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mtd: rawnand: denali_dt: insert udelay() after reset deassert

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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>
This commit is contained in:
Masahiro Yamada 2020-01-30 00:55:54 +09:00
parent 9925df051a
commit 21d4a3ca54
1 changed files with 10 additions and 2 deletions
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12
drivers/mtd/nand/raw/denali_dt.c
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@ -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);
}