linux-kernel - Re: [PATCH v5] irqchip/mmp: only touch the PJ4 & FIQ bits on enable/disable

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Date:   Mon, 28 Jan 2019 18:35:40 +0000
From:   Marc Zyngier <marc.zyngier@....com>
To:     Lubomir Rintel <lkundrak@...sk>
Cc:     Jason Cooper <jason@...edaemon.net>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, stable@...nel.org,
        Pavel Machek <pavel@....cz>
Subject: Re: [PATCH v5] irqchip/mmp: only touch the PJ4 & FIQ bits on
 enable/disable

I guess the subject is supposed to read: "only touch the PJ4 *IRQ* & FIQ
bits on enable/disable", right?

If that's the case, let me know, and I'll fix it up when applying it.

On 28/01/2019 15:59, Lubomir Rintel wrote:
> Resetting the bit 4 disables the interrupt delivery to the "secure
> processor" core. This breaks the keyboard on a OLPC XO 1.75 laptop,
> where the firmware running on the "secure processor" bit-bangs the
> PS/2 protocol over the GPIO lines.
> 
> It is not clear what the rest of the bits are and Marvel was unhelpful
> when asked for documentation. Aside from the SP bit, there are probably
> priority bits.
> 
> Leaving the unknown bits as the firmware set them up seems to be a wiser
> course of action compared to just turning them off.
> 
> Signed-off-by: Lubomir Rintel <lkundrak@...sk>
> Acked-by: Pavel Machek <pavel@....cz>
> 
> ---
> Changes since v4:
> - Remove unused ICU_INT_ROUTE_SP_IRQ define
> - Try to further clarify the commit message
> 
> Changes since v3:
> - Use #defined instead of integer literals
> 
> Changes since v2:
> - Correct subsystem maintainers on Cc (irqchip)
> 
> Changes since v1:
> - Adjusted wording & ack from Pavel
> ---
>  drivers/irqchip/irq-mmp.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-mmp.c b/drivers/irqchip/irq-mmp.c
> index 37a54797a137..fac8f1365f76 100644
> --- a/drivers/irqchip/irq-mmp.c
> +++ b/drivers/irqchip/irq-mmp.c
> @@ -34,6 +34,9 @@
>  #define SEL_INT_PENDING		(1 << 6)
>  #define SEL_INT_NUM_MASK	0x3f
>  
> +#define MMP2_ICU_INT_ROUTE_PJ4_IRQ	(1 << 5)
> +#define MMP2_ICU_INT_ROUTE_PJ4_FIQ	(1 << 6)
> +
>  struct icu_chip_data {
>  	int			nr_irqs;
>  	unsigned int		virq_base;
> @@ -190,7 +193,8 @@ static const struct mmp_intc_conf mmp_conf = {
>  static const struct mmp_intc_conf mmp2_conf = {
>  	.conf_enable	= 0x20,
>  	.conf_disable	= 0x0,
> -	.conf_mask	= 0x7f,
> +	.conf_mask	= MMP2_ICU_INT_ROUTE_PJ4_IRQ |
> +			  MMP2_ICU_INT_ROUTE_PJ4_FIQ,
>  };
>  
>  static void __exception_irq_entry mmp_handle_irq(struct pt_regs *regs)
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...