lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[MTD] Simplify NAND locking

Browse Source 
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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner
2006-05-23 11:37:03 +02:00
parent 819d6a32c3
commit a36ed2995c
2 changed files with 47 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

81
drivers/mtd/nand/nand_base.c
View File

@@ -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);
}
/* 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);
}
/**
@@ -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
this->controller->active = this;
}
if (active == this && this->state == FL_READY) {
/* Hardware controller shared among independend devices */
if (!this->controller->active)
this->controller->active = this;
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);