/****************************************************************************
 * arch/arm/src/stm32f7/stm32_qspi.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

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

#include "stm32_qspi.h"

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>

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

#include <nuttx/arch.h>
#include <nuttx/wdog.h>
#include <nuttx/clock.h>
#include <nuttx/cache.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mutex.h>
#include <nuttx/nuttx.h>
#include <nuttx/spi/qspi.h>

#include "arm_internal.h"

#include "stm32_gpio.h"
#include "stm32_dma.h"
#include "stm32_rcc.h"
#include "hardware/stm32_qspi.h"

#ifdef CONFIG_STM32F7_QUADSPI

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/* Debug ********************************************************************/

/* Check if QSPI debug is enabled */

#ifndef CONFIG_DEBUG_DMA
#  undef CONFIG_STM32F7_QSPI_DMADEBUG
#endif

#define DMA_INITIAL      0
#define DMA_AFTER_SETUP  1
#define DMA_AFTER_START  2
#define DMA_CALLBACK     3
#define DMA_TIMEOUT      3
#define DMA_END_TRANSFER 4
#define DMA_NSAMPLES     5

/* Can't have both interrupt-driven QSPI and DMA QSPI */

#if defined(CONFIG_STM32F7_QSPI_INTERRUPTS) && defined(CONFIG_STM32F7_QSPI_DMA)
#  error "Cannot enable both interrupt mode and DMA mode for QSPI"
#endif

/* Sanity check that board.h defines requisite QSPI pinmap options for */

#if (!defined(GPIO_QSPI_CS) || !defined(GPIO_QSPI_IO0) || !defined(GPIO_QSPI_IO1) || \
    !defined(GPIO_QSPI_IO2) || !defined(GPIO_QSPI_IO3) || !defined(GPIO_QSPI_SCK))
#  error you must define QSPI pinmapping options for GPIO_QSPI_CS GPIO_QSPI_IO0 \
    GPIO_QSPI_IO1 GPIO_QSPI_IO2 GPIO_QSPI_IO3 GPIO_QSPI_SCK in your board.h
#endif

#ifdef CONFIG_STM32F7_QSPI_DMA

#  ifdef DMAMAP_QUADSPI

/* QSPI DMA Channel/Stream selection.  There
 * are multiple DMA stream options that must be dis-ambiguated in the board.h
 * file.
 */

#    define DMACHAN_QUADSPI           DMAMAP_QUADSPI
#  endif

#  if defined(CONFIG_STM32F7_QSPI_DMAPRIORITY_LOW)
#    define QSPI_DMA_PRIO  DMA_SCR_PRILO
#  elif defined(CONFIG_STM32F7_QSPI_DMAPRIORITY_MEDIUM)
#    define QSPI_DMA_PRIO  DMA_SCR_PRIMED
#  elif defined(CONFIG_STM32F7_QSPI_DMAPRIORITY_HIGH)
#    define QSPI_DMA_PRIO  DMA_SCR_PRIHI
#  elif defined(CONFIG_STM32F7_QSPI_DMAPRIORITY_VERYHIGH)
#    define QSPI_DMA_PRIO  DMA_SCR_PRIVERYHI
#  else
#    define QSPI_DMA_PRIO  DMA_SCR_PRIMED
#  endif

#endif /* CONFIG_STM32F7_QSPI_DMA */

#ifndef STM32_SYSCLK_FREQUENCY
#  error your board.h needs to define the value of STM32_SYSCLK_FREQUENCY
#endif

#if !defined(CONFIG_STM32F7_QSPI_FLASH_SIZE) || 0 == CONFIG_STM32F7_QSPI_FLASH_SIZE
#  error you must specify a positive flash size via CONFIG_STM32F7_QSPI_FLASH_SIZE
#endif

/* DMA timeout.  The value is not critical; we just don't want the system to
 * hang in the event that a DMA does not finish.
 */

#define DMA_TIMEOUT_MS    (800)
#define DMA_TIMEOUT_TICKS MSEC2TICK(DMA_TIMEOUT_MS)

/* Clocking *****************************************************************/

/* The QSPI bit rate clock is generated by dividing the peripheral clock by
 * a value between 1 and 255
 */

#define STL32F7_QSPI_CLOCK    STM32_SYSCLK_FREQUENCY  /* Frequency of the QSPI clock */

/****************************************************************************
 * Private Types
 ****************************************************************************/

/* The state of the QSPI controller.
 *
 * NOTE: the STM32F7 supports only a single QSPI peripheral.  Logic here is
 * designed to support multiple QSPI peripherals.
 */

struct stm32f7_qspidev_s
{
  struct qspi_dev_s qspi;       /* Externally visible part of the QSPI interface */
  uint32_t base;                /* QSPI controller register base address */
  uint32_t frequency;           /* Requested clock frequency */
  uint32_t actual;              /* Actual clock frequency */
  uint8_t mode;                 /* Mode 0,3 */
  uint8_t nbits;                /* Width of word in bits (8 to 32) */
  uint8_t intf;                 /* QSPI controller number (0) */
  bool initialized;             /* TRUE: Controller has been initialized */
  mutex_t lock;                 /* Assures mutually exclusive access to QSPI */
  bool memmap;                  /* TRUE: Controller is in memory mapped mode */

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  xcpt_t handler;               /* Interrupt handler */
  uint8_t irq;                  /* Interrupt number */
  sem_t op_sem;                 /* Block until complete */
  struct qspi_xctnspec_s *xctn; /* context of transaction in progress */
#endif

#ifdef CONFIG_STM32F7_QSPI_DMA
  bool candma;                  /* DMA is supported */
  sem_t dmawait;                /* Used to wait for DMA completion */
  int result;                   /* DMA result */
  DMA_HANDLE dmach;             /* QSPI DMA handle */
  struct wdog_s dmadog;         /* Watchdog that handles DMA timeouts */
#endif

  /* Debug stuff */

#ifdef CONFIG_STM32F7_QSPI_DMADEBUG
  struct stm32f7_dmaregs_s dmaregs[DMA_NSAMPLES];
#endif

#ifdef CONFIG_STM32F7_QSPI_REGDEBUG
  bool     wrlast;              /* Last was a write */
  uint32_t addresslast;         /* Last address */
  uint32_t valuelast;           /* Last value */
  int      ntimes;              /* Number of times */
#endif
};

/* The QSPI transaction specification
 *
 * This is mostly the values of the CCR and DLR, AR, ABR, broken out into a C
 * structure since these fields need to be considered at various phases of
 * the transaction processing activity.
 */

struct qspi_xctnspec_s
{
  uint8_t instrmode;      /* 'instruction mode'; 0=none, 1=single, 2=dual, 3=quad */
  uint8_t instr;          /* the (8-bit) Instruction (if any) */

  uint8_t addrmode;       /* 'address mode'; 0=none, 1=single, 2=dual, 3=quad */
  uint8_t addrsize;       /* address size (n - 1); 0, 1, 2, 3 */
  uint32_t addr;          /* the address (if any) (1 to 4 bytes as per addrsize) */

  uint8_t altbytesmode;   /* 'alt bytes mode'; 0=none, 1=single, 2=dual, 3=quad */
  uint8_t altbytessize;   /* 'alt bytes' size (n - 1); 0, 1, 2, 3 */
  uint32_t altbytes;      /* the 'alt bytes' (if any) */

  uint8_t dummycycles;    /* number of Dummy Cycles; 0 - 32 */

  uint8_t datamode;       /* 'data mode'; 0=none, 1=single, 2=dual, 3=quad */
  uint32_t datasize;      /* number of data bytes (0xffffffff == undefined) */
  void     *buffer;       /* Data buffer */

  uint8_t isddr;          /* true if 'double data rate' */
  uint8_t issioo;         /* true if 'send instruction only once' mode */

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  uint8_t function;       /* functional mode; to distinguish a read or write */
  int8_t disposition;     /* how it all turned out */
  uint32_t idxnow;        /* index into databuffer of current byte in transfer */
#endif
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/* Helpers */

#ifdef CONFIG_STM32F7_QSPI_REGDEBUG
static bool     qspi_checkreg(struct stm32f7_qspidev_s *priv, bool wr,
                  uint32_t value, uint32_t address);
#else
#  define       qspi_checkreg(priv,wr,value,address) (false)
#endif

static inline uint32_t qspi_getreg(struct stm32f7_qspidev_s *priv,
                  unsigned int offset);
static inline void qspi_putreg(struct stm32f7_qspidev_s *priv,
                  uint32_t value, unsigned int offset);

#ifdef CONFIG_DEBUG_SPI_INFO
static void     qspi_dumpregs(struct stm32f7_qspidev_s *priv,
                  const char *msg);
#else
#  define       qspi_dumpregs(priv,msg)
#endif

#if defined(CONFIG_DEBUG_SPI_INFO) && defined(CONFIG_DEBUG_GPIO)
static void     qspi_dumpgpioconfig(const char *msg);
#else
#  define       qspi_dumpgpioconfig(msg)
#endif

/* Interrupts */

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
static int     qspi0_interrupt(int irq, void *context, void *arg);

#endif

/* DMA support */

#ifdef CONFIG_STM32F7_QSPI_DMA

#  ifdef CONFIG_STM32F7_QSPI_DMADEBUG
#    define qspi_dma_sample(s,i) stm32f7_dmasample((s)->dmach, &(s)->dmaregs[i])
static void     qspi_dma_sampleinit(struct stm32f7_qspidev_s *priv);
static void     qspi_dma_sampledone(struct stm32f7_qspidev_s *priv);
#  else
#    define qspi_dma_sample(s,i)
#    define qspi_dma_sampleinit(s)
#    define qspi_dma_sampledone(s)
#  endif

#  ifndef CONFIG_STM32F7_QSPI_DMATHRESHOLD
#    define CONFIG_STM32F7_QSPI_DMATHRESHOLD 4
#  endif

#endif

/* QSPI methods */

static int      qspi_lock(struct qspi_dev_s *dev, bool lock);
static uint32_t qspi_setfrequency(struct qspi_dev_s *dev,
                                  uint32_t frequency);
static void     qspi_setmode(struct qspi_dev_s *dev, enum qspi_mode_e mode);
static void     qspi_setbits(struct qspi_dev_s *dev, int nbits);
static int      qspi_command(struct qspi_dev_s *dev,
                  struct qspi_cmdinfo_s *cmdinfo);
static int      qspi_memory(struct qspi_dev_s *dev,
                  struct qspi_meminfo_s *meminfo);
static void *qspi_alloc(struct qspi_dev_s *dev, size_t buflen);
static void     qspi_free(struct qspi_dev_s *dev, void *buffer);

