Re: [PATCH usb-next v10 3/8] usb: core: add a wrapper for the USB PHYs on the HCD

Martin Blumenstingl
2018-03-20T22:01:05Z

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Hi Roger, Hi Chunfeng,

On Tue, Mar 20, 2018 at 1:04 PM, Chunfeng Yun <chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
> Hi Martin & Roger:
>
> On Mon, 2018-03-19 at 17:12 +0100, Martin Blumenstingl wrote:
>> Hi Roger,
>>
>> On Mon, Mar 19, 2018 at 9:49 AM, Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> wrote:
>> > Hi,
>> >
>> > On 19/03/18 00:29, Martin Blumenstingl wrote:
>> >> Hi Roger,
>> >>
>> >> On Fri, Mar 16, 2018 at 3:32 PM, Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> wrote:
>> >>> +some TI folks
>> >>>
>> >>> Hi Martin,
>> >>>
>> >>> On 18/02/18 20:44, Martin Blumenstingl wrote:
>> >>>> Many SoC platforms have separate devices for the USB PHY which are
>> >>>> registered through the generic PHY framework. These PHYs have to be
>> >>>> enabled to make the USB controller actually work. They also have to be
>> >>>> disabled again on shutdown/suspend.
>> >>>>
>> >>>> Currently (at least) the following HCI platform drivers are using custom
>> >>>> code to obtain all PHYs via devicetree for the roothub/controller and
>> >>>> disable/enable them when required:
>> >>>> - ehci-platform.c has ehci_platform_power_{on,off}
>> >>>> - xhci-mtk.c has xhci_mtk_phy_{init,exit,power_on,power_off}
>> >>>> - ohci-platform.c has ohci_platform_power_{on,off}
>> >>>>
>> >>>> With this new wrapper the USB PHYs can be specified directly in the
>> >>>> USB controller's devicetree node (just like on the drivers listed
>> >>>> above). This allows SoCs like the Amlogic Meson GXL family to operate
>> >>>> correctly once this is wired up correctly. These SoCs use a dwc3
>> >>>> controller and require all USB PHYs to be initialized (if one of the USB
>> >>>> PHYs it not initialized then none of USB port works at all).
>> >>>>
>> >>>> Signed-off-by: Martin Blumenstingl <martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
>> >>>> Tested-by: Yixun Lan <yixun.lan-LpR1jeaWuhtBDgjK7y7TUQ@public.gmane.org>
>> >>>> Cc: Neil Armstrong <narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
>> >>>> Cc: Chunfeng Yun <chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>> >>>
>> >>> This patch is breaking low power cases on TI SoCs when USB is in host mode.
>> >>> I'll explain why below.
>> >> based on your explanation and reading the TI PHY drivers I am assuming
>> >> that the affected SoCs are using the "phy-omap-usb2" driver
>> >>
>> > yes and phy-ti-pipe3 as well i.e. "ti,phy-usb3" and "ti,omap-usb3"
>> I missed that, thanks
>>
>> >>>> ---
>> >>>> drivers/usb/core/Makefile | 2 +-
>> >>>> drivers/usb/core/phy.c | 158 ++++++++++++++++++++++++++++++++++++++++++++++
>> >>>> drivers/usb/core/phy.h | 7 ++
>> >>>> 3 files changed, 166 insertions(+), 1 deletion(-)
>> >>>> create mode 100644 drivers/usb/core/phy.c
>> >>>> create mode 100644 drivers/usb/core/phy.h
>> >>>>
>> >>>> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
>> >>>> index 92c9cefb4317..18e874b0441e 100644
>> >>>> --- a/drivers/usb/core/Makefile
>> >>>> +++ b/drivers/usb/core/Makefile
>> >>>> @@ -6,7 +6,7 @@
>> >>>> usbcore-y := usb.o hub.o hcd.o urb.o message.o driver.o
>> >>>> usbcore-y += config.o file.o buffer.o sysfs.o endpoint.o
>> >>>> usbcore-y += devio.o notify.o generic.o quirks.o devices.o
>> >>>> -usbcore-y += port.o
>> >>>> +usbcore-y += phy.o port.o
>> >>>>
>> >>>> usbcore-$(CONFIG_OF) += of.o
>> >>>> usbcore-$(CONFIG_USB_PCI) += hcd-pci.o
>> >>>> diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
>> >>>> new file mode 100644
>> >>>> index 000000000000..09b7c43c0ea4
>> >>>> --- /dev/null
>> >>>> +++ b/drivers/usb/core/phy.c
>> >>>> @@ -0,0 +1,158 @@
>> >>>> +// SPDX-License-Identifier: GPL-2.0+
>> >>>> +/*
>> >>>> + * A wrapper for multiple PHYs which passes all phy_* function calls to
