linux-kernel - Re: [PATCH 4/6] irqchip/renesas-rzv2h: Add CA55 software interrupt support

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Message-ID: <CA+V-a8uUkBdFdY2k66onXStB3wjy_wocoqVviGKEzEOyvojR5Q@mail.gmail.com>
Date: Fri, 23 Jan 2026 11:24:08 +0000
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Thomas Gleixner <tglx@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Magnus Damm <magnus.damm@...il.com>, linux-kernel@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org, Biju Das <biju.das.jz@...renesas.com>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH 4/6] irqchip/renesas-rzv2h: Add CA55 software interrupt support

Hi Geert,

Thank you for the review.

On Fri, Jan 23, 2026 at 10:45 AM Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Wed, 21 Jan 2026 at 16:01, Prabhakar <prabhakar.csengg@...il.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> >
> > The Renesas RZ/V2H ICU provides a software interrupt register (ICU_SWINT)
> > that allows software to explicitly assert interrupts toward individual
> > CA55 cores. Writing BIT(n) to ICU_SWINT triggers the corresponding
> > interrupt.
> >
> > Introduce a debug mechanism to trigger software interrupts on individual
> > Cortex-A55 cores via the RZ/V2H ICU. The interface is gated behind
> > CONFIG_DEBUG_FS and a module parameter to ensure it only exists when
> > explicitly enabled.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> Thanks for your patch!
>
> > --- a/drivers/irqchip/irq-renesas-rzv2h.c
> > +++ b/drivers/irqchip/irq-renesas-rzv2h.c
> > @@ -11,16 +11,23 @@
> >
> >  #include <linux/bitfield.h>
> >  #include <linux/cleanup.h>
> > +#include <linux/cpu.h>
> > +#include <linux/debugfs.h>
> >  #include <linux/err.h>
> > +#include <linux/fs.h>
> >  #include <linux/io.h>
> >  #include <linux/irqchip.h>
> >  #include <linux/irqchip/irq-renesas-rzv2h.h>
> >  #include <linux/irqdomain.h>
> > +#include <linux/kconfig.h>
> > +#include <linux/kstrtox.h>
> > +#include <linux/moduleparam.h>
> >  #include <linux/of_platform.h>
> >  #include <linux/pm_runtime.h>
> >  #include <linux/reset.h>
> >  #include <linux/spinlock.h>
> >  #include <linux/syscore_ops.h>
> > +#include <linux/uaccess.h>
> >
>
> [...]
>
> > +static int rzv2h_icu_setup_debug_irqs(struct platform_device *pdev)
> > +{
> > +       static const u8 swint_idx[ICU_SWINT_NUM] = { 0, 1, 2, 3 };
> > +       static const char * const rzv2h_swint_names[] = {
> > +               "int-ca55-0", "int-ca55-1",
> > +               "int-ca55-2", "int-ca55-3",
> > +       };
> > +       struct device *dev = &pdev->dev;
> > +       struct dentry *dentry;
> > +       struct dentry *dir;
> > +       unsigned int i;
> > +       int icu_irq;
> > +       int ret;
> > +
> > +       if (!IS_ENABLED(CONFIG_DEBUG_FS) || !enable_icu_debug)
> > +               return 0;
> > +
> > +       dev_info(dev, "RZ/V2H ICU debug interrupts enabled\n");
> > +
> > +       for (i = 0; i < ICU_SWINT_NUM; i++) {
> > +               icu_irq = platform_get_irq_byname(pdev, rzv2h_swint_names[i]);
> > +               if (icu_irq < 0)
> > +                       return dev_err_probe(dev, icu_irq,
> > +                                            "Failed to get %s IRQ\n", rzv2h_swint_names[i]);
> > +               ret = devm_request_irq(dev, icu_irq, rzv2h_icu_swint_irq, 0, dev_name(dev),
> > +                                      (void *)&swint_idx[i]);
>
> drivers/irqchip/irq-renesas-rzv2h.c:730:23: error: implicit
> declaration of function ‘devm_request_irq’; did you mean
> ‘can_request_irq’? [-Werror=implicit-function-declaration]
>
> How does this build for you, without including <linux/interrupt.h>?
>
While posting the patches, I had rebased them on next-20260119 (and
used defconfig), but I didn't see any build issues. Below is the
snippet from irq-renesas-rzv2h.i:

struct ns_common;
int open_related_ns(struct ns_common *ns, struct ns_common
*(*get_ns)(struct ns_common *ns));

static inline __attribute__((__gnu_inline__))
__attribute__((__unused__))
__attribute__((__no_instrument_function__)) struct pid_namespace
*proc_pid_ns(struct super_block *sb)
{
return proc_sb_info(sb)->pid_ns;
}

bool proc_ns_file(const struct file *file);
# 20 "./include/linux/efi.h" 2
# 1 "./include/linux/rtc.h" 1
# 17 "./include/linux/rtc.h"
# 1 "./include/linux/interrupt.h" 1
# 9 "./include/linux/interrupt.h"
# 1 "./include/linux/irqreturn.h" 1
# 11 "./include/linux/irqreturn.h"

enum irqreturn {
IRQ_NONE = (0 << 0),
IRQ_HANDLED = (1 << 0),
IRQ_WAKE_THREAD = (1 << 1),
};

typedef enum irqreturn irqreturn_t;
# 10 "./include/linux/interrupt.h" 2
# 1 "./include/linux/hardirq.h" 1


Tracing through the above interrupt.h was included in below :
-------------------------------------------------------------------------------
drivers/irqchip/irq-renesas-rzv2h.c - (line 19)
#include <linux/irqchip.h>
#include <linux/acpi.h>
#include <acpi/acpi_io.h>
#include <asm/acpi.h>
#include <linux/efi.h>
#include <linux/rtc.h>
#include <linux/interrupt.h>


Now that you mentioned there was a build issue, I tried with
renesas_defconfig and I do get the build issue which you pointed out.
I'll respin a v2 with #include <linux/interrupt.h> included
explicitly.

Cheers,
Prabhakar