/* Initialization */

static int      qspi_hw_initialize(struct stm32f7_qspidev_s *priv);

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

/* QSPI0 driver operations */

static const struct qspi_ops_s g_qspi0ops =
{
  .lock              = qspi_lock,
  .setfrequency      = qspi_setfrequency,
  .setmode           = qspi_setmode,
  .setbits           = qspi_setbits,
#ifdef CONFIG_QSPI_HWFEATURES
  .hwfeatures        = NULL,
#endif
  .command           = qspi_command,
  .memory            = qspi_memory,
  .alloc             = qspi_alloc,
  .free              = qspi_free,
};

/* This is the overall state of the QSPI0 controller */

static struct stm32f7_qspidev_s g_qspi0dev =
{
  .qspi              =
  {
    .ops             = &g_qspi0ops,
  },
  .base              = STM32_QUADSPI_BASE,
  .lock              = NXMUTEX_INITIALIZER,
#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  .handler           = qspi0_interrupt,
  .irq               = STM32_IRQ_QUADSPI,
  .op_sem            = SEM_INITIALIZER(0),
#endif
  .intf              = 0,
#ifdef CONFIG_STM32F7_QSPI_DMA
  .candma            = true,
  .dmawait           = SEM_INITIALIZER(0),
#endif
};

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

/****************************************************************************
 * Name: qspi_checkreg
 *
 * Description:
 *   Check if the current register access is a duplicate of the preceding.
 *
 * Input Parameters:
 *   value   - The value to be written
 *   address - The address of the register to write to
 *
 * Returned Value:
 *   true:  This is the first register access of this type.
 *   false: This is the same as the preceding register access.
 *
 ****************************************************************************/

#ifdef CONFIG_STM32F7_QSPI_REGDEBUG
static bool qspi_checkreg(struct stm32f7_qspidev_s *priv, bool wr,
                          uint32_t value, uint32_t address)
{
  if (wr      == priv->wrlast &&     /* Same kind of access? */
      value   == priv->valuelast &&  /* Same value? */
      address == priv->addresslast)  /* Same address? */
    {
      /* Yes, then just keep a count of the number of times we did this. */

      priv->ntimes++;
      return false;
    }
  else
    {
      /* Did we do the previous operation more than once? */

      if (priv->ntimes > 0)
        {
          /* Yes... show how many times we did it */

          spiinfo("...[Repeats %d times]...\n", priv->ntimes);
        }

      /* Save information about the new access */

      priv->wrlast      = wr;
      priv->valuelast   = value;
      priv->addresslast = address;
      priv->ntimes      = 0;
    }

  /* Return true if this is the first time that we have done this operation */

  return true;
}
#endif

/****************************************************************************
 * Name: qspi_getreg
 *
 * Description:
 *  Read an QSPI register
 *
 ****************************************************************************/

static inline uint32_t qspi_getreg(struct stm32f7_qspidev_s *priv,
                                  unsigned int offset)
{
  uint32_t address = priv->base + offset;
  uint32_t value = getreg32(address);

#ifdef CONFIG_STM32F7_QSPI_REGDEBUG
  if (qspi_checkreg(priv, false, value, address))
    {
      spiinfo("%08x->%08x\n", address, value);
    }
#endif

  return value;
}

/****************************************************************************
 * Name: qspi_putreg
 *
 * Description:
 *  Write a value to an QSPI register
 *
 ****************************************************************************/

static inline void qspi_putreg(struct stm32f7_qspidev_s *priv,
                               uint32_t value, unsigned int offset)
{
  uint32_t address = priv->base + offset;

#ifdef CONFIG_STM32F7_QSPI_REGDEBUG
  if (qspi_checkreg(priv, true, value, address))
    {
      spiinfo("%08x<-%08x\n", address, value);
    }
#endif

  putreg32(value, address);
}

/****************************************************************************
 * Name: qspi_dumpregs
 *
 * Description:
 *   Dump the contents of all QSPI registers
 *
 * Input Parameters:
 *   priv - The QSPI controller to dump
 *   msg - Message to print before the register data
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

#ifdef CONFIG_DEBUG_SPI_INFO
static void qspi_dumpregs(struct stm32f7_qspidev_s *priv, const char *msg)
{
  uint32_t regval;
  spiinfo("%s:\n", msg);

#if 0
  /* this extra verbose output may be helpful in some cases; you'll need
   * to make sure your syslog is large enough to accommodate the extra
   * output.
   */

  regval = getreg32(priv->base + STM32_QUADSPI_CR_OFFSET);    /* Control Register */
  spiinfo("CR:%08x\n", regval);
  spiinfo("  EN:%1d ABORT:%1d DMAEN:%1d TCEN:%1d SSHIFT:%1d\n"
          "  FTHRES: %d\n"
          "  TEIE:%1d TCIE:%1d FTIE:%1d SMIE:%1d TOIE:%1d APMS:%1d PMM:%1d\n"
          "  PRESCALER: %d\n",
          (regval & QSPI_CR_EN) ? 1 : 0,
          (regval & QSPI_CR_ABORT) ? 1 : 0,
          (regval & QSPI_CR_DMAEN) ? 1 : 0,
          (regval & QSPI_CR_TCEN) ? 1 : 0,
          (regval & QSPI_CR_SSHIFT) ? 1 : 0,
          (regval & QSPI_CR_FTHRES_MASK) >> QSPI_CR_FTHRES_SHIFT,
          (regval & QSPI_CR_TEIE) ? 1 : 0,
          (regval & QSPI_CR_TCIE) ? 1 : 0,
          (regval & QSPI_CR_FTIE) ? 1 : 0,
          (regval & QSPI_CR_SMIE) ? 1 : 0,
          (regval & QSPI_CR_TOIE) ? 1 : 0,
          (regval & QSPI_CR_APMS) ? 1 : 0,
          (regval & QSPI_CR_PMM) ? 1 : 0,
          (regval & QSPI_CR_PRESCALER_MASK) >> QSPI_CR_PRESCALER_SHIFT);

  regval = getreg32(priv->base + STM32_QUADSPI_DCR_OFFSET);   /* Device Configuration Register */
  spiinfo("DCR:%08x\n", regval);
  spiinfo("  CKMODE:%1d CSHT:%d FSIZE:%d\n",
          (regval & QSPI_DCR_CKMODE) ? 1 : 0,
          (regval & QSPI_DCR_CSHT_MASK) >> QSPI_DCR_CSHT_SHIFT,
          (regval & QSPI_DCR_FSIZE_MASK) >> QSPI_DCR_FSIZE_SHIFT);

  regval = getreg32(priv->base + STM32_QUADSPI_CCR_OFFSET);   /* Communication Configuration Register */
  spiinfo("CCR:%08x\n", regval);
  spiinfo("   INST:%02x IMODE:%d ADMODE:%d ADSIZE:%d ABMODE:%d\n"
          "   ABSIZE:%d DCYC:%d DMODE:%d FMODE:%d\n"
          "   SIOO:%1d DDRM:%1d\n",
          (regval & QSPI_CCR_INSTRUCTION_MASK) >> QSPI_CCR_INSTRUCTION_SHIFT,
          (regval & QSPI_CCR_IMODE_MASK) >> QSPI_CCR_IMODE_SHIFT,
          (regval & QSPI_CCR_ADMODE_MASK) >> QSPI_CCR_ADMODE_SHIFT,
          (regval & QSPI_CCR_ADSIZE_MASK) >> QSPI_CCR_ABSIZE_SHIFT,
          (regval & QSPI_CCR_ABMODE_MASK) >> QSPI_CCR_ABMODE_SHIFT,
          (regval & QSPI_CCR_ABSIZE_MASK) >> QSPI_CCR_ABSIZE_SHIFT,
          (regval & QSPI_CCR_DCYC_MASK) >> QSPI_CCR_DCYC_SHIFT,
          (regval & QSPI_CCR_DMODE_MASK) >> QSPI_CCR_DMODE_SHIFT,
          (regval & QSPI_CCR_FMODE_MASK) >> QSPI_CCR_FMODE_SHIFT,
          (regval & QSPI_CCR_SIOO) ? 1 : 0,
          (regval & QSPI_CCR_DDRM) ? 1 : 0);

  regval = getreg32(priv->base + STM32_QUADSPI_SR_OFFSET);    /* Status Register */
  spiinfo("SR:%08x\n", regval);
  spiinfo("  TEF:%1d TCF:%1d FTF:%1d SMF:%1d TOF:%1d BUSY:%1d FLEVEL:%d\n",
          (regval & QSPI_SR_TEF) ? 1 : 0,
          (regval & QSPI_SR_TCF) ? 1 : 0,
          (regval & QSPI_SR_FTF) ? 1 : 0,
          (regval & QSPI_SR_SMF) ? 1 : 0,
          (regval & QSPI_SR_TOF) ? 1 : 0,
          (regval & QSPI_SR_BUSY) ? 1 : 0,
          (regval & QSPI_SR_FLEVEL_MASK) >> QSPI_SR_FLEVEL_SHIFT);

#else
  spiinfo("    CR:%08x   DCR:%08x   CCR:%08x    SR:%08x\n",
          getreg32(priv->base + STM32_QUADSPI_CR_OFFSET),     /* Control Register */
          getreg32(priv->base + STM32_QUADSPI_DCR_OFFSET),    /* Device Configuration Register */
          getreg32(priv->base + STM32_QUADSPI_CCR_OFFSET),    /* Communication Configuration Register */
          getreg32(priv->base + STM32_QUADSPI_SR_OFFSET));    /* Status Register */
  spiinfo("   DLR:%08x   ABR:%08x PSMKR:%08x PSMAR:%08x\n",
          getreg32(priv->base + STM32_QUADSPI_DLR_OFFSET),    /* Data Length Register */
          getreg32(priv->base + STM32_QUADSPI_ABR_OFFSET),    /* Alternate Bytes Register */
          getreg32(priv->base + STM32_QUADSPI_PSMKR_OFFSET),  /* Polling Status mask Register */
          getreg32(priv->base + STM32_QUADSPI_PSMAR_OFFSET)); /* Polling Status match Register */
  spiinfo("   PIR:%08x  LPTR:%08x\n",
          getreg32(priv->base + STM32_QUADSPI_PIR_OFFSET),    /* Polling Interval Register */
          getreg32(priv->base + STM32_QUADSPI_LPTR_OFFSET));  /* Low-Power Timeout Register */
  UNUSED(regval);
#endif
}
#endif

