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linux-next/include/linux/mtd/mtd.h
Richard Purdie 388bbb09b9 [MTD] Add mtd panic_write function pointer 
MTDs are well suited for logging critical data and the mtdoops driver
allows kernel panics/oops to be written to flash in a blackbox flight
recorder fashion allowing better debugging and analysis of crashes.

Any kernel oops in user context can be easily handled since the kernel
continues as normal and any queued mtd writes are scheduled. Any kernel
oops in interrupt context results in a panic and the delayed writes will
not be scheduled however. The existing mtd->write function cannot be
called in interrupt context so these messages can never be written to
flash.

This patch adds a panic_write function pointer that drivers can
optionally implement which can be called in interrupt context. It is
only intended to be called when its known the kernel is about to panic
and we need to write to succeed. Since the kernel is not going to be
running for much longer, this function can break locks and delay to
ensure the write succeeds (but not sleep).

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-02-07 10:30:48 +00:00

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/*
* $Id: mtd.h,v 1.61 2005/11/07 11:14:54 gleixner Exp $
*
* Copyright (C) 1999-2003 David Woodhouse <dwmw2@infradead.org> et al.
*
* Released under GPL
*/
#ifndef __MTD_MTD_H__
#define __MTD_MTD_H__
#include <linux/types.h>
#include <linux/module.h>
#include <linux/uio.h>
#include <linux/notifier.h>
#include <linux/mtd/compatmac.h>
#include <mtd/mtd-abi.h>
#define MTD_CHAR_MAJOR 90
#define MTD_BLOCK_MAJOR 31
#define MAX_MTD_DEVICES 32
#define MTD_ERASE_PENDING 0x01
#define MTD_ERASING 0x02
#define MTD_ERASE_SUSPEND 0x04
#define MTD_ERASE_DONE 0x08
#define MTD_ERASE_FAILED 0x10
/* If the erase fails, fail_addr might indicate exactly which block failed. If
fail_addr = 0xffffffff, the failure was not at the device level or was not
specific to any particular block. */
struct erase_info {
struct mtd_info *mtd;
u_int32_t addr;
u_int32_t len;
u_int32_t fail_addr;
u_long time;
u_long retries;
u_int dev;
u_int cell;
void (*callback) (struct erase_info *self);
u_long priv;
u_char state;
struct erase_info *next;
};
struct mtd_erase_region_info {
u_int32_t offset; /* At which this region starts, from the beginning of the MTD */
u_int32_t erasesize; /* For this region */
u_int32_t numblocks; /* Number of blocks of erasesize in this region */
unsigned long *lockmap; /* If keeping bitmap of locks */
};
/*
* oob operation modes
*
* MTD_OOB_PLACE: oob data are placed at the given offset
* MTD_OOB_AUTO: oob data are automatically placed at the free areas
* which are defined by the ecclayout
* MTD_OOB_RAW: mode to read raw data+oob in one chunk. The oob data
* is inserted into the data. Thats a raw image of the
* flash contents.
*/
typedef enum {
MTD_OOB_PLACE,
MTD_OOB_AUTO,
MTD_OOB_RAW,
} mtd_oob_mode_t;
/**
* struct mtd_oob_ops - oob operation operands
* @mode: operation mode
*
* @len: number of data bytes to write/read
*
* @retlen: number of data bytes written/read
*
* @ooblen: number of oob bytes to write/read
* @oobretlen: number of oob bytes written/read
* @ooboffs: offset of oob data in the oob area (only relevant when
* mode = MTD_OOB_PLACE)
* @datbuf: data buffer - if NULL only oob data are read/written
* @oobbuf: oob data buffer
*
* Note, it is allowed to read more then one OOB area at one go, but not write.
* The interface assumes that the OOB write requests program only one page's
* OOB area.
*/
struct mtd_oob_ops {
mtd_oob_mode_t mode;
size_t len;
size_t retlen;
size_t ooblen;
size_t oobretlen;
uint32_t ooboffs;
uint8_t *datbuf;
uint8_t *oobbuf;
};
struct mtd_info {
u_char type;
u_int32_t flags;
u_int32_t size; // Total size of the MTD
/* "Major" erase size for the device. Naïve users may take this
* to be the only erase size available, or may use the more detailed
* information below if they desire
*/
u_int32_t erasesize;
/* Minimal writable flash unit size. In case of NOR flash it is 1 (even
* though individual bits can be cleared), in case of NAND flash it is
* one NAND page (or half, or one-fourths of it), in case of ECC-ed NOR
* it is of ECC block size, etc. It is illegal to have writesize = 0.
* Any driver registering a struct mtd_info must ensure a writesize of
* 1 or larger.
*/
u_int32_t writesize;
u_int32_t oobsize; // Amount of OOB data per block (e.g. 16)
u_int32_t oobavail; // Available OOB bytes per block
// Kernel-only stuff starts here.
char *name;
int index;
/* ecc layout structure pointer - read only ! */
struct nand_ecclayout *ecclayout;
/* Data for variable erase regions. If numeraseregions is zero,
