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Date: Wed, 18 Jul 2018 14:02:41 +0800
From: Honghui Zhang <honghui.zhang@...iatek.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
CC: <marc.zyngier@....com>, <bhelgaas@...gle.com>,
<matthias.bgg@...il.com>, <linux-arm-kernel@...ts.infradead.org>,
<linux-mediatek@...ts.infradead.org>, <linux-pci@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<yingjoe.chen@...iatek.com>, <eddie.huang@...iatek.com>,
<ryder.lee@...iatek.com>, <hongkun.cao@...iatek.com>,
<youlin.pei@...iatek.com>, <yong.wu@...iatek.com>,
<yt.shen@...iatek.com>, <sean.wang@...iatek.com>,
<rjw@...ysocki.net>, <khilman@...nel.org>, <ulf.hansson@...aro.org>
Subject: Re: [PATCH v3 3/4] PCI: mediatek: Add system pm support for MT2712
and MT7622
On Tue, 2018-07-17 at 18:15 +0100, Lorenzo Pieralisi wrote:
> [+Rafael, Kevin, Ulf]
>
> On Mon, Jul 02, 2018 at 03:57:43PM +0800, honghui.zhang@...iatek.com wrote:
> > From: Honghui Zhang <honghui.zhang@...iatek.com>
> >
> > The MTCMOS of PCIe Host for MT2712 and MT7622 will be off when system
> > suspend, and all the internal control register will be reset after system
> > resume. The PCIe link should be re-established and the related control
> > register values should be re-set after system resume.
> >
> > Signed-off-by: Honghui Zhang <honghui.zhang@...iatek.com>
> > Acked-by: Ryder Lee <ryder.lee@...iatek.com>
> > ---
> > drivers/pci/controller/pcie-mediatek.c | 67 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 67 insertions(+)
> >
> > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > index 86918d4..175d7b6 100644
> > --- a/drivers/pci/controller/pcie-mediatek.c
> > +++ b/drivers/pci/controller/pcie-mediatek.c
> > @@ -134,12 +134,14 @@ struct mtk_pcie_port;
> > /**
> > * struct mtk_pcie_soc - differentiate between host generations
> > * @need_fix_class_id: whether this host's class ID needed to be fixed or not
> > + * @pm_support: whether the host's MTCMOS will be off when suspend
> > * @ops: pointer to configuration access functions
> > * @startup: pointer to controller setting functions
> > * @setup_irq: pointer to initialize IRQ functions
> > */
> > struct mtk_pcie_soc {
> > bool need_fix_class_id;
> > + bool pm_support;
> > struct pci_ops *ops;
> > int (*startup)(struct mtk_pcie_port *port);
> > int (*setup_irq)(struct mtk_pcie_port *port, struct device_node *node);
> > @@ -1197,12 +1199,75 @@ static int mtk_pcie_probe(struct platform_device *pdev)
> > return err;
> > }
> >
> > +static int __maybe_unused mtk_pcie_suspend_noirq(struct device *dev)
> > +{
> > + struct mtk_pcie *pcie = dev_get_drvdata(dev);
> > + const struct mtk_pcie_soc *soc = pcie->soc;
> > + struct mtk_pcie_port *port;
> > +
> > + if (!soc->pm_support)
> > + return 0;
> > +
> > + if (list_empty(&pcie->ports))
> > + return 0;
> > +
> > + list_for_each_entry(port, &pcie->ports, list) {
> > + clk_disable_unprepare(port->pipe_ck);
> > + clk_disable_unprepare(port->obff_ck);
> > + clk_disable_unprepare(port->axi_ck);
> > + clk_disable_unprepare(port->aux_ck);
> > + clk_disable_unprepare(port->ahb_ck);
> > + clk_disable_unprepare(port->sys_ck);
> > + phy_power_off(port->phy);
> > + phy_exit(port->phy);
> > + }
> > +
> > + mtk_pcie_subsys_powerdown(pcie);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev)
> > +{
> > + struct mtk_pcie *pcie = dev_get_drvdata(dev);
> > + const struct mtk_pcie_soc *soc = pcie->soc;
> > + struct mtk_pcie_port *port, *tmp;
> > +
> > + if (!soc->pm_support)
> > + return 0;
> > +
> > + if (list_empty(&pcie->ports))
> > + return 0;
> > +
> > + if (dev->pm_domain) {
> > + pm_runtime_enable(dev);
> > + pm_runtime_get_sync(dev);
> > + }
>
> Are these runtime PM calls needed/abused here ?
>
> Mind explaining the logic ?
>
> There is certainly an asymmetry with the suspend callback which made me
> suspicious, I am pretty certain Rafael/Kevin/Ulf can help me clarify so
> that we can make progress with this patch.
>
> Lorenzo
>
Hi Lorenzo, thanks for your comments.
Sorry I don't get you.
I believe that in suspend callbacks the pm_runtime_put_sync and
pm_runtime_disable should be called to gated the CMOS for this module,
while the pm_rumtime_enable and pm_rumtime_get_sync should be called in
resume callback.
That's exactly this patch doing.
But the pm_rumtime_put_sync and pm_runtime_disable functions was wrapped
in the mtk_pcie_subsys_powerdown.
I did not call mtk_pcie_subsys_powerup since it does not just wrapped
pm_rumtime related functions but also do the platform_resource_get,
devm_ioremap, and free_ck clock get which I do not needed in resume
callback.
Do you think it will be much clear if I abstract the
platform_resource_get, devm_ioremap functions from
mtk_pcie_subsys_powerup and put it to a new functions like
mtk_pcie_subsys_resource_get, and then we may call the
mtk_pcie_subsys_powerup in the resume function?
thanks
> > +
> > + clk_prepare_enable(pcie->free_ck);
> > +
> > + list_for_each_entry_safe(port, tmp, &pcie->ports, list)
> > + mtk_pcie_enable_port(port);
> > +
> > + /* In case of EP was removed while system suspend. */
> > + if (list_empty(&pcie->ports))
> > + mtk_pcie_subsys_powerdown(pcie);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct dev_pm_ops mtk_pcie_pm_ops = {
> > + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mtk_pcie_suspend_noirq,
> > + mtk_pcie_resume_noirq)
> > +};
> > +
> > static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
> > .ops = &mtk_pcie_ops,
> > .startup = mtk_pcie_startup_port,
> > };
> >
> > static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
> > + .pm_support = true,
> > .ops = &mtk_pcie_ops_v2,
> > .startup = mtk_pcie_startup_port_v2,
> > .setup_irq = mtk_pcie_setup_irq,
> > @@ -1210,6 +1275,7 @@ static const struct mtk_pcie_soc mtk_pcie_soc_mt2712 = {
> >
> > static const struct mtk_pcie_soc mtk_pcie_soc_mt7622 = {
> > .need_fix_class_id = true,
> > + .pm_support = true,
> > .ops = &mtk_pcie_ops_v2,
> > .startup = mtk_pcie_startup_port_v2,
> > .setup_irq = mtk_pcie_setup_irq,
> > @@ -1229,6 +1295,7 @@ static struct platform_driver mtk_pcie_driver = {
> > .name = "mtk-pcie",
> > .of_match_table = mtk_pcie_ids,
> > .suppress_bind_attrs = true,
> > + .pm = &mtk_pcie_pm_ops,
> > },
> > };
> > builtin_platform_driver(mtk_pcie_driver);
> > --
> > 2.6.4
> >
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