#if defined(CONFIG_DEBUG_SPI_INFO) && defined(CONFIG_DEBUG_GPIO)
static void qspi_dumpgpioconfig(const char *msg)
{
  uint32_t regval;
  spiinfo("%s:\n", msg);

  /* Port B */

  regval = getreg32(STM32_GPIOB_MODER);
  spiinfo("B_MODER:%08x\n", regval);

  regval = getreg32(STM32_GPIOB_OTYPER);
  spiinfo("B_OTYPER:%08x\n", regval);

  regval = getreg32(STM32_GPIOB_OSPEED);
  spiinfo("B_OSPEED:%08x\n", regval);

  regval = getreg32(STM32_GPIOB_PUPDR);
  spiinfo("B_PUPDR:%08x\n", regval);

  regval = getreg32(STM32_GPIOB_AFRL);
  spiinfo("B_AFRL:%08x\n", regval);

  regval = getreg32(STM32_GPIOB_AFRH);
  spiinfo("B_AFRH:%08x\n", regval);

  /* Port D */

  regval = getreg32(STM32_GPIOD_MODER);
  spiinfo("D_MODER:%08x\n", regval);

  regval = getreg32(STM32_GPIOD_OTYPER);
  spiinfo("D_OTYPER:%08x\n", regval);

  regval = getreg32(STM32_GPIOD_OSPEED);
  spiinfo("D_OSPEED:%08x\n", regval);

  regval = getreg32(STM32_GPIOD_PUPDR);
  spiinfo("D_PUPDR:%08x\n", regval);

  regval = getreg32(STM32_GPIOD_AFRL);
  spiinfo("D_AFRL:%08x\n", regval);

  regval = getreg32(STM32_GPIOD_AFRH);
  spiinfo("D_AFRH:%08x\n", regval);

  /* Port E */

  regval = getreg32(STM32_GPIOE_MODER);
  spiinfo("E_MODER:%08x\n", regval);

  regval = getreg32(STM32_GPIOE_OTYPER);
  spiinfo("E_OTYPER:%08x\n", regval);

  regval = getreg32(STM32_GPIOE_OSPEED);
  spiinfo("E_OSPEED:%08x\n", regval);

  regval = getreg32(STM32_GPIOE_PUPDR);
  spiinfo("E_PUPDR:%08x\n", regval);

  regval = getreg32(STM32_GPIOE_AFRL);
  spiinfo("E_AFRL:%08x\n", regval);

  regval = getreg32(STM32_GPIOE_AFRH);
  spiinfo("E_AFRH:%08x\n", regval);
}
#endif

#ifdef CONFIG_STM32F7_QSPI_DMADEBUG
/****************************************************************************
 * Name: qspi_dma_sampleinit
 *
 * Description:
 *   Initialize sampling of DMA registers
 *
 * Input Parameters:
 *   priv - QSPI driver instance
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_dma_sampleinit(struct stm32f7_qspidev_s *priv)
{
  /* Put contents of register samples into a known state */

  memset(priv->dmaregs, 0xff,
         DMA_NSAMPLES * sizeof(struct stm32f7_dmaregs_s));

  /* Then get the initial samples */

  stm32f7_dmasample(priv->dmach, &priv->dmaregs[DMA_INITIAL]);
}

/****************************************************************************
 * Name: qspi_dma_sampledone
 *
 * Description:
 *   Dump sampled DMA registers
 *
 * Input Parameters:
 *   priv - QSPI driver instance
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_dma_sampledone(struct stm32f7_qspidev_s *priv)
{
  /* Sample the final registers */

  stm32f7_dmasample(priv->dmach, &priv->dmaregs[DMA_END_TRANSFER]);

  /* Then dump the sampled DMA registers */

  /* Initial register values */

  stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_INITIAL],
              "Initial Registers");

  /* Register values after DMA setup */

  stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_AFTER_SETUP],
              "After DMA Setup");

  /* Register values after DMA start */

  stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_AFTER_START],
              "After DMA Start");

  /* Register values at the time of the TX and RX DMA callbacks
   * -OR- DMA timeout.
   *
   * If the DMA timed out, then there will not be any RX DMA
   * callback samples.  There is probably no TX DMA callback
   * samples either, but we don't know for sure.
   */

  if (priv->result == -ETIMEDOUT)
    {
      stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_TIMEOUT],
                  "At DMA timeout");
    }
  else
    {
      stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_CALLBACK],
                  "At DMA callback");
    }

  stm32f7_dmadump(priv->dmach, &priv->dmaregs[DMA_END_TRANSFER],
              "At End-of-Transfer");
}
#endif

/****************************************************************************
 * Name: qspi_setupxctnfromcmd
 *
 * Description:
 *   Setup our transaction descriptor from a command info structure
 *
 * Input Parameters:
 *   xctn  - the transaction descriptor we setup
 *   cmdinfo  - the command info (originating from the MTD device)
 *
 * Returned Value:
 *   OK, or -errno if invalid
 *
 ****************************************************************************/

static int qspi_setupxctnfromcmd(struct qspi_xctnspec_s *xctn,
                                  const struct qspi_cmdinfo_s *cmdinfo)
{
  DEBUGASSERT(xctn != NULL && cmdinfo != NULL);

#ifdef CONFIG_DEBUG_SPI_INFO
  spiinfo("Transfer:\n");
  spiinfo("  flags: %02x\n", cmdinfo->flags);
  spiinfo("  cmd: %04x\n", cmdinfo->cmd);

  if (QSPICMD_ISADDRESS(cmdinfo->flags))
    {
      spiinfo("  address/length: %08lx/%d\n",
              (unsigned long)cmdinfo->addr, cmdinfo->addrlen);
    }

  if (QSPICMD_ISDATA(cmdinfo->flags))
    {
      spiinfo("  %s Data:\n",
              QSPICMD_ISWRITE(cmdinfo->flags) ? "Write" : "Read");
      spiinfo("    buffer/length: %p/%d\n",
              cmdinfo->buffer, cmdinfo->buflen);
    }
#endif

  DEBUGASSERT(cmdinfo->cmd < 256);

  /* Specify the instruction as per command info */

  /* XXX III instruction mode, single dual quad option bits */

  xctn->instrmode = CCR_IMODE_SINGLE;
  xctn->instr = cmdinfo->cmd;

  /* XXX III option bits for 'send instruction only once' */

  xctn->issioo = 0;

  /* XXX III options for alt bytes, dummy cycles */

  xctn->altbytesmode = CCR_ABMODE_NONE;
  xctn->altbytessize = CCR_ABSIZE_8;
  xctn->altbytes = 0;
  xctn->dummycycles = 0;

  /* Specify the address size as needed */

  if (QSPICMD_ISADDRESS(cmdinfo->flags))
    {
      /* XXX III address mode mode, single, dual, quad option bits */

      xctn->addrmode = CCR_ADMODE_SINGLE;
      if (cmdinfo->addrlen == 1)
        {
          xctn->addrsize = CCR_ADSIZE_8;
        }
      else if (cmdinfo->addrlen == 2)
        {
          xctn->addrsize = CCR_ADSIZE_16;
        }
      else if (cmdinfo->addrlen == 3)
        {
          xctn->addrsize = CCR_ADSIZE_24;
        }
      else if (cmdinfo->addrlen == 4)
        {
          xctn->addrsize = CCR_ADSIZE_32;
        }
      else
        {
          return -EINVAL;
        }

      xctn->addr = cmdinfo->addr;
    }
  else
    {
      xctn->addrmode = CCR_ADMODE_NONE;
      xctn->addrsize = 0;
      xctn->addr = cmdinfo->addr;
    }

  /* Specify the data as needed */

  xctn->buffer = cmdinfo->buffer;
  if (QSPICMD_ISDATA(cmdinfo->flags))
    {
      /* XXX III data mode mode, single, dual, quad option bits */

      xctn->datamode = CCR_DMODE_SINGLE;
      xctn->datasize = cmdinfo->buflen;

      /* XXX III double data rate option bits */

      xctn->isddr = 0;
    }
  else
    {
      xctn->datamode = CCR_DMODE_NONE;
      xctn->datasize = 0;
      xctn->isddr = 0;
    }

#if defined(CONFIG_STM32F7_QSPI_INTERRUPTS)
  xctn->function = QSPICMD_ISWRITE(cmdinfo->flags) ? CCR_FMODE_INDWR :
                                                     CCR_FMODE_INDRD;
  xctn->disposition = - EIO;
  xctn->idxnow = 0;
#endif

  return OK;
}

/****************************************************************************
 * Name: qspi_setupxctnfrommem
 *
 * Description:
 *   Setup our transaction descriptor from a memory info structure
 *
 * Input Parameters:
 *   xctn  - the transaction descriptor we setup
 *   meminfo  - the memory info (originating from the MTD device)
 *
 * Returned Value:
 *   OK, or -errno if invalid
 *
 ****************************************************************************/

static int qspi_setupxctnfrommem(struct qspi_xctnspec_s *xctn,
                                 const struct qspi_meminfo_s *meminfo)
{
  DEBUGASSERT(xctn != NULL && meminfo != NULL);

#ifdef CONFIG_DEBUG_SPI_INFO
  spiinfo("Transfer:\n");
  spiinfo("  flags: %02x\n", meminfo->flags);
  spiinfo("  cmd: %04x\n", meminfo->cmd);
  spiinfo("  address/length: %08lx/%d\n",
          (unsigned long)meminfo->addr, meminfo->addrlen);
  spiinfo("  %s Data:\n",
          QSPIMEM_ISWRITE(meminfo->flags) ? "Write" : "Read");
  spiinfo("    buffer/length: %p/%d\n", meminfo->buffer, meminfo->buflen);
#endif