>> >>>> + * multiple (actual) PHY devices. This is comes handy when initializing
>> >>>> + * all PHYs on a HCD and to keep them all in the same state.
>> >>>> + *
>> >>>> + * Copyright (C) 2018 Martin Blumenstingl <martin.blumenstingl-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
>> >>>> + */
>> >>>> +
>> >>>> +#include <linux/device.h>
>> >>>> +#include <linux/list.h>
>> >>>> +#include <linux/phy/phy.h>
>> >>>> +#include <linux/of.h>
>> >>>> +
>> >>>> +#include "phy.h"
>> >>>> +
>> >>>> +struct usb_phy_roothub {
>> >>>> + struct phy *phy;
>> >>>> + struct list_head list;
>> >>>> +};
>> >>>> +
>> >>>> +static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> +
>> >>>> + roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
>> >>>> + if (!roothub_entry)
>> >>>> + return ERR_PTR(-ENOMEM);
>> >>>> +
>> >>>> + INIT_LIST_HEAD(&roothub_entry->list);
>> >>>> +
>> >>>> + return roothub_entry;
>> >>>> +}
>> >>>> +
>> >>>> +static int usb_phy_roothub_add_phy(struct device *dev, int index,
>> >>>> + struct list_head *list)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> + struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index);
>> >>>> +
>> >>>> + if (IS_ERR_OR_NULL(phy)) {
>> >>>> + if (!phy || PTR_ERR(phy) == -ENODEV)
>> >>>> + return 0;
>> >>>> + else
>> >>>> + return PTR_ERR(phy);
>> >>>> + }
>> >>>> +
>> >>>> + roothub_entry = usb_phy_roothub_alloc(dev);
>> >>>> + if (IS_ERR(roothub_entry))
>> >>>> + return PTR_ERR(roothub_entry);
>> >>>> +
>> >>>> + roothub_entry->phy = phy;
>> >>>> +
>> >>>> + list_add_tail(&roothub_entry->list, list);
>> >>>> +
>> >>>> + return 0;
>> >>>> +}
>> >>>> +
>> >>>> +struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *phy_roothub;
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> + struct list_head *head;
>> >>>> + int i, num_phys, err;
>> >>>> +
>> >>>> + num_phys = of_count_phandle_with_args(dev->of_node, "phys",
>> >>>> + "#phy-cells");
>> >>>> + if (num_phys <= 0)
>> >>>> + return NULL;
>> >>>> +
>> >>>> + phy_roothub = usb_phy_roothub_alloc(dev);
>> >>>> + if (IS_ERR(phy_roothub))
>> >>>> + return phy_roothub;
>> >>>> +
>> >>>> + for (i = 0; i < num_phys; i++) {
>> >>>> + err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
>> >>>> + if (err)
>> >>>> + goto err_out;
>> >>>> + }
>> >>>> +
>> >>>> + head = &phy_roothub->list;
>> >>>> +
>> >>>> + list_for_each_entry(roothub_entry, head, list) {
>> >>>> + err = phy_init(roothub_entry->phy);
>> >>>
>> >>> The phy_init() function actually enables the PHY clocks.
>> >>> It should be moved to the usb_phy_roothub_exit() routine just before calling phy_power_on().
>> >> do you mean that phy_init should be moved to usb_phy_roothub_power_on
>> >> (just before phy_power_on is called within usb_phy_roothub_power_on)?
>> >>
>> >
>> > Yes.
>> >
>> >> an earlier version of my patch did exactly this, but it caused
>> >> problems during a suspend/resume cycle on Mediatek devices
>> >> Chunfeng Yun reported that issue here [0], quote from that mail for
>> >> easier reading:
>> >> "In order to keep link state on mt8173, we just power off all phys(not
>> >> exit) when system enter suspend, then power on them again (needn't
>> >> init, otherwise device will be disconnected) when system resume, this
>> >> can avoid re-enumerating device."
>> >>
>> >>>> + if (err)
>> >>>> + goto err_exit_phys;
>> >>>> + }
>> >>>> +
>> >>>> + return phy_roothub;
>> >>>> +
>> >>>> +err_exit_phys:
>> >>>> + list_for_each_entry_continue_reverse(roothub_entry, head, list)
>> >>>> + phy_exit(roothub_entry->phy);
>> >>>> +
>> >>>> +err_out:
>> >>>> + return ERR_PTR(err);
>> >>>> +}
>> >>>> +EXPORT_SYMBOL_GPL(usb_phy_roothub_init);
>> >>>> +
>> >>>> +int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> + struct list_head *head;
>> >>>> + int err, ret = 0;
>> >>>> +
>> >>>> + if (!phy_roothub)
>> >>>> + return 0;
