[PATCH] [MTD] NAND: Add support for driver-specific wait_ready function

[Harald Welte]

This enables a driver to implement RnB-interrupt based waiting
for the RnB line to become ready, as opposed to the busy-waiting
polling implementation in the core NAND layer.

This is particularly important on battery-powered devices where
you try to save CPU cycles where you can.

Signed-off-by: Harald Welte <laforge at openmoko.org>
---
 drivers/mtd/nand/nand_base.c |   10 ++++++----
 include/linux/mtd/nand.h     |    2 ++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index e29c1da..81996b3 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -533,7 +533,7 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
 	 * any case on any machine. */
 	ndelay(100);
 
-	nand_wait_ready(mtd);
+	chip->wait_ready(mtd);
 }
 
 /**
@@ -654,7 +654,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
 	 * any case on any machine. */
 	ndelay(100);
 
-	nand_wait_ready(mtd);
+	chip->wait_ready(mtd);
 }
 
 /**
@@ -1033,7 +1033,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 				if (!chip->dev_ready)
 					udelay(chip->chip_delay);
 				else
-					nand_wait_ready(mtd);
+					chip->wait_ready(mtd);
 			}
 		} else {
 			memcpy(buf, chip->buffers->databuf + col, bytes);
@@ -1318,7 +1318,7 @@ static int nand_do_read_oob(struct mtd_info *mtd, loff_t from,
 			if (!chip->dev_ready)
 				udelay(chip->chip_delay);
 			else
-				nand_wait_ready(mtd);
+				chip->wait_ready(mtd);
 		}
 
 		readlen -= len;
@@ -2211,6 +2211,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw)
 		chip->verify_buf = busw ? nand_verify_buf16 : nand_verify_buf;
 	if (!chip->scan_bbt)
 		chip->scan_bbt = nand_default_bbt;
+	if (!chip->wait_ready)
+		chip->wait_ready = nand_wait_ready;
 
 	if (!chip->controller) {
 		chip->controller = &chip->hwcontrol;
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index c42bc7f..ac0fd71 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -320,6 +320,7 @@ struct nand_buffers {
  * @dev_ready:		[BOARDSPECIFIC] hardwarespecific function for accesing device ready/busy line
  *			If set to NULL no access to ready/busy is available and the ready/busy information
  *			is read from the chip status register
+ * @wait_ready:		[REPLACEABLE] hardwarespecific function for waiting read/busy line
  * @cmdfunc:		[REPLACEABLE] hardwarespecific function for writing commands to the chip
  * @waitfunc:		[REPLACEABLE] hardwarespecific function for wait on ready
  * @ecc:		[BOARDSPECIFIC] ecc control ctructure
@@ -377,6 +378,7 @@ struct nand_chip {
 	void		(*cmd_ctrl)(struct mtd_info *mtd, int dat,
 				    unsigned int ctrl);
 	int		(*dev_ready)(struct mtd_info *mtd);
+	void		(*wait_ready)(struct mtd_info *mtd);
 	void		(*cmdfunc)(struct mtd_info *mtd, unsigned command, int column, int page_addr);
 	int		(*waitfunc)(struct mtd_info *mtd, struct nand_chip *this);
 	void		(*erase_cmd)(struct mtd_info *mtd, int page);
-- 
1.5.6.5


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Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="0002--MTD-S3C24XX-NAND-Use-interrupt-based-RnB.patch"