Messages in this thread | | | Date | Thu, 2 May 2024 16:37:15 -0700 | Subject | Re: [PATCH v20 06/41] usb: host: xhci-sideband: Expose a sideband interrupter enable API | From | Wesley Cheng <> |
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Hi Mathias,
On 5/2/2024 4:07 AM, Mathias Nyman wrote: > On 26.4.2024 0.50, Wesley Cheng wrote: >> Some use cases maybe require that the secondary interrupter's events to >> be handled by the OS. In this case, configure the IMOD and the >> skip_events property to enable the interrupter's events. By default, >> assume that the secondary interrupter doesn't want to enable OS event >> handling. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> drivers/usb/host/xhci-sideband.c | 28 ++++++++++++++++++++++++++++ >> include/linux/usb/xhci-sideband.h | 2 ++ >> 2 files changed, 30 insertions(+) >> >> diff --git a/drivers/usb/host/xhci-sideband.c >> b/drivers/usb/host/xhci-sideband.c >> index 255feae33c6e..6fdae9840c11 100644 >> --- a/drivers/usb/host/xhci-sideband.c >> +++ b/drivers/usb/host/xhci-sideband.c >> @@ -237,6 +237,30 @@ xhci_sideband_get_event_buffer(struct >> xhci_sideband *sb) >> } >> EXPORT_SYMBOL_GPL(xhci_sideband_get_event_buffer); >> +/** >> + * xhci_sideband_enable_interrupt - enable interrupt for secondary >> interrupter >> + * @sb: sideband instance for this usb device >> + * @imod_interval: number of event ring segments to allocate >> + * >> + * Enables OS owned event handling for a particular interrupter if >> client >> + * requests for it. In addition, set the IMOD interval for this >> particular >> + * interrupter. >> + * >> + * Returns 0 on success, negative error otherwise >> + */ >> +int xhci_sideband_enable_interrupt(struct xhci_sideband *sb, u32 >> imod_interval) >> +{ >> + if (!sb || !sb->ir) >> + return -ENODEV; >> + >> + xhci_set_interrupter_moderation(sb->ir, imod_interval); > > Is there a need to adjust the moderation after initial setup? > > If not then maybe we could pass the imod_interval as a parameter to > xhci_create_secondary_interrupter(), and avoid exporting > xhci_set_interrupter_moderation() > >
Let me preface my comments by saying that I was trying to include some aspects of enabling the secondary interrupter line within the main apps proc. If this gets too confusing, I can remove these mechanisms for now. For example, as you mentioned below xhci_sideband_enable_interrupt() isn't going to be used in the offload path.
However, I decided to add it so we can have some corresponding function that will utilize/set skip_events = false. (as it is "true" by default) Again, I can remove this part and revisit later when we actually have a use case to handle secondary interrupts on apps.
As for the IMOD setting, depending on what you think, I can add it as part of xhci_create_secondary_interrupter()
>> + sb->ir->skip_events = false; >> + xhci_enable_interrupter(sb->ir); >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(xhci_sideband_enable_interrupt); > > I can't find the place where xhci_sideband_enable_interrupt() is called in > this series. How is it planned to be used? > > Thanks > Mathias
Thanks Wesley Cheng
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