Re: [PATCH v4 2/3] irqchip: Add Actions Semi Owl SIRQ controller

From: Cristian Ciocaltea
Date: Wed Aug 19 2020 - 12:52:19 EST

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In reply to: Marc Zyngier: "Re: [PATCH v4 2/3] irqchip: Add Actions Semi Owl SIRQ controller"
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On Tue, Aug 18, 2020 at 09:48:41PM +0100, Marc Zyngier wrote:
> On Tue, 18 Aug 2020 18:42:41 +0100,
> Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxx> wrote:
> >
> > Hi Marc,
> >
> > Thanks for your quick and detailed review!
> >
> > On Mon, Aug 17, 2020 at 02:52:06PM +0100, Marc Zyngier wrote:
> > > On 2020-08-16 12:33, Cristian Ciocaltea wrote:
> > > > This controller appears on Actions Semi Owl family SoC's S500, S700 and
> > > > S900 and provides support for 3 external interrupt controllers through
> > >
> > > Is that really 3 interrupt controllers? Or merely 3 interrupt lines?
> >
> > This is mostly a leftover statement from the previous patch revision.
> > I will change it to something like:
> >
> > "This interrupt controller is found in the Actions Semi Owl SoCs (S500,
> > S700 and S900) and provides support for handling up to 3 external
> > interrupt lines."
>
> Looks good.
>
> >
> > > > dedicated SIRQ pins.
> > > >
> > > > Each line can be independently configured as interrupt and triggers
> > > > on either of the edges (raising or falling) or either of the levels
> > > > (high or low). Each line can also be masked independently.
> > > >
> > > > This is based on the patch series submitted by Parthiban Nallathambi:
> > > > https://lore.kernel.org/lkml/20181126100356.2840578-1-pn@xxxxxxx/
> > > >
> > > > Signed-off-by: Parthiban Nallathambi <pn@xxxxxxx>
> > > > Signed-off-by: Saravanan Sekar <sravanhome@xxxxxxxxx>
> > > > [cristi: optimized DT, various fixes/cleanups/improvements]
> > > > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxx>
> > > > ---
> > > > drivers/irqchip/Makefile | 1 +
> > > > drivers/irqchip/irq-owl-sirq.c | 318 +++++++++++++++++++++++++++++++++
> > > > 2 files changed, 319 insertions(+)
> > > > create mode 100644 drivers/irqchip/irq-owl-sirq.c
> > > >
> > > > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > > > index 133f9c45744a..b8eb5b8b766d 100644
> > > > --- a/drivers/irqchip/Makefile
> > > > +++ b/drivers/irqchip/Makefile
> > > > @@ -7,6 +7,7 @@ obj-$(CONFIG_ATH79) += irq-ath79-cpu.o
> > > > obj-$(CONFIG_ATH79) += irq-ath79-misc.o
> > > > obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o
> > > > obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2836.o
> > > > +obj-$(CONFIG_ARCH_ACTIONS) += irq-owl-sirq.o
> > > > obj-$(CONFIG_DAVINCI_AINTC) += irq-davinci-aintc.o
> > > > obj-$(CONFIG_DAVINCI_CP_INTC) += irq-davinci-cp-intc.o
> > > > obj-$(CONFIG_EXYNOS_IRQ_COMBINER) += exynos-combiner.o
> > > > diff --git a/drivers/irqchip/irq-owl-sirq.c
> > > > b/drivers/irqchip/irq-owl-sirq.c
> > > > new file mode 100644
> > > > index 000000000000..29b7ffc40ac7
> > > > --- /dev/null
> > > > +++ b/drivers/irqchip/irq-owl-sirq.c
> > > > @@ -0,0 +1,318 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Actions Semi Owl SoCs SIRQ interrupt controller driver
> > > > + *
> > > > + * Copyright (C) 2014 Actions Semi Inc.
> > > > + * David Liu <liuwei@xxxxxxxxxxxxxxxx>
> > > > + *
> > > > + * Author: Parthiban Nallathambi <pn@xxxxxxx>
> > > > + * Author: Saravanan Sekar <sravanhome@xxxxxxxxx>
> > > > + * Author: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxx>
> > > > + */
> > > > +
> > > > +#include <linux/interrupt.h>
> > > > +#include <linux/irqchip.h>
> > > > +#include <linux/of_address.h>
> > > > +#include <linux/of_irq.h>
> > > > +
> > > > +#define NUM_SIRQ 3
> > > > +
> > > > +#define INTC_EXTCTL_PENDING BIT(0)
> > > > +#define INTC_EXTCTL_CLK_SEL BIT(4)
> > > > +#define INTC_EXTCTL_EN BIT(5)
> > > > +#define INTC_EXTCTL_TYPE_MASK GENMASK(7, 6)
> > > > +#define INTC_EXTCTL_TYPE_HIGH 0
> > > > +#define INTC_EXTCTL_TYPE_LOW BIT(6)
> > > > +#define INTC_EXTCTL_TYPE_RISING BIT(7)
> > > > +#define INTC_EXTCTL_TYPE_FALLING (BIT(6) | BIT(7))
> > > > +
> > > > +/* S900 SIRQ1 & SIRQ2 control register offsets, relative to SIRQ0 */