  DEBUGASSERT(meminfo->cmd < 256);

  /* Specify the instruction as per command info */

  /* XXX III instruction mode, single dual quad option bits */

  xctn->instrmode = CCR_IMODE_SINGLE;
  xctn->instr = meminfo->cmd;

  /* XXX III option bits for 'send instruction only once' */

  xctn->issioo = 0;

  /* XXX III options for alt bytes */

  xctn->altbytesmode = CCR_ABMODE_NONE;
  xctn->altbytessize = CCR_ABSIZE_8;
  xctn->altbytes = 0;

  xctn->dummycycles = meminfo->dummies;

  /* Specify the address size as needed */

  /* XXX III there should be a separate flags for single/dual/quad for each
   * of i,a,d
   */

  if (QSPIMEM_ISDUALIO(meminfo->flags))
    {
      xctn->addrmode = CCR_ADMODE_DUAL;
    }
  else if (QSPIMEM_ISQUADIO(meminfo->flags))
    {
      xctn->addrmode = CCR_ADMODE_QUAD;
    }
  else
    {
      xctn->addrmode = CCR_ADMODE_SINGLE;
    }

  if (meminfo->addrlen == 1)
    {
      xctn->addrsize = CCR_ADSIZE_8;
    }
  else if (meminfo->addrlen == 2)
    {
      xctn->addrsize = CCR_ADSIZE_16;
    }
  else if (meminfo->addrlen == 3)
    {
      xctn->addrsize = CCR_ADSIZE_24;
    }
  else if (meminfo->addrlen == 4)
    {
      xctn->addrsize = CCR_ADSIZE_32;
    }
  else
    {
      return -EINVAL;
    }

  xctn->addr = meminfo->addr;

  /* Specify the data as needed */

  xctn->buffer = meminfo->buffer;

  /* XXX III there should be a separate flags for single/dual/quad for each
   * of i,a,d
   */

  if (QSPIMEM_ISDUALIO(meminfo->flags))
    {
      xctn->datamode = CCR_DMODE_DUAL;
    }
  else if (QSPIMEM_ISQUADIO(meminfo->flags))
    {
      xctn->datamode = CCR_DMODE_QUAD;
    }
  else
    {
      xctn->datamode = CCR_DMODE_SINGLE;
    }

  xctn->datasize = meminfo->buflen;

  /* XXX III double data rate option bits */

  xctn->isddr = 0;

#if defined(CONFIG_STM32F7_QSPI_INTERRUPTS)
  xctn->function = QSPIMEM_ISWRITE(meminfo->flags) ? CCR_FMODE_INDWR :
                                                     CCR_FMODE_INDRD;
  xctn->disposition = - EIO;
  xctn->idxnow = 0;
#endif

  return OK;
}

/****************************************************************************
 * Name: qspi_waitstatusflags
 *
 * Description:
 *   Spin wait for specified status flags to be set as desired
 *
 * Input Parameters:
 *   priv  - The QSPI controller to dump
 *   mask  - bits to check, can be multiple
 *   polarity - true wait if any set, false to wait if all reset
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_waitstatusflags(struct stm32f7_qspidev_s *priv,
                                 uint32_t mask, int polarity)
{
  uint32_t regval;

  if (polarity)
    {
      while (!((regval = qspi_getreg(priv, STM32_QUADSPI_SR_OFFSET))
               & mask));
    }
  else
    {
      while (((regval = qspi_getreg(priv, STM32_QUADSPI_SR_OFFSET)) & mask));
    }
}

/****************************************************************************
 * Name: qspi_abort
 *
 * Description:
 *   Abort any transaction in progress
 *
 * Input Parameters:
 *   priv  - The QSPI controller to dump
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_abort(struct stm32f7_qspidev_s *priv)
{
  uint32_t regval;

  regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval |= QSPI_CR_ABORT;
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
}

/****************************************************************************
 * Name: qspi_ccrconfig
 *
 * Description:
 *   Do common Communications Configuration Register setup
 *
 * Input Parameters:
 *   priv  - The QSPI controller to dump
 *   xctn  - the transaction descriptor; CCR setup
 *   fctn  - 'functional mode'; 0=indwrite, 1=indread, 2=autopoll, 3=memmmap
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_ccrconfig(struct stm32f7_qspidev_s *priv,
                           struct qspi_xctnspec_s *xctn,
                           uint8_t fctn)
{
  uint32_t regval;

  /* If we have data, and it's not memory mapped, write the length */

  if (CCR_DMODE_NONE != xctn->datamode && CCR_FMODE_MEMMAP != fctn)
    {
      qspi_putreg(priv, xctn->datasize - 1, STM32_QUADSPI_DLR_OFFSET);
    }

  /* If we have alternate bytes, stick them in now */

  if (CCR_ABMODE_NONE != xctn->altbytesmode)
    {
      qspi_putreg(priv, xctn->altbytes, STM32_QUADSPI_ABR_OFFSET);
    }

  /* Build the CCR value and set it */

  regval  = QSPI_CCR_INST(xctn->instr) |
            QSPI_CCR_IMODE(xctn->instrmode) |
            QSPI_CCR_ADMODE(xctn->addrmode) |
            QSPI_CCR_ADSIZE(xctn->addrsize) |
            QSPI_CCR_ABMODE(xctn->altbytesmode) |
            QSPI_CCR_ABSIZE(xctn->altbytessize) |
            QSPI_CCR_DCYC(xctn->dummycycles) |
            QSPI_CCR_DMODE(xctn->datamode) |
            QSPI_CCR_FMODE(fctn) |
            (xctn->isddr ? QSPI_CCR_SIOO : 0) |
            (xctn->issioo ? QSPI_CCR_DDRM : 0);
  qspi_putreg(priv, regval, STM32_QUADSPI_CCR_OFFSET);

  /* If we have and need and address, set that now, too */

  if (CCR_ADMODE_NONE != xctn->addrmode && CCR_FMODE_MEMMAP != fctn)
    {
      qspi_putreg(priv, xctn->addr, STM32_QUADSPI_AR_OFFSET);
    }
}

#if defined(CONFIG_STM32F7_QSPI_INTERRUPTS)
/****************************************************************************
 * Name: qspi0_interrupt
 *
 * Description:
 *   Interrupt handler; we handle all QSPI cases -- reads, writes,
 *   automatic status polling, etc.
 *
 * Input Parameters:
 *   irq  -
 *   context  -
 *
 * Returned Value:
 *   OK means we handled it
 *
 ****************************************************************************/

static int qspi0_interrupt(int irq, void *context, void *arg)
{
  uint32_t status;
  uint32_t cr;
  uint32_t regval;

  /* Let's find out what is going on */

  status  = qspi_getreg(&g_qspi0dev, STM32_QUADSPI_SR_OFFSET);
  cr  = qspi_getreg(&g_qspi0dev, STM32_QUADSPI_CR_OFFSET);

  /* Is it 'FIFO Threshold'? */

  if ((status & QSPI_SR_FTF) && (cr & QSPI_CR_FTIE))
    {
      volatile uint32_t *datareg =
        (volatile uint32_t *)(g_qspi0dev.base + STM32_QUADSPI_DR_OFFSET);

      if (g_qspi0dev.xctn->function == CCR_FMODE_INDWR)
        {
          /* Write data until we have no more or have no place to put it */

          while (((regval = qspi_getreg(&g_qspi0dev,
                                        STM32_QUADSPI_SR_OFFSET)) &
                 QSPI_SR_FTF) != 0)
            {
              if (g_qspi0dev.xctn->idxnow < g_qspi0dev.xctn->datasize)
                {
                  *(volatile uint8_t *)datareg =
                    ((uint8_t *)g_qspi0dev.xctn->buffer)
                     [g_qspi0dev.xctn->idxnow];
                  ++g_qspi0dev.xctn->idxnow;
                }
              else
                {
                  /* Fresh out of data to write */

                  break;
                }
            }
        }
      else if (g_qspi0dev.xctn->function == CCR_FMODE_INDRD)
        {
          /* Read data until we have no more or have no place to put it */

          while (((regval = qspi_getreg(&g_qspi0dev,
                                        STM32_QUADSPI_SR_OFFSET)) &
                 QSPI_SR_FTF) != 0)
            {
              if (g_qspi0dev.xctn->idxnow < g_qspi0dev.xctn->datasize)
                {
                  ((uint8_t *)g_qspi0dev.xctn->buffer)
                   [g_qspi0dev.xctn->idxnow] =
                    *(volatile uint8_t *)datareg;
                  ++g_qspi0dev.xctn->idxnow;
                }
              else
                {
                  /* no room at the inn */

                  break;
                }
            }
        }
    }

  /* Is it 'Transfer Complete'? */

  if ((status & QSPI_SR_TCF) && (cr & QSPI_CR_TCIE))
    {
      /* Acknowledge interrupt */

      qspi_putreg(&g_qspi0dev, QSPI_FCR_CTCF, STM32_QUADSPI_FCR_OFFSET);

      /* Disable the QSPI FIFO Threshold, Transfer Error and Transfer
       * complete Interrupts
       */

      regval  = qspi_getreg(&g_qspi0dev, STM32_QUADSPI_CR_OFFSET);
      regval &= ~(QSPI_CR_TEIE | QSPI_CR_TCIE | QSPI_CR_FTIE);
      qspi_putreg(&g_qspi0dev, regval, STM32_QUADSPI_CR_OFFSET);

      /* Do the last bit of read if needed */

      if (g_qspi0dev.xctn->function == CCR_FMODE_INDRD)
        {
          volatile uint32_t *datareg =
            (volatile uint32_t *)(g_qspi0dev.base + STM32_QUADSPI_DR_OFFSET);

