[MTD] Simplify NAND locking
Linux-MTD Mailing List
linux-mtd at lists.infradead.org
Tue May 23 06:59:02 EDT 2006
Commit: a36ed2995c56d4f858ecb524a78837473e7115ae
Parent: 819d6a32c397534c819d3c72a3947b7e7e4bec4b
Author: Thomas Gleixner <tglx at cruncher.tec.linutronix.de>
AuthorDate: Tue May 23 11:37:03 2006 +0200
Commit: Thomas Gleixner <tglx at cruncher.tec.linutronix.de>
CommitDate: Tue May 23 11:37:03 2006 +0200
[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: Thomas Gleixner <tglx at linutronix.de>
drivers/mtd/nand/nand_base.c | 81 ++++++++++++++++++++++--------------------
include/linux/mtd/nand.h | 7 ++--
2 files changed, 47 insertions(+), 41 deletions(-)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 08dffb7..7933ca2 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -172,20 +172,12 @@ static void nand_release_device(struct m
/* 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_i
*/
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
}
+/*
+ * 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
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
/* 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 @@ #endif
/* 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);
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index da5e67b..b8792be 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -227,6 +227,8 @@ #define NAND_HWECC_SYNDROME 0x00020000
#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;
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