> > > > +#define INTC_EXTCTL1 0x0328
> > > > +#define INTC_EXTCTL2 0x032c
> > > > +
> > > > +struct owl_sirq_params {
> > > > + /* INTC_EXTCTL reg shared for all three SIRQ lines */
> > > > + bool reg_shared;
> > > > + /* INTC_EXTCTL reg offsets relative to controller base address */
> > > > + u16 reg_offset[NUM_SIRQ];
> > > > +};
> > > > +
> > > > +struct owl_sirq_chip_data {
> > > > + const struct owl_sirq_params *params;
> > > > + void __iomem *base;
> > > > + raw_spinlock_t lock;
> > > > + u32 ext_irqs[NUM_SIRQ];
> > > > + u8 trigger;
> > >
> > > Nit: Please align data structure members vertically:
> > >
> > > struct owl_sirq_chip_data {
> > > const struct owl_sirq_params *params;
> > > void __iomem *base;
> > > raw_spinlock_t lock;
> > > u32 ext_irqs[NUM_SIRQ];
> > > u8 trigger;
> > > };
> >
> > Done.
> >
> > > > +};
> > > > +
> > > > +/* S500 and S700 SoCs */
> > > > +static const struct owl_sirq_params owl_sirq_s500_params = {
> > > > + .reg_shared = true,
> > > > + .reg_offset = { 0, 0, 0 },
> > > > +};
> > > > +
> > > > +/* S900 SoC */
> > > > +static const struct owl_sirq_params owl_sirq_s900_params = {
> > > > + .reg_shared = false,
> > > > + .reg_offset = { 0, INTC_EXTCTL1, INTC_EXTCTL2 },
> > >
> > > 0 *is* an offset, right? Why doesn't it have a name too?
> >
> > Right, I updated the defines section:
> >
> > /* S900 SIRQ control register offsets, relative to controller base address */
> > #define INTC_EXTCTL0 0x0000
> > #define INTC_EXTCTL1 0x0328
> > [...]
> >
> > The controller base address points to SIRQ0 control register, so this
> > offset is always 0, but I totally agree we should have a name for it.
> >
> > > > +};
> > > > +
> > > > +static u32 owl_sirq_read_extctl(struct owl_sirq_chip_data *data, u32
> > > > index)
> > > > +{
> > > > + u32 val;
> > > > +
> > > > + val = readl_relaxed(data->base + data->params->reg_offset[index]);
> > > > + if (data->params->reg_shared)
> > > > + val = (val >> (2 - index) * 8) & 0xff;
> > >
> > > base = (2 - index) * 8;
> > > val = FIELD_GET(GENMASK(base + 7, base), val);
> >
> > Unfortunately the context doesn't allow using FIELD_GET:
> >
> > ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_159’
> > declared with attribute error: FIELD_GET: mask is not constant
>
> Bah. Turning the whole thing into compile-time values would actually
> be more readable, so how about this:
>
> diff --git a/drivers/irqchip/irq-owl-sirq.c b/drivers/irqchip/irq-owl-sirq.c
> index 29b7ffc40ac7..b771acbda7d5 100644
> --- a/drivers/irqchip/irq-owl-sirq.c
> +++ b/drivers/irqchip/irq-owl-sirq.c
> @@ -57,13 +57,39 @@ static const struct owl_sirq_params owl_sirq_s900_params = {
> .reg_offset = { 0, INTC_EXTCTL1, INTC_EXTCTL2 },
> };
>
> +static u32 owl_field_get(u32 val, int index)
> +{
> + switch(index) {
> + case 0:
> + return FIELD_GET(GENMASK(23, 16), val);
> + case 1:
> + return FIELD_GET(GENMASK(15, 8), val);
> + case 2:
> + default:
> + return FIELD_GET(GENMASK(7, 0), val);
> + }
> +}
> +
> +static u32 owl_field_prep(u32 val, int index)
> +{
> + switch(index) {
> + case 0:
> + return FIELD_PREP(GENMASK(23, 16), val);
> + case 1:
> + return FIELD_PREP(GENMASK(15, 8), val);
> + case 2:
> + default:
> + return FIELD_PREP(GENMASK(7, 0), val);
> + }
> +}
> +
> static u32 owl_sirq_read_extctl(struct owl_sirq_chip_data *data, u32 index)
> {
> u32 val;
>
> val = readl_relaxed(data->base + data->params->reg_offset[index]);
> if (data->params->reg_shared)
> - val = (val >> (2 - index) * 8) & 0xff;
> + val = owl_field_get(val, index);
>
> return val;
> }
> @@ -75,9 +101,8 @@ static void owl_sirq_write_extctl(struct owl_sirq_chip_data *data,
>
> if (data->params->reg_shared) {
> val = readl_relaxed(data->base + data->params->reg_offset[index]);
> - val &= ~(0xff << (2 - index) * 8);
> - extctl &= 0xff;
> - extctl = (extctl << (2 - index) * 8) | val;
> + val &= ~owl_field_prep(0xff, index);
> + extctl = owl_field_prep(extctl, index) | val;
> }
>
> writel_relaxed(extctl, data->base + data->params->reg_offset[index]);
>
> Yes, this is a bit more code, but it *is* readable. Bonus points if
> you add proper defines for the masks.

