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authorRoger Quadros <rogerq@ti.com>2015-02-23 18:26:39 +0300
committerBrian Norris <computersforpeace@gmail.com>2015-03-31 03:39:15 +0300
commit60c70d66cdd39eb560bba5a95c429bf2ad5294d0 (patch)
tree52eb33f58905f89256ebd8836ff25af072b65f16 /drivers/mtd
parent8cc7f33aadc8fb37b5a3f4c46f5fa83748a92a01 (diff)
downloadlinux-60c70d66cdd39eb560bba5a95c429bf2ad5294d0.tar.xz
mtd: nand: Prevent possible kernel lockup in nand_command()
If a NAND device is not really present or pin muxes are not correctly configured we can lock up the kernel waiting infinitely for NAND_STATUS to be ready. This can be easily reproduced on TI's DRA7-evm board by booting it without NAND support in u-boot and disabling NAND pin muxes in the kernel. Add timeout when waiting for NAND_CMD_RESET completion. As per ONFi v4.0 tRST can be upto 250ms for EZ-NAND and 5ms for raw NAND. Signed-off-by: Roger Quadros <rogerq@ti.com> Tested-by: Nishanth Menon <nm@ti.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/nand/nand_base.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ff5652211607..c2e1232cd45c 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -566,6 +566,25 @@ void nand_wait_ready(struct mtd_info *mtd)
EXPORT_SYMBOL_GPL(nand_wait_ready);
/**
+ * nand_wait_status_ready - [GENERIC] Wait for the ready status after commands.
+ * @mtd: MTD device structure
+ * @timeo: Timeout in ms
+ *
+ * Wait for status ready (i.e. command done) or timeout.
+ */
+static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
+{
+ register struct nand_chip *chip = mtd->priv;
+
+ timeo = jiffies + msecs_to_jiffies(timeo);
+ do {
+ if ((chip->read_byte(mtd) & NAND_STATUS_READY))
+ break;
+ touch_softlockup_watchdog();
+ } while (time_before(jiffies, timeo));
+};
+
+/**
* nand_command - [DEFAULT] Send command to NAND device
* @mtd: MTD device structure
* @command: the command to be sent
@@ -643,8 +662,8 @@ 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))
- ;
+ /* EZ-NAND can take upto 250ms as per ONFi v4.0 */
+ nand_wait_status_ready(mtd, 250);
return;
/* This applies to read commands */
@@ -740,8 +759,8 @@ 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))
- ;
+ /* EZ-NAND can take upto 250ms as per ONFi v4.0 */
+ nand_wait_status_ready(mtd, 250);
return;
case NAND_CMD_RNDOUT: