xhci: support setting interrupt moderation IMOD for secondary interrupters

Allow creators of seconday interrupters to specify the interrupt
moderation interval value in nanoseconds when creating the interrupter.

If not sure what value to use then use the xhci driver default
xhci->imod_interval

Suggested-by: Wesley Cheng <[e-mail]>
Signed-off-by: Mathias Nyman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-mem.c

···
 }
 
 struct xhci_interrupter *
-xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs)
+xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
+				  u32 imod_interval)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 	struct xhci_interrupter *ir;
···
 		xhci_free_interrupter(xhci, ir);
 		return NULL;
 	}
+
+	err = xhci_set_interrupter_moderation(ir, imod_interval);
+	if (err)
+		xhci_warn(xhci, "Failed to set interrupter %d moderation to %uns\n",
+			  i, imod_interval);
 
 	xhci_dbg(xhci, "Add secondary interrupter %d, max interrupters %d\n",
 		 i, xhci->max_interrupters);

drivers/usb/host/xhci.c

···
 }
 
 /* interrupt moderation interval imod_interval in nanoseconds */
-static int xhci_set_interrupter_moderation(struct xhci_interrupter *ir,
-					   u32 imod_interval)
+int xhci_set_interrupter_moderation(struct xhci_interrupter *ir,
+				    u32 imod_interval)
 {
 	u32 imod;
 

drivers/usb/host/xhci.h

···
 void xhci_free_container_ctx(struct xhci_hcd *xhci,
 		struct xhci_container_ctx *ctx);
 struct xhci_interrupter *
-xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs);
+xhci_create_secondary_interrupter(struct usb_hcd *hcd, unsigned int segs,
+				  u32 imod_interval);
 void xhci_remove_secondary_interrupter(struct usb_hcd
 				       *hcd, struct xhci_interrupter *ir);
 
···
 		struct xhci_virt_device *virt_dev,
 		struct usb_device *hdev,
 		struct usb_tt *tt, gfp_t mem_flags);
+int xhci_set_interrupter_moderation(struct xhci_interrupter *ir,
+				    u32 imod_interval);
 
 /* xHCI ring, segment, TRB, and TD functions */
 dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg, union xhci_trb *trb);