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

[Simon Horman <horms@verge.net.au>]

On Mon, Apr 09, 2018 at 01:47:38PM +0200, Geert Uytterhoeven wrote:
> 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 ;-)

Understood. I think that is reasonable.
Marek, would you care to respin?