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From: Peter Chen <hzpeterchen@gmail.com>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Peter Chen <peter.chen@nxp.com>,
	balbi@kernel.org, mathias.nyman@intel.com,
	USB list <linux-usb@vger.kernel.org>,
	linux-imx@nxp.com, pawell@cadence.com, rogerq@ti.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	jun.li@nxp.com
Subject: Re: [PATCH v2 2/9] usb: cdns3: add runtime PM support
Date: Wed, 3 Jun 2020 17:27:00 +0800	[thread overview]
Message-ID: <CAL411-qedvd0fWiBt7WixeND03ZMYLeiqSxVmsKFCyZwsDz8YQ@mail.gmail.com> (raw)
In-Reply-To: <1591174278.15527.6.camel@mhfsdcap03>

> > Introduce runtime PM and wakeup interrupt handler for cdns3,
> > the runtime PM is default off since other cdns3 has not implemented
> > glue layer support for runtime PM.
> >
> > When the controller is in low power mode, the lpm flag will be set.
> > The interrupt triggered later than lpm flag is set considers as
> > wakeup interrupt and handled at cdns_drd_irq.
> Wonder to know that CPUs may be powered off in this case?

Yes

> Do you consider the case when usb controller is in low power mode, and
> also power off CPUs, then how to wakeup usb controller?
>

About USB wakeup for system suspend, there are still some works need
to do for this driver, will do later.

For system wakeup, it is platform specific. If the main cores are
powered off totally,
and do not respond any wakeup events, it needs the other core to get this wakeup
event, and power on main cores. After main cores are powered on, the
wakeup interrupt
status are there (if controller is not powered off), the controller
driver could handle
this wakeup event.

Peter

> Thanks
>
> > Once the wakeup
> > occurs, it first disables interrupt to avoid later interrupt
> > occurrence since the controller is in low power mode at that
> > time, and access registers may be invalid at that time. At wakeup
> > handler, it will call pm_runtime_get to wakeup controller, and
> > at runtime resume handler, it will enable interrupt again.
> >
> > The API platform_suspend is introduced for glue layer to implement
> > platform specific PM sequence.
> >
> > Signed-off-by: Peter Chen <peter.chen@nxp.com>
> > ---
> >  drivers/usb/cdns3/core.c   | 119 +++++++++++++++++++++++++++++++------
> >  drivers/usb/cdns3/core.h   |  14 +++++
> >  drivers/usb/cdns3/drd.c    |   7 +++
> >  drivers/usb/cdns3/gadget.c |   4 ++
> >  drivers/usb/cdns3/host.c   |   7 +++
> >  5 files changed, 134 insertions(+), 17 deletions(-)
>

  reply	other threads:[~2020-06-03  9:27 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-23 23:22 [PATCH v2 0/9] usb: some PM changes for cdns3 and xhci-plat Peter Chen
2020-05-23 23:22 ` [PATCH v2 1/9] usb: cdns3: introduce cdns3_set_phy_power API Peter Chen
2020-05-24  5:56   ` Jun Li
2020-05-23 23:22 ` [PATCH v2 2/9] usb: cdns3: add runtime PM support Peter Chen
2020-05-24  5:57   ` Jun Li
2020-05-24  6:43     ` Jun Li
2020-05-25  2:57     ` Peter Chen
2020-05-25 12:23       ` Jun Li
2020-05-26  2:03         ` Peter Chen
2020-06-03  8:51   ` Chunfeng Yun
2020-06-03  9:27     ` Peter Chen [this message]
2020-05-23 23:22 ` [PATCH v2 3/9] usb: cdns3: imx: add glue layer runtime pm implementation Peter Chen
2020-05-24  6:55   ` Jun Li
2020-05-25  2:59     ` Peter Chen
2020-05-25  4:53   ` kbuild test robot
2020-05-25  6:31     ` Peter Chen
2020-05-25  8:25   ` kbuild test robot
2020-05-23 23:22 ` [PATCH v2 4/9] usb: host: xhci-plat: add platform data support Peter Chen
2020-05-29 10:21   ` Mathias Nyman
2020-05-23 23:23 ` [PATCH v2 5/9] usb: host: xhci-plat: add .suspend_quirk for struct xhci_plat_priv Peter Chen
2020-05-29 10:22   ` Mathias Nyman
2020-05-23 23:23 ` [PATCH v2 6/9] usb: host: xhci-plat: delete the unnecessary code Peter Chen
2020-05-24  7:40   ` Jun Li
2020-05-29 10:23   ` Mathias Nyman
2020-05-23 23:23 ` [PATCH v2 7/9] usb: host: xhci-plat: add priv flag for skip_phy_initialization Peter Chen
2020-05-24  7:40   ` Jun Li
2020-05-25  3:03     ` Peter Chen
2020-05-25 12:30       ` Jun Li
2020-05-26  0:26         ` Peter Chen
2020-05-29 13:10   ` Mathias Nyman
2020-05-29 13:15     ` Peter Chen
2020-05-23 23:23 ` [PATCH v2 8/9] usb: cdns3: host: add .suspend_quirk for xhci-plat.c Peter Chen
2020-05-23 23:23 ` [PATCH v2 9/9] usb: cdns3: host: add xhci_plat_priv's flag skip_phy_initialization Peter Chen
2020-05-29  7:22 ` [PATCH v2 0/9] usb: some PM changes for cdns3 and xhci-plat Peter Chen

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