Date:   Mon, 29 Apr 2019 11:06:53 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Simon Horman <horms@...ge.net.au>,
        Magnus Damm <magnus.damm@...il.com>,
        Chris Brandt <chris.brandt@...esas.com>
Cc:     devicetree@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] irqchip: Add Renesas RZ/A1 Interrupt Controller
 driver

Hi Geert,

On 29/04/2019 10:36, Geert Uytterhoeven wrote:
> Add a driver for the Renesas RZ/A1 Interrupt Controller.
> 
> This supports using up to 8 external interrupts on RZ/A1, with
> configurable sense select.
> 
> NMI edge select is not yet supported.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> ---
>  drivers/irqchip/Kconfig            |   4 +
>  drivers/irqchip/Makefile           |   1 +
>  drivers/irqchip/irq-renesas-rza1.c | 238 +++++++++++++++++++++++++++++
>  3 files changed, 243 insertions(+)
>  create mode 100644 drivers/irqchip/irq-renesas-rza1.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 5438abb1babaf042..cd5b9bbf6122afce 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -221,6 +221,10 @@ config RENESAS_IRQC
>  	select GENERIC_IRQ_CHIP
>  	select IRQ_DOMAIN
>  
> +config RENESAS_RZA1_IRQC
> +	bool
> +	select IRQ_DOMAIN_HIERARCHY
> +
>  config ST_IRQCHIP
>  	bool
>  	select REGMAP
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 85972ae1bd7f978b..c0e23ce9f2619de3 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_JCORE_AIC)			+= irq-jcore-aic.o
>  obj-$(CONFIG_RDA_INTC)			+= irq-rda-intc.o
>  obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
>  obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
> +obj-$(CONFIG_RENESAS_RZA1_IRQC)		+= irq-renesas-rza1.o
>  obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
>  obj-$(CONFIG_ARCH_NSPIRE)		+= irq-zevio.o
>  obj-$(CONFIG_ARCH_VT8500)		+= irq-vt8500.o
> diff --git a/drivers/irqchip/irq-renesas-rza1.c b/drivers/irqchip/irq-renesas-rza1.c
> new file mode 100644
> index 0000000000000000..65110019adda5a8f
> --- /dev/null
> +++ b/drivers/irqchip/irq-renesas-rza1.c
> @@ -0,0 +1,238 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/A1 IRQC Driver
> + *
> + * Copyright (C) 2019 Glider bvba
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irqdomain.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +#define IRQC_NUM_IRQ		8
> +
> +#define ICR0			0	/* Interrupt Control Register 0 */
> +
> +#define ICR0_NMIL		BIT(15)	/* NMI Input Level (0=low, 1=high) */
> +#define ICR0_NMIE		BIT(8)	/* Edge Select (0=falling, 1=rising) */
> +#define ICR0_NMIF		BIT(1)	/* NMI Interrupt Request */
> +
> +#define ICR1			2	/* Interrupt Control Register 1 */
> +
> +#define ICR1_IRQS(n, sense)	((sense) << ((n) * 2))	/* IRQ Sense Select */
> +#define ICR1_IRQS_LEVEL_LOW	0
> +#define ICR1_IRQS_EDGE_FALLING	1
> +#define ICR1_IRQS_EDGE_RISING	2
> +#define ICR1_IRQS_EDGE_BOTH	3
> +#define ICR1_IRQS_MASK(n)	ICR1_IRQS((n), 3)
> +
> +#define IRQRR			4	/* IRQ Interrupt Request Register */
> +
> +
> +struct rza1_irqc_info {
> +	unsigned int gic_spi_base;
> +};
> +
> +struct rza1_irqc_priv {
> +	struct device *dev;
> +	void __iomem *base;
> +	struct irq_chip chip;
> +	struct irq_domain *irq_domain;
> +	unsigned int gic_spi_base;
> +};
> +
> +static struct rza1_irqc_priv *irq_data_to_priv(struct irq_data *data)
> +{
> +	return data->domain->host_data;
> +}
> +
> +static void rza1_irqc_eoi(struct irq_data *d)
> +{
> +	struct rza1_irqc_priv *priv = irq_data_to_priv(d);
> +	unsigned int bit = BIT(irqd_to_hwirq(d));

Please use u32 instead of "unsigned int" for something that operates on
HW registers.

> +	u16 tmp;
> +
> +	tmp = readw(priv->base + IRQRR);

Same thing here. It's less confusing to use a u32 and mask out the top
bits if needed rather than having this implicit cast (applies all over
the code).

> +	if (tmp & bit)
> +		writew(GENMASK(IRQC_NUM_IRQ - 1, 0) & ~bit, priv->base + IRQRR);

Please use the _relaxed accessors all over the driver, you really do not
need a DSB on each of these accesses.

> +
> +	irq_chip_eoi_parent(d);
> +}
> +
> +static int rza1_irqc_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct rza1_irqc_priv *priv = irq_data_to_priv(d);
> +	unsigned int hw_irq = irqd_to_hwirq(d);
> +	u16 sense, tmp;
> +
> +	switch (type & IRQ_TYPE_SENSE_MASK) {
> +	case IRQ_TYPE_LEVEL_LOW:
> +		sense = ICR1_IRQS_LEVEL_LOW;
> +		break;
> +
> +	case IRQ_TYPE_EDGE_FALLING:
> +		sense = ICR1_IRQS_EDGE_FALLING;
> +		break;
> +
> +	case IRQ_TYPE_EDGE_RISING:
> +		sense = ICR1_IRQS_EDGE_RISING;
> +		break;
> +
> +	case IRQ_TYPE_EDGE_BOTH:
> +		sense = ICR1_IRQS_EDGE_BOTH;
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	tmp = readw(priv->base + ICR1);
> +	tmp &= ~ICR1_IRQS_MASK(hw_irq);
> +	tmp |= ICR1_IRQS(hw_irq, sense);
> +	writew(tmp, priv->base + ICR1);
> +	return 0;

Don't you need to propagate the trigger configuration to the parent irqchip?

