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Date:   Wed, 1 Apr 2020 14:58:27 -0700
From:   Tao Ren <rentao.bupt@gmail.com>
To:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Stephen Boyd <swboyd@chromium.org>, linux-usb@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        openbmc@lists.ozlabs.org, taoren@fb.com
Subject: Re: [PATCH v3] usb: gadget: aspeed: improve vhub port irq handling
Message-ID: <20200401215826.GA8248@taoren-ubuntu-R90MNF91>
References: <20200315191430.12379-1-rentao.bupt@gmail.com>
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Hi Ben,

Any further comments on the patch?


Cheers,

Tao

On Sun, Mar 15, 2020 at 12:14:30PM -0700, rentao.bupt@gmail.com wrote:
> From: Tao Ren <rentao.bupt@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@gmail.com>
> ---
>  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 |  8 +++-----
>  2 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/aspeed-vhub/core.c b/drivers/usb/gadget/udc/aspeed-vhub/core.c
> index f8d35dd60c34..555e8645fb1e 100644
> --- a/drivers/usb/gadget/udc/aspeed-vhub/core.c
> +++ b/drivers/usb/gadget/udc/aspeed-vhub/core.c
> @@ -134,11 +134,15 @@ 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 & vhub->port_irq_mask) {
> +		unsigned long bitmap = istat;
> +		int offset = VHUB_IRQ_DEV1_BIT;
> +		int size = VHUB_IRQ_DEV1_BIT + vhub->max_ports;
>  
> -		if (istat & dev_mask)
> +		for_each_set_bit_from(offset, &bitmap, size) {
> +			i = offset - VHUB_IRQ_DEV1_BIT;
>  			ast_vhub_dev_irq(&vhub->ports[i].dev);
> +		}
>  	}
>  
>  	/* Handle top-level vHub EP0 interrupts */
> @@ -332,6 +336,8 @@ 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..23a1ac91f8d2 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)
> @@ -402,6 +399,7 @@ 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
>