    uint32_t ptr = FMC_FPGA_BASE_ADDR + (addr & FMC_FPGA_ADDR_MASK);

    // perform dummy read transaction
    HAL_StatusTypeDef ok = HAL_SRAM_Read_32b(&_fmc_fpga_inst, (uint32_t *)ptr, data, 1);

    // check for error
    if (ok != HAL_OK) return -1;

    // wait for dummy transaction to complete
    int wait = _fmc_nwait_idle();

    // check for timeout
    if (wait != 0) return -1;

    // read data from fpga
    ok = HAL_SRAM_Read_32b(&_fmc_fpga_inst, (uint32_t *)ptr, data, 1);

    // check for error
    if (ok != HAL_OK) return -1;

    // wait for read transaction to complete
    wait = _fmc_nwait_idle();

    // check for timeout
    if (wait != 0) return -1;

    // everything went ok
    return 0;
}


static int _fmc_nwait_idle()
{
    int cnt; // counter

    // poll NWAIT (number of iterations is limited)
    for (cnt=0; cnt<FMC_FPGA_NWAIT_MAX_POLL_TICKS; cnt++)
	{
	    // read pin state
	    GPIO_PinState nwait = HAL_GPIO_ReadPin(FMC_GPIO_PORT_NWAIT, FMC_GPIO_PIN_NWAIT);

	    // stop waiting if fpga is ready
	    if (nwait == FMC_NWAIT_IDLE) break;
	}

    // check for timeout
    if (cnt >= FMC_FPGA_NWAIT_MAX_POLL_TICKS) return -1;

    // ok
    return 0;
}

static void _fmc_init_gpio(void)
{
    // enable gpio clocks
    __GPIOA_CLK_ENABLE();
    __GPIOB_CLK_ENABLE();
    __GPIOD_CLK_ENABLE();
    __GPIOE_CLK_ENABLE();
    __GPIOF_CLK_ENABLE();
    __GPIOG_CLK_ENABLE();
    __GPIOH_CLK_ENABLE();
    __GPIOI_CLK_ENABLE();

    // enable fmc clock
    __FMC_CLK_ENABLE();

    // structure
    GPIO_InitTypeDef GPIO_InitStruct;

    // Port B
    GPIO_InitStruct.Pin = GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

    // Port D
    GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15
	|GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_3|GPIO_PIN_4
	|GPIO_PIN_5|GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

    /*
     * When FMC is working with fixed latency, NWAIT pin must not be
     * configured in AF mode, according to STM32F429 errata.
     */

    // Port D (GPIO!)
    GPIO_InitStruct.Pin = GPIO_PIN_6;
    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

    // Port E
    GPIO_InitStruct.Pin = GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7
	|GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

    // Port F
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
	|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_12|GPIO_PIN_13
	|GPIO_PIN_14|GPIO_PIN_15;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);

    // Port G
    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
	|GPIO_PIN_4|GPIO_PIN_5;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

    // Port H
    GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
	|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOH, &GPIO_InitStruct);

    // Port I
    GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_0|GPIO_PIN_1
	|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_6|GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF12_FMC;
    HAL_GPIO_Init(GPIOI, &GPIO_InitStruct);
}


static void _fmc_init_params(void)
{
    /*
     * fill internal fields
     */
    _fmc_fpga_inst.Instance = FMC_NORSRAM_DEVICE;
    _fmc_fpga_inst.Extended = FMC_NORSRAM_EXTENDED_DEVICE;


    /*
     * configure fmc interface settings
     */

    // use the first bank and corresponding chip select
    _fmc_fpga_inst.Init.NSBank = FMC_NORSRAM_BANK1;

    // data and address buses are separate
    _fmc_fpga_inst.Init.DataAddressMux = FMC_DATA_ADDRESS_MUX_DISABLE;

    // fpga mimics psram-type memory
    _fmc_fpga_inst.Init.MemoryType = FMC_MEMORY_TYPE_PSRAM;

    // data bus is 32-bit
    _fmc_fpga_inst.Init.MemoryDataWidth = FMC_NORSRAM_MEM_BUS_WIDTH_32;

    // read transaction is sync
    _fmc_fpga_inst.Init.BurstAccessMode = FMC_BURST_ACCESS_MODE_ENABLE;

    // this _must_ be configured to high, according to errata, otherwise
    // the processor may hang after trying to access fpga via fmc
    _fmc_fpga_inst.Init.WaitSignalPolarity = FMC_WAIT_SIGNAL_POLARITY_HIGH;

    // wrap mode is not supported
    _fmc_fpga_inst.Init.WrapMode = FMC_WRAP_MODE_DISABLE;

    // don't care in fixed latency mode
    _fmc_fpga_inst.Init.WaitSignalActive = FMC_WAIT_TIMING_DURING_WS;

    // allow write access to fpga
    _fmc_fpga_inst.Init.WriteOperation = FMC_WRITE_OPERATION_ENABLE;

    // use fixed latency mode (ignore wait signal)
    _fmc_fpga_inst.Init.WaitSignal = FMC_WAIT_SIGNAL_DISABLE;

    // write and read have same timing
    _fmc_fpga_inst.Init.ExtendedMode = FMC_EXTENDED_MODE_DISABLE;

    // don't care in sync mode
    _fmc_fpga_inst.Init.AsynchronousWait = FMC_ASYNCHRONOUS_WAIT_DISABLE;

    // write transaction is sync
    _fmc_fpga_inst.Init.WriteBurst = FMC_WRITE_BURST_ENABLE;

    // keep clock always active
    _fmc_fpga_inst.Init.ContinuousClock = FMC_CONTINUOUS_CLOCK_SYNC_ASYNC;

    /*
     * configure fmc timing parameters
     */
    FMC_NORSRAM_TimingTypeDef fmc_timing;

    // don't care in sync mode
    fmc_timing.AddressSetupTime = 15;

    // don't care in sync mode
    fmc_timing.AddressHoldTime = 15;

    // don't care in sync mode
    fmc_timing.DataSetupTime = 255;

    // not needed, since nwait will be polled manually
    fmc_timing.BusTurnAroundDuration = 0;

    // use smallest allowed divisor for best performance
    fmc_timing.CLKDivision = 2;

    // stm is too slow to work with min allowed 2-cycle latency
    fmc_timing.DataLatency = 3;

    // don't care in sync mode
    fmc_timing.AccessMode = FMC_ACCESS_MODE_A;

    // initialize fmc
    HAL_SRAM_Init(&_fmc_fpga_inst, &fmc_timing, NULL);
}