>> >>>> +
>> >>>> + head = &phy_roothub->list;
>> >>>> +
>> >>>> + list_for_each_entry(roothub_entry, head, list) {
>> >>>> + err = phy_exit(roothub_entry->phy);
>> >>>> + if (err)
>> >>>> + ret = ret;
>> >>>> + }
>> >>>
>> >>> phy_exit() should be moved to usb_phy_roothub_poweroff() just after calling phy_power_off().
>> >> if I understood Chunfeng Yun correctly this will require
>> >> re-enumeration of the USB devices after a suspend/resume cycle on
>> >> Mediatek SoCs
>> >>
>> >
>> > OK. I suppose that there are 2 cases
>> > 1) Mediatek's case: USB controller context retained across suspend/resume.
>> > Remote wakeup probably required.
>> > No re-enumeration preferred after resume. phy_exit()/phy_init() must not be called
>> > during suspend/resume to keep PHY link active.
>> Documentation/devicetree/bindings/usb/mediatek,mtu3.txt indeed shows
>> that the parent of the USB controller can be marked as "wakeup-source"
>>
>> > 2) TI's case: low power important: USB context is lost, OK to re-enumerate.
>> > phy_exit()/phy_init() must be called during suspend/resume.
>> ACK
>>
>> >>> With that there is nothing else being done here. Shouldn't we be doing the equivalent of
>> >>> usb_phy_roothub_del_phy() and usb_phy_roothub_free() here?
>> >>>
>> >>>> +
>> >>>> + return ret;
>> >>>> +}
>> >>>> +EXPORT_SYMBOL_GPL(usb_phy_roothub_exit);
>> >>>> +
>> >>>> +int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> + struct list_head *head;
>> >>>> + int err;
>> >>>> +
>> >>>> + if (!phy_roothub)
>> >>>> + return 0;
>> >>>> +
>> >>>> + head = &phy_roothub->list;
>> >>>> +
>> >>>> + list_for_each_entry(roothub_entry, head, list) {
>> >>>> + err = phy_power_on(roothub_entry->phy);
>> >>>> + if (err)
>> >>>> + goto err_out;
>> >>>> + }
>> >>>> +
>> >>>> + return 0;
>> >>>> +
>> >>>> +err_out:
>> >>>> + list_for_each_entry_continue_reverse(roothub_entry, head, list)
>> >>>> + phy_power_off(roothub_entry->phy);
>> >>>> +
>> >>>> + return err;
>> >>>> +}
>> >>>> +EXPORT_SYMBOL_GPL(usb_phy_roothub_power_on);
>> >>>> +
>> >>>> +void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub)
>> >>>> +{
>> >>>> + struct usb_phy_roothub *roothub_entry;
>> >>>> +
>> >>>> + if (!phy_roothub)
>> >>>> + return;
>> >>>> +
>> >>>> + list_for_each_entry_reverse(roothub_entry, &phy_roothub->list, list)
>> >>>> + phy_power_off(roothub_entry->phy);
>> >>>
>> >>> Not doing the phy_exit() here leaves the clocks enabled on our SoC and
>> >>> we're no longer able to reach low power states on system suspend.
>> >> I'm not sure where this problem should be solved:
>> >> - set skip_phy_initialization in struct usb_hcd to 1 for the affected
>> >> TI platforms
>> >
>> > Many TI platforms are affected, omap5*, dra7*, am43*
>> >
>> >> - fix this in the usb_phy_roothub code
>> >
>> > I'd vote for fixing it in the usb_phy_roothub code. How?
>> > How about using the device_can_wakeup() to decide if we should call phy_exit()/init() or not?
>> > If the USB device can't wakeup the system there is no point in keeping it powered/clocked right?
>> @Chunfeng: can you confirm Roger's idea that we could call phy_exit if
>> the controller is *NOT* marked as "wakeup-source"?
>> I am also not sure if it would work, since the "wakeup-source"
>> property is defined on the USB controller's parent node in case of the
>> Mediatek MTU3 (Mediatek USB3.0 DRD) controller
>>
> Very sorry, I forgot that MTU3 & xHCI drivers always set them as wakeup
> devices by device_init_wakeup(dev, true),but not dependent on
> "wakeup-source" property, so maybe we can use device_can_wakeup() to
> decide whether call phy_exit()/init() or not.
the 64-bit Amlogic Meson GXL/GXM SoCs don't support suspend/resume
yet, so I cannot test this
based on this suggestion I threw up two patches which are *compile
tested only* based on Greg's usb-next branch
you can find them here: [0] (as well as attached to this mail)

