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nuttx/arch/arm/src/stm32/stm32_bbsram.c

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/****************************************************************************
* arch/arm/src/stm32/stm32_bbsram.c
*
* Copyright (C) 2015 Gregory Nutt. All rights reserved.
* Author: 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.
*
****************************************************************************/
/* This will driver create a set of files in the STM32's Battery backed up
* SRAM. That can be used to store data retained across power cycles.
*
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <poll.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <nuttx/fs/fs.h>
#include <crc32.h>
#include "stm32_bbsram.h"
#include "chip.h"
#include "stm32_pwr.h"
#include "stm32_rtc.h"
#ifdef CONFIG_STM32_BBSRAM
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if !defined(CONFIG_STM32_BKPSRAM)
#error Driver Requires CONFIG_STM32_BKPSRAM to be enabled
#endif
#define MAX_OPENCNT (255) /* Limit of uint8_t */
#ifndef CONFIG_DEBUG_INFO
# undef CONFIG_BBSRAM_DEBUG
#endif
#if defined(CONFIG_BBSRAM_DEBUG)
# define BBSRAM_DEBUG_READ() stm32_bbsram_rd()
# define BBSRAM_DUMP(p,s) stm32_bbsram_dump(p,s)
#else
# define BBSRAM_DEBUG_READ()
# define BBSRAM_DUMP(p,s)
#endif
#define BBSRAM_HEADER_SIZE (sizeof(struct bbsramfh_s))
#define BBSRAM_CRCED_OFFSET (sizeof(((struct bbsramfh_s *)0)->crc))
#define BBSRAM_CRCED_SIZE(l) (BBSRAM_HEADER_SIZE-(BBSRAM_CRCED_OFFSET)+(l))
#define BBSRAM_ALIGNMENT (sizeof(((struct bbsramfh_s *)0)->crc))
#define BBSRAM_ALIGNMENT_MASK (BBSRAM_ALIGNMENT-1)
/****************************************************************************
* Private Types
****************************************************************************/
/* File Header */
struct bbsramfh_s
{
uint32_t crc; /* CRC calculated over data and this struct
* starting at fileno */
uint8_t fileno; /* The minor number */
uint8_t dirty; /* Data has been written to the file */
uint16_t len; /* Total Bytes in this file */
struct timespec lastwrite; /* Last write time */
uint8_t data[]; /* Data in the file */
};
struct stm32_bbsram_s
{
sem_t exclsem; /* For atomic accesses to this structure */
uint8_t refs; /* Number of references */
FAR struct bbsramfh_s *bbf; /* File in bbram */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int stm32_bbsram_open(FAR struct file *filep);
static int stm32_bbsram_close(FAR struct file *filep);
static off_t stm32_bbsram_seek(FAR struct file *filep, off_t offset,
int whence);
static ssize_t stm32_bbsram_read(FAR struct file *filep, FAR char *buffer,
size_t len);
static ssize_t stm32_bbsram_write(FAR struct file *filep,
FAR const char *buffer, size_t len);
static int stm32_bbsram_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
#ifndef CONFIG_DISABLE_POLL
static int stm32_bbsram_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int stm32_bbsram_unlink(FAR struct inode *inode);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
#if defined(CONFIG_BBSRAM_DEBUG)
static uint8_t debug[STM32_BBSRAM_SIZE];
#endif
static const struct file_operations stm32_bbsram_fops =
{
.open = stm32_bbsram_open,
.close = stm32_bbsram_close,
.read = stm32_bbsram_read,
.write = stm32_bbsram_write,
.seek = stm32_bbsram_seek,
.ioctl = stm32_bbsram_ioctl,
#ifndef CONFIG_DISABLE_POLL
.poll = stm32_bbsram_poll,
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
.unlink = stm32_bbsram_unlink,
#endif
};
static struct stm32_bbsram_s g_bbsram[CONFIG_STM32_BBSRAM_FILES];
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_bbsram_rd
****************************************************************************/
#if defined(CONFIG_BBSRAM_DEBUG)
static void stm32_bbsram_rd(void)
{
memcpy(&debug, (uint8_t *)STM32_BKPSRAM_BASE, sizeof debug);
}
#endif
/****************************************************************************
* Name: stm32_bbsram_rd
****************************************************************************/
#if defined(CONFIG_BBSRAM_DEBUG)
static void stm32_bbsram_dump(FAR struct bbsramfh_s *bbf, char *op)
{
BBSRAM_DEBUG_READ();
_info("%s:\n", op);
_info(" File Address:0x%8x\n", bbf);
_info(" crc:0x%8x\n", bbf->crc);
_info(" fileno:%d\n", (int) bbf->fileno);
_info(" dirty:%d\n", (int) bbf->dirty);
_info(" length:%d\n", (int) bbf->len);
_info(" time:%ld:%ld\n", bbf->lastwrite.tv_sec, bbf->lastwrite.tv_nsec);
_info(" data: 0x%2x 0x%2x 0x%2x 0x%2x 0x%2x\n",
bbf->data[0], bbf->data[1], bbf->data[2], bbf->data[3], bbf->data[4]);
}
#endif
/************************************************************************************
* Name: stm32_bbsram_semgive
************************************************************************************/
static void stm32_bbsram_semgive(FAR struct stm32_bbsram_s *priv)
{
sem_post(&priv->exclsem);
}
/************************************************************************************
* Name: stm32_bbsram_semtake
*
* Description:
* Take a semaphore handling any exceptional conditions
*
* Input Parameters:
* priv - A reference to the CAN peripheral state
*
* Returned Value:
* None
*
****************************************************************************/
static void stm32_bbsram_semtake(FAR struct stm32_bbsram_s *priv)
{
int ret;
/* Wait until we successfully get the semaphore. EINTR is the only
* expected 'failure' (meaning that the wait for the semaphore was
* interrupted by a signal.
*/
do
{
ret = sem_wait(&priv->exclsem);
DEBUGASSERT(ret == 0 || errno == EINTR);
}
while (ret < 0);
}
/****************************************************************************
* Name: stm32_bbsram_ulock
*
* Description:
* Unprotects RTC registers, RTC backup data registers and backup SRAM
* against parasitic write access
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
static inline void stm32_bbsram_unlock(void)
{
stm32_pwr_enablebkp(true);
}
/****************************************************************************
* Name: stm32_bbsram_lock
*
* Description:
* Protects RTC registers, RTC backup data registers and backup SRAM
* against parasitic write access
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
static inline void stm32_bbsram_lock(void)
{
stm32_pwr_enablebkp(false);
}
/****************************************************************************
* Name: stm32_bbsram_crc
*
* Description:
* Calculates the CRC of the block
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
****************************************************************************/
static uint32_t stm32_bbsram_crc(FAR struct bbsramfh_s *pf)
{
return crc32((uint8_t *)pf + BBSRAM_CRCED_OFFSET, BBSRAM_CRCED_SIZE(pf->len));
}
/****************************************************************************
* Name: stm32_bbsram_open
*
* Description: Open the device
*
****************************************************************************/
static int stm32_bbsram_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
/* Increment the reference count */
