From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] mtd: nand: mxc_nand: implement exec_op
Date: Tue, 14 May 2024 12:16:02 +0200 [thread overview]
Message-ID: <20240514121602.273f788e@xps-13> (raw)
In-Reply-To: <ZkMsS1jj-ZTpZyE1@pengutronix.de>
Hi Sascha,
> > > > + case NAND_OP_WAITRDY_INSTR:
> > > > + /*
> > > > + * NFC handles R/B internally. Therefore, this function
> > > > + * always returns status as ready.
> > >
> > > This is no longer a standalone function, maybe:
> > >
> > > "The controller handles the R/B pin internally, therefore there is
> > > nothing to do here."
>
> Ok.
>
> >
> > And this is actually very wrong.
> >
> > You should call wait_op_done() instead.
>
> No, I don't think so. wait_op_done() is called to wait for the interrupt
> of the controller indicating a basic operation is done. A basic operation
> can be that a command is being sent or an address byte has been sent to
> the chip during an address cycle.
>
> With this arbitrary example:
>
> struct nand_op_instr instrs[] = {
> NAND_OP_CMD(NAND_CMD_READ0, 0),
> NAND_OP_ADDR(4, addrs, 0),
> NAND_OP_CMD(NAND_CMD_READSTART, NAND_COMMON_TIMING_NS(conf, tWB_max)),
> NAND_OP_WAIT_RDY(NAND_COMMON_TIMING_MS(conf, tR_max),
> NAND_COMMON_TIMING_NS(conf, tRR_min)),
> NAND_OP_DATA_IN(len, buf, 0),
> };
>
> I'll call wait_op_done() once for NAND_CMD_READ0, four times for the NAND_OP_ADDR,
> then once again for the NAND_CMD_READSTART command and four times (on i.MX27, once
> per subpage) for the NAND_OP_DATA_IN operation. Calling wait_op_done() for the
> NAND_OP_WAIT_RDY operation woul only timeout because there is no operation in flight
> currently.
Ah, ok, makes sense as well. If you want (this is not mandatory) you
may want to rename the function wait_instr_done() to fit the core's
naming: an operation being an aggregate of instructions/cycles.
Thanks,
Miquèl
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next prev parent reply other threads:[~2024-05-14 10:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 11:08 [PATCH v2 0/3] mtd: nand: mxc_nand: Convert to exec_op Sascha Hauer
2024-05-08 11:08 ` [PATCH v2 1/3] mtd: nand: mxc_nand: separate page read from ecc calc Sascha Hauer
2024-05-08 11:08 ` [PATCH v2 2/3] mtd: nand: mxc_nand: implement exec_op Sascha Hauer
2024-05-13 7:19 ` Miquel Raynal
2024-05-13 7:32 ` Miquel Raynal
2024-05-13 9:08 ` Sascha Hauer
2024-05-13 12:55 ` Miquel Raynal
2024-05-14 9:18 ` Sascha Hauer
2024-05-14 10:16 ` Miquel Raynal [this message]
2024-05-08 11:08 ` [PATCH v2 3/3] mtd: nand: mxc_nand: support software ECC Sascha Hauer
2024-05-13 7:42 ` Miquel Raynal
2024-05-13 9:19 ` Sascha Hauer
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