linux-kernel - Re: [PATCH v6 02/10] usb: dwc3: omap: Make the wrapper interrupt shared

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Date:	Mon, 11 Apr 2016 15:13:43 +0300
From:	Felipe Balbi <balbi@...nel.org>
To:	Roger Quadros <rogerq@...com>
Cc:	tony@...mide.com, Joao.Pinto@...opsys.com,
	sergei.shtylyov@...entembedded.com, peter.chen@...escale.com,
	jun.li@...escale.com, grygorii.strashko@...com,
	yoshihiro.shimoda.uh@...esas.com, nsekhar@...com,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org, Roger Quadros <rogerq@...com>
Subject: Re: [PATCH v6 02/10] usb: dwc3: omap: Make the wrapper interrupt shared


Hi,

Roger Quadros <rogerq@...com> writes:
> The wrapper interrupt is shared with OTG core so mark it IRQF_SHARED.
>
> Use request_threaded_irq() to ensure that irqflags match for the
> shared interrupt handlers. If we don't use request_treaded_irq() then
> forced threaded irq will set IRQF_ONESHOT and this won't match with
> the OTG irq handler.

then it seems you need to _first_ fix the OTG IRQ handler. Why does it
defer ? At a minimum, first switch to threaded IRQ handler, then (in
another patch) switch to IRQF_SHARED

> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
>  drivers/usb/dwc3/dwc3-omap.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
> index 22e9606..51ca098 100644
> --- a/drivers/usb/dwc3/dwc3-omap.c
> +++ b/drivers/usb/dwc3/dwc3-omap.c
> @@ -274,19 +274,25 @@ static irqreturn_t dwc3_omap_interrupt(int irq, void *_omap)
>  {
>  	struct dwc3_omap	*omap = _omap;
>  	u32			reg;
> +	int			ret = IRQ_NONE;
>  
>  	reg = dwc3_omap_read_irqmisc_status(omap);
>  
> +	if (reg)
> +		ret = IRQ_HANDLED;

you can avoid the local variable by returning early here.

	if (!reg)
        	return IRQ_NONE;

>  	if (reg & USBOTGSS_IRQMISC_DMADISABLECLR)
>  		omap->dma_status = false;
>  
>  	dwc3_omap_write_irqmisc_status(omap, reg);
>  
>  	reg = dwc3_omap_read_irq0_status(omap);
> +	if (reg)
> +		ret = IRQ_HANDLED;

and this check is probably unnecessary.

> @@ -506,8 +512,8 @@ static int dwc3_omap_probe(struct platform_device *pdev)
>  	reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
>  	omap->dma_status = !!(reg & USBOTGSS_SYSCONFIG_DMADISABLE);
>  
> -	ret = devm_request_irq(dev, omap->irq, dwc3_omap_interrupt, 0,
> -			"dwc3-omap", omap);
> +	ret = devm_request_threaded_irq(dev, omap->irq, dwc3_omap_interrupt,

this switch to threaded IRQ is not part of $subject.

-- 
balbi

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