stm32_bbsram_semtake(bbr);
if (bbr->refs == MAX_OPENCNT)
{
return -EMFILE;
}
else
{
bbr->refs++;
}
stm32_bbsram_semgive(bbr);
return OK;
}
/****************************************************************************
* Name: stm32_bbsram_internal_close
*
* Description:
* Close BBSRAM entry; Recalculate the time and crc
*
****************************************************************************/
static int stm32_bbsram_internal_close(FAR struct bbsramfh_s *bbf)
{
bbf->dirty = 0;
(void)clock_gettime(CLOCK_REALTIME, &bbf->lastwrite);
bbf->crc = stm32_bbsram_crc(bbf);
BBSRAM_DUMP(bbf, "close done");
return bbf->len;
}
/****************************************************************************
* Name: stm32_bbsram_close
*
* Description: close the device
*
****************************************************************************/
static int stm32_bbsram_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
int ret = OK;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
stm32_bbsram_semtake(bbr);
BBSRAM_DUMP(bbr->bbf, "close");
if (bbr->refs == 0)
{
ret = -EIO;
}
else
{
bbr->refs--;
if (bbr->refs == 0)
{
if (bbr->bbf->dirty)
{
/* Recalculate the time and crc */
stm32_bbsram_unlock();
stm32_bbsram_internal_close(bbr->bbf);
stm32_bbsram_lock();
}
}
}
stm32_bbsram_semgive(bbr);
return ret;
}
/****************************************************************************
* Name: stm32_bbsram_seek
****************************************************************************/
static off_t stm32_bbsram_seek(FAR struct file *filep, off_t offset,
int whence)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
off_t newpos;
int ret;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
stm32_bbsram_semtake(bbr);
/* Determine the new, requested file position */
switch (whence)
{
case SEEK_CUR:
newpos = filep->f_pos + offset;
break;
case SEEK_SET:
newpos = offset;
break;
case SEEK_END:
newpos = bbr->bbf->len + offset;
break;
default:
/* Return EINVAL if the whence argument is invalid */
stm32_bbsram_semgive(bbr);
return -EINVAL;
}
/* Opengroup.org:
*
* "The lseek() function shall allow the file offset to be set beyond the end
* of the existing data in the file. If data is later written at this point,
* subsequent reads of data in the gap shall return bytes with the value 0
* until data is actually written into the gap."
*
* We can conform to the first part, but not the second. But return EINVAL if
*
* "...the resulting file offset would be negative for a regular file, block
* special file, or directory."
*/
if (newpos >= 0)
{
filep->f_pos = newpos;
ret = newpos;
}
else
{
ret = -EINVAL;
}
stm32_bbsram_semgive(bbr);
return ret;
}
/****************************************************************************
* Name: stm32_bbsram_read
****************************************************************************/
static ssize_t stm32_bbsram_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
stm32_bbsram_semtake(bbr);
/* Trim len if read would go beyond end of device */
if ((filep->f_pos + len) > bbr->bbf->len)
{
len = bbr->bbf->len - filep->f_pos;
}
memcpy(buffer, &bbr->bbf->data[filep->f_pos], len);
filep->f_pos += len;
stm32_bbsram_semgive(bbr);
return len;
}
/****************************************************************************
* Name: stm32_bbsram_internal_write
****************************************************************************/
static ssize_t stm32_bbsram_internal_write(FAR struct bbsramfh_s *bbf,
FAR const char *buffer,
off_t offset, size_t len)
{
bbf->dirty = 1;
memcpy(&bbf->data[offset], buffer, len);
return len;
}
/****************************************************************************
* Name: stm32_bbsram_write
****************************************************************************/
static ssize_t stm32_bbsram_write(FAR struct file *filep, FAR const char *buffer,
size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
int ret = -EFBIG;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
/* Forbid writes past the end of the device */
if (filep->f_pos < bbr->bbf->len)
{
/* Clamp len to avoid crossing the end of the memory */
if ((filep->f_pos + len) > bbr->bbf->len)
{
len = bbr->bbf->len - filep->f_pos;
}
ret = len; /* save number of bytes written */
stm32_bbsram_semtake(bbr);
BBSRAM_DUMP(bbr->bbf, "write");
stm32_bbsram_unlock();
stm32_bbsram_internal_write(bbr->bbf, buffer, filep->f_pos, len);
stm32_bbsram_lock();
filep->f_pos += len;
BBSRAM_DUMP(bbr->bbf, "write done");
stm32_bbsram_semgive(bbr);
}
BBSRAM_DEBUG_READ();
return ret;
}
/****************************************************************************
* Name: stm32_bbsram_poll
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
static int stm32_bbsram_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
if (setup)
{
fds->revents |= (fds->events & (POLLIN | POLLOUT));
if (fds->revents != 0)
{
sem_post(fds->sem);
}
}
return OK;
}
#endif
/****************************************************************************
* Name: stm32_bbsram_ioctl
*
* Description: Return device geometry
*
****************************************************************************/
static int stm32_bbsram_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct stm32_bbsram_s *bbr;
int ret = -ENOTTY;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
if (cmd == STM32_BBSRAM_GETDESC_IOCTL)
{
FAR struct bbsramd_s *bbrr = (FAR struct bbsramd_s *)((uintptr_t)arg);
stm32_bbsram_semtake(bbr);
if (!bbrr)
{
ret = -EINVAL;
}
else
{
bbrr->fileno = bbr->bbf->fileno;
bbrr->lastwrite = bbr->bbf->lastwrite;
bbrr->len = bbr->bbf->len;
bbrr->flags = ((bbr->bbf->crc == stm32_bbsram_crc(bbr->bbf))
? BBSRAM_CRC_VALID : 0);
bbrr->flags |= ((bbr->bbf->dirty) ? BBSRAM_DIRTY : 0);
ret = OK;
}
stm32_bbsram_semgive(bbr);
}
return ret;
}
/****************************************************************************
* Name: stm32_bbsram_unlink
*
* Description:
* This function will remove the remove the file from the file system
* it will zero the contents and time stamp. It will leave the fileno
* and pointer to the BBSRAM intact.
* It should be called called on the the file used for the crash dump
* to remove it from visibility in the file system after it is created or
* read thus arming it.
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int stm32_bbsram_unlink(FAR struct inode *inode)
{
FAR struct stm32_bbsram_s *bbr;
DEBUGASSERT(inode && inode->i_private);
bbr = (FAR struct stm32_bbsram_s *)inode->i_private;
stm32_bbsram_semtake(bbr);
stm32_bbsram_unlock();
memset(bbr->bbf->data, 0, bbr->bbf->len);
bbr->bbf->lastwrite.tv_nsec = 0;
bbr->bbf->lastwrite.tv_sec = 0;
bbr->bbf->crc = stm32_bbsram_crc(bbr->bbf);
stm32_bbsram_lock();
bbr->refs = 0;
stm32_bbsram_semgive(bbr);
sem_destroy(&bbr->exclsem);
return 0;
}
#endif
/****************************************************************************
* Name: stm32_bbsram_probe
*
* Description: Based on the number of files defined and their sizes
* Initializes the base pointers to the file entries.
*
****************************************************************************/
static int stm32_bbsram_probe(int *ent, struct stm32_bbsram_s pdev[])
{
int i;
int avail = STM32_BBSRAM_SIZE;
int alloc;
int size;
int ret = -EFBIG;
struct bbsramfh_s *pf = (struct bbsramfh_s *) STM32_BKPSRAM_BASE;
for (i = 0; (i < CONFIG_STM32_BBSRAM_FILES) && ent[i] && (avail > 0); i++)
{
/* Validate the actual allocations against what is in the BBSRAM */
size = ent[i];
/* Use all that is left */
if (size == -1)
{
size = avail - (BBSRAM_HEADER_SIZE + BBSRAM_ALIGNMENT_MASK);
}
/* Add in header size and keep aligned */
alloc = size + BBSRAM_HEADER_SIZE + BBSRAM_ALIGNMENT_MASK;
alloc &= ~(BBSRAM_ALIGNMENT_MASK);
/* Does it fit? */
if (alloc <= avail)
{
ret = i + 1;
BBSRAM_DUMP(pf, "probe");
if (pf->len != size ||
pf->fileno != i ||
pf->crc != stm32_bbsram_crc(pf))
{
/* Not Valid so wipe the file in BBSRAM */
memset((uint8_t *)pf, 0, alloc);
pf->fileno = i;
pf->len = size;
pf->crc = stm32_bbsram_crc(pf);
BBSRAM_DUMP(pf, "probe reset");
}
pdev[i].bbf = pf;
pf = (struct bbsramfh_s *)((uint8_t *)pf + alloc);
sem_init(&g_bbsram[i].exclsem, 0, 1);
}
avail -= alloc;
}
BBSRAM_DEBUG_READ();
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* 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_STM32_BBSRAM_FILES
* CONFIG_STM32_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)
{
int i;
int fcnt;
char path[32];
char devname[32];
int ret = OK;
if (devpath == NULL)
{
return -EINVAL;
}
i = strlen(devpath);
if (i == 0 || i > sizeof(path) + 3)
{
return -EINVAL;
}
memset(g_bbsram, 0, sizeof(g_bbsram));
/* Clocking for the PWR block must be provided. However, this is done
* unconditionally in stm32f40xxx_rcc.c on power up. This done
* unconditionally because the PWR block is also needed to set the
* internal voltage regulator for maximum performance.
*/
/* Enable backup SRAM clock is done in rcc_enableahb1() when
* CONFIG_STM32_BKPSRAM is defined.
*/
/* Allow Access */
stm32_bbsram_unlock();
/* Enable backup regulator so that the data is retained in Standby and
* VBAT modes
*/
stm32_pwr_enablebreg(true);
fcnt = stm32_bbsram_probe(sizes, g_bbsram);
strncpy(path, devpath, sizeof(path));
strcat(path, "%d");
for (i = 0; i < fcnt && ret >= OK; i++)
{
snprintf(devname, sizeof(devname), path, i);
ret = register_driver(devname, &stm32_bbsram_fops, 0666, &g_bbsram[i]);
}
/* Disallow Access */
stm32_bbsram_lock();
return ret < OK ? ret : fcnt;
}
/****************************************************************************
* Function: stm32_bbsram_savepanic
*
* Description:
* Saves the panic context in a previously allocated BBSRAM file
*
* Parameters:
* fileno - the value returned by the ioctl STM32_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_STM32_SAVE_CRASHDUMP)
int stm32_bbsram_savepanic(int fileno, uint8_t *context, int length)
{
FAR struct bbsramfh_s *bbf;
int fill;
int ret = -ENOSPC;
/* On a bad day we could panic while panicking, (and we debug assert)
* this is a potential feeble attempt at only writing the first
* panic's context to the file
*/
static bool once = false;
if (!once)
{
once = true;
DEBUGASSERT(fileno > 0 && fileno < CONFIG_STM32_BBSRAM_FILES);
bbf = g_bbsram[fileno].bbf;
DEBUGASSERT(bbf);
/* If the g_bbsram has been nulled out we return ENXIO.
*
* As once ensures we will keep the first dump. Checking the time for
* 0 protects from over writing a previous crash dump that has not
* been saved to long term storage and erased. The dreaded reboot
* loop.
*/
if (!bbf)
{
ret = -ENXIO;
}
else if ((bbf->lastwrite.tv_sec == 0 && bbf->lastwrite.tv_nsec == 0))
{
/* Clamp length if too big */
if (length > bbf->len)
{
length = bbf->len;
}
stm32_bbsram_unlock();
stm32_bbsram_internal_write(bbf, (char *) context, 0, length);
/* Fill with 0 if data is less then file size */
fill = (int) bbf->len - length;
if (fill > 0)
{
memset(&bbf->data[length], 0, fill);
}
/* Seal the file */
stm32_bbsram_internal_close(bbf);
stm32_bbsram_lock();
ret = length;
}
}
return ret;
}
#endif
#endif /* CONFIG_BBSRAM_DRIVER */
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