From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Neil Armstrong <narmstrong@baylibre.com>
Cc: dwmw2@infradead.org, computersforpeace@gmail.com, richard@nod.at,
linux-mtd@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-oxnas@lists.tuxfamily.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, daniel@makrotopia.org
Subject: Re: [PATCH] mtd: nand: Add OX820 NAND Support
Date: Wed, 19 Oct 2016 17:54:28 +0200 [thread overview]
Message-ID: <20161019175428.6ea3998d@bbrezillon> (raw)
In-Reply-To: <0f5398bb-52f1-d5bb-834c-dead4f708fd3@baylibre.com>
On Wed, 19 Oct 2016 17:46:01 +0200
Neil Armstrong <narmstrong@baylibre.com> wrote:
> >> +/* Single CS command control */
> >> +static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
> >> + unsigned int ctrl)
> >> +{
> >> + struct nand_chip *chip = mtd_to_nand(mtd);
> >> + struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> >> +
> >> + if (ctrl & NAND_CTRL_CHANGE) {
> >> + if (ctrl & NAND_CLE)
> >> + oxnas->ctrl = OXNAS_NAND_CMD_CLE;
> >> + else if (ctrl & NAND_ALE)
> >> + oxnas->ctrl = OXNAS_NAND_CMD_ALE;
> >> + else
> >> + oxnas->ctrl = 0;
> >> + }
> >> +
> >> + if (cmd != NAND_CMD_NONE)
> >> + writeb(cmd, oxnas->io_base + oxnas->ctrl);
> >
> > There's no need to test the NAND_CTRL_CHANGE here, and I don't think
> > the CLE or ALE flag is ever set when cmd == CMD_NONE. So, you can kill
> > the ->ctrl field and simply do:
> >
> > if (ctrl & NAND_CLE)
> > writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_CLE);
> > else if (ctrl & NAND_ALE)
> > writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_ALE);
> >
> >> +}
>
> Hmm, except it's needed back in the oxnas_nand_write_buf() call (don't ask me why)
> so I don't see how to simplify more this function.
Are you sure? Can you add a WARN(oxnas->ctrl) in oxnas_nand_write_buf()
to check if it's ever the case? I'm almost sure there is a call to
->cmd_ctrl() with none of the CLE and ALE flags set before the
->write_buf() call.
WARNING: multiple messages have this Message-ID (diff)
From: boris.brezillon@free-electrons.com (Boris Brezillon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] mtd: nand: Add OX820 NAND Support
Date: Wed, 19 Oct 2016 17:54:28 +0200 [thread overview]
Message-ID: <20161019175428.6ea3998d@bbrezillon> (raw)
In-Reply-To: <0f5398bb-52f1-d5bb-834c-dead4f708fd3@baylibre.com>
On Wed, 19 Oct 2016 17:46:01 +0200
Neil Armstrong <narmstrong@baylibre.com> wrote:
> >> +/* Single CS command control */
> >> +static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
> >> + unsigned int ctrl)
> >> +{
> >> + struct nand_chip *chip = mtd_to_nand(mtd);
> >> + struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> >> +
> >> + if (ctrl & NAND_CTRL_CHANGE) {
> >> + if (ctrl & NAND_CLE)
> >> + oxnas->ctrl = OXNAS_NAND_CMD_CLE;
> >> + else if (ctrl & NAND_ALE)
> >> + oxnas->ctrl = OXNAS_NAND_CMD_ALE;
> >> + else
> >> + oxnas->ctrl = 0;
> >> + }
> >> +
> >> + if (cmd != NAND_CMD_NONE)
> >> + writeb(cmd, oxnas->io_base + oxnas->ctrl);
> >
> > There's no need to test the NAND_CTRL_CHANGE here, and I don't think
> > the CLE or ALE flag is ever set when cmd == CMD_NONE. So, you can kill
> > the ->ctrl field and simply do:
> >
> > if (ctrl & NAND_CLE)
> > writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_CLE);
> > else if (ctrl & NAND_ALE)
> > writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_ALE);
> >
> >> +}
>
> Hmm, except it's needed back in the oxnas_nand_write_buf() call (don't ask me why)
> so I don't see how to simplify more this function.
Are you sure? Can you add a WARN(oxnas->ctrl) in oxnas_nand_write_buf()
to check if it's ever the case? I'm almost sure there is a call to
->cmd_ctrl() with none of the CLE and ALE flags set before the
->write_buf() call.
next prev parent reply other threads:[~2016-10-19 15:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 14:55 [PATCH] mtd: nand: Add OX820 NAND Support Neil Armstrong
2016-10-19 14:55 ` Neil Armstrong
2016-10-19 14:55 ` Neil Armstrong
2016-10-19 15:30 ` Neil Armstrong
2016-10-19 15:30 ` Neil Armstrong
2016-10-19 15:37 ` Boris Brezillon
2016-10-19 15:37 ` Boris Brezillon
2016-10-19 15:37 ` Boris Brezillon
2016-10-19 15:46 ` Neil Armstrong
2016-10-19 15:46 ` Neil Armstrong
2016-10-19 15:46 ` Neil Armstrong
2016-10-19 15:54 ` Boris Brezillon [this message]
2016-10-19 15:54 ` Boris Brezillon
2016-10-19 16:21 ` Boris Brezillon
2016-10-19 16:21 ` Boris Brezillon
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