Re: [PATCH V5] PCI: rcar: Use runtime PM to control controller clock

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Simon, Marek,

On Mon, Apr 9, 2018 at 1:41 PM, Simon Horman <horms@verge.net.au> wrote:
> On Mon, Apr 09, 2018 at 10:20:05AM +0200, Marek Vasut wrote:
>> On 04/09/2018 10:07 AM, Geert Uytterhoeven wrote:
>> > On Sun, Apr 8, 2018 at 3:09 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
>> >> From: Dien Pham <dien.pham.ry@rvc.renesas.com>
>> >>
>> >> The controller clock can be switched off during suspend/resume,
>> >> let runtime PM take care of that.
>> >>
>> >> Signed-off-by: Dien Pham <dien.pham.ry@rvc.renesas.com>
>> >> Signed-off-by: Hien Dang <hien.dang.eb@renesas.com>
>> >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
>> >> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
>> >> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>> >> Cc: Phil Edworthy <phil.edworthy@renesas.com>
>> >> Cc: Simon Horman <horms+renesas@verge.net.au>
>> >> Cc: Wolfram Sang <wsa@the-dreams.de>
>> >> Cc: linux-renesas-soc@vger.kernel.org
>> >> To: linux-pci@vger.kernel.org
>> >> ---
>> >> V2: - Reorder the fail path in rcar_pcie_probe() to cater for the
>> >>       reordering of function calls in probe
>> >>     - Dispose of fail_clk in rcar_pcie_get_resources()
>> >> V3: - Fix up the failpath in probe function
>> >> V4: - Rebase on recent linux-next
>> >> V5: - Do not call pci_free_resource_list(&pcie->resources) if
>> >>       rcar_pcie_parse_request_of_pci_ranges() fails, since that
>> >>       functiona calls pci_free_resource_list() already.
>> >
>> > Thanks for the update!
>> >
>> >> --- a/drivers/pci/host/pcie-rcar.c
>> >> +++ b/drivers/pci/host/pcie-rcar.c
>> >
>> >> @@ -1124,22 +1111,22 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>> >>         if (err)
>> >>                 goto err_free_bridge;
>> >>
>> >> +       pm_runtime_enable(pcie->dev);
>> >> +       err = pm_runtime_get_sync(pcie->dev);
>> >> +       if (err < 0) {
>> >> +               dev_err(pcie->dev, "pm_runtime_get_sync failed\n");
>> >> +               goto err_pm_disable;
>> >> +       }
>> >> +
>> >
>> > As you moved the pm_runtime setup up...
>> >
>> >>         err = rcar_pcie_get_resources(pcie);
>> >>         if (err < 0) {
>> >>                 dev_err(dev, "failed to request resources: %d\n", err);
>> >> -               goto err_free_resource_list;
>> >> +               goto err_pm_put;
>> >>         }
>> >>
>> >>         err = rcar_pcie_parse_map_dma_ranges(pcie, dev->of_node);
>> >>         if (err)
>> >> -               goto err_free_resource_list;
>> >> -
>> >> -       pm_runtime_enable(dev);
>> >> -       err = pm_runtime_get_sync(dev);
>> >> -       if (err < 0) {
>> >> -               dev_err(dev, "pm_runtime_get_sync failed\n");
>> >> -               goto err_pm_disable;
>> >> -       }
>> >> +               goto err_pm_put;
>> >>
>> >>         /* Failure to get a link might just be that no cards are inserted */
>> >>         hw_init_fn = of_device_get_match_data(dev);
>> >> @@ -1174,9 +1161,8 @@ static int rcar_pcie_probe(struct platform_device *pdev)
>> >>
>> >>  err_pm_disable:
>> >>         pm_runtime_disable(dev);
>> >
>> > ... shouldn't it be moved down here, for symmetry?
>>
>> I am reasonably certain the failpath should be correct now. Did I still
>> miss something ?
>
> It looks correct to me too. Geert are Marek and I missing something?

Probably it will still work fine, but after this patch, Runtime PM is enabled
early, and disabled early, which is not symmetrical.

I like symmetry ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds