Without the timeout present an infinite loop can occur if the NAND device is broken or not present.
Signed-off-by: Peter Tyser ptyser@xes-inc.com --- drivers/mtd/nand/nand_base.c | 19 +++++++++++++++++-- 1 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index bfa7874..a2656eb 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -75,6 +75,17 @@ #include <jffs2/jffs2.h> #endif
+/* + * CONFIG_SYS_NAND_RESET_CNT is used as a timeout mechanism when resetting + * a flash. NAND flash is initialized prior to interrupts so standard timers + * can't be used. CONFIG_SYS_NAND_RESET_CNT should be set to a value + * which is greater than (max NAND reset time / NAND status read time). + * A conservative default of 200000 (500 us / 25 ns) is used as a default. + */ +#ifndef CONFIG_SYS_NAND_RESET_CNT +#define CONFIG_SYS_NAND_RESET_CNT 200000 +#endif + /* Define default oob placement schemes for large and small page devices */ static struct nand_ecclayout nand_oob_8 = { .eccbytes = 3, @@ -524,6 +535,7 @@ static void nand_command(struct mtd_info *mtd, unsigned int command, { register struct nand_chip *chip = mtd->priv; int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE; + uint32_t rst_sts_cnt = CONFIG_SYS_NAND_RESET_CNT;
/* * Write out the command to the device. @@ -590,7 +602,8 @@ static void nand_command(struct mtd_info *mtd, unsigned int command, NAND_CTRL_CLE | NAND_CTRL_CHANGE); chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE); - while (!(chip->read_byte(mtd) & NAND_STATUS_READY)) ; + while (!(chip->read_byte(mtd) & NAND_STATUS_READY) && + (rst_sts_cnt--)); return;
/* This applies to read commands */ @@ -626,6 +639,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command, int column, int page_addr) { register struct nand_chip *chip = mtd->priv; + uint32_t rst_sts_cnt = CONFIG_SYS_NAND_RESET_CNT;
/* Emulate NAND_CMD_READOOB */ if (command == NAND_CMD_READOOB) { @@ -696,7 +710,8 @@ 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); - while (!(chip->read_byte(mtd) & NAND_STATUS_READY)) ; + while (!(chip->read_byte(mtd) & NAND_STATUS_READY) && + (rst_sts_cnt--)); return;
case NAND_CMD_RNDOUT: