linux-kernel - Re: [PATCH v2 2/5] irqchip: Add RZ/G2L IA55 Interrupt Controller driver

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Date:   Mon, 9 May 2022 11:10:10 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Biju Das <biju.das.jz@...renesas.com>
Cc:     Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        Prabhakar <prabhakar.csengg@...il.com>
Subject: Re: [PATCH v2 2/5] irqchip: Add RZ/G2L IA55 Interrupt Controller driver

On Mon, May 9, 2022 at 9:22 AM Biju Das <biju.das.jz@...renesas.com> wrote:
> > Subject: [PATCH v2 2/5] irqchip: Add RZ/G2L IA55 Interrupt Controller
> > driver
> >
> > Add a driver for the Renesas RZ/G2L Interrupt Controller.
> >
> > This supports external pins being used as interrupts. It supports one line
> > for NMI, 8 external pins and 32 GPIO pins (out of 123) to be used as IRQ
> > lines.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

> > --- /dev/null
> > +++ b/drivers/irqchip/irq-renesas-rzg2l.c

> > +static void rzg2l_irqc_irq_disable(struct irq_data *d) {
> > +     unsigned int hw_irq = irqd_to_hwirq(d);
> > +
> > +     if (hw_irq >= IRQC_TINT_START && hw_irq <= IRQC_TINT_COUNT) {
> > +             struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> > +             u32 offset = hw_irq - IRQC_TINT_START;
> > +             u32 tssr_offset = TSSR_OFFSET(offset);
> > +             u8 tssr_index = TSSR_INDEX(offset);
> > +             u32 reg;
> > +
> > +             raw_spin_lock(&priv->lock);
> > +             reg = readl_relaxed(priv->base + TSSR(tssr_index));
> > +             reg &= ~(TSSEL_MASK << tssr_offset);
> > +             writel_relaxed(reg, priv->base + TSSR(tssr_index));
> > +             raw_spin_unlock(&priv->lock);
> > +     }
> > +     irq_chip_disable_parent(d);
> > +}

> > +static int rzg2l_tint_set_edge(struct irq_data *d, unsigned int type) {
> > +     struct rzg2l_irqc_priv *priv = irq_data_to_priv(d);
> > +     unsigned int hwirq = irqd_to_hwirq(d);
> > +     u32 titseln = hwirq - IRQC_TINT_START;
> > +     u32 offset;
> > +     u8 sense;
> > +     u32 reg;
> > +
> > +     switch (type & IRQ_TYPE_SENSE_MASK) {
> > +     case IRQ_TYPE_EDGE_RISING:
> > +             sense = TITSR_TITSEL_EDGE_RISING;
> > +             break;
> > +
> > +     case IRQ_TYPE_EDGE_FALLING:
> > +             sense = TITSR_TITSEL_EDGE_FALLING;
> > +             break;
> > +
> > +     default:
> > +             return -EINVAL;
> > +     }
> > +
>
> > +     if (titseln < TITSR0_MAX_INT) {
> > +             offset = TITSR0;
> > +     } else {
> > +             titseln /= TITSEL_WIDTH;
> > +             offset  = TITSR1;
> > +     }
>
> as TITSR0 (0x24) and TITSR1(0x28) are contiguous address location
>
> May be like others, above declare it as
> u32 offset = TITSR0; ??
>
> and here
>  if ((titseln >= TITSR0_MAX_INT) {
>         titseln /= TITSEL_WIDTH;
>         offset  += 4;
>  }

Why "titseln /= TITSEL_WIDTH"?
Shouldn't that be "titseln -= TITSR0_MAX_INT"?
Do I need more coffee?

Can't you define TITSR_{OFFSET,INDEX}() helper macros, like for
TSSR above?

> > +
> > +     raw_spin_lock(&priv->lock);
> > +     reg = readl_relaxed(priv->base + offset);
> > +     reg &= ~(IRQ_MASK << (titseln * TITSEL_WIDTH));
> > +     reg |= sense << (titseln * TITSEL_WIDTH);
> > +     writel_relaxed(reg, priv->base + offset);
> > +     raw_spin_unlock(&priv->lock);
> > +
> > +     return 0;
> > +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds