linux-kernel - Re: [PATCH 2/2] IRQCHIP: bcm7120-l2: perform suspend/resume even without installed child IRQs

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Date:	Fri, 19 Jun 2015 16:39:22 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Brian Norris <computersforpeace@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	Florian Fainelli <f.fainelli@...il.com>,
	Gregory Fong <gregory.0xf0@...il.com>,
	bcm-kernel-feedback-list@...adcom.com,
	linux-kernel@...r.kernel.org, linux-mips@...ux-mips.org,
	Kevin Cernekee <cernekee@...il.com>,
	Jason Cooper <jason@...edaemon.net>
Subject: Re: [PATCH 2/2] IRQCHIP: bcm7120-l2: perform suspend/resume even
 without installed child IRQs

On 19/06/15 16:26, Brian Norris wrote:
> Make use of the new irq_chip chip_{suspend,resume} callbacks.
> 
> This is required because if there are no installed child IRQs for
> this chip, the irq_{suspend,resume} functions will not be called.
> However, we still need to save/restore the forwarding mask, to enable
> the top-level GIC interrupt; otherwise, we lose UART output after S3
> resume.
> 
> In addition to refactoring the callbacks, we have to self-initialize the
> mask cache, since the genirq core also doesn't initialize this until the
> first child IRQ is installed.
> 
> The original problem report is described in extra detail here:
> http://lkml.kernel.org/g/20150619224123.GL4917@ld-irv-0074
> 
> Signed-off-by: Brian Norris <computersforpeace@...il.com>

Acked-by: Florian Fainelli <f.fainelli@...il.com>

> ---
>  drivers/irqchip/irq-bcm7120-l2.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-bcm7120-l2.c b/drivers/irqchip/irq-bcm7120-l2.c
> index 299d4de2deb5..98f0129fe843 100644
> --- a/drivers/irqchip/irq-bcm7120-l2.c
> +++ b/drivers/irqchip/irq-bcm7120-l2.c
> @@ -81,10 +81,9 @@ static void bcm7120_l2_intc_irq_handle(unsigned int irq, struct irq_desc *desc)
>  	chained_irq_exit(chip, desc);
>  }
>  
> -static void bcm7120_l2_intc_suspend(struct irq_data *d)
> +static void bcm7120_l2_intc_suspend(struct irq_chip_generic *gc)
>  {
> -	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> -	struct irq_chip_type *ct = irq_data_get_chip_type(d);
> +	struct irq_chip_type *ct = gc->chip_types;
>  	struct bcm7120_l2_intc_data *b = gc->private;
>  
>  	irq_gc_lock(gc);
> @@ -94,10 +93,9 @@ static void bcm7120_l2_intc_suspend(struct irq_data *d)
>  	irq_gc_unlock(gc);
>  }
>  
> -static void bcm7120_l2_intc_resume(struct irq_data *d)
> +static void bcm7120_l2_intc_resume(struct irq_chip_generic *gc)
>  {
> -	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> -	struct irq_chip_type *ct = irq_data_get_chip_type(d);
> +	struct irq_chip_type *ct = gc->chip_types;
>  
>  	/* Restore the saved mask */
>  	irq_gc_lock(gc);
> @@ -281,8 +279,15 @@ int __init bcm7120_l2_intc_probe(struct device_node *dn,
>  		ct->chip.irq_mask = irq_gc_mask_clr_bit;
>  		ct->chip.irq_unmask = irq_gc_mask_set_bit;
>  		ct->chip.irq_ack = irq_gc_noop;
> -		ct->chip.irq_suspend = bcm7120_l2_intc_suspend;
> -		ct->chip.irq_resume = bcm7120_l2_intc_resume;
> +		ct->chip.chip_suspend = bcm7120_l2_intc_suspend;
> +		ct->chip.chip_resume = bcm7120_l2_intc_resume;
> +
> +		/*
> +		 * Initialize mask-cache, in case we need it for
> +		 * saving/restoring fwd mask even w/o any child interrupts
> +		 * installed
> +		 */

Your commit message is a tad clearer than this comment, but this is
still good enough to understand what is being done here.

> +		gc->mask_cache = irq_reg_readl(gc, ct->regs.mask);
>  
>  		if (data->can_wake) {
>  			/* This IRQ chip can wake the system, set all
> 


-- 
Florian
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