Re: [linux-oxnas] [PATCH v2] irqchip/versatile-fpga: Handle chained IRQs properly

Hi Sungbo,

I've imported your patch to openwrt master and will backport for
Linux 4.14 to also have it in the 19.07 release branch.
Thanks for your efforts and congratulations to your first upstream fix!

Once the OpenWrt buildbot[1] gets to it, we'll have snapshot images[2]
including the fix.

[1]: http://buildbot.openwrt.org/master/images/builders/oxnas%2Fox820
[2]: http://downloads.openwrt.org/snapshots/targets/oxnas/ox820/

On Thu, Mar 19, 2020 at 11:34:48AM +0900, Sungbo Eo wrote:
> Enclose the chained handler with chained_irq_{enter,exit}(), so that the
> muxed interrupts get properly acked.
> 
> This patch also fixes a reboot bug on OX820 SoC, where the jiffies timer
> interrupt is never acked. The kernel waits a clock tick forever in
> calibrate_delay_converge(), which leads to a boot hang.
> 
> Fixes: c41b16f8c9d9 ("ARM: integrator/versatile: consolidate FPGA IRQ handling code")
> Signed-off-by: Sungbo Eo <[email protected]>
> Cc: Neil Armstrong <[email protected]>
> ---
> v2: moved readl below chained_irq_enter()
>     added Fixes tag
> 
>  drivers/irqchip/irq-versatile-fpga.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-versatile-fpga.c b/drivers/irqchip/irq-versatile-fpga.c
> index 928858dada75..70e2cfff8175 100644
> --- a/drivers/irqchip/irq-versatile-fpga.c
> +++ b/drivers/irqchip/irq-versatile-fpga.c
> @@ -6,6 +6,7 @@
>  #include <linux/irq.h>
>  #include <linux/io.h>
>  #include <linux/irqchip.h>
> +#include <linux/irqchip/chained_irq.h>
>  #include <linux/irqchip/versatile-fpga.h>
>  #include <linux/irqdomain.h>
>  #include <linux/module.h>
> @@ -68,12 +69,16 @@ static void fpga_irq_unmask(struct irq_data *d)
>  
>  static void fpga_irq_handle(struct irq_desc *desc)
>  {
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
>  	struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
> -	u32 status = readl(f->base + IRQ_STATUS);
> +	u32 status;
> +
> +	chained_irq_enter(chip, desc);
>  
> +	status = readl(f->base + IRQ_STATUS);
>  	if (status == 0) {
>  		do_bad_IRQ(desc);
> -		return;
> +		goto out;
>  	}
>  
>  	do {
> @@ -82,6 +87,9 @@ static void fpga_irq_handle(struct irq_desc *desc)
>  		status &= ~(1 << irq);
>  		generic_handle_irq(irq_find_mapping(f->domain, irq));
>  	} while (status);
> +
> +out:
> +	chained_irq_exit(chip, desc);
>  }
>  
>  /*
> -- 
> 2.25.1
> 
> 
> 
>