          /* Read any remaining data */

          while (((regval = qspi_getreg(&g_qspi0dev,
                                        STM32_QUADSPI_SR_OFFSET)) &
                 QSPI_SR_FLEVEL_MASK) != 0)
            {
              if (g_qspi0dev.xctn->idxnow < g_qspi0dev.xctn->datasize)
                {
                  ((uint8_t *)g_qspi0dev.xctn->buffer)
                   [g_qspi0dev.xctn->idxnow] =
                    *(volatile uint8_t *)datareg;
                  ++g_qspi0dev.xctn->idxnow;
                }
              else
                {
                  /* No room at the inn */

                  break;
                }
            }
        }

      /* Use 'abort' to ditch any stray fifo contents and clear BUSY flag */

      qspi_abort(&g_qspi0dev);

      /* Set success status */

      g_qspi0dev.xctn->disposition = OK;

      /* Signal complete */

      nxsem_post(&g_qspi0dev.op_sem);
    }

  /* Is it 'Status Match'? */

  if ((status & QSPI_SR_SMF) && (cr & QSPI_CR_SMIE))
    {
      /* Acknowledge interrupt */

      qspi_putreg(&g_qspi0dev, QSPI_FCR_CSMF, STM32_QUADSPI_FCR_OFFSET);

      /* If 'automatic poll mode stop' is activated, we're done */

      if (cr & QSPI_CR_APMS)
        {
          /* Disable the QSPI Transfer Error and Status Match Interrupts */

          regval  = qspi_getreg(&g_qspi0dev, STM32_QUADSPI_CR_OFFSET);
          regval &= ~(QSPI_CR_TEIE | QSPI_CR_SMIE);
          qspi_putreg(&g_qspi0dev, regval, STM32_QUADSPI_CR_OFFSET);

          /* Set success status */

          g_qspi0dev.xctn->disposition = OK;

          /* Signal complete */

          nxsem_post(&g_qspi0dev.op_sem);
        }
      else
        {
          /* XXX if it's NOT auto stop; something needs to happen here;
           * a callback?
           */
        }
    }

  /* Is it' Transfer Error'? :( */

  if ((status & QSPI_SR_TEF) && (cr & QSPI_CR_TEIE))
    {
      /* Acknowledge interrupt */

      qspi_putreg(&g_qspi0dev, QSPI_FCR_CTEF, STM32_QUADSPI_FCR_OFFSET);

      /* Disable all the QSPI Interrupts */

      regval  = qspi_getreg(&g_qspi0dev, STM32_QUADSPI_CR_OFFSET);
      regval &= ~(QSPI_CR_TEIE | QSPI_CR_TCIE | QSPI_CR_FTIE |
                  QSPI_CR_SMIE | QSPI_CR_TOIE);
      qspi_putreg(&g_qspi0dev, regval, STM32_QUADSPI_CR_OFFSET);

      /* Set error status; 'transfer error' means that, in 'indirect mode',
       * an invalid address is attempted to be accessed.  'Invalid' is
       * presumably relative to the FSIZE field in CCR; the manual is not
       * explicit, but what else could it be?
       */

      g_qspi0dev.xctn->disposition = - EIO;

      /* Signal complete */

      nxsem_post(&g_qspi0dev.op_sem);
    }

  /* Is it 'Timeout'? */

  if ((status & QSPI_SR_TOF) && (cr & QSPI_CR_TOIE))
    {
      /* Acknowledge interrupt */

      qspi_putreg(&g_qspi0dev, QSPI_FCR_CTOF, STM32_QUADSPI_FCR_OFFSET);

      /* XXX this interrupt simply means that, in 'memory mapped mode',
       * the QSPI memory has not been accessed for a while, and the
       * IP block was configured to automatically de-assert CS after
       * a timeout.  And now we're being informed that has happened.
       *
       * But who cares?  If someone does, perhaps a user callback is
       * appropriate, or some signal?  Either way, realize the xctn
       * member is /not/ valid, so you can't set the disposition
       * field.  Also, note signaling completion has no meaning here
       * because in memory mapped mode no one holds the semaphore.
       */
    }

  return OK;
}

#elif defined(CONFIG_STM32F7_QSPI_DMA)
/****************************************************************************
 * Name: qspi_dma_timeout
 *
 * Description:
 *   The watchdog timeout setup when a has expired without completion of a
 *   DMA.
 *
 * Input Parameters:
 *   arg    - The argument
 *
 * Returned Value:
 *   None
 *
 * Assumptions:
 *   Always called from the interrupt level with interrupts disabled.
 *
 ****************************************************************************/

static void qspi_dma_timeout(wdparm_t arg)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)arg;
  DEBUGASSERT(priv != NULL);

  /* Sample DMA registers at the time of the timeout */

  qspi_dma_sample(priv, DMA_CALLBACK);

  /* Report timeout result, perhaps overwriting any failure reports from
   * the TX callback.
   */

  priv->result = -ETIMEDOUT;

  /* Then wake up the waiting thread */

  nxsem_post(&priv->dmawait);
}

/****************************************************************************
 * Name: qspi_dma_callback
 *
 * Description:
 *   This callback function is invoked at the completion of the QSPI DMA.
 *
 * Input Parameters:
 *   handle - The DMA handler
 *   isr - source of the DMA interrupt
 *   arg - A pointer to the chip select structure
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void qspi_dma_callback(DMA_HANDLE handle, uint8_t isr, void *arg)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)arg;
  DEBUGASSERT(priv != NULL);

  /* Cancel the watchdog timeout */

  wd_cancel(&priv->dmadog);

  /* Sample DMA registers at the time of the callback */

  qspi_dma_sample(priv, DMA_CALLBACK);

  /* Report the result of the transfer only if the callback has not already
   * reported an error.
   */

  if (priv->result == -EBUSY)
    {
      /* Save the result of the transfer if no error was previously
       * reported
       */

      if (isr & DMA_STREAM_TCIF_BIT)
        {
          priv->result = OK;
        }
      else if (isr & DMA_STREAM_TEIF_BIT)
        {
          priv->result = -EIO;
        }
      else
        {
          priv->result = OK;
        }
    }

  /* Then wake up the waiting thread */

  nxsem_post(&priv->dmawait);
}

/****************************************************************************
 * Name: qspi_regaddr
 *
 * Description:
 *   Return the address of an QSPI register
 *
 ****************************************************************************/

static inline uintptr_t qspi_regaddr(struct stm32f7_qspidev_s *priv,
                                    unsigned int offset)
{
  return priv->base + offset;
}

/****************************************************************************
 * Name: qspi_memory_dma
 *
 * Description:
 *   Perform one QSPI memory transfer using DMA
 *
 * Input Parameters:
 *   priv    - Device-specific state data
 *   meminfo - Describes the memory transfer to be performed.
 *   xctn    - Describes the transaction context.
 *
 * Returned Value:
 *   Zero (OK) on SUCCESS, a negated errno on value of failure
 *
 ****************************************************************************/

static int qspi_memory_dma(struct stm32f7_qspidev_s *priv,
                           struct qspi_meminfo_s *meminfo,
                           struct qspi_xctnspec_s *xctn)
{
  uint32_t dmaflags;
  uint32_t regval;
  int ret;

  /* Initialize register sampling */

  qspi_dma_sampleinit(priv);

  /* Determine DMA flags and setup the DMA */

  if (QSPIMEM_ISWRITE(meminfo->flags))
    {
      /* Setup the DMA (memory-to-peripheral) */

      dmaflags = (QSPI_DMA_PRIO | DMA_SCR_MSIZE_8BITS |
                  DMA_SCR_PSIZE_8BITS | DMA_SCR_MINC | DMA_SCR_DIR_M2P);

      up_clean_dcache((uintptr_t)meminfo->buffer,
                      (uintptr_t)meminfo->buffer + meminfo->buflen);
    }
  else
    {
      /* Setup the DMA (peripheral-to-memory) */

      dmaflags = (QSPI_DMA_PRIO | DMA_SCR_MSIZE_8BITS |
                  DMA_SCR_PSIZE_8BITS | DMA_SCR_MINC | DMA_SCR_DIR_P2M);
    }

  stm32_dmasetup(priv->dmach, qspi_regaddr(priv, STM32_QUADSPI_DR_OFFSET),
                 (uint32_t)meminfo->buffer, meminfo->buflen, dmaflags);

  qspi_dma_sample(priv, DMA_AFTER_SETUP);

  /* Enable the memory transfer */

  regval = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval |= QSPI_CR_DMAEN;
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Set up the Communications Configuration Register as per command info */

  qspi_ccrconfig(priv, xctn,
                 QSPIMEM_ISWRITE(meminfo->flags) ? CCR_FMODE_INDWR :
                                                   CCR_FMODE_INDRD);

  /* Start the DMA */

  priv->result = -EBUSY;
  stm32_dmastart(priv->dmach, qspi_dma_callback, priv, false);

  qspi_dma_sample(priv, DMA_AFTER_START);

  /* Wait for DMA completion.  This is done in a loop because there may be
   * false alarm semaphore counts that cause nxsem_wait() not fail to wait
   * or to wake-up prematurely (for example due to the receipt of a signal).
   * We know that the DMA has completed when the result is anything other
   * that -EBUSY.
   */

  do
    {
      /* Start (or re-start) the watchdog timeout */

      ret = wd_start(&priv->dmadog, DMA_TIMEOUT_TICKS,
                     qspi_dma_timeout, (wdparm_t)priv);
      if (ret < 0)
        {
           spierr("ERROR: wd_start failed: %d\n", ret);
        }

      /* Wait for the DMA complete */

      ret = nxsem_wait_uninterruptible(&priv->dmawait);

      if (QSPIMEM_ISREAD(meminfo->flags))
        {
          up_invalidate_dcache((uintptr_t)meminfo->buffer,
                               (uintptr_t)meminfo->buffer + meminfo->buflen);
        }

      /* Cancel the watchdog timeout */

      wd_cancel(&priv->dmadog);

      /* Check if we were awakened by an error of some kind */

      if (ret < 0)
        {
          DEBUGPANIC();
          regval = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
          regval &= ~QSPI_CR_DMAEN;
          qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
          return ret;
        }

      /* Note that we might be awakened before the wait is over due to
       * residual counts on the semaphore.  So, to handle, that case,
       * we loop until something changes the DMA result to any value other
       * than -EBUSY.
       */
    }
  while (priv->result == -EBUSY);

  /* Wait for Transfer complete, and not busy */

  qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);
  UP_MB();

  /* Dump the sampled DMA registers */

  qspi_dma_sampledone(priv);