@Chunfeng: can you please test this on one of your Mediatek SoCs?
@Roger: can you please test this on a TI SoC?

(apologies in advance if these patches don't work)

please note that I won't have access to my computer until Saturday.
if these patches need to be rewritten/replaced/etc. then feel free to
send your own version to the list

>> >> - fix this in the PHY driver
>> >
>> > There is nothing to fix in the PHY driver. It is doing what it is supposed to do.
>> I actually wonder if phy_ops should have explicit suspend/resume support:
>> - assuming we define two new callbacks: .suspend and .resume
>> - the PHY framework could call .power_off by default if .suspend is not defined
>> - the PHY framework could call .power_on by default if .resume is not defined
>> - drivers could set .suspend and .resume on their own, allowing more
>> fine-grained control by for example *only* stopping the clock (but not
>> re-initializing the registers, etc.)
>>
>> @Roger: what do you think about this?
>> Kishon (the PHY framework maintainer) is also CC'ed - I would like to
>> hear his opinion too
>>
>> >> - somewhere else
>> >>
>> >>>> +}
>> >>>> +EXPORT_SYMBOL_GPL(usb_phy_roothub_power_off);
>> >>>> diff --git a/drivers/usb/core/phy.h b/drivers/usb/core/phy.h
>> >>>> new file mode 100644
>> >>>> index 000000000000..6fde59bfbff8
>> >>>> --- /dev/null
>> >>>> +++ b/drivers/usb/core/phy.h
>> >>>> @@ -0,0 +1,7 @@
>> >>>> +struct usb_phy_roothub;
>> >>>> +
>> >>>> +struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev);
>> >>>> +int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);
>> >>>> +
>> >>>> +int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
>> >>>> +void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub);
>> >>>>
>> >>>
>> >
>> > <snip>
>> >
>> > --
>> > cheers,
>> > -roger
>> >
>> > Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>
>>
>> Regards
>> Martin
>
>

Regards
Martin

[0] https://github.com/xdarklight/linux/commits/usb-phy-roothub-suspend-rfc-v1

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From 78afe3dfbf21dd521076d1fd625096fa440f5195 Mon Sep 17 00:00:00 2001
From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date: Tue, 20 Mar 2018 22:36:39 +0100
Subject: [PATCH 1/2] usb: core: split usb_phy_roothub_{init,alloc}

Before this patch usb_phy_roothub_init served two purposes (from a
caller's point of view - like hcd.c):
- parsing the PHYs and allocating the list entries
- calling phy_init on each list entry

While this worked so far it has one disadvantage: if we need to call
phy_init for each PHY instance then the existing code cannot be re-used.
Solve this by splitting off usb_phy_roothub_alloc which only parses the
PHYs and allocates the list entries.
usb_phy_roothub_init then gets a struct usb_phy_roothub and only calls
phy_init on each PHY instance (along with the corresponding cleanup if
that failed somewhere).