* it means that the whole device has erasesize as given above.
*/
int numeraseregions;
struct mtd_erase_region_info *eraseregions;
/*
* Erase is an asynchronous operation. Device drivers are supposed
* to call instr->callback() whenever the operation completes, even
* if it completes with a failure.
* Callers are supposed to pass a callback function and wait for it
* to be called before writing to the block.
*/
int (*erase) (struct mtd_info *mtd, struct erase_info *instr);
/* This stuff for eXecute-In-Place */
int (*point) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf);
/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
void (*unpoint) (struct mtd_info *mtd, u_char * addr, loff_t from, size_t len);
int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
/* In blackbox flight recorder like scenarios we want to make successful
writes in interrupt context. panic_write() is only intended to be
called when its known the kernel is about to panic and we need the
write to succeed. Since the kernel is not going to be running for much
longer, this function can break locks and delay to ensure the write
succeeds (but not sleep). */
int (*panic_write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
int (*read_oob) (struct mtd_info *mtd, loff_t from,
struct mtd_oob_ops *ops);
int (*write_oob) (struct mtd_info *mtd, loff_t to,
struct mtd_oob_ops *ops);
/*
* Methods to access the protection register area, present in some
* flash devices. The user data is one time programmable but the
* factory data is read only.
*/
int (*get_fact_prot_info) (struct mtd_info *mtd, struct otp_info *buf, size_t len);
int (*read_fact_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*get_user_prot_info) (struct mtd_info *mtd, struct otp_info *buf, size_t len);
int (*read_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*write_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*lock_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len);
/* kvec-based read/write methods.
NB: The 'count' parameter is the number of _vectors_, each of
which contains an (ofs, len) tuple.
*/
int (*writev) (struct mtd_info *mtd, const struct kvec *vecs, unsigned long count, loff_t to, size_t *retlen);
/* Sync */
void (*sync) (struct mtd_info *mtd);
/* Chip-supported device locking */
int (*lock) (struct mtd_info *mtd, loff_t ofs, size_t len);
int (*unlock) (struct mtd_info *mtd, loff_t ofs, size_t len);
/* Power Management functions */
int (*suspend) (struct mtd_info *mtd);
void (*resume) (struct mtd_info *mtd);
/* Bad block management functions */
int (*block_isbad) (struct mtd_info *mtd, loff_t ofs);
int (*block_markbad) (struct mtd_info *mtd, loff_t ofs);
struct notifier_block reboot_notifier; /* default mode before reboot */
/* ECC status information */
struct mtd_ecc_stats ecc_stats;
/* Subpage shift (NAND) */
int subpage_sft;
void *priv;
struct module *owner;
int usecount;
/* If the driver is something smart, like UBI, it may need to maintain
* its own reference counting. The below functions are only for driver.
* The driver may register its callbacks. These callbacks are not
* supposed to be called by MTD users */
int (*get_device) (struct mtd_info *mtd);
void (*put_device) (struct mtd_info *mtd);
};
/* Kernel-side ioctl definitions */
extern int add_mtd_device(struct mtd_info *mtd);
extern int del_mtd_device (struct mtd_info *mtd);
extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
extern struct mtd_info *get_mtd_device_nm(const char *name);
extern void put_mtd_device(struct mtd_info *mtd);
struct mtd_notifier {
void (*add)(struct mtd_info *mtd);
void (*remove)(struct mtd_info *mtd);
struct list_head list;
};
extern void register_mtd_user (struct mtd_notifier *new);
extern int unregister_mtd_user (struct mtd_notifier *old);
int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
unsigned long count, loff_t to, size_t *retlen);
int default_mtd_readv(struct mtd_info *mtd, struct kvec *vecs,
unsigned long count, loff_t from, size_t *retlen);
#ifdef CONFIG_MTD_PARTITIONS
void mtd_erase_callback(struct erase_info *instr);
#else
static inline void mtd_erase_callback(struct erase_info *instr)
{
if (instr->callback)
instr->callback(instr);
}
#endif
/*
* Debugging macro and defines
*/
#define MTD_DEBUG_LEVEL0 (0) /* Quiet */
#define MTD_DEBUG_LEVEL1 (1) /* Audible */
#define MTD_DEBUG_LEVEL2 (2) /* Loud */
#define MTD_DEBUG_LEVEL3 (3) /* Noisy */
#ifdef CONFIG_MTD_DEBUG
#define DEBUG(n, args...) \
do { \
if (n <= CONFIG_MTD_DEBUG_VERBOSE) \
printk(KERN_INFO args); \
} while(0)
#else /* CONFIG_MTD_DEBUG */
#define DEBUG(n, args...) do { } while(0)
#endif /* CONFIG_MTD_DEBUG */
#endif /* __MTD_MTD_H__ */
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