| Message ID | 20240726-s2r-cdns-v5-9-8664bfb032ac@bootlin.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix USB suspend on TI J7200 (cdns3-ti, cdns3, xhci) | expand |
On 26/07/2024 21:17, Théo Lebrun wrote: > The XHCI_RESET_ON_RESUME quirk allows wrappers to signal that they > expect a reset after resume. It is also used by some to enforce a XHCI > reset on resume (see needs-reset-on-resume DT prop). > > Some wrappers are unsure beforehands if they will reset. Add a mechanism > to signal *at resume* if power has been lost. Parent devices can set > this flag, that defaults to the XHCI_RESET_ON_RESUME value. > > The XHCI_RESET_ON_RESUME quirk still triggers a runtime_pm_get() on the > controller. This is required as we do not know if a suspend will > trigger a reset, so the best guess is to avoid runtime PM. > > Reset the xhci->lost_power value each time in xhci_resume(), making it > safe for devices to only set lost_power on some resumes. > > Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> > --- > drivers/usb/host/xhci.c | 8 +++++++- > drivers/usb/host/xhci.h | 6 ++++++ > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > index 0a8cf6c17f82..2c9b32d339f9 100644 > --- a/drivers/usb/host/xhci.c > +++ b/drivers/usb/host/xhci.c > @@ -1029,9 +1029,12 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg) > > spin_lock_irq(&xhci->lock); > > - if (hibernated || xhci->quirks & XHCI_RESET_ON_RESUME || xhci->broken_suspend) > + if (hibernated || xhci->lost_power || xhci->broken_suspend) Why not treat xhci->lost_power and xhci->quriks & XHCI_RESET_ON_RESUME independently? XHCI_RESET_ON_RESUME is sued by devices that know they always need to be reset on resume. xhci->lost_power is used by devices that don't have consistent behavior. > reinit_xhc = true; > > + /* Reset to default value, parent devices might correct it at next resume. */ > + xhci->lost_power = !!(xhci->quirks & XHCI_RESET_ON_RESUME); > + then you don't need to do this. > if (!reinit_xhc) { > /* > * Some controllers might lose power during suspend, so wait > @@ -5228,6 +5231,9 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks) > if (get_quirks) > get_quirks(dev, xhci); > > + /* Default value, that can be corrected at resume. */ > + xhci->lost_power = !!(xhci->quirks & XHCI_RESET_ON_RESUME); > + nor this. > /* In xhci controllers which follow xhci 1.0 spec gives a spurious > * success event after a short transfer. This quirk will ignore such > * spurious event. > diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h > index ebd0afd59a60..ec7c6061363f 100644 > --- a/drivers/usb/host/xhci.h > +++ b/drivers/usb/host/xhci.h > @@ -1640,6 +1640,12 @@ struct xhci_hcd { > unsigned broken_suspend:1; > /* Indicates that omitting hcd is supported if root hub has no ports */ > unsigned allow_single_roothub:1; > + /* > + * Signal from upper stacks that we lost power during system-wide > + * suspend. Its default value is based on XHCI_RESET_ON_RESUME, meaning > + * it is safe for wrappers to not modify lost_power at resume. > + */ > + unsigned lost_power:1; > /* cached extended protocol port capabilities */ > struct xhci_port_cap *port_caps; > unsigned int num_port_caps; >
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 0a8cf6c17f82..2c9b32d339f9 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1029,9 +1029,12 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg) spin_lock_irq(&xhci->lock); - if (hibernated || xhci->quirks & XHCI_RESET_ON_RESUME || xhci->broken_suspend) + if (hibernated || xhci->lost_power || xhci->broken_suspend) reinit_xhc = true; + /* Reset to default value, parent devices might correct it at next resume. */ + xhci->lost_power = !!(xhci->quirks & XHCI_RESET_ON_RESUME); + if (!reinit_xhc) { /* * Some controllers might lose power during suspend, so wait @@ -5228,6 +5231,9 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks) if (get_quirks) get_quirks(dev, xhci); + /* Default value, that can be corrected at resume. */ + xhci->lost_power = !!(xhci->quirks & XHCI_RESET_ON_RESUME); + /* In xhci controllers which follow xhci 1.0 spec gives a spurious * success event after a short transfer. This quirk will ignore such * spurious event. diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index ebd0afd59a60..ec7c6061363f 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1640,6 +1640,12 @@ struct xhci_hcd { unsigned broken_suspend:1; /* Indicates that omitting hcd is supported if root hub has no ports */ unsigned allow_single_roothub:1; + /* + * Signal from upper stacks that we lost power during system-wide + * suspend. Its default value is based on XHCI_RESET_ON_RESUME, meaning + * it is safe for wrappers to not modify lost_power at resume. + */ + unsigned lost_power:1; /* cached extended protocol port capabilities */ struct xhci_port_cap *port_caps; unsigned int num_port_caps;
The XHCI_RESET_ON_RESUME quirk allows wrappers to signal that they expect a reset after resume. It is also used by some to enforce a XHCI reset on resume (see needs-reset-on-resume DT prop). Some wrappers are unsure beforehands if they will reset. Add a mechanism to signal *at resume* if power has been lost. Parent devices can set this flag, that defaults to the XHCI_RESET_ON_RESUME value. The XHCI_RESET_ON_RESUME quirk still triggers a runtime_pm_get() on the controller. This is required as we do not know if a suspend will trigger a reset, so the best guess is to avoid runtime PM. Reset the xhci->lost_power value each time in xhci_resume(), making it safe for devices to only set lost_power on some resumes. Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> --- drivers/usb/host/xhci.c | 8 +++++++- drivers/usb/host/xhci.h | 6 ++++++ 2 files changed, 13 insertions(+), 1 deletion(-)