linux-kernel - Re: [RFC PATCH 4/4] pinctrl: rockchip: avoid hardirq-unsafe functions in irq

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Message-ID: <8279144.RSoYI8sFdD@phil>
Date:   Wed, 15 Mar 2017 18:04:37 +0100
From:   Heiko Stuebner <heiko@...ech.de>
To:     John Keeping <john@...anate.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 4/4] pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip

Am Montag, 13. März 2017, 18:38:13 CET schrieb John Keeping:
> With real-time preemption, regmap functions cannot be used in the
> implementation of irq_chip since they use spinlocks which may sleep.
> 
> Move the setting of the mux for IRQs to an irq_bus_sync_unlock handler
> where we are allowed to sleep.
> 
> Signed-off-by: John Keeping <john@...anate.com>

Looks good
Reviewed-by: Heiko Stuebner <heiko@...ech.de>

> ---
>  drivers/pinctrl/pinctrl-rockchip.c | 44
> ++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4
> deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-rockchip.c
> b/drivers/pinctrl/pinctrl-rockchip.c index 52e70c4aef7c..80f7c23d12d4
> 100644
> --- a/drivers/pinctrl/pinctrl-rockchip.c
> +++ b/drivers/pinctrl/pinctrl-rockchip.c
> @@ -143,6 +143,9 @@ struct rockchip_drv {
>   * @gpio_chip: gpiolib chip
>   * @grange: gpio range
>   * @slock: spinlock for the gpio bank
> + * @irq_lock: bus lock for irq chip
> + * @new_irqs: newly configured irqs which must be muxed as GPIOs in
> + *	irq_bus_sync_unlock()
>   */
>  struct rockchip_pin_bank {
>  	void __iomem			*reg_base;
> @@ -165,6 +168,8 @@ struct rockchip_pin_bank {
>  	struct pinctrl_gpio_range	grange;
>  	raw_spinlock_t			slock;
>  	u32				toggle_edge_mode;
> +	struct mutex			irq_lock;
> +	u32				new_irqs;
>  };
> 
>  #define PIN_BANK(id, pins, label)			\
> @@ -2045,11 +2050,12 @@ static int rockchip_irq_set_type(struct irq_data *d,
> unsigned int type) int ret;
> 
>  	/* make sure the pin is configured as gpio input */
> -	ret = rockchip_set_mux(bank, d->hwirq, RK_FUNC_GPIO);
> +	ret = rockchip_verify_mux(bank, d->hwirq, RK_FUNC_GPIO);
>  	if (ret < 0)
>  		return ret;
> 
> -	clk_enable(bank->clk);
> +	bank->new_irqs |= mask;
> +
>  	raw_spin_lock_irqsave(&bank->slock, flags);
> 
>  	data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
> @@ -2107,7 +2113,6 @@ static int rockchip_irq_set_type(struct irq_data *d,
> unsigned int type) default:
>  		irq_gc_unlock(gc);
>  		raw_spin_unlock_irqrestore(&bank->slock, flags);
> -		clk_disable(bank->clk);
>  		return -EINVAL;
>  	}
> 
> @@ -2116,7 +2121,6 @@ static int rockchip_irq_set_type(struct irq_data *d,
> unsigned int type)
> 
>  	irq_gc_unlock(gc);
>  	raw_spin_unlock_irqrestore(&bank->slock, flags);
> -	clk_disable(bank->clk);
> 
>  	return 0;
>  }
> @@ -2160,6 +2164,34 @@ static void rockchip_irq_gc_mask_set_bit(struct
> irq_data *d) clk_disable(bank->clk);
>  }
> 
> +static void rockchip_irq_bus_lock(struct irq_data *d)
> +{
> +	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> +	struct rockchip_pin_bank *bank = gc->private;
> +
> +	clk_enable(bank->clk);
> +	mutex_lock(&bank->irq_lock);
> +}
> +
> +static void rockchip_irq_bus_sync_unlock(struct irq_data *d)
> +{
> +	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
> +	struct rockchip_pin_bank *bank = gc->private;
> +
> +	while (bank->new_irqs) {
> +		unsigned int irq = __ffs(bank->new_irqs);
> +		int ret;
> +
> +		ret = rockchip_set_mux(bank, irq, RK_FUNC_GPIO);
> +		WARN_ON(ret < 0);
> +
> +		bank->new_irqs &= ~BIT(irq);
> +	}
> +
> +	mutex_unlock(&bank->irq_lock);
> +	clk_disable(bank->clk);
> +}
> +
>  static int rockchip_interrupts_register(struct platform_device *pdev,
>  						struct rockchip_pinctrl *info)
>  {
> @@ -2225,6 +2257,9 @@ static int rockchip_interrupts_register(struct
> platform_device *pdev, gc->chip_types[0].chip.irq_suspend =
> rockchip_irq_suspend;
>  		gc->chip_types[0].chip.irq_resume = rockchip_irq_resume;
>  		gc->chip_types[0].chip.irq_set_type = rockchip_irq_set_type;
> +		gc->chip_types[0].chip.irq_bus_lock = rockchip_irq_bus_lock;
> +		gc->chip_types[0].chip.irq_bus_sync_unlock =
> +						rockchip_irq_bus_sync_unlock;
>  		gc->wake_enabled = IRQ_MSK(bank->nr_pins);
> 
>  		irq_set_chained_handler_and_data(bank->irq,
> @@ -2398,6 +2433,7 @@ static struct rockchip_pin_ctrl
> *rockchip_pinctrl_get_soc_data( int bank_pins = 0;
> 
>  		raw_spin_lock_init(&bank->slock);
> +		mutex_init(&bank->irq_lock);
>  		bank->drvdata = d;
>  		bank->pin_base = ctrl->nr_pins;
>  		ctrl->nr_pins += bank->nr_pins;