Re: [PATCH 3/3] mtd: rawnand: marvell: add suspend and resume hooks

[Boris Brezillon <boris.brezillon@bootlin.com>]

On Fri,  6 Jul 2018 22:14:15 +0200
Daniel Mack <daniel@zonque.org> wrote:

> This patch restores the suspend and resume hooks that the old driver used
> to have. Apart from stopping and starting the clocks, the resume callback
> also nullifies the selected_chip pointer, so the next command that is issued
> will re-select the chip and thereby restore the timing registers.
> 
> Without this patch, a PXA3xx based system would cough up an error similar to
> the one below after resume.
> 
> [   44.660162] marvell-nfc 43100000.nand-controller: Timeout waiting for  RB signal
> [   44.671492] ubi0 error: ubi_io_write: error -110 while writing 2048 bytes to PEB 102:38912, written 0 bytes
> [   44.682887] CPU: 0 PID: 1417 Comm: remote-control Not tainted 4.18.0-rc2+ #344
> [   44.691197] Hardware name: Marvell PXA3xx (Device Tree Support)
> [   44.697111] Backtrace:
> [   44.699593] [<c0106458>] (dump_backtrace) from [<c0106718>] (show_stack+0x18/0x1c)
> [   44.708931]  r7:00000800 r6:00009800 r5:00000066 r4:c6139000
> [   44.715833] [<c0106700>] (show_stack) from [<c0678a60>] (dump_stack+0x20/0x28)
> [   44.724206] [<c0678a40>] (dump_stack) from [<c0456cbc>] (ubi_io_write+0x3d4/0x630)
> [   44.732925] [<c04568e8>] (ubi_io_write) from [<c0454428>] (ubi_eba_write_leb+0x690/0x6fc)
> ...
> 
> Signed-off-by: Daniel Mack <daniel@zonque.org>

You probably want patch 2 and 3 backported to stable. Would be better
if we don't need patch 2 though, since this is not exactly a fix. Maybe
you can re-order things and add IS_ERR() tests in the suspend/resume
funcs, which you'll then remove but this time, the cleanup patch won't
be flagged "for stable".

> ---
>  drivers/mtd/nand/raw/marvell_nand.c | 47 +++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> index 0511d0979cc6..9246c3ea6ebc 100644
> --- a/drivers/mtd/nand/raw/marvell_nand.c
> +++ b/drivers/mtd/nand/raw/marvell_nand.c
> @@ -2824,6 +2824,52 @@ static int marvell_nfc_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int __maybe_unused marvell_nfc_suspend(struct device *dev)
> +{
> +	struct marvell_nfc *nfc = dev_get_drvdata(dev);
> +	struct marvell_nand_chip *chip;
> +
> +	list_for_each_entry(chip, &nfc->chips, node)
> +		marvell_nfc_wait_ndrun(&chip->chip);
> +
> +	clk_disable_unprepare(nfc->reg_clk);
> +	clk_disable_unprepare(nfc->core_clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused marvell_nfc_resume(struct device *dev)
> +{
> +	struct marvell_nfc *nfc = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(nfc->core_clk);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = clk_prepare_enable(nfc->reg_clk);
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * Reset nfc->selected_chip so the next command will cause the timing
> +	 * registers to be restored in marvell_nfc_select_chip().
> +	 */
> +	nfc->selected_chip = NULL;
> +
> +	/* Reset registers that have lots its contents */
> +	writel_relaxed(NDCR_ALL_INT | NDCR_ND_ARB_EN | NDCR_SPARE_EN |
> +		       NDCR_RD_ID_CNT(NFCV1_READID_LEN), nfc->regs + NDCR);
> +	writel_relaxed(0xFFFFFFFF, nfc->regs + NDSR);
> +	writel_relaxed(0, nfc->regs + NDECCCTRL);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops marvell_nfc_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(marvell_nfc_suspend, marvell_nfc_resume)
> +};
> +
>  static const struct marvell_nfc_caps marvell_armada_8k_nfc_caps = {
>  	.max_cs_nb = 4,
>  	.max_rb_nb = 2,
> @@ -2908,6 +2954,7 @@ static struct platform_driver marvell_nfc_driver = {
>  	.driver	= {
>  		.name		= "marvell-nfc",
>  		.of_match_table = marvell_nfc_of_ids,
> +		.pm		= &marvell_nfc_pm_ops,
>  	},
>  	.id_table = marvell_nfc_platform_ids,
>  	.probe = marvell_nfc_probe,