text: /****************************************************************************
   * arch/arm/src/stm32h7/stm32_bbsram.h
   *
   *   Copyright (C) 2015-2016 Gregory Nutt. All rights reserved.
   *   Authors: Gregory Nutt <gnutt@nuttx.org>
   *            David Sidrane <david_s5@nscdg.com>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  #ifndef __ARCH_ARM_SRC_STM32H7_STM32_BBSRAM_H
  #define __ARCH_ARM_SRC_STM32H7_STM32_BBSRAM_H
  
  /****************************************************************************
   * The purpose of this driver is to add battery backup file to the file
   * system. There can be CONFIG_STM32H7_BBRSRAM_COUNT files defined.
   * These files are of fixed size up to the maximum of the backing 4K SRAM.
   *
   * If CONFIG_SAVE_CRASHDUMP is defined The driver also supports a feature
   * to save the context of a PANIC in one of these files.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  #include <nuttx/fs/ioctl.h>
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #define STM32H7_BBSRAM_SIZE 4096
  
  #if !defined(CONFIG_STM32H7_BBSRAM_FILES)
  #  define CONFIG_STM32H7_BBSRAM_FILES 4
  #endif
  
  /* REVISIT: What guarantees that STM32H7_BBSRAM_GETDESC_IOCTL has a unique
   * value among all over _DIOC() values?
   */
  
  #define STM32H7_BBSRAM_GETDESC_IOCTL _DIOC(0x0010) /* Returns a bbsramd_s */
  
  /****************************************************************************
   * Public Types
   ****************************************************************************/
  
  #ifndef __ASSEMBLY__
  
  enum bbsramdf_e
  {
    BBSRAM_CRC_VALID = 1,        /* The crc is valid */
    BBSRAM_DIRTY     = 2,        /* The file was closed */
  };
  
  struct bbsramd_s
  {
    uint8_t flags;               /* The crc is valid and the file was closed */
    uint8_t fileno;              /* The minor number */
    uint16_t len;                /* Total Bytes in this file*/
    struct timespec lastwrite;   /* Last write time */
  };
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  #undef EXTERN
  #if defined(__cplusplus)
  #  define EXTERN extern "C"
  extern "C"
  {
  #else
  #  define EXTERN extern
  #endif
  
  /****************************************************************************
   * Public Function Prototypes
   ****************************************************************************/
  
  /****************************************************************************
   * Function: stm32_bbsraminitialize
   *
   * Description:
   *   Initialize the Battery Backed up SRAM driver.
   *
   * Input Parameters:
   *   devpath - the path to instantiate the files.
   *   sizes   - Pointer to a any array of file sizes to create
   *             the last entry should be 0
   *             A size of -1 will use all the remaining spaces
   *
   * If the length of sizes is greater then CONFIG_STM32H7_BBSRAM_FILES
   * CONFIG_STM32H7_BBSRAM_FILES will be returned.
   *
   * Returned Value:
   *   Number of files created on success; Negated errno on failure.
   *
   * Assumptions:
   *
   ****************************************************************************/
  
  int stm32_bbsraminitialize(char *devpath, int *sizes);
  
  /****************************************************************************
  * Function: stm32_bbsram_savepanic
  *
  * Description:
  *   Saves the panic context in a previously allocated BBSRAM file
  *
  * Parameters:
  *   fileno  - the value returned by the ioctl STM32H7_BBSRAM_GETDESC_IOCTL
  *   context - Pointer to a any array of bytes to save
  *   length  - The length of the data pointed to byt context
  *
  * Returned Value:
  *   Length saved or negated errno.
  *
  * Assumptions:
  *
  ****************************************************************************/
  
  #if defined(CONFIG_STM32H7_SAVE_CRASHDUMP)
  int stm32_bbsram_savepanic(int fileno, uint8_t *context, int length);
  #endif
  
  #undef EXTERN
  #ifdef __cplusplus
  }
  #endif
  #endif /* __ASSEMBLY__ */
  #endif /* __ARCH_ARM_SRC_STM32H7_STM32_BBSRAM_H */
  