Commit 6ea40a3b authored by Boris Brezillon's avatar Boris Brezillon
Browse files

mtd: nand: Wait tCCS after a column change 



Drivers implementing ->cmd_ctrl() and relying on the default ->cmdfunc()
implementation usually don't wait tCCS when a column change (RNDIN or
RNDOUT) is requested.
Add an option flag to ask the core to do so (note that we keep this as
an opt-in to avoid breaking existing implementations), and make use of
the ->data_interface information is available (otherwise, wait 500ns).

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: default avatarMarc Gonzalez <marc_gonzalez@sigmadesigns.com>
parent 204e7ecd

drivers/mtd/nand/nand_base.c

+25 −1
Original line number Diff line number Diff line
@@ -709,6 +709,25 @@ static void nand_command(struct mtd_info *mtd, unsigned int command, 
	nand_wait_ready(mtd);

}



static void nand_ccs_delay(struct nand_chip *chip)

{

	/*

	 * The controller already takes care of waiting for tCCS when the RNDIN

	 * or RNDOUT command is sent, return directly.

	 */

	if (!(chip->options & NAND_WAIT_TCCS))

		return;



	/*

	 * Wait tCCS_min if it is correctly defined, otherwise wait 500ns

	 * (which should be safe for all NANDs).

	 */

	if (chip->data_interface && chip->data_interface->timings.sdr.tCCS_min)

		ndelay(chip->data_interface->timings.sdr.tCCS_min / 1000);

	else

		ndelay(500);

}



/**

 * nand_command_lp - [DEFAULT] Send command to NAND large page device

 * @mtd: MTD device structure
@@ -773,10 +792,13 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command, 
	case NAND_CMD_ERASE1:

	case NAND_CMD_ERASE2:

	case NAND_CMD_SEQIN:

	case NAND_CMD_RNDIN:

	case NAND_CMD_STATUS:

		return;



	case NAND_CMD_RNDIN:

		nand_ccs_delay(chip);

		return;



	case NAND_CMD_RESET:

		if (chip->dev_ready)

			break;
@@ -795,6 +817,8 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command, 
			       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);

		chip->cmd_ctrl(mtd, NAND_CMD_NONE,

			       NAND_NCE | NAND_CTRL_CHANGE);



		nand_ccs_delay(chip);

		return;



	case NAND_CMD_READ0:

include/linux/mtd/nand.h

+10 −0
Original line number Diff line number Diff line
@@ -210,6 +210,16 @@ enum nand_ecc_algo { 
 */

#define NAND_USE_BOUNCE_BUFFER	0x00100000



/*

 * In case your controller is implementing ->cmd_ctrl() and is relying on the

 * default ->cmdfunc() implementation, you may want to let the core handle the

 * tCCS delay which is required when a column change (RNDIN or RNDOUT) is

 * requested.

 * If your controller already takes care of this delay, you don't need to set

 * this flag.

 */

#define NAND_WAIT_TCCS		0x00200000



/* Options set by nand scan */

/* Nand scan has allocated controller struct */

#define NAND_CONTROLLER_ALLOC	0x80000000

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