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[MTD] NAND: Add suspend/resume functionality 

The changes introduced allow to suspend/resume NAND flash.
A new state (FL_PM_SUSPENDED) is introduced, as well as
routines for mtd->suspend and mtd->resume to put the flash in
suspended state from software pov.

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Vitaly Wool 2005-09-15 14:58:53 +01:00 committed by Thomas Gleixner
parent 9c517e6c80
commit 962034f439
2 changed files with 42 additions and 7 deletions
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46
drivers/mtd/nand/nand_base.c
View File

@ -46,6 +46,8 @@
* perform extra error status checks on erase and write failures. This required
* adding a wrapper function for nand_read_ecc.
*
* 08-20-2005 vwool: suspend/resume added
*
* Credits:
* David Woodhouse for adding multichip support
*
@ -59,7 +61,7 @@
* The AG-AND chips have nice features for speed improvement,
* which are not supported yet. Read / program 4 pages in one go.
*
* $Id: nand_base.c,v 1.148 2005/08/04 17:14:48 gleixner Exp $
* $Id: nand_base.c,v 1.150 2005/09/15 13:58:48 vwool Exp $
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@ -153,7 +155,7 @@ static int nand_verify_pages (struct mtd_info *mtd, struct nand_chip *this, int
#define nand_verify_pages(...) (0)
#endif
static void nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state);
static int nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state);
/**
* nand_release_device - [GENERIC] release chip
@ -756,7 +758,7 @@ static void nand_command_lp (struct mtd_info *mtd, unsigned command, int column,
*
* Get the device and lock it for exclusive access
*/
static void nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state)
static int nand_get_device (struct nand_chip *this, struct mtd_info *mtd, int new_state)
{
struct nand_chip *active;
spinlock_t *lock;
@ -779,7 +781,11 @@ retry:
if (active == this && this->state == FL_READY) {
this->state = new_state;
spin_unlock(lock);
return;
return 0;
}
if (new_state == FL_PM_SUSPENDED) {
spin_unlock(lock);
return (this->state == FL_PM_SUSPENDED) ? 0 : -EAGAIN;
}
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(wq, &wait);
@ -2284,6 +2290,34 @@ static int nand_block_markbad (struct mtd_info *mtd, loff_t ofs)
return this->block_markbad(mtd, ofs);
}
/**
* nand_suspend - [MTD Interface] Suspend the NAND flash
* @mtd: MTD device structure
*/
static int nand_suspend(struct mtd_info *mtd)
{
struct nand_chip *this = mtd->priv;
return nand_get_device (this, mtd, FL_PM_SUSPENDED);
}
/**
* nand_resume - [MTD Interface] Resume the NAND flash
* @mtd: MTD device structure
*/
static void nand_resume(struct mtd_info *mtd)
{
struct nand_chip *this = mtd->priv;
if (this->state == FL_PM_SUSPENDED)
nand_release_device(mtd);
else
printk(KERN_ERR "resume() called for the chip which is not "
"in suspended state\n");
}
/**
* nand_scan - [NAND Interface] Scan for the NAND device
* @mtd: MTD device structure
@ -2643,8 +2677,8 @@ int nand_scan (struct mtd_info *mtd, int maxchips)
mtd->sync = nand_sync;
mtd->lock = NULL;
mtd->unlock = NULL;
mtd->suspend = NULL;
mtd->resume = NULL;
mtd->suspend = nand_suspend;
mtd->resume = nand_resume;
mtd->block_isbad = nand_block_isbad;
mtd->block_markbad = nand_block_markbad;

3
include/linux/mtd/nand.h
View File

@ -5,7 +5,7 @@
* Steven J. Hill <sjhill@realitydiluted.com>
* Thomas Gleixner <tglx@linutronix.de>
*
* $Id: nand.h,v 1.73 2005/05/31 19:39:17 gleixner Exp $
* $Id: nand.h,v 1.74 2005/09/15 13:58:50 vwool Exp $
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@ -244,6 +244,7 @@ typedef enum {
FL_ERASING,
FL_SYNCING,
FL_CACHEDPRG,
FL_PM_SUSPENDED,
} nand_state_t;
/* Keep gcc happy */