mtd: nand: Wait tCCS after a column change

[mirror_ubuntu-zesty-kernel.git] / drivers / mtd / nand / nand_base.c

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index e5718e5ecf925868012eb0332c43d071f32a727f..0acb0070280a9090700347b54cb9ec9e16c4cb6e 100644 (file)
--- 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: