On Thu, Jan 30, 2020 at 12:57 AM Masahiro Yamada yamada.masahiro@socionext.com wrote:
When the reset signal is de-asserted, the HW-controlled bootstrap starts running unless it is disabled in the SoC integration. It issues some commands to detect a NAND chip, and sets up registers automatically. Until this process finishes, software should avoid any register access.
Without this delay function, some of UniPhier boards hangs up while executing nand_scan_ident(). (denali_read_byte() is blocked)
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com
Applied to u-boot-uniphier.
Changes in v2: None
drivers/mtd/nand/raw/denali_dt.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/raw/denali_dt.c b/drivers/mtd/nand/raw/denali_dt.c index 91d0f20aae..1afc61f876 100644 --- a/drivers/mtd/nand/raw/denali_dt.c +++ b/drivers/mtd/nand/raw/denali_dt.c @@ -136,11 +136,19 @@ static int denali_dt_probe(struct udevice *dev) }
ret = reset_get_bulk(dev, &resets);
if (ret)
if (ret) { dev_warn(dev, "Can't get reset: %d\n", ret);
else
} else { reset_deassert_bulk(&resets);/** When the reset is deasserted, the initialization sequence is* kicked (bootstrap process). The driver must wait until it is* finished. Otherwise, it will result in unpredictable behavior.*/udelay(200);}return denali_init(denali);}
-- 2.17.1