This is a preparation step for adding proper suspend support for some
hardware that requires phy_exit to be called during suspend and phy_init
to be called during resume.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
drivers/usb/core/hcd.c | 10 +++++++---
drivers/usb/core/phy.c | 45 ++++++++++++++++++++++-----------------------
drivers/usb/core/phy.h | 4 +++-
3 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 5a92d8f7c484..89b10d859047 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2758,12 +2758,16 @@ int usb_add_hcd(struct usb_hcd *hcd,
}

if (!hcd->skip_phy_initialization) {
- hcd->phy_roothub = usb_phy_roothub_init(hcd->self.sysdev);
+ hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
if (IS_ERR(hcd->phy_roothub)) {
retval = PTR_ERR(hcd->phy_roothub);
- goto err_phy_roothub_init;
+ goto err_phy_roothub_alloc;
}

+ retval = usb_phy_roothub_init(hcd->phy_roothub);
+ if (retval)
+ goto err_phy_roothub_alloc;
+
retval = usb_phy_roothub_power_on(hcd->phy_roothub);
if (retval)
goto err_usb_phy_roothub_power_on;
@@ -2936,7 +2940,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
usb_phy_roothub_power_off(hcd->phy_roothub);
err_usb_phy_roothub_power_on:
usb_phy_roothub_exit(hcd->phy_roothub);
-err_phy_roothub_init:
+err_phy_roothub_alloc:
if (hcd->remove_phy && hcd->usb_phy) {
usb_phy_shutdown(hcd->usb_phy);
usb_put_phy(hcd->usb_phy);
diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
index 09b7c43c0ea4..50a80dbe776c 100644
--- a/drivers/usb/core/phy.c
+++ b/drivers/usb/core/phy.c
@@ -19,19 +19,6 @@ struct usb_phy_roothub {
struct list_head list;
};

-static struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
-{
- struct usb_phy_roothub *roothub_entry;
-
- roothub_entry = devm_kzalloc(dev, sizeof(*roothub_entry), GFP_KERNEL);
- if (!roothub_entry)
- return ERR_PTR(-ENOMEM);
-
- INIT_LIST_HEAD(&roothub_entry->list);
-
- return roothub_entry;
-}
-
static int usb_phy_roothub_add_phy(struct device *dev, int index,
struct list_head *list)
{
@@ -56,11 +43,9 @@ static int usb_phy_roothub_add_phy(struct device *dev, int index,
return 0;
}

-struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
+struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev)
{
struct usb_phy_roothub *phy_roothub;
- struct usb_phy_roothub *roothub_entry;
- struct list_head *head;
int i, num_phys, err;

num_phys = of_count_phandle_with_args(dev->of_node, "phys",
@@ -68,16 +53,31 @@ struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
if (num_phys <= 0)
return NULL;

- phy_roothub = usb_phy_roothub_alloc(dev);
- if (IS_ERR(phy_roothub))
- return phy_roothub;
+ phy_roothub = devm_kzalloc(dev, sizeof(*phy_roothub), GFP_KERNEL);
+ if (!phy_roothub)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&phy_roothub->list);

for (i = 0; i < num_phys; i++) {
err = usb_phy_roothub_add_phy(dev, i, &phy_roothub->list);
if (err)
- goto err_out;
+ return ERR_PTR(err);
}

+ return phy_roothub;
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_alloc);
+
+int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub)
+{
+ struct usb_phy_roothub *roothub_entry;
+ struct list_head *head;
+ int err;
+
+ if (!phy_roothub)
+ return 0;
+
head = &phy_roothub->list;

list_for_each_entry(roothub_entry, head, list) {
@@ -86,14 +86,13 @@ struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev)
goto err_exit_phys;
}

- return phy_roothub;
+ return 0;

err_exit_phys:
list_for_each_entry_continue_reverse(roothub_entry, head, list)
phy_exit(roothub_entry->phy);

-err_out:
- return ERR_PTR(err);
+ return err;
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_init);

diff --git a/drivers/usb/core/phy.h b/drivers/usb/core/phy.h
index 6fde59bfbff8..eb31253201ad 100644
--- a/drivers/usb/core/phy.h
+++ b/drivers/usb/core/phy.h
@@ -1,6 +1,8 @@
struct usb_phy_roothub;

-struct usb_phy_roothub *usb_phy_roothub_init(struct device *dev);
+struct usb_phy_roothub *usb_phy_roothub_alloc(struct device *dev);
+
+int usb_phy_roothub_init(struct usb_phy_roothub *phy_roothub);
int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);

int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
--
2.16.2

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From 1367f49ff49cec249bd9ba95e5395dd1760eee8b Mon Sep 17 00:00:00 2001
From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date: Tue, 20 Mar 2018 22:47:38 +0100
Subject: [PATCH 2/2] usb: core: use phy_exit during suspend if wake up is not
supported

