This particular unbounded loop in the Denali NAND reset routine can lead to a system hang in case neither of the Timeout and Completed bits get set.
Refactor the code a bit so it's readable and implement timer so the loop is bounded instead. This way the complete hang can be prevented even if the NAND fails to reset.
Signed-off-by: Marek Vasut marex@denx.de Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Scott Wood scottwood@freescale.com --- drivers/mtd/nand/denali.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 192be7d..8a8cca9 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -199,6 +199,7 @@ static void reset_bank(struct denali_nand_info *denali) static uint32_t denali_nand_reset(struct denali_nand_info *denali) { int i; + u32 start, reg;
for (i = 0; i < denali->max_banks; i++) writel(INTR_STATUS__RST_COMP | INTR_STATUS__TIME_OUT, @@ -206,12 +207,25 @@ static uint32_t denali_nand_reset(struct denali_nand_info *denali)
for (i = 0; i < denali->max_banks; i++) { writel(1 << i, denali->flash_reg + DEVICE_RESET); - while (!(readl(denali->flash_reg + INTR_STATUS(i)) & - (INTR_STATUS__RST_COMP | INTR_STATUS__TIME_OUT))) - if (readl(denali->flash_reg + INTR_STATUS(i)) & - INTR_STATUS__TIME_OUT) - debug("NAND Reset operation timed out on bank" - " %d\n", i); + + start = get_timer(0); + while (1) { + reg = readl(denali->flash_reg + INTR_STATUS(i)); + if (reg & INTR_STATUS__TIME_OUT) { + debug("NAND Reset operation timed out on bank %d\n", + i); + break; + } + + /* Reset completed and did not time out, all good. */ + if (reg & INTR_STATUS__RST_COMP) + break; + + if (get_timer(start) > (CONFIG_SYS_HZ / 1000)) { + debug("%s: Reset timed out!\n", __func__); + break; + } + } }
for (i = 0; i < denali->max_banks; i++)