Message-ID: <87r1djv26j.wl-maz@kernel.org>
Date:   Mon, 20 Sep 2021 13:53:08 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Claudiu Beznea <claudiu.beznea@...rochip.com>
Cc:     <tglx@...utronix.de>, <robh+dt@...nel.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3 2/2] irqchip/mchp-eic: add support

On Fri, 10 Sep 2021 07:06:56 +0100,
Claudiu Beznea <claudiu.beznea@...rochip.com> wrote:
> 
> Add support for Microchip External Interrupt Controller. The controller
> supports 2 external interrupt lines. For every external input there is
> a connection to GIC. The interrupt controllers contains only 4
> registers:
> - EIC_GFCS (read only): which indicates that glitch filter configuration
>   is ready (not addressed in this implementation)
> - EIC_SCFG0R, EIC_SCFG1R (read, write): allows per interrupt specific
>   settings: enable, polarity/edge settings, glitch filter settings
> - EIC_WPMR, EIC_WPSR: enables write protection mode specific settings
>   (which are architecture specific) for the controller and are not
>   addressed in this implementation
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
> ---
>  MAINTAINERS                    |   6 +
>  drivers/irqchip/Kconfig        |   8 +
>  drivers/irqchip/Makefile       |   1 +
>  drivers/irqchip/irq-mchp-eic.c | 314 +++++++++++++++++++++++++++++++++
>  4 files changed, 329 insertions(+)
>  create mode 100644 drivers/irqchip/irq-mchp-eic.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a61f4f3b78a9..87174babb0ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12141,6 +12141,12 @@ L:	linux-crypto@...r.kernel.org
>  S:	Maintained
>  F:	drivers/crypto/atmel-ecc.*
>  
> +MICROCHIP EIC DRIVER
> +M:	Claudiu Beznea <claudiu.beznea@...rochip.com>
> +L:	linux-arm-kernel@...ts.infradead.org (moderated for non-subscribers)
> +S:	Supported
> +F:	drivers/irqchip/irq-mchp-eic.c
> +
>  MICROCHIP I2C DRIVER
>  M:	Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
>  L:	linux-i2c@...r.kernel.org
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 4d5924e9f766..450c7b8ab30f 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -601,4 +601,12 @@ config APPLE_AIC
>  	  Support for the Apple Interrupt Controller found on Apple Silicon SoCs,
>  	  such as the M1.
>  
> +config MCHP_EIC
> +	bool "Microchip External Interrupt Controller"
> +	depends on ARCH_AT91 || COMPILE_TEST
> +	select IRQ_DOMAIN
> +	select IRQ_DOMAIN_HIERARCHY
> +	help
> +	  Support for Microchip External Interrupt Controller.
> +
>  endmenu
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index f88cbf36a9d2..c1f611cbfbf8 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -116,3 +116,4 @@ obj-$(CONFIG_MACH_REALTEK_RTL)		+= irq-realtek-rtl.o
>  obj-$(CONFIG_WPCM450_AIC)		+= irq-wpcm450-aic.o
>  obj-$(CONFIG_IRQ_IDT3243X)		+= irq-idt3243x.o
>  obj-$(CONFIG_APPLE_AIC)			+= irq-apple-aic.o
> +obj-$(CONFIG_MCHP_EIC)			+= irq-mchp-eic.o
> diff --git a/drivers/irqchip/irq-mchp-eic.c b/drivers/irqchip/irq-mchp-eic.c
> new file mode 100644
> index 000000000000..ab24a464b929
> --- /dev/null
> +++ b/drivers/irqchip/irq-mchp-eic.c
> @@ -0,0 +1,314 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Microchip External Interrupt Controller driver
> + *
> + * Copyright (C) 2021 Microchip Technology Inc. and its subsidiaries
> + *
> + * Author: Claudiu Beznea <claudiu.beznea@...rochip.com>
> + */
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqchip.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +
> +#include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +#define MCHP_EIC_GFCS			(0x0)
> +#define MCHP_EIC_SCFG(x)		(0x4 + (x) * 0x4)
> +#define MCHP_EIC_SCFG_EN		BIT(16)
> +#define MCHP_EIC_SCFG_LVL		BIT(9)
> +#define MCHP_EIC_SCFG_POL		BIT(8)
> +
> +#define MCHP_EIC_NIRQ			(2)
> +
> +/*
> + * struct mchp_eic - EIC private data structure
> + * @base: base address
> + * @dev: eic device
> + * @clk: peripheral clock
> + * @domain: irq domain
> + * @irqs: irqs b/w eic and gic
> + * @scfg: backup for scfg registers (necessary for backup and self-refresh mode)
> + * @wakeup_source: wakeup source mask
> + */
> +struct mchp_eic {
> +	void __iomem *base;
> +	struct device *dev;
> +	struct clk *clk;
> +	struct irq_domain *domain;
> +	u32 irqs[MCHP_EIC_NIRQ];
> +	u32 scfg[MCHP_EIC_NIRQ];
> +	u32 wakeup_source;
> +};
> +
> +static void mchp_eic_irq_mask(struct irq_data *d)
> +{
> +	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
> +	unsigned int tmp;
> +
> +	tmp = readl_relaxed(eic->base + MCHP_EIC_SCFG(d->hwirq));
> +	tmp &= ~MCHP_EIC_SCFG_EN;
> +	writel_relaxed(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
> +
> +	irq_chip_mask_parent(d);
> +}
> +
> +static void mchp_eic_irq_unmask(struct irq_data *d)
> +{
> +	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
> +	unsigned int tmp;
> +
> +	tmp = readl_relaxed(eic->base + MCHP_EIC_SCFG(d->hwirq));
> +	tmp |= MCHP_EIC_SCFG_EN;
> +	writel_relaxed(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
> +
> +	irq_chip_unmask_parent(d);
> +}
> +
> +static int mchp_eic_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
> +	unsigned int parent_irq_type;
> +	unsigned int tmp;
> +
> +	tmp = readl_relaxed(eic->base + MCHP_EIC_SCFG(d->hwirq));
> +	tmp &= ~(MCHP_EIC_SCFG_POL | MCHP_EIC_SCFG_LVL);
> +	switch (type) {
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		tmp |= MCHP_EIC_SCFG_POL | MCHP_EIC_SCFG_LVL;
> +		parent_irq_type = IRQ_TYPE_LEVEL_HIGH;
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		tmp |= MCHP_EIC_SCFG_LVL;
> +		parent_irq_type = IRQ_TYPE_LEVEL_HIGH;
> +		break;
> +	case IRQ_TYPE_EDGE_RISING:
> +		parent_irq_type = IRQ_TYPE_EDGE_RISING;
> +		break;
> +	case IRQ_TYPE_EDGE_FALLING:
> +		tmp |= MCHP_EIC_SCFG_POL;
> +		parent_irq_type = IRQ_TYPE_EDGE_RISING;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	writel_relaxed(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
> +
> +	return irq_chip_set_type_parent(d, parent_irq_type);
> +}
> +
> +static int mchp_eic_irq_set_wake(struct irq_data *d, unsigned int on)
> +{
> +	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
> +
> +	irq_set_irq_wake(eic->irqs[d->hwirq], on);
> +	if (on)
> +		eic->wakeup_source |= BIT(d->hwirq);
> +	else
> +		eic->wakeup_source &= ~BIT(d->hwirq);
> +
> +	return 0;
> +}
> +
> +static struct irq_chip mchp_eic_chip = {
> +	.name		= "eic",
> +	.flags		= IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SET_TYPE_MASKED,
> +	.irq_mask	= mchp_eic_irq_mask,
> +	.irq_unmask	= mchp_eic_irq_unmask,
> +	.irq_set_type	= mchp_eic_irq_set_type,
> +	.irq_ack	= irq_chip_ack_parent,
> +	.irq_eoi	= irq_chip_eoi_parent,
> +	.irq_retrigger	= irq_chip_retrigger_hierarchy,
> +	.irq_set_wake	= mchp_eic_irq_set_wake,
> +};
> +
> +static int mchp_eic_domain_translate(struct irq_domain *d,
> +				     struct irq_fwspec *fwspec,
> +				     unsigned long *hwirq,
> +				     unsigned int *type)
> +{
> +	if (!is_of_node(fwspec->fwnode))
> +		return -EINVAL;
> +
> +	if (fwspec->param_count != 2 || fwspec->param[0] >= MCHP_EIC_NIRQ)
> +		return -EINVAL;
> +
> +	*hwirq = fwspec->param[0];
> +	*type = fwspec->param[1];
> +
> +	return 0;
> +}

