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

[Benjamin Herrenschmidt]

On Thu, 2020-04-09 at 13:40 -0700, rentao.bupt@xxxxxxxxx wrote:
> From: Tao Ren <rentao.bupt@xxxxxxxxx>
> 
> 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@xxxxxxxxx>

Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>

> ---
>  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_DEVIC
> E1 << (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;