> +}
> +
> +static int rza1_irqc_alloc(struct irq_domain *domain, unsigned int virq,
> +			   unsigned int nr_irqs, void *arg)
> +{
> +	struct rza1_irqc_priv *priv = domain->host_data;
> +	struct irq_fwspec *fwspec = arg;
> +	struct irq_fwspec spec;
> +	int ret;
> +
> +	ret = irq_domain_set_hwirq_and_chip(domain, virq, fwspec->param[0],
> +					    &priv->chip, priv);
> +	if (ret)
> +		return ret;
> +
> +	spec.fwnode = &priv->dev->of_node->fwnode;
> +	spec.param_count = 3;
> +	spec.param[0] = GIC_SPI;
> +	spec.param[1] = priv->gic_spi_base + fwspec->param[0];
> +	spec.param[2] = IRQ_TYPE_LEVEL_HIGH;

This is related to my earlier question: Does this block turn everything
into level interrupts?

> +
> +	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &spec);
> +}
> +
> +static int rza1_irqc_translate(struct irq_domain *domain,
> +			       struct irq_fwspec *fwspec, unsigned long *hwirq,
> +			       unsigned int *type)
> +{
> +	if (fwspec->param_count != 2 || fwspec->param[0] >= IRQC_NUM_IRQ)
> +		return -EINVAL;
> +
> +	*hwirq = fwspec->param[0];
> +	*type = fwspec->param[1];
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops rza1_irqc_domain_ops = {
> +	.alloc = rza1_irqc_alloc,
> +	.translate = rza1_irqc_translate,
> +};
> +
> +static int rza1_irqc_probe(struct platform_device *pdev)
> +{
> +	const struct rza1_irqc_info *info;
> +	struct irq_domain *parent = NULL;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *gic_node;
> +	struct rza1_irqc_priv *priv;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	info = of_device_get_match_data(dev);
> +	priv->gic_spi_base = info->gic_spi_base;
> +	platform_set_drvdata(pdev, priv);
> +	priv->dev = dev;
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	gic_node = of_irq_find_parent(dev->of_node);
> +	if (gic_node) {
> +		parent = irq_find_host(gic_node);
> +		of_node_put(gic_node);
> +	}
> +
> +	if (!parent) {
> +		dev_err(dev, "cannot find parent domain\n");
> +		return -ENODEV;
> +	}
> +
> +	priv->chip.name = dev_name(dev);

name should normally be used to identify the overall "class" of
interrupt. .device is what should be used for the device itself.

> +	priv->chip.irq_mask = irq_chip_mask_parent,
> +	priv->chip.irq_unmask = irq_chip_unmask_parent,
> +	priv->chip.irq_eoi = rza1_irqc_eoi,
> +	priv->chip.irq_retrigger = irq_chip_retrigger_hierarchy,
> +	priv->chip.irq_set_type = rza1_irqc_set_type,
> +	priv->chip.flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE;
> +
> +	priv->irq_domain = irq_domain_add_hierarchy(parent, 0, IRQC_NUM_IRQ,
> +						    dev->of_node,
> +						    &rza1_irqc_domain_ops,
> +						    priv);
> +	if (!priv->irq_domain) {
> +		dev_err(dev, "cannot initialize irq domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +static int rza1_irqc_remove(struct platform_device *pdev)
> +{
> +	struct rza1_irqc_priv *priv = platform_get_drvdata(pdev);
> +
> +	irq_domain_remove(priv->irq_domain);
> +	return 0;
> +}
> +
> +struct rza1_irqc_info rza1_irqc_info = {
> +	.gic_spi_base = 0,
> +};

To answer your question in the cover letter, I'd rather this came from
DT. And otherwise, it should be be static.

> +
> +static const struct of_device_id rza1_irqc_dt_ids[] = {
> +	{ .compatible = "renesas,rza1-irqc", &rza1_irqc_info },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, rza1_irqc_dt_ids);
> +
> +static struct platform_driver rza1_irqc_device_driver = {
> +	.probe		= rza1_irqc_probe,
> +	.remove		= rza1_irqc_remove,
> +	.driver		= {
> +		.name	= "renesas_rza1_irqc",
> +		.of_match_table	= rza1_irqc_dt_ids,
> +	}
> +};
> +
> +static int __init rza1_irqc_init(void)
> +{
> +	return platform_driver_register(&rza1_irqc_device_driver);
> +}
> +postcore_initcall(rza1_irqc_init);
> +
> +static void __exit rza1_irqc_exit(void)
> +{
> +	platform_driver_unregister(&rza1_irqc_device_driver);
> +}
> +module_exit(rza1_irqc_exit);
> +
> +MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@...der.be>");
> +MODULE_DESCRIPTION("Renesas RZ/A1 IRQC Driver");
> +MODULE_LICENSE("GPL v2");
> 

It otherwise looks good to me. If you respin it quickly enough, I'm
happy to take it for 5.2.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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