If the USB controller can wake up the system (which is the case for
example with the Mediatek USB3 IP) then we must not call phy_exit during
suspend to ensure that the USB controller doesn't have to re-enumerate
the devices during resume.
However, if the USB controller cannot wake up the system (which is the
case for example on various TI platforms using a dwc3 controller) then
we must call phy_exit during suspend. Otherwise the PHY driver keeps the
clocks enabled, which prevents the system from entering the suspend
state.

Solve this by introducing two new functions in the PHY wrapper which are
dedicated to the suspend and resume handling.
If the controller can wake up the system the new usb_phy_roothub_suspend
function will simply call usb_phy_roothub_power_off. However, if wake up
is not supported by the controller it will also call
usb_phy_roothub_exit.
The also new usb_phy_roothub_resume function takes care of calling
usb_phy_roothub_init (if the controller can't wake up the system) in
addition to usb_phy_roothub_power_on.

Fixes: 07dbff0ddbd86c ("usb: core: add a wrapper for the USB PHYs on the HCD")
Fixes: 178a0bce05cbc1 ("usb: core: hcd: integrate the PHY wrapper into the HCD core")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
drivers/usb/core/hcd.c | 6 +++---
drivers/usb/core/phy.c | 29 +++++++++++++++++++++++++++++
drivers/usb/core/phy.h | 5 +++++
3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 89b10d859047..6d4a4195ca00 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2262,7 +2262,7 @@ int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg)
hcd->state = HC_STATE_SUSPENDED;

if (!PMSG_IS_AUTO(msg))
- usb_phy_roothub_power_off(hcd->phy_roothub);
+ usb_phy_roothub_suspend(hcd->phy_roothub);

/* Did we race with a root-hub wakeup event? */
if (rhdev->do_remote_wakeup) {
@@ -2302,7 +2302,7 @@ int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
}

if (!PMSG_IS_AUTO(msg)) {
- status = usb_phy_roothub_power_on(hcd->phy_roothub);
+ status = usb_phy_roothub_resume(hcd->phy_roothub);
if (status)
return status;
}
@@ -2344,7 +2344,7 @@ int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
}
} else {
hcd->state = old_state;
- usb_phy_roothub_power_off(hcd->phy_roothub);
+ usb_phy_roothub_suspend(hcd->phy_roothub);
dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
"resume", status);
if (status != -ESHUTDOWN)
diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
index 50a80dbe776c..2eca371684fa 100644
--- a/drivers/usb/core/phy.c
+++ b/drivers/usb/core/phy.c
@@ -155,3 +155,32 @@ void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub)
phy_power_off(roothub_entry->phy);
}
EXPORT_SYMBOL_GPL(usb_phy_roothub_power_off);
+
+int usb_phy_roothub_suspend(struct device *dev,
+ struct usb_phy_roothub *phy_roothub)
+{
+ usb_phy_roothub_power_off(phy_roothub);
+
+ /* keep the PHYs initialized so the device can wake up the system */
+ if (device_can_wakeup(dev))
+ return 0;
+
+ return usb_phy_roothub_exit(phy_roothub);
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_suspend);
+
+int usb_phy_roothub_resume(struct device *dev,
+ struct usb_phy_roothub *phy_roothub)
+{
+ int err;
+
+ /* if the device can't wake up the system _exit was called */
+ if (device_can_wakeup(dev)) {
+ err = usb_phy_roothub_init(phy_roothub);
+ if (err)
+ return err;
+ }
+
+ return usb_phy_roothub_power_on(phy_roothub);
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_resume);
diff --git a/drivers/usb/core/phy.h b/drivers/usb/core/phy.h
index eb31253201ad..601aefd41878 100644
--- a/drivers/usb/core/phy.h
+++ b/drivers/usb/core/phy.h
@@ -7,3 +7,8 @@ int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);

int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub);
+
+int usb_phy_roothub_suspend(struct device *dev,
+ struct usb_phy_roothub *phy_roothub);
+int usb_phy_roothub_resume(struct device *dev,
+ struct usb_phy_roothub *phy_roothub);
--
2.16.2

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