[PATCH v13 17/53] usb: host: xhci-sideband: Expose a sideband interrupter enable API

Wesley Cheng
2024-02-03T02:38:03Z

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 0944bf31d772..504a6f1586b5 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);
+ sb->ir->skip_events = false;
+ xhci_enable_interrupter(sb->ir);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_sideband_enable_interrupt);
+
/**
* xhci_sideband_create_interrupter - creates a new interrupter for this sideband
* @sb: sideband instance for this usb device
@@ -275,6 +299,8 @@ xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
}

sb->ir->ip_autoclear = ip_autoclear;
+ /* skip events for secondary interrupters by default */
+ sb->ir->skip_events = true;

out:
mutex_unlock(&sb->mutex);
@@ -297,6 +323,8 @@ xhci_sideband_remove_interrupter(struct xhci_sideband *sb)
return;

mutex_lock(&sb->mutex);
+ if (!sb->ir->skip_events)
+ xhci_disable_interrupter(sb->ir);
xhci_remove_secondary_interrupter(xhci_to_hcd(sb->xhci), sb->ir);

sb->ir = NULL;
diff --git a/include/linux/usb/xhci-sideband.h b/include/linux/usb/xhci-sideband.h
index 1035dae43cee..a749ae307ba7 100644
--- a/include/linux/usb/xhci-sideband.h
+++ b/include/linux/usb/xhci-sideband.h
@@ -54,6 +54,8 @@ xhci_sideband_get_endpoint_buffer(struct xhci_sideband *sb,
struct sg_table *
xhci_sideband_get_event_buffer(struct xhci_sideband *sb);

+int xhci_sideband_enable_interrupt(struct xhci_sideband *sb, u32 imod_interval);
+
int
xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
bool ip_autoclear);