text: /*
   * Copyright (c) 2016 Linaro Limited
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #define DT_DRV_COMPAT openisa_rv32m1_ftfe
  #define SOC_NV_FLASH_NODE DT_INST(0, soc_nv_flash)
  
  #include <kernel.h>
  #include <device.h>
  #include <string.h>
  #include <drivers/flash.h>
  #include <errno.h>
  #include <init.h>
  #include <soc.h>
  #include "flash_priv.h"
  
  #include "fsl_common.h"
  #include "fsl_flash.h"
  
  struct flash_priv {
  	flash_config_t config;
  	/*
  	 * HACK: flash write protection is managed in software.
  	 */
  	struct k_sem write_lock;
  	uint32_t pflash_block_base;
  };
  
  static const struct flash_parameters flash_mcux_parameters = {
  	.write_block_size = FSL_FEATURE_FLASH_PFLASH_BLOCK_WRITE_UNIT_SIZE,
  	.erase_value = 0xff,
  };
  
  /*
   * Interrupt vectors could be executed from flash hence the need for locking.
   * The underlying MCUX driver takes care of copying the functions to SRAM.
   *
   * For more information, see the application note below on Read-While-Write
   * http://cache.freescale.com/files/32bit/doc/app_note/AN4695.pdf
   *
   */
  
  static int flash_mcux_erase(const struct device *dev, off_t offset,
  			    size_t len)
  {
  	struct flash_priv *priv = dev->data;
  	uint32_t addr;
  	status_t rc;
  	unsigned int key;
  
  	if (k_sem_take(&priv->write_lock, K_FOREVER)) {
  		return -EACCES;
  	}
  
  	addr = offset + priv->pflash_block_base;
  
  	key = irq_lock();
  	rc = FLASH_Erase(&priv->config, addr, len, kFLASH_ApiEraseKey);
  	irq_unlock(key);
  
  	k_sem_give(&priv->write_lock);
  
  	return (rc == kStatus_Success) ? 0 : -EINVAL;
  }
  
  static int flash_mcux_read(const struct device *dev, off_t offset,
  				void *data, size_t len)
  {
  	struct flash_priv *priv = dev->data;
  	uint32_t addr;
  
  	/*
  	 * The MCUX supports different flash chips whose valid ranges are
  	 * hidden below the API: until the API export these ranges, we can not
  	 * do any generic validation
  	 */
  	addr = offset + priv->pflash_block_base;
  
  	memcpy(data, (void *) addr, len);
  
  	return 0;
  }
  
  static int flash_mcux_write(const struct device *dev, off_t offset,
  				const void *data, size_t len)
  {
  	struct flash_priv *priv = dev->data;
  	uint32_t addr;
  	status_t rc;
  	unsigned int key;
  
  	if (k_sem_take(&priv->write_lock, K_FOREVER)) {
  		return -EACCES;
  	}
  
  	addr = offset + priv->pflash_block_base;
  
  	key = irq_lock();
  	rc = FLASH_Program(&priv->config, addr, (uint32_t *) data, len);
  	irq_unlock(key);
  
  	k_sem_give(&priv->write_lock);
  
  	return (rc == kStatus_Success) ? 0 : -EINVAL;
  }
  
  #if defined(CONFIG_FLASH_PAGE_LAYOUT)
  static const struct flash_pages_layout dev_layout = {
  	.pages_count = DT_REG_SIZE(SOC_NV_FLASH_NODE) /
  				DT_PROP(SOC_NV_FLASH_NODE, erase_block_size),
  	.pages_size = DT_PROP(SOC_NV_FLASH_NODE, erase_block_size),
  };
  
  static void flash_mcux_pages_layout(const struct device *dev,
  				    const struct flash_pages_layout **layout,
  				    size_t *layout_size)
  {
  	*layout = &dev_layout;
  	*layout_size = 1;
  }
  #endif /* CONFIG_FLASH_PAGE_LAYOUT */
  
  static const struct flash_parameters *
  flash_mcux_get_parameters(const struct device *dev)
  {
  	ARG_UNUSED(dev);
  
  	return &flash_mcux_parameters;
  }
  
  static struct flash_priv flash_data;
  
  static const struct flash_driver_api flash_mcux_api = {
  	.erase = flash_mcux_erase,
  	.write = flash_mcux_write,
  	.read = flash_mcux_read,
  	.get_parameters = flash_mcux_get_parameters,
  #if defined(CONFIG_FLASH_PAGE_LAYOUT)
  	.page_layout = flash_mcux_pages_layout,
  #endif
  };
  
  static int flash_mcux_init(const struct device *dev)
  {
  	struct flash_priv *priv = dev->data;
  	uint32_t pflash_block_base;
  	status_t rc;
  
  	CLOCK_EnableClock(kCLOCK_Mscm);
  
  	k_sem_init(&priv->write_lock, 1, 1);
  
  	rc = FLASH_Init(&priv->config);
  
  	FLASH_GetProperty(&priv->config, kFLASH_PropertyPflashBlockBaseAddr,
  			(uint32_t *)&pflash_block_base);
  	priv->pflash_block_base = (uint32_t) pflash_block_base;
  
  	return (rc == kStatus_Success) ? 0 : -EIO;
  }
  
  DEVICE_DT_INST_DEFINE(0, flash_mcux_init, NULL,
  			&flash_data, NULL, POST_KERNEL,
  			CONFIG_FLASH_INIT_PRIORITY, &flash_mcux_api);
  