nuttx/arch/arm/src/stm32f7/stm32_bbsram.h

/****************************************************************************
 * arch/arm/src/stm32f7/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_STM32F7_STM32_BBSRAM_H
#define __ARCH_ARM_SRC_STM32F7_STM32_BBSRAM_H

/****************************************************************************
 * The purpose of this driver is to add battery backup file to the file
 * system. There can be CONFIG_STM32F7_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
 ****************************************************************************/

#if defined(CONFIG_STM32F7_STM32F74XX) || defined(CONFIG_STM32F7_STM32F75XX) || \
    defined(CONFIG_STM32F7_STM32F76XX) || defined(CONFIG_STM32F7_STM32F77XX)
#  define STM32F7_BBSRAM_SIZE 4096
#else
#  error "No backup SRAM on this STM32 Device"
#endif

#if !defined(CONFIG_STM32F7_BBSRAM_FILES)
#  define CONFIG_STM32F7_BBSRAM_FILES 4
#endif

/* REVISIT: What guarantees that STM32F7_BBSRAM_GETDESC_IOCTL has a unique
 * value among all over _DIOC() values?
 */

#define STM32F7_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.
 *
 * 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_STM32F7_BBSRAM_FILES
 * CONFIG_STM32F7_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 STM32F7_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_STM32F7_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_STM32F7_STM32_BBSRAM_H */