That's great, thanks a lot!

I have submitted a new revision:
https://lore.kernel.org/lkml/cover.1597852360.git.cristian.ciocaltea@xxxxxxxxx/

Regards,
Cristi

> >
> > > > +
> > > > + return val;
> > > > +}
> > > > +
> > > > +static void owl_sirq_write_extctl(struct owl_sirq_chip_data *data,
> > > > + u32 extctl, u32 index)
> > > > +{
> > > > + u32 val;
> > > > +
> > > > + if (data->params->reg_shared) {
> > > > + val = readl_relaxed(data->base + data->params->reg_offset[index]);
> > > > + val &= ~(0xff << (2 - index) * 8);
> > > > + extctl &= 0xff;
> > > > + extctl = (extctl << (2 - index) * 8) | val;
> > >
> > > Please make use of FIELD_PREP, FIELD_GET and GENMASK.
> >
> > I'm not sure how to deal with the mask constness restriction, except
> > using static defines and if/else statements, which is not quite
> > elegant.
>
> See above.
>
> >
> > > > + }
> > > > +
> > > > + writel_relaxed(extctl, data->base + data->params->reg_offset[index]);
> > > > +}
> > > > +
> > > > +static void owl_sirq_clear_set_extctl(struct owl_sirq_chip_data *d,
> > > > + u32 clear, u32 set, u32 index)
> > > > +{
> > > > + unsigned long flags;
> > > > + u32 val;
> > > > +
> > > > + raw_spin_lock_irqsave(&d->lock, flags);
> > > > + val = owl_sirq_read_extctl(d, index);
> > > > + val &= ~clear;
> > > > + val |= set;
> > > > + owl_sirq_write_extctl(d, val, index);
> > > > + raw_spin_unlock_irqrestore(&d->lock, flags);
> > > > +}
> > > > +
> > > > +static void owl_sirq_eoi(struct irq_data *data)
> > > > +{
> > > > + struct owl_sirq_chip_data *chip_data =
> > > > irq_data_get_irq_chip_data(data);
> > > > +
> > > > + /*
> > > > + * Software must clear external interrupt pending, when interrupt type
> > > > + * is edge triggered, so we need per SIRQ based clearing.
> > > > + */
> > > > + if (chip_data->trigger & (1 << data->hwirq))
> > >
> > > BIT(d->hwirq)
> > >
> > > But it also begs the question: we already have all the trigger information
> > > in the irqdesc. Why do you need some additional bookkeeping?
> >
> > That's another leftover from the original work. Thanks for pointing
> > this out, I missed it. I dropped the redundant handling of the IRQ
> > trigger information and just replaced this with:
> >
> > if (!irqd_is_level_type(data))
>
> Yup.
>
> >
> > > > + owl_sirq_clear_set_extctl(chip_data, 0, INTC_EXTCTL_PENDING,
> > > > + data->hwirq);
> > > > +
> > > > + irq_chip_eoi_parent(data);
> > > > +}
> > > > +
> > > > +static void owl_sirq_mask(struct irq_data *data)
> > > > +{
> > > > + struct owl_sirq_chip_data *chip_data =
> > > > irq_data_get_irq_chip_data(data);
> > > > +
> > > > + owl_sirq_clear_set_extctl(chip_data, INTC_EXTCTL_EN, 0, data->hwirq);
> > > > + irq_chip_mask_parent(data);
> > > > +}
> > > > +
> > > > +static void owl_sirq_unmask(struct irq_data *data)
