diff options
| author | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-10-01 10:24:03 +0200 |
|---|---|---|
| committer | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-11-07 14:48:37 +0100 |
| commit | 6ea40a3ba93e1b14ffb349e276f9dfefc4334b99 (patch) | |
| tree | f37e804a5eecaa681957ff24739964e7bd0c55e5 | |
| parent | 204e7ecd47e26cc12d9e8e8a7e7a2eeb9573f0ba (diff) | |
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: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
| -rw-r--r-- | drivers/mtd/nand/nand_base.c | 26 | ||||
| -rw-r--r-- | include/linux/mtd/nand.h | 10 |
2 files changed, 35 insertions, 1 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index e5718e5ecf92..0acb0070280a 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -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: diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 6fe83bce83a6..970ceb948835 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -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 |