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Commit a36ed299 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

[MTD] Simplify NAND locking 



Replace the chip lock by a the controller lock. For simple drivers a
dummy controller structure is created by the scan code.
This simplifies the locking algorithm in nand_get/release_chip().

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 819d6a32

drivers/mtd/nand/nand_base.c

+43 −38
Original line number Diff line number Diff line
@@ -172,20 +172,12 @@ static void nand_release_device(struct mtd_info *mtd) 
	/* De-select the NAND device */

	this->select_chip(mtd, -1);



	if (this->controller) {

	/* Release the controller and the chip */

	spin_lock(&this->controller->lock);

	this->controller->active = NULL;

	this->state = FL_READY;

	wake_up(&this->controller->wq);

	spin_unlock(&this->controller->lock);

	} else {

		/* Release the chip */

		spin_lock(&this->chip_lock);

		this->state = FL_READY;

		wake_up(&this->wq);

		spin_unlock(&this->chip_lock);

	}

}



/**
@@ -765,25 +757,18 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned command, int column, 
 */

static int nand_get_device(struct nand_chip *this, struct mtd_info *mtd, int new_state)

{

	struct nand_chip *active;

	spinlock_t *lock;

	wait_queue_head_t *wq;

	spinlock_t *lock = &this->controller->lock;

	wait_queue_head_t *wq = &this->controller->wq;

	DECLARE_WAITQUEUE(wait, current);



	lock = (this->controller) ? &this->controller->lock : &this->chip_lock;

	wq = (this->controller) ? &this->controller->wq : &this->wq;

 retry:

	active = this;

	spin_lock(lock);



	/* Hardware controller shared among independend devices */

	if (this->controller) {

		if (this->controller->active)

			active = this->controller->active;

		else

	/* Hardware controller shared among independend devices */

	if (!this->controller->active)

		this->controller->active = this;

	}

	if (active == this && this->state == FL_READY) {



	if (this->controller->active == this && this->state == FL_READY) {

		this->state = new_state;

		spin_unlock(lock);

		return 0;
@@ -2312,6 +2297,22 @@ static void nand_resume(struct mtd_info *mtd) 


}



/*

 * Free allocated data structures

 */

static void nand_free_kmem(struct nand_chip *this)

{

	/* Buffer allocated by nand_scan ? */

	if (this->options & NAND_OOBBUF_ALLOC)

		kfree(this->oob_buf);

	/* Buffer allocated by nand_scan ? */

	if (this->options & NAND_DATABUF_ALLOC)

		kfree(this->data_buf);

	/* Controller allocated by nand_scan ? */

	if (this->options & NAND_CONTROLLER_ALLOC)

		kfree(this->controller);

}



/* module_text_address() isn't exported, and it's mostly a pointless

   test if this is a module _anyway_ -- they'd have to try _really_ hard

   to call us from in-kernel code if the core NAND support is modular. */
@@ -2522,9 +2523,8 @@ int nand_scan(struct mtd_info *mtd, int maxchips) 
		len = mtd->oobblock + mtd->oobsize;

		this->data_buf = kmalloc(len, GFP_KERNEL);

		if (!this->data_buf) {

			if (this->options & NAND_OOBBUF_ALLOC)

				kfree(this->oob_buf);

			printk(KERN_ERR "nand_scan(): Cannot allocate data_buf\n");

			nand_free_kmem(this);

			return -ENOMEM;

		}

		this->options |= NAND_DATABUF_ALLOC;
@@ -2657,8 +2657,17 @@ int nand_scan(struct mtd_info *mtd, int maxchips) 


	/* Initialize state, waitqueue and spinlock */

	this->state = FL_READY;

	init_waitqueue_head(&this->wq);

	spin_lock_init(&this->chip_lock);

	if (!this->controller) {

		this->controller = kzalloc(sizeof(struct nand_hw_control),

					   GFP_KERNEL);

		if (!this->controller) {

			nand_free_kmem(this);

			return -ENOMEM;

		}

		this->options |= NAND_CONTROLLER_ALLOC;

	}

	init_waitqueue_head(&this->controller->wq);

	spin_lock_init(&this->controller->lock);



	/* De-select the device */

	this->select_chip(mtd, -1);
@@ -2718,12 +2727,8 @@ void nand_release(struct mtd_info *mtd) 


	/* Free bad block table memory */

	kfree(this->bbt);

	/* Buffer allocated by nand_scan ? */

	if (this->options & NAND_OOBBUF_ALLOC)

		kfree(this->oob_buf);

	/* Buffer allocated by nand_scan ? */

	if (this->options & NAND_DATABUF_ALLOC)

		kfree(this->data_buf);

	/* Free buffers */

	nand_free_kmem(this);

}



EXPORT_SYMBOL_GPL(nand_scan);

include/linux/mtd/nand.h

+4 −3
Original line number Diff line number Diff line
@@ -227,6 +227,8 @@ extern int nand_read_raw (struct mtd_info *mtd, uint8_t *buf, loff_t from, size_ 
#define NAND_SKIP_BBTSCAN	0x00040000



/* Options set by nand scan */

/* Nand scan has allocated controller struct */

#define NAND_CONTROLLER_ALLOC	0x20000000

/* Nand scan has allocated oob_buf */

#define NAND_OOBBUF_ALLOC	0x40000000

/* Nand scan has allocated data_buf */
@@ -294,7 +296,6 @@ struct nand_hw_control { 
 * @eccbytes: 		[INTERN] number of ecc bytes per ecc-calculation step

 * @eccsteps:		[INTERN] number of ecc calculation steps per page

 * @chip_delay:		[BOARDSPECIFIC] chip dependent delay for transfering data from array to read regs (tR)

 * @chip_lock:		[INTERN] spinlock used to protect access to this structure and the chip

 * @wq:			[INTERN] wait queue to sleep on if a NAND operation is in progress

 * @state: 		[INTERN] the current state of the NAND device

 * @page_shift:		[INTERN] number of address bits in a page (column address bits)
@@ -317,7 +318,8 @@ struct nand_hw_control { 
 * @bbt_td:		[REPLACEABLE] bad block table descriptor for flash lookup

 * @bbt_md:		[REPLACEABLE] bad block table mirror descriptor

 * @badblock_pattern:	[REPLACEABLE] bad block scan pattern used for initial bad block scan

 * @controller:		[OPTIONAL] a pointer to a hardware controller structure which is shared among multiple independend devices

 * @controller:		[REPLACEABLE] a pointer to a hardware controller structure

 *			which is shared among multiple independend devices

 * @priv:		[OPTIONAL] pointer to private chip date

 * @errstat:		[OPTIONAL] hardware specific function to perform additional error status checks

 *			(determine if errors are correctable)
@@ -352,7 +354,6 @@ struct nand_chip { 
	int		eccbytes;

	int		eccsteps;

	int 		chip_delay;

	spinlock_t	chip_lock;

	wait_queue_head_t wq;

	nand_state_t 	state;

	int 		page_shift;