> > > > +{
> > > > + struct owl_sirq_chip_data *chip_data =
> > > > irq_data_get_irq_chip_data(data);
> > > > +
> > > > + owl_sirq_clear_set_extctl(chip_data, 0, INTC_EXTCTL_EN, data->hwirq);
> > > > + irq_chip_unmask_parent(data);
> > > > +}
> > > > +
> > > > +/*
> > > > + * GIC does not handle falling edge or active low, hence SIRQ shall be
> > > > + * programmed to convert falling edge to rising edge signal and active
> > > > + * low to active high signal.
> > > > + */
> > > > +static int owl_sirq_set_type(struct irq_data *data, unsigned int type)
> > > > +{
> > > > + struct owl_sirq_chip_data *chip_data =
> > > > irq_data_get_irq_chip_data(data);
> > > > + u32 sirq_type;
> > > > +
> > > > + switch (type) {
> > > > + case IRQ_TYPE_LEVEL_LOW:
> > > > + sirq_type = INTC_EXTCTL_TYPE_LOW;
> > > > + chip_data->trigger &= ~(1 << data->hwirq);
> > > > + type = IRQ_TYPE_LEVEL_HIGH;
> > > > + break;
> > > > + case IRQ_TYPE_LEVEL_HIGH:
> > > > + sirq_type = INTC_EXTCTL_TYPE_HIGH;
> > > > + chip_data->trigger &= ~(1 << data->hwirq);
> > > > + break;
> > > > + case IRQ_TYPE_EDGE_FALLING:
> > > > + sirq_type = INTC_EXTCTL_TYPE_FALLING;
> > > > + chip_data->trigger |= 1 << data->hwirq;
> > > > + type = IRQ_TYPE_EDGE_RISING;
> > > > + break;
> > > > + case IRQ_TYPE_EDGE_RISING:
> > > > + sirq_type = INTC_EXTCTL_TYPE_RISING;
> > > > + chip_data->trigger |= 1 << data->hwirq;
> > > > + break;
> > > > + default:
> > > > + WARN_ON(1);
> > >
> > > No need for this WARN_ON(), the core kernel is loud enough.
> >
> > Done.
> >
> > > > + return -EINVAL;
> > > > + }
> > > > +
> > > > + owl_sirq_clear_set_extctl(chip_data, INTC_EXTCTL_TYPE_MASK, sirq_type,
> > > > + data->hwirq);
> > > > +
> > > > + return irq_chip_set_type_parent(data, type);
> > > > +}
> > > > +
> > > > +static struct irq_chip owl_sirq_chip = {
> > > > + .name = "owl-sirq",
> > > > + .irq_mask = owl_sirq_mask,
> > > > + .irq_unmask = owl_sirq_unmask,
> > > > + .irq_eoi = owl_sirq_eoi,
> > > > + .irq_set_type = owl_sirq_set_type,
> > > > + .irq_retrigger = irq_chip_retrigger_hierarchy,
> > >
> > > How about irq_set_affinity? Or does it only exist on UP systems?
> >
> > I have just added:
> >
> > #ifdef CONFIG_SMP
> > .irq_set_affinity = irq_chip_set_affinity_parent,
> > #endif
>
> Looks OK.
>
> Cheers,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.

Next message: Randy Dunlap: "Re: [PATCH v2] seqlock: <linux/seqlock.h>: fix multiple kernel-doc warnings"
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In reply to: Marc Zyngier: "Re: [PATCH v4 2/3] irqchip: Add Actions Semi Owl SIRQ controller"
Next in thread: Cristian Ciocaltea: "[PATCH v4 1/3] dt-bindings: interrupt-controller: Add Actions SIRQ controller binding"
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