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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Thu, 7 Feb 2019 16:49:25 +0100
Message-ID: <CAMRc=Me9gqfN6WuWPZ61M2pNC+ZrhxAX_=BzAr4_zxnfdL4G7Q@mail.gmail.com>
Subject: Re: [PATCH 02/35] ARM: davinci: select GENERIC_IRQ_MULTI_HANDLER
To:     Sekhar Nori <nsekhar@ti.com>
Cc:     Kevin Hilman <khilman@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
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=C5=9Br., 6 lut 2019 o 13:39 Sekhar Nori <nsekhar@ti.com> napisa=C5=82(a):
>
> On 31/01/19 7:08 PM, Bartosz Golaszewski wrote:
>
> > diff --git a/arch/arm/mach-davinci/cp_intc.c b/arch/arm/mach-davinci/cp=
_intc.c
> > index 67805ca74ff8..b9aec3c48a6a 100644
> > --- a/arch/arm/mach-davinci/cp_intc.c
> > +++ b/arch/arm/mach-davinci/cp_intc.c
> > @@ -19,6 +19,7 @@
> >  #include <linux/of_address.h>
> >  #include <linux/of_irq.h>
> >
> > +#include <asm/exception.h>
> >  #include <mach/common.h>
> >  #include "cp_intc.h"
> >
> > @@ -97,6 +98,16 @@ static struct irq_chip cp_intc_irq_chip =3D {
> >
> >  static struct irq_domain *cp_intc_domain;
> >
> > +static asmlinkage void __exception_irq_entry
> > +cp_intc_handle_irq(struct pt_regs *regs)
> > +{
> > +     int irqnr =3D cp_intc_read(CP_INTC_PRIO_IDX);
> > +
> > +     irqnr &=3D 0xff;
> > +
> > +     handle_domain_irq(cp_intc_domain, irqnr, regs);
>
> This leaves out spurious interrupt handling present in existing assembly
> code. Can you add it back. May be use omap_intc_handle_irq() as an
> example for handling spurious IRQs.
>

Hi Sekhar,

I started looking at this one and noticed that the manual says
PRI_INDX field in the GPIR register is in bits 0-9 (mask 0x3ff) while
the assembly logically ANDs it with 0xff. I guess it's because there
can be no more interrupts than 255 but I'd at least explain it in a
comment. Or should we use the proper mask? What do you think?

Bart

> > +}
> > +
>
> > diff --git a/arch/arm/mach-davinci/irq.c b/arch/arm/mach-davinci/irq.c
> > index 952dc126c390..3bbbef78d9ac 100644
> > --- a/arch/arm/mach-davinci/irq.c
> > +++ b/arch/arm/mach-davinci/irq.c
> > @@ -28,11 +28,13 @@
> >  #include <mach/cputype.h>
> >  #include <mach/common.h>
> >  #include <asm/mach/irq.h>
> > +#include <asm/exception.h>
> >
> >  #define FIQ_REG0_OFFSET              0x0000
> >  #define FIQ_REG1_OFFSET              0x0004
> >  #define IRQ_REG0_OFFSET              0x0008
> >  #define IRQ_REG1_OFFSET              0x000C
> > +#define IRQ_IRQENTRY_OFFSET  0x0014
> >  #define IRQ_ENT_REG0_OFFSET  0x0018
> >  #define IRQ_ENT_REG1_OFFSET  0x001C
> >  #define IRQ_INCTL_REG_OFFSET 0x0020
> > @@ -45,6 +47,11 @@ static inline void davinci_irq_writel(unsigned long =
value, int offset)
> >       __raw_writel(value, davinci_intc_base + offset);
> >  }
> >
> > +static inline unsigned long davinci_irq_readl(int offset)
> > +{
> > +     return __raw_readl(davinci_intc_base + offset);
> > +}
>
> Can we use readl_relaxed() here? I know there is existing __raw_writel()
> usage. May be add a patch to fix the existing code first.
>
> Thanks,
> Sekhar