Re: [PATCH v11 04/11] PCI: brcmstb: Add suspend and resume pm_ops

Jim Quinlan
2020-09-10T19:11:43Z

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On Thu, Sep 10, 2020 at 2:50 PM Rob Herring <robh@kernel.org> wrote:
>
> On Thu, Sep 10, 2020 at 10:42 AM Jim Quinlan <james.quinlan@broadcom.com> wrote:
> >
> > On Thu, Sep 10, 2020 at 11:56 AM Rob Herring <robh@kernel.org> wrote:
> > >
> > > On Mon, Aug 24, 2020 at 03:30:17PM -0400, Jim Quinlan wrote:
> > > > From: Jim Quinlan <jquinlan@broadcom.com>
> > > >
> > > > Broadcom Set-top (BrcmSTB) boards typically support S2, S3, and S5 suspend
> > > > and resume. Now the PCIe driver may do so as well.
> > > >
> > > > Signed-off-by: Jim Quinlan <jquinlan@broadcom.com>
> > > > Acked-by: Florian Fainelli <f.fainelli@gmail.com>
> > > > ---
> > > > drivers/pci/controller/pcie-brcmstb.c | 47 +++++++++++++++++++++++++++
> > > > 1 file changed, 47 insertions(+)
> > > >
> > > > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> > > > index c2b3d2946a36..3d588ab7a6dd 100644
> > > > --- a/drivers/pci/controller/pcie-brcmstb.c
> > > > +++ b/drivers/pci/controller/pcie-brcmstb.c
> > > > @@ -978,6 +978,47 @@ static void brcm_pcie_turn_off(struct brcm_pcie *pcie)
> > > > brcm_pcie_bridge_sw_init_set(pcie, 1);
> > > > }
> > > >
> > > > +static int brcm_pcie_suspend(struct device *dev)
> > > > +{
> > > > + struct brcm_pcie *pcie = dev_get_drvdata(dev);
> > > > +
> > > > + brcm_pcie_turn_off(pcie);
> > > > + clk_disable_unprepare(pcie->clk);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int brcm_pcie_resume(struct device *dev)
> > > > +{
> > > > + struct brcm_pcie *pcie = dev_get_drvdata(dev);
> > > > + void __iomem *base;
> > > > + u32 tmp;
> > > > + int ret;
> > > > +
> > > > + base = pcie->base;
> > > > + clk_prepare_enable(pcie->clk);
> > > > +
> > > > + /* Take bridge out of reset so we can access the SERDES reg */
> > > > + brcm_pcie_bridge_sw_init_set(pcie, 0);
> > > > +
> > > > + /* SERDES_IDDQ = 0 */
> > > > + tmp = readl(base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
> > > > + u32p_replace_bits(&tmp, 0, PCIE_MISC_HARD_PCIE_HARD_DEBUG_SERDES_IDDQ_MASK);
> > > > + writel(tmp, base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
> > > > +
> > > > + /* wait for serdes to be stable */
> > > > + udelay(100);
> > >
> > > Really needs to be a spinloop?
> > >
> > > > +
> > > > + ret = brcm_pcie_setup(pcie);
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + if (pcie->msi)
> > > > + brcm_msi_set_regs(pcie->msi);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > static void __brcm_pcie_remove(struct brcm_pcie *pcie)
> > > > {
> > > > brcm_msi_remove(pcie);
> > > > @@ -1087,12 +1128,18 @@ static int brcm_pcie_probe(struct platform_device *pdev)
> > > >
> > > > MODULE_DEVICE_TABLE(of, brcm_pcie_match);
> > > >
> > > > +static const struct dev_pm_ops brcm_pcie_pm_ops = {
> > > > + .suspend_noirq = brcm_pcie_suspend,
> > > > + .resume_noirq = brcm_pcie_resume,
> > >
> > > Why do you need interrupts disabled? There's 39 cases of .suspend_noirq
> > > and 1352 of .suspend in the tree.
> >
> > I will test switching this to suspend_late/resume_early.
>
> Why not just the 'regular' flavor suspend/resume?
>
> Rob
We must have our PCIe driver suspend last and resume first because our
current driver turns off/on the power for the EPs. Note that this
code isn't in the driver as we are still figuring out a way to make it
upstreamable.

Jim

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