[PATCH v4] usb: gadget: aspeed: improve vhub port irq handling

[rentao.bupt at gmail.com]

From: Tao Ren <rentao.bupt at gmail.com>

This patch evaluates vhub ports' irq mask before going through per-port
irq handling one by one, which helps to speed up irq handling in case
there is no port interrupt.

Signed-off-by: Tao Ren <rentao.bupt at gmail.com>
---
 Changes in v4:
   - use simple for() loop as it runs faster than for_each_set_bit()
     loop on aspeed BMCs.
 Changes in v3:
   - assign istat to (unsigned long) bitmap before calling
     "for_each_set_bit_from".
 Changes in v2:
   - use "for_each_set_bit" to speed up port irq handling.

 drivers/usb/gadget/udc/aspeed-vhub/core.c | 12 +++++++-----
 drivers/usb/gadget/udc/aspeed-vhub/vhub.h | 11 ++++++-----
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/gadget/udc/aspeed-vhub/core.c b/drivers/usb/gadget/udc/aspeed-vhub/core.c
index f8d35dd60c34..fb36bad2c0b7 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/core.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/core.c
@@ -134,11 +134,11 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
 	}
 
 	/* Handle device interrupts */
-	for (i = 0; i < vhub->max_ports; i++) {
-		u32 dev_mask = VHUB_IRQ_DEVICE1 << i;
-
-		if (istat & dev_mask)
-			ast_vhub_dev_irq(&vhub->ports[i].dev);
+	if (istat & vhub->port_irq_mask) {
+		for (i = 0; i < vhub->max_ports; i++) {
+			if (istat & VHUB_DEV_IRQ(i))
+				ast_vhub_dev_irq(&vhub->ports[i].dev);
+		}
 	}
 
 	/* Handle top-level vHub EP0 interrupts */
@@ -332,6 +332,8 @@ static int ast_vhub_probe(struct platform_device *pdev)
 
 	spin_lock_init(&vhub->lock);
 	vhub->pdev = pdev;
+	vhub->port_irq_mask = GENMASK(VHUB_IRQ_DEV1_BIT + vhub->max_ports - 1,
+				      VHUB_IRQ_DEV1_BIT);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	vhub->regs = devm_ioremap_resource(&pdev->dev, res);
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/vhub.h b/drivers/usb/gadget/udc/aspeed-vhub/vhub.h
index fac79ef6d669..b80e3ddff797 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/vhub.h
+++ b/drivers/usb/gadget/udc/aspeed-vhub/vhub.h
@@ -51,14 +51,11 @@
 #define VHUB_CTRL_UPSTREAM_CONNECT		(1 << 0)
 
 /* IER & ISR */
+#define VHUB_IRQ_DEV1_BIT			9
 #define VHUB_IRQ_USB_CMD_DEADLOCK		(1 << 18)
 #define VHUB_IRQ_EP_POOL_NAK			(1 << 17)
 #define VHUB_IRQ_EP_POOL_ACK_STALL		(1 << 16)
-#define VHUB_IRQ_DEVICE5			(1 << 13)
-#define VHUB_IRQ_DEVICE4			(1 << 12)
-#define VHUB_IRQ_DEVICE3			(1 << 11)
-#define VHUB_IRQ_DEVICE2			(1 << 10)
-#define VHUB_IRQ_DEVICE1			(1 << 9)
+#define VHUB_IRQ_DEVICE1			(1 << (VHUB_IRQ_DEV1_BIT))
 #define VHUB_IRQ_BUS_RESUME			(1 << 8)
 #define VHUB_IRQ_BUS_SUSPEND 			(1 << 7)
 #define VHUB_IRQ_BUS_RESET 			(1 << 6)
@@ -70,6 +67,9 @@
 #define VHUB_IRQ_HUB_EP0_SETUP			(1 << 0)
 #define VHUB_IRQ_ACK_ALL			0x1ff
 
+/* Downstream device IRQ mask. */
+#define VHUB_DEV_IRQ(n)				(VHUB_IRQ_DEVICE1 << (n))
+
 /* SW reset reg */
 #define VHUB_SW_RESET_EP_POOL			(1 << 9)
 #define VHUB_SW_RESET_DMA_CONTROLLER		(1 << 8)
@@ -402,6 +402,7 @@ struct ast_vhub {
 	/* Per-port info */
 	struct ast_vhub_port		*ports;
 	u32				max_ports;
+	u32				port_irq_mask;
 
 	/* Generic EP data structures */
 	struct ast_vhub_ep		*epns;
-- 
2.17.1