[PATCH 3/3] usb: dwc3: gadget: Skip reading GEVNTSIZn

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

The driver knows what it needs to set for GEVNTSIZn, and the controller
doesn't modify this register unless there's a hard reset. To save a few
microseconds of register read in read-modify-write operation, simply do
register write with the expected values. This can improve performance
when there are many interrupts generated, which the driver needs to
check and handle.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
 drivers/usb/dwc3/gadget.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index f66baaef8a40..c0c89374716b 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4082,7 +4082,6 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt)
 	struct dwc3 *dwc = evt->dwc;
 	irqreturn_t ret = IRQ_NONE;
 	int left;
-	u32 reg;
 
 	left = evt->count;
 
@@ -4114,9 +4113,8 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt)
 	ret = IRQ_HANDLED;
 
 	/* Unmask interrupt */
-	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
-	reg &= ~DWC3_GEVNTSIZ_INTMASK;
-	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0),
+		    DWC3_GEVNTSIZ_SIZE(evt->length));
 
 	if (dwc->imod_interval) {
 		dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), DWC3_GEVNTCOUNT_EHB);
@@ -4145,7 +4143,6 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 	struct dwc3 *dwc = evt->dwc;
 	u32 amount;
 	u32 count;
-	u32 reg;
 
 	if (pm_runtime_suspended(dwc->dev)) {
 		pm_runtime_get(dwc->dev);
@@ -4172,9 +4169,8 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 	evt->flags |= DWC3_EVENT_PENDING;
 
 	/* Mask interrupt */
-	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
-	reg |= DWC3_GEVNTSIZ_INTMASK;
-	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0),
+		    DWC3_GEVNTSIZ_INTMASK | DWC3_GEVNTSIZ_SIZE(evt->length));
 
 	amount = min(count, evt->length - evt->lpos);
 	memcpy(evt->cache + evt->lpos, evt->buf + evt->lpos, amount);
-- 
2.28.0