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@xxxxxxxxxxx>
---
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