  /* Make sure that the DMA is stopped (it will be stopped automatically
   * on normal transfers, but not necessarily when the transfer terminates
   * on an error condition).
   */

  stm32_dmastop(priv->dmach);

  regval = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval &= ~QSPI_CR_DMAEN;
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Complain if the DMA fails */

  if (priv->result)
    {
      spierr("ERROR: DMA failed with result: %d\n", priv->result);
    }

  return priv->result;
}
#endif

#if !defined(CONFIG_STM32F7_QSPI_INTERRUPTS)
/****************************************************************************
 * Name: qspi_receive_blocking
 *
 * Description:
 *   Do common data receive in a blocking (status polling) way
 *
 * Input Parameters:
 *   priv  - The QSPI controller to dump
 *   xctn  - the transaction descriptor
 *
 * Returned Value:
 *   OK, or -errno on error
 *
 ****************************************************************************/

static int qspi_receive_blocking(struct stm32f7_qspidev_s *priv,
                                 struct qspi_xctnspec_s *xctn)
{
  int ret = OK;
  volatile uint32_t *datareg =
    (volatile uint32_t *)(priv->base + STM32_QUADSPI_DR_OFFSET);
  uint8_t *dest = (uint8_t *)xctn->buffer;
  uint32_t addrval;
  uint32_t regval;

  addrval = qspi_getreg(priv, STM32_QUADSPI_AR_OFFSET);
  if (dest != NULL)
    {
      /* Counter of remaining data */

      uint32_t remaining = xctn->datasize;

      /* Ensure CCR register specifies indirect read */

      regval  = qspi_getreg(priv, STM32_QUADSPI_CCR_OFFSET);
      regval &= ~QSPI_CCR_FMODE_MASK;
      regval |= QSPI_CCR_FMODE(CCR_FMODE_INDRD);
      qspi_putreg(priv, regval, STM32_QUADSPI_CCR_OFFSET);

      /* Start the transfer by re-writing the address in AR register */

      qspi_putreg(priv, addrval, STM32_QUADSPI_AR_OFFSET);

      /* Transfer loop */

      while (remaining > 0)
        {
          /* Wait for Fifo Threshold, or Transfer Complete, to read data */

          qspi_waitstatusflags(priv, QSPI_SR_FTF | QSPI_SR_TCF, 1);

          *dest = *(volatile uint8_t *)datareg;
          dest++;
          remaining--;
        }

      if (ret == OK)
        {
          /* Wait for transfer complete, then clear it */

          qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
          qspi_putreg(priv, QSPI_FCR_CTCF, STM32_QUADSPI_FCR_OFFSET);

          /* Use Abort to clear the busy flag, and ditch any extra bytes in
           * fifo
           */

          qspi_abort(priv);
        }
    }
  else
    {
      ret = -EINVAL;
    }

  return ret;
}

/****************************************************************************
 * Name: qspi_transmit_blocking
 *
 * Description:
 *   Do common data transmit in a blocking (status polling) way
 *
 * Input Parameters:
 *   priv  - The QSPI controller to dump
 *   xctn  - the transaction descriptor
 *
 * Returned Value:
 *   OK, or -errno on error
 *
 ****************************************************************************/

static int qspi_transmit_blocking(struct stm32f7_qspidev_s *priv,
                                 struct qspi_xctnspec_s *xctn)
{
  int ret = OK;
  volatile uint32_t *datareg =
    (volatile uint32_t *)(priv->base + STM32_QUADSPI_DR_OFFSET);
  uint8_t *src = (uint8_t *)xctn->buffer;

  if (src != NULL)
    {
      /* Counter of remaining data */

      uint32_t remaining = xctn->datasize;

      /* Transfer loop */

      while (remaining > 0)
        {
          /* Wait for Fifo Threshold to write data */

          qspi_waitstatusflags(priv, QSPI_SR_FTF, 1);

          *(volatile uint8_t *)datareg = *src++;
          remaining--;
        }

      if (ret == OK)
        {
          /* Wait for transfer complete, then clear it */

          qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
          qspi_putreg(priv, QSPI_FCR_CTCF, STM32_QUADSPI_FCR_OFFSET);

          /* Use Abort to clear the Busy flag */

          qspi_abort(priv);
        }
    }
  else
    {
      ret = -EINVAL;
    }

  return ret;
}

#endif

/****************************************************************************
 * Name: qspi_lock
 *
 * Description:
 *   On QSPI buses where there are multiple devices, it will be necessary to
 *   lock QSPI to have exclusive access to the buses for a sequence of
 *   transfers.  The bus should be locked before the chip is selected. After
 *   locking the QSPI bus, the caller should then also call the setfrequency,
 *   setbits, and setmode methods to make sure that the QSPI is properly
 *   configured for the device.  If the QSPI bus is being shared, then it
 *   may have been left in an incompatible state.
 *
 * Input Parameters:
 *   dev  - Device-specific state data
 *   lock - true: Lock QSPI bus, false: unlock QSPI bus
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static int qspi_lock(struct qspi_dev_s *dev, bool lock)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  int ret;

  spiinfo("lock=%d\n", lock);
  if (lock)
    {
      ret = nxmutex_lock(&priv->lock);
    }
  else
    {
      ret = nxmutex_unlock(&priv->lock);
    }

  return ret;
}

/****************************************************************************
 * Name: qspi_setfrequency
 *
 * Description:
 *   Set the QSPI frequency.
 *
 * Input Parameters:
 *   dev -       Device-specific state data
 *   frequency - The QSPI frequency requested
 *
 * Returned Value:
 *   Returns the actual frequency selected
 *
 ****************************************************************************/

static uint32_t qspi_setfrequency(struct qspi_dev_s *dev, uint32_t frequency)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  uint32_t actual;
  uint32_t prescaler;
  uint32_t regval;

  if (priv->memmap)
    {
      /* XXX we have no better return here, but the caller will find out
       * in their subsequent calls.
       */

      return 0;
    }

  spiinfo("frequency=%" PRId32 "\n", frequency);
  DEBUGASSERT(priv);

  /* Wait till BUSY flag reset */

  qspi_abort(priv);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* Check if the requested frequency is the same as the frequency
   * selection
   */

  if (priv->frequency == frequency)
    {
      /* We are already at this frequency.  Return the actual. */

      return priv->actual;
    }

  /* Configure QSPI to a frequency as close as possible to the requested
   * frequency.
   *
   *   QSCK frequency = STL32F7_QSPI_CLOCK / prescaler, or
   *     prescaler = STL32F7_QSPI_CLOCK / frequency
   *
   * Where prescaler can have the range 1 to 256 and the
   * STM32_QUADSPI_CR_OFFSET register field holds prescaler - 1.
   * NOTE that a "ceiling" type of calculation is performed.
   * 'frequency' is treated as a not-to-exceed value.
   */

  prescaler = (frequency + STL32F7_QSPI_CLOCK - 1) / frequency;

  /* Make sure that the divider is within range */

  if (prescaler < 1)
    {
      prescaler = 1;
    }
  else if (prescaler > 256)
    {
      prescaler = 256;
    }

  /* Save the new prescaler value (minus one) */

  regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval &= ~(QSPI_CR_PRESCALER_MASK);
  regval |= (prescaler - 1) << QSPI_CR_PRESCALER_SHIFT;
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Calculate the new actual frequency */

  actual = STL32F7_QSPI_CLOCK / prescaler;
  spiinfo("prescaler=%" PRId32 " actual=%" PRId32 "\n", prescaler, actual);

  /* Save the frequency setting */

  priv->frequency = frequency;
  priv->actual    = actual;

  spiinfo("Frequency %" PRId32 "->%" PRId32 "\n", frequency, actual);
  return actual;
}

/****************************************************************************
 * Name: qspi_setmode
 *
 * Description:
 *   Set the QSPI mode. Optional.  See enum qspi_mode_e for mode definitions.
 *   NOTE:  the STM32F7 QSPI supports only modes 0 and 3.
 *
 * Input Parameters:
 *   dev -  Device-specific state data
 *   mode - The QSPI mode requested
 *
 * Returned Value:
 *   none
 *
 ****************************************************************************/

static void qspi_setmode(struct qspi_dev_s *dev, enum qspi_mode_e mode)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  uint32_t regval;

  if (priv->memmap)
    {
      /* XXX we have no better return here, but the caller will find out
       * in their subsequent calls.
       */

      return;
    }

  spiinfo("mode=%d\n", mode);

  /* Has the mode changed? */

  if (mode != priv->mode)
    {
      /* Yes... Set the mode appropriately:
       *
       * QSPI  CPOL CPHA
       * MODE
       *  0    0    0
       *  1    0    1
       *  2    1    0
       *  3    1    1
       */

      regval  = qspi_getreg(priv, STM32_QUADSPI_DCR_OFFSET);
      regval &= ~(QSPI_DCR_CKMODE);

      switch (mode)
        {
        case QSPIDEV_MODE0: /* CPOL=0; CPHA=0 */
          break;

        case QSPIDEV_MODE3: /* CPOL=1; CPHA=1 */
          regval |= (QSPI_DCR_CKMODE);
          break;

        case QSPIDEV_MODE1: /* CPOL=0; CPHA=1 */
        case QSPIDEV_MODE2: /* CPOL=1; CPHA=0 */
          spiinfo("unsupported mode=%d\n", mode);
        default:
          DEBUGASSERT(FALSE);
          return;
        }

      qspi_putreg(priv, regval, STM32_QUADSPI_DCR_OFFSET);
      spiinfo("DCR=%08" PRIx32 "\n", regval);

      /* Save the mode so that subsequent re-configurations will be faster */

      priv->mode = mode;
    }
}

/****************************************************************************
 * Name: qspi_setbits
 *
 * Description:
 *   Set the number if bits per word.
 *   NOTE:  the STM32F7 QSPI only supports 8 bits, so this does nothing.
 *
 * Input Parameters:
 *   dev -  Device-specific state data
 *   nbits - The number of bits requests
 *
 * Returned Value:
 *   none
 *
 ****************************************************************************/

static void qspi_setbits(struct qspi_dev_s *dev, int nbits)
{
  /* Not meaningful for the STM32F7x6 */

  if (8 != nbits)
    {
      spiinfo("unsupported nbits=%d\n", nbits);
      DEBUGASSERT(FALSE);
    }
}

/****************************************************************************
 * Name: qspi_command
 *
 * Description:
 *   Perform one QSPI data transfer
 *
 * Input Parameters:
 *   dev     - Device-specific state data
 *   cmdinfo - Describes the command transfer to be performed.
 *
 * Returned Value:
 *   Zero (OK) on SUCCESS, a negated errno on value of failure
 *
 ****************************************************************************/

static int qspi_command(struct qspi_dev_s *dev,
                        struct qspi_cmdinfo_s *cmdinfo)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  struct qspi_xctnspec_s xctn;
  int ret;

  /* Reject commands issued while in memory mapped mode, which will
   * automatically cancel the memory mapping.  You must exit the
   * memory mapped mode first.
   */

  if (priv->memmap)
    {
      return -EBUSY;
    }

  /* Set up the transaction descriptor as per command info */

  ret = qspi_setupxctnfromcmd(&xctn, cmdinfo);
  if (OK != ret)
    {
      return ret;
    }

  /* Prepare for transaction */

  /* Wait 'till non-busy */

  qspi_abort(priv);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* Clear flags */

  qspi_putreg(priv,
              QSPI_FCR_CTEF | QSPI_FCR_CTCF | QSPI_FCR_CSMF | QSPI_FCR_CTOF,
              STM32_QUADSPI_FCR_OFFSET);

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  /* interrupt mode will need access to the transaction context */

  priv->xctn = &xctn;

  if (QSPICMD_ISDATA(cmdinfo->flags))
    {
      DEBUGASSERT(cmdinfo->buffer != NULL && cmdinfo->buflen > 0);
      DEBUGASSERT(IS_ALIGNED((uintptr_t)cmdinfo->buffer, 4));

      if (QSPICMD_ISWRITE(cmdinfo->flags))
        {
          uint32_t regval;

          /* Set up the Communications Configuration Register as per command
           * info
           */

          qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDWR);

          /* Enable 'Transfer Error' 'FIFO Threshold' and 'Transfer
           * Complete' interrupts.
           */

          regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
          regval |= (QSPI_CR_TEIE | QSPI_CR_FTIE | QSPI_CR_TCIE);
          qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
        }
      else
        {
          uint32_t regval;
          uint32_t addrval;

          addrval = qspi_getreg(priv, STM32_QUADSPI_AR_OFFSET);

          /* Set up the Communications Configuration Register as per command
           * info
           */

          qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDRD);

          /* Start the transfer by re-writing the address in AR register */

          qspi_putreg(priv, addrval, STM32_QUADSPI_AR_OFFSET);

          /* Enable 'Transfer Error' 'FIFO Threshold' and 'Transfer
           * Complete' interrupts
           */

          regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
          regval |= (QSPI_CR_TEIE | QSPI_CR_FTIE | QSPI_CR_TCIE);
          qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
        }
    }
  else
    {
      uint32_t regval;

      /* We have no data phase, the command will execute as soon as we emit
       * the CCR
       */

      /* Enable 'Transfer Error' and 'Transfer Complete' interrupts */

      regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
      regval |= (QSPI_CR_TEIE | QSPI_CR_TCIE);
      qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

      /* Set up the Communications Configuration Register as per command
       * info
       */

      qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDRD);
    }

  /* Wait for the interrupt routine to finish it's magic */

  nxsem_wait(&priv->op_sem);
  UP_MB();

  /* Convey the result */

  ret = xctn.disposition;

  /* because command transfers are so small, we're not going to use
   * DMA for them, only interrupts or polling
   */

#else
  /* Polling mode */

  /* Set up the Communications Configuration Register as per command info */

  qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDWR);

  /* That may be it, unless there is also data to transfer */

  if (QSPICMD_ISDATA(cmdinfo->flags))
    {
      DEBUGASSERT(cmdinfo->buffer != NULL && cmdinfo->buflen > 0);
      DEBUGASSERT(IS_ALIGNED((uintptr_t)cmdinfo->buffer, 4));

      if (QSPICMD_ISWRITE(cmdinfo->flags))
        {
          ret = qspi_transmit_blocking(priv, &xctn);
        }
      else
        {
          ret = qspi_receive_blocking(priv, &xctn);
        }

      UP_MB();
    }
  else
    {
      ret = OK;
    }

  /* Wait for Transfer complete, and not busy */

  qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

#endif

  return ret;
}

/****************************************************************************
 * Name: qspi_memory
 *
 * Description:
 *   Perform one QSPI memory transfer
 *
 * Input Parameters:
 *   dev     - Device-specific state data
 *   meminfo - Describes the memory transfer to be performed.
 *
 * Returned Value:
 *   Zero (OK) on SUCCESS, a negated errno on value of failure
 *
 ****************************************************************************/

static int qspi_memory(struct qspi_dev_s *dev,
                       struct qspi_meminfo_s *meminfo)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  struct qspi_xctnspec_s xctn;
  int ret;

  /* Reject commands issued while in memory mapped mode, which will
   * automatically cancel the memory mapping.  You must exit the
   * memory mapped mode first.
   */

  if (priv->memmap)
    {
      return -EBUSY;
    }

  /* Set up the transaction descriptor as per command info */

  ret = qspi_setupxctnfrommem(&xctn, meminfo);
  if (OK != ret)
    {
      return ret;
    }

  /* Prepare for transaction */

  /* Wait 'till non-busy */

  qspi_abort(priv);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* Clear flags */

  qspi_putreg(priv,
              QSPI_FCR_CTEF | QSPI_FCR_CTCF | QSPI_FCR_CSMF | QSPI_FCR_CTOF,
              STM32_QUADSPI_FCR_OFFSET);

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  /* interrupt mode will need access to the transaction context */

  priv->xctn = &xctn;

  DEBUGASSERT(meminfo->buffer != NULL && meminfo->buflen > 0);
  DEBUGASSERT(IS_ALIGNED((uintptr_t)meminfo->buffer, 4));

  if (QSPIMEM_ISWRITE(meminfo->flags))
    {
      uint32_t regval;

      /* Set up the Communications Configuration Register as per command
       * info
       */

      qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDWR);

      /* Enable 'Transfer Error' 'FIFO Threshhold' and 'Transfer Complete'
       * interrupts
       */

      regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
      regval |= (QSPI_CR_TEIE | QSPI_CR_FTIE | QSPI_CR_TCIE);
      qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
    }
  else
    {
      uint32_t regval;
      uint32_t addrval;

      addrval = qspi_getreg(priv, STM32_QUADSPI_AR_OFFSET);

      /* Set up the Communications Configuration Register as per command
       * info
       */

      qspi_ccrconfig(priv, &xctn, CCR_FMODE_INDRD);

      /* Start the transfer by re-writing the address in AR register */

      qspi_putreg(priv, addrval, STM32_QUADSPI_AR_OFFSET);

      /* Enable 'Transfer Error' 'FIFO Threshhold' and 'Transfer Complete'
       * interrupts
       */

      regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
      regval |= (QSPI_CR_TEIE | QSPI_CR_FTIE | QSPI_CR_TCIE);
      qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
    }

  /* Wait for the interrupt routine to finish it's magic */

  nxsem_wait(&priv->op_sem);
  UP_MB();

  /* convey the result */

  ret = xctn.disposition;

#elif defined(CONFIG_STM32F7_QSPI_DMA)
  /* Can we perform DMA?  Should we perform DMA? */

  if (priv->candma &&
      meminfo->buflen > CONFIG_STM32F7_QSPI_DMATHRESHOLD &&
      IS_ALIGNED((uintptr_t)meminfo->buffer, 4) &&
      IS_ALIGNED(meminfo->buflen, 4))
    {
      ret = qspi_memory_dma(priv, meminfo, &xctn);
    }
  else
    {
      /* polling mode */

      /* Set up the Communications Configuration Register as per command
       * info
       */

      qspi_ccrconfig(priv, &xctn,
                     QSPIMEM_ISWRITE(meminfo->flags) ? CCR_FMODE_INDWR :
                                                       CCR_FMODE_INDRD);

      /* Transfer data */

      DEBUGASSERT(meminfo->buffer != NULL && meminfo->buflen > 0);
      DEBUGASSERT(IS_ALIGNED((uintptr_t)meminfo->buffer, 4));

      if (QSPIMEM_ISWRITE(meminfo->flags))
        {
          ret = qspi_transmit_blocking(priv, &xctn);
        }
      else
        {
          ret = qspi_receive_blocking(priv, &xctn);
        }

      /* Wait for Transfer complete, and not busy */

      qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
      qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

      UP_MB();
    }

#else
  /* polling mode */

  /* Set up the Communications Configuration Register as per command info */

  qspi_ccrconfig(priv, &xctn,
                 QSPIMEM_ISWRITE(meminfo->flags) ? CCR_FMODE_INDWR :
                                                   CCR_FMODE_INDRD);

  /* Transfer data */

  DEBUGASSERT(meminfo->buffer != NULL && meminfo->buflen > 0);
  DEBUGASSERT(IS_ALIGNED((uintptr_t)meminfo->buffer, 4));

  if (QSPIMEM_ISWRITE(meminfo->flags))
    {
      ret = qspi_transmit_blocking(priv, &xctn);
    }
  else
    {
      ret = qspi_receive_blocking(priv, &xctn);
    }

  /* Wait for Transfer complete, and not busy */

  qspi_waitstatusflags(priv, QSPI_SR_TCF, 1);
  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  UP_MB();

#endif

  return ret;
}

/****************************************************************************
 * Name: qspi_alloc
 *
 * Description:
 *   Allocate a buffer suitable for DMA data transfer
 *
 * Input Parameters:
 *   dev    - Device-specific state data
 *   buflen - Buffer length to allocate in bytes
 *
 * Returned Value:
 *   Address of the allocated memory on success; NULL is returned on any
 *   failure.
 *
 ****************************************************************************/

static void *qspi_alloc(struct qspi_dev_s *dev, size_t buflen)
{
  /* Here we exploit the carnal knowledge the kmm_malloc() will return memory
   * aligned to 64-bit addresses.  The buffer length must be large enough to
   * hold the rested buflen in units a 32-bits.
   */

