Messages in this thread | | | Date | Wed, 19 Sep 2018 23:26:30 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH 1/2] mtd: rawnand: denali: remove ->dev_ready() hook |
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Hi Masahiro,
Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Fri, 7 Sep 2018 16:28:28 +0900:
> The Denali NAND IP has no way to read out the current signal level > of the R/B# pin. Instead, denali_dev_ready() checks if the R/B# > transition has already happened. (The INTR__INT_ACT interrupt is > asserted at the rising edge of the R/B# pin.) It is not a correct > way to implement the ->dev_ready() hook. > > In fact, it has a drawback; in the nand_scan_ident phase, the chip > detection iterates over maxchips until it fails to find a homogeneous > chip. For the last loop, nand_reset() fails if no chip is there. > > If ->dev_ready hook exists, nand_command(_lp) calls nand_wait_ready() > after NAND_CMD_RESET. However, we know denali_dev_ready() never > returns 1 unless there exists a chip that toggles R/B# in that chip > select. Then, nand_wait_ready() just ends up with wasting 400 msec, > in the end, shows the "timeout while waiting for chip to become ready" > warning. > > Let's remove the mis-implemented dev_ready hook, and fallback to > sending the NAND_CMD_STATUS and nand_wait_status_ready(), which > bails out more quickly. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > ---
Both patches applied on nand/next.
Thanks, Miquèl
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