[PATCH] mtd: nand: Add OX820 NAND Support
Boris Brezillon
boris.brezillon at free-electrons.com
Wed Oct 19 08:54:28 PDT 2016
On Wed, 19 Oct 2016 17:46:01 +0200
Neil Armstrong <narmstrong at 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.
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