  /* Ensure that the DMA buffers are word-aligned. */

  return kmm_malloc(ALIGN_UP(buflen, 4));
}

/****************************************************************************
 * Name: QSPI_FREE
 *
 * Description:
 *   Free memory returned by QSPI_ALLOC
 *
 * Input Parameters:
 *   dev    - Device-specific state data
 *   buffer - Buffer previously allocated via QSPI_ALLOC
 *
 * Returned Value:
 *   None.
 *
 ****************************************************************************/

static void qspi_free(struct qspi_dev_s *dev, void *buffer)
{
  if (buffer)
    {
      kmm_free(buffer);
    }
}

/****************************************************************************
 * Name: qspi_hw_initialize
 *
 * Description:
 *   Initialize the QSPI peripheral from hardware reset.
 *
 * Input Parameters:
 *   priv - Device state structure.
 *
 * Returned Value:
 *   Zero (OK) on SUCCESS, a negated errno on value of failure
 *
 ****************************************************************************/

static int qspi_hw_initialize(struct stm32f7_qspidev_s *priv)
{
  uint32_t regval;

  /* Disable the QSPI; abort anything happening, disable, wait for not busy */

  qspi_abort(priv);

  regval  = 0;
  regval &= ~(QSPI_CR_EN);
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Wait till BUSY flag reset */

  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* Disable all interrupt sources for starters */

  regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval &= ~(QSPI_CR_TEIE | QSPI_CR_TCIE | QSPI_CR_FTIE | QSPI_CR_SMIE |
              QSPI_CR_TOIE | QSPI_CR_FSEL | QSPI_CR_DFM);

#if defined(CONFIG_STM32F7_QSPI_MODE_BANK2)
  regval |= QSPI_CR_FSEL;
#endif

#if defined(CONFIG_STM32F7_QSPI_MODE_DUAL)
  regval |= QSPI_CR_DFM;
#endif

  /* Configure QSPI FIFO Threshold */

  regval &= ~(QSPI_CR_FTHRES_MASK);
  regval |= ((CONFIG_STM32F7_QSPI_FIFO_THESHOLD - 1)
              << QSPI_CR_FTHRES_SHIFT);
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Wait till BUSY flag reset */

  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* Configure QSPI Clock Prescaler and Sample Shift */

  regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval &= ~(QSPI_CR_PRESCALER_MASK | QSPI_CR_SSHIFT);
  regval |= (0x01 << QSPI_CR_PRESCALER_SHIFT);
  regval |= (0x00);
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Configure QSPI Flash Size, CS High Time and Clock Mode */

  regval  = qspi_getreg(priv, STM32_QUADSPI_DCR_OFFSET);
  regval &= ~(QSPI_DCR_CKMODE | QSPI_DCR_CSHT_MASK | QSPI_DCR_FSIZE_MASK);
  regval |= (0x00);
  regval |= ((CONFIG_STM32F7_QSPI_CSHT - 1) << QSPI_DCR_CSHT_SHIFT);
  if (0 != CONFIG_STM32F7_QSPI_FLASH_SIZE)
    {
      unsigned int nsize = CONFIG_STM32F7_QSPI_FLASH_SIZE;
      int nlog2size = 31;

      while ((nsize & 0x80000000) == 0)
        {
          --nlog2size;
          nsize <<= 1;
        }

      regval |= ((nlog2size - 1) << QSPI_DCR_FSIZE_SHIFT);
    }

  qspi_putreg(priv, regval, STM32_QUADSPI_DCR_OFFSET);

  /* Enable QSPI */

  regval = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
  regval |= QSPI_CR_EN;
  qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);

  /* Wait till BUSY flag reset */

  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  qspi_dumpregs(priv, "After initialization");
  qspi_dumpgpioconfig("GPIO");

  return OK;
}

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

/****************************************************************************
 * Name: stm32f7_qspi_initialize
 *
 * Description:
 *   Initialize the selected QSPI port in master mode
 *
 * Input Parameters:
 *   intf - Interface number(must be zero)
 *
 * Returned Value:
 *   Valid QSPI device structure reference on success; a NULL on failure
 *
 ****************************************************************************/

struct qspi_dev_s *stm32f7_qspi_initialize(int intf)
{
  struct stm32f7_qspidev_s *priv;
  uint32_t regval;
  int ret;

  /* The STM32F7 has only a single QSPI port */

  spiinfo("intf: %d\n", intf);
  DEBUGASSERT(intf == 0);

  /* Select the QSPI interface */

  if (intf == 0)
    {
      /* If this function is called multiple times, the following operations
       * will be performed multiple times.
       */

      /* Select QSPI0 */

      priv = &g_qspi0dev;

      /* Enable clocking to the QSPI peripheral */

      regval = getreg32(STM32_RCC_AHB3ENR);
      regval |= RCC_AHB3ENR_QSPIEN;
      putreg32(regval, STM32_RCC_AHB3ENR);

      /* Reset the QSPI peripheral */

      regval = getreg32(STM32_RCC_AHB3RSTR);
      regval |= RCC_AHB3RSTR_QSPIRST;
      putreg32(regval, STM32_RCC_AHB3RSTR);
      regval &= ~RCC_AHB3RSTR_QSPIRST;
      putreg32(regval, STM32_RCC_AHB3RSTR);

      /* Configure multiplexed pins as connected on the board. */

      stm32_configgpio(GPIO_QSPI_CS);
      stm32_configgpio(GPIO_QSPI_IO0);
      stm32_configgpio(GPIO_QSPI_IO1);
      stm32_configgpio(GPIO_QSPI_IO2);
      stm32_configgpio(GPIO_QSPI_IO3);
      stm32_configgpio(GPIO_QSPI_SCK);
    }
  else
    {
      spierr("ERROR: QSPI%d not supported\n", intf);
      return NULL;
    }

  /* Has the QSPI hardware been initialized? */

  if (!priv->initialized)
    {
      /* Now perform one time initialization. */

#ifdef CONFIG_STM32F7_QSPI_DMA
      /* Pre-allocate DMA channels. */

      if (priv->candma)
        {
          priv->dmach = stm32_dmachannel(DMACHAN_QUADSPI);
          if (!priv->dmach)
            {
              spierr("ERROR: Failed to allocate the DMA channel\n");
              priv->candma = false;
            }
        }
#endif

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
      /* Attach the interrupt handler */

      ret = irq_attach(priv->irq, priv->handler, NULL);
      if (ret < 0)
        {
          spierr("ERROR: Failed to attach irq %d\n", priv->irq);
          goto errout_with_dmach;
        }
#endif

      /* Perform hardware initialization.  Puts the QSPI into an active
       * state.
       */

      ret = qspi_hw_initialize(priv);
      if (ret < 0)
        {
          spierr("ERROR: Failed to initialize QSPI hardware\n");
          goto errout_with_irq;
        }

      /* Enable interrupts at the NVIC */

      priv->initialized = true;
      priv->memmap = false;
#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
      up_enable_irq(priv->irq);
#endif
    }

  return &priv->qspi;

errout_with_irq:
#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  irq_detach(priv->irq);

errout_with_dmach:
#endif
#ifdef CONFIG_STM32F7_QSPI_DMA
  if (priv->dmach)
    {
      stm32_dmafree(priv->dmach);
      priv->dmach = NULL;
    }
#endif

  return NULL;
}

/****************************************************************************
 * Name: stm32f7_qspi_enter_memorymapped
 *
 * Description:
 *   Put the QSPI device into memory mapped mode
 *
 * Input Parameters:
 *   dev - QSPI device
 *   meminfo - parameters like for a memory transfer used for reading
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void stm32f7_qspi_enter_memorymapped(struct qspi_dev_s *dev,
                                     const struct qspi_meminfo_s *meminfo,
                                     uint32_t lpto)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;
  uint32_t regval;
  struct qspi_xctnspec_s xctn;

  /* lock during this mode change */

  qspi_lock(dev, true);

  if (priv->memmap)
    {
      qspi_lock(dev, false);
      return;
    }

  /* Abort anything in-progress */

  qspi_abort(priv);

  /* Wait till BUSY flag reset */

  qspi_waitstatusflags(priv, QSPI_SR_BUSY, 0);

  /* if we want the 'low-power timeout counter' */

  if (lpto > 0)
    {
      /* Set the Low Power Timeout value (automatically de-assert
       * CS if memory is not accessed for a while)
       */

      qspi_putreg(priv, lpto, STM32_QUADSPI_LPTR_OFFSET);

      /* Clear Timeout interrupt */

      qspi_putreg(&g_qspi0dev, QSPI_FCR_CTOF, STM32_QUADSPI_FCR_OFFSET);

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
      /* Enable Timeout interrupt */

      regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
      regval |= (QSPI_CR_TCEN | QSPI_CR_TOIE);
      qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
#endif
    }
  else
    {
      regval  = qspi_getreg(priv, STM32_QUADSPI_CR_OFFSET);
      regval &= ~QSPI_CR_TCEN;
      qspi_putreg(priv, regval, STM32_QUADSPI_CR_OFFSET);
    }

  /* create a transaction object */

  qspi_setupxctnfrommem(&xctn, meminfo);

#ifdef CONFIG_STM32F7_QSPI_INTERRUPTS
  priv->xctn = NULL;
#endif

  /* set it into the ccr */

  qspi_ccrconfig(priv, &xctn, CCR_FMODE_MEMMAP);
  priv->memmap = true;

  /* we should be in memory mapped mode now */

  qspi_dumpregs(priv, "After memory mapped:");

  /* finished this mode change */

  qspi_lock(dev, false);
}

/****************************************************************************
 * Name: stm32f7_qspi_exit_memorymapped
 *
 * Description:
 *   Take the QSPI device out of memory mapped mode
 *
 * Input Parameters:
 *   dev - QSPI device
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void stm32f7_qspi_exit_memorymapped(struct qspi_dev_s *dev)
{
  struct stm32f7_qspidev_s *priv = (struct stm32f7_qspidev_s *)dev;

  qspi_lock(dev, true);

  /* A simple abort is sufficient */

  qspi_abort(priv);
  priv->memmap = false;

  qspi_lock(dev, false);
}

#endif /* CONFIG_STM32F7_QSPI */