Commit ace21625 authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
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xhci: Add helper to set an interrupters interrupt moderation interval 



Add a helper to set the interrupt moderation interval for an interrupter.
Each interrupter can have its own moderation value.

Hardware has a 16bit register for the moderation value, each step is 250ns.

Helper function imod_interval argument is in nanoseconds.

Values from 0 to 16383750 (250 x 0xffff) are accepted.
0 means no interrupt throttling.

Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarWesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20240217001017.29969-3-quic_wcheng@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4f022aad

drivers/usb/host/xhci.c

+18 −7
Original line number Diff line number Diff line
@@ -346,6 +346,23 @@ static int xhci_disable_interrupter(struct xhci_interrupter *ir) 
	return 0;

}



/* interrupt moderation interval imod_interval in nanoseconds */

static int xhci_set_interrupter_moderation(struct xhci_interrupter *ir,

					   u32 imod_interval)

{

	u32 imod;



	if (!ir || !ir->ir_set || imod_interval > U16_MAX * 250)

		return -EINVAL;



	imod = readl(&ir->ir_set->irq_control);

	imod &= ~ER_IRQ_INTERVAL_MASK;

	imod |= (imod_interval / 250) & ER_IRQ_INTERVAL_MASK;

	writel(imod, &ir->ir_set->irq_control);



	return 0;

}



static void compliance_mode_recovery(struct timer_list *t)

{

	struct xhci_hcd *xhci;
@@ -528,7 +545,6 @@ static int xhci_run_finished(struct xhci_hcd *xhci) 
 */

int xhci_run(struct usb_hcd *hcd)

{

	u32 temp;

	u64 temp_64;

	int ret;

	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
@@ -551,12 +567,7 @@ int xhci_run(struct usb_hcd *hcd) 
	xhci_dbg_trace(xhci, trace_xhci_dbg_init,

			"ERST deq = 64'h%0lx", (long unsigned int) temp_64);



	xhci_dbg_trace(xhci, trace_xhci_dbg_init,

			"// Set the interrupt modulation register");

	temp = readl(&ir->ir_set->irq_control);

	temp &= ~ER_IRQ_INTERVAL_MASK;

	temp |= (xhci->imod_interval / 250) & ER_IRQ_INTERVAL_MASK;

	writel(temp, &ir->ir_set->irq_control);

	xhci_set_interrupter_moderation(ir, xhci->imod_interval);



	if (xhci->quirks & XHCI_NEC_HOST) {

		struct xhci_command *command;