linux-kernel - Re: [PATCH 1/2] genirq: add chip_{suspend,resume} PM support to irq

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Date:	Fri, 19 Jun 2015 16:38:05 -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 1/2] genirq: add chip_{suspend,resume} PM support to irq_chip

On 19/06/15 16:26, Brian Norris wrote:
> Some (admittedly odd) irqchips perform functions that are not directly
> related to any of their child IRQ lines, and therefore need to perform
> some tasks during suspend/resume regardless of whether there are
> any "installed" interrupts for the irqchip. However, the current
> generic-chip framework does not call the chip's irq_{suspend,resume}
> when there are no interrupts installed (this makes sense, because there
> are no irq_data objects for such a call to be made).
> 
> More specifically, irq-bcm7120-l2 configures both a forwarding mask
> (which affects other top-level GIC IRQs) and a second-level interrupt
> mask (for managing its own child interrupts). The former must be
> saved/restored on suspend/resume, even when there's nothing to do for
> the latter.
> 
> This patch adds a second set of suspend/resume hooks to irq_chip, this
> time to represent *chip* suspend/resume, rather than IRQ suspend/resume.
> These callbacks will always be called for an irqchip and are based on
> the per-chip irq_chip_generic struct, rather than the per-IRQ irq_data
> struct.
> 
> 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>

> ---
>  include/linux/irq.h       | 10 ++++++++++
>  kernel/irq/generic-chip.c |  6 ++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index de3213d271ff..2a672d2434a5 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -293,6 +293,8 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
>  	return d->hwirq;
>  }
>  
> +struct irq_chip_generic;
> +
>  /**
>   * struct irq_chip - hardware interrupt chip descriptor
>   *
> @@ -317,6 +319,12 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
>   * @irq_suspend:	function called from core code on suspend once per chip
>   * @irq_resume:		function called from core code on resume once per chip
>   * @irq_pm_shutdown:	function called from core code on shutdown once per chip
> + * @chip_suspend:	function called from core code on suspend once per
> + *			chip; for handling chip details even when no interrupts
> + *			are in use
> + * @chip_resume:	function called from core code on resume once per chip;
> + *			for handling chip details even when no interrupts are
> + *			in use
>   * @irq_calc_mask:	Optional function to set irq_data.mask for special cases
>   * @irq_print_chip:	optional to print special chip info in show_interrupts
>   * @irq_request_resources:	optional to request resources before calling
> @@ -357,6 +365,8 @@ struct irq_chip {
>  	void		(*irq_suspend)(struct irq_data *data);
>  	void		(*irq_resume)(struct irq_data *data);
>  	void		(*irq_pm_shutdown)(struct irq_data *data);
> +	void		(*chip_suspend)(struct irq_chip_generic *gc);
> +	void		(*chip_resume)(struct irq_chip_generic *gc);
>  
>  	void		(*irq_calc_mask)(struct irq_data *data);
>  
> diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
> index 15b370daf234..fe25e72d5d13 100644
> --- a/kernel/irq/generic-chip.c
> +++ b/kernel/irq/generic-chip.c
> @@ -553,6 +553,9 @@ static int irq_gc_suspend(void)
>  			if (data)
>  				ct->chip.irq_suspend(data);
>  		}
> +
> +		if (ct->chip.chip_suspend)
> +			ct->chip.chip_suspend(gc);
>  	}
>  	return 0;
>  }
> @@ -564,6 +567,9 @@ static void irq_gc_resume(void)
>  	list_for_each_entry(gc, &gc_list, list) {
>  		struct irq_chip_type *ct = gc->chip_types;
>  
> +		if (ct->chip.chip_resume)
> +			ct->chip.chip_resume(gc);
> +
>  		if (ct->chip.irq_resume) {
>  			struct irq_data *data = irq_gc_get_irq_data(gc);
>  
> 


-- 
Florian
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