linux-kernel - Re: [PATCH 1/3] pinctrl: exynos: Add spinlocks to irq_mask and irq

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Date:	Thu, 13 Jun 2013 13:03:12 +0200
From:	Tomasz Figa <tomasz.figa@...il.com>
To:	Doug Anderson <dianders@...omium.org>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Olof Johansson <olof@...om.net>,
	Simon Glass <sjg@...omium.org>,
	Luigi Semenzato <semenzato@...omium.org>,
	ilho215.lee@...sung.com, eunki_kim@...sung.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] pinctrl: exynos: Add spinlocks to irq_mask and irq_unmask

Hi Doug,

On Wednesday 12 of June 2013 10:33:17 Doug Anderson wrote:
> The patch:
>   1984695 pinctrl: samsung: Protect bank registers with a spinlock
> 
> ...added spinlocks to protect many accesses.  However, the irq_mask
> and irq_unmask functions still do an unprotected read/modify/write.
> Add the spinlock there.

Right, that's correct.

I always thought that the IRQ core already does some irqchip level 
locking, but it seems like I got confused by irq_desc spinlock. Thanks for 
spotting this.

Acked-by: Tomasz Figa <t.figa@...sung.com>

Best regards,
Tomasz

> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
>  drivers/pinctrl/pinctrl-exynos.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/pinctrl/pinctrl-exynos.c
> b/drivers/pinctrl/pinctrl-exynos.c index 2d76f66..c29a28e 100644
> --- a/drivers/pinctrl/pinctrl-exynos.c
> +++ b/drivers/pinctrl/pinctrl-exynos.c
> @@ -56,10 +56,15 @@ static void exynos_gpio_irq_unmask(struct irq_data
> *irqd) struct samsung_pinctrl_drv_data *d = bank->drvdata;
>  	unsigned long reg_mask = d->ctrl->geint_mask + bank->eint_offset;
>  	unsigned long mask;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&bank->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
>  	mask &= ~(1 << irqd->hwirq);
>  	writel(mask, d->virt_base + reg_mask);
> +
> +	spin_unlock_irqrestore(&bank->slock, flags);
>  }
> 
>  static void exynos_gpio_irq_mask(struct irq_data *irqd)
> @@ -68,10 +73,15 @@ static void exynos_gpio_irq_mask(struct irq_data
> *irqd) struct samsung_pinctrl_drv_data *d = bank->drvdata;
>  	unsigned long reg_mask = d->ctrl->geint_mask + bank->eint_offset;
>  	unsigned long mask;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&bank->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
>  	mask |= 1 << irqd->hwirq;
>  	writel(mask, d->virt_base + reg_mask);
> +
> +	spin_unlock_irqrestore(&bank->slock, flags);
>  }
> 
>  static void exynos_gpio_irq_ack(struct irq_data *irqd)
> @@ -264,10 +274,15 @@ static void exynos_wkup_irq_unmask(struct irq_data
> *irqd) struct samsung_pinctrl_drv_data *d = b->drvdata;
>  	unsigned long reg_mask = d->ctrl->weint_mask + b->eint_offset;
>  	unsigned long mask;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&b->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
>  	mask &= ~(1 << irqd->hwirq);
>  	writel(mask, d->virt_base + reg_mask);
> +
> +	spin_unlock_irqrestore(&b->slock, flags);
>  }
> 
>  static void exynos_wkup_irq_mask(struct irq_data *irqd)
> @@ -276,10 +291,15 @@ static void exynos_wkup_irq_mask(struct irq_data
> *irqd) struct samsung_pinctrl_drv_data *d = b->drvdata;
>  	unsigned long reg_mask = d->ctrl->weint_mask + b->eint_offset;
>  	unsigned long mask;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&b->slock, flags);
> 
>  	mask = readl(d->virt_base + reg_mask);
>  	mask |= 1 << irqd->hwirq;
>  	writel(mask, d->virt_base + reg_mask);
> +
> +	spin_unlock_irqrestore(&b->slock, flags);
>  }
> 
>  static void exynos_wkup_irq_ack(struct irq_data *irqd)
--
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