Re: Re: [PATCH 1/7] media: hantro: add support for reset lines

Jernej Škrabec
2021-11-23T16:46:37Z

Hi all,

Dne torek, 23. november 2021 ob 17:36:57 CET je Andrzej Pietrasiewicz
napisal(a):
> Hi Dan, hi Jernej,
>
> W dniu 23.11.2021 o 15:59, Dan Carpenter pisze:
> > On Tue, Nov 23, 2021 at 12:09:03PM +0100, Andrzej Pietrasiewicz wrote:
> >>> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/
media/hantro/hantro_drv.c
> >>> index ab2467998d29..8c3de31f51b3 100644
> >>> --- a/drivers/staging/media/hantro/hantro_drv.c
> >>> +++ b/drivers/staging/media/hantro/hantro_drv.c
> >>> @@ -905,6 +905,10 @@ static int hantro_probe(struct platform_device
*pdev)
> >>> return PTR_ERR(vpu->clocks[0].clk);
> >>> }
> >>> + vpu->resets = devm_reset_control_array_get(&pdev->dev, false,
true);
> >>> + if (IS_ERR(vpu->resets))
> >>> + return PTR_ERR(vpu->resets);
> >>> +
> >>> num_bases = vpu->variant->num_regs ?: 1;
> >>> vpu->reg_bases = devm_kcalloc(&pdev->dev, num_bases,
> >>> sizeof(*vpu->reg_bases),
GFP_KERNEL);
> >>> @@ -978,10 +982,16 @@ static int hantro_probe(struct platform_device
*pdev)
> >>> pm_runtime_use_autosuspend(vpu->dev);
> >>> pm_runtime_enable(vpu->dev);
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > It looks like this is the pm stuff that we have to unwind on error
> >
> >>> + ret = reset_control_deassert(vpu->resets);
> >>> + if (ret) {
> >>> + dev_err(&pdev->dev, "Failed to deassert resets\n");
> >>> + return ret;
> > ^^^^^^^^^^
> > So this return should be a goto undo_pm_stuff
> >
> >
> >>> + }
> >>> +
> >>> ret = clk_bulk_prepare(vpu->variant->num_clocks, vpu->clocks);
> >>> if (ret) {
> >>> dev_err(&pdev->dev, "Failed to prepare clocks\n");
> >>> - return ret;
> >
> > And this return should also have been a goto so it's a bug in the
> > original code.
>
> So we probably want a separate patch addressing that first, and then
> the series proper on top of that.

I was just about to suggest that.

Other drivers usually enable PM last, so they don't have PM calls in unwind
code. However, I think current approach is just as valid (with a fix).

Best regards,
Jernej

>
> Regards,
>
> Andrzej
>
> >
> >>> + goto err_rst_assert;
> >>
> >> Before your patch is applied if clk_bulk_prepare() fails, we
> >> simply return on the spot. After the patch is applied not only
> >> do you...
> >>
> >>> }
> >>> ret = v4l2_device_register(&pdev->dev, &vpu->v4l2_dev);
> >>> @@ -1037,6 +1047,8 @@ static int hantro_probe(struct platform_device
*pdev)
> >>> v4l2_device_unregister(&vpu->v4l2_dev);
> >>> err_clk_unprepare:
> >>> clk_bulk_unprepare(vpu->variant->num_clocks, vpu->clocks);
> >>> +err_rst_assert:
> >>> + reset_control_assert(vpu->resets);
> >>
> >> ...revert the effect of reset_control_deassert(), you also...
> >>
> >>> pm_runtime_dont_use_autosuspend(vpu->dev);
> >>> pm_runtime_disable(vpu->dev);
> >>
> >> ... do pm_*() stuff. Is there any reason why this is needed?
> >
> > So, yes, it's needed, but you're correct to spot that it's not
> > consistent.
> >
> > regards,
> > dan carpenter
> >
>
>