Which is pretty much irq_domain_translate_twocell(). Please use that.

> +
> +static int mchp_eic_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +				 unsigned int nr_irqs, void *data)
> +{
> +	struct mchp_eic *eic = domain->host_data;
> +	struct irq_fwspec *fwspec = data;
> +	struct irq_fwspec parent_fwspec;
> +	irq_hw_number_t hwirq;
> +	unsigned int type;
> +	int ret;
> +
> +	if (WARN_ON(nr_irqs != 1))
> +		return -EINVAL;
> +
> +	ret = mchp_eic_domain_translate(domain, fwspec, &hwirq, &type);
> +	if (ret)
> +		return ret;
> +
> +	switch (type) {
> +	case IRQ_TYPE_EDGE_RISING:
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		break;
> +	case IRQ_TYPE_EDGE_FALLING:
> +		type = IRQ_TYPE_EDGE_RISING;
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		type = IRQ_TYPE_LEVEL_HIGH;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, &mchp_eic_chip, eic);
> +
> +	parent_fwspec.fwnode = domain->parent->fwnode;
> +	parent_fwspec.param_count = 3;
> +	parent_fwspec.param[0] = GIC_SPI;
> +	parent_fwspec.param[1] = eic->irqs[hwirq];
> +	parent_fwspec.param[2] = type;
> +
> +	return irq_domain_alloc_irqs_parent(domain, virq, 1, &parent_fwspec);
> +}
> +
> +static const struct irq_domain_ops mchp_eic_domain_ops = {
> +	.translate	= mchp_eic_domain_translate,
> +	.alloc		= mchp_eic_domain_alloc,
> +	.free		= irq_domain_free_irqs_common,
> +};
> +
> +static int mchp_eic_probe(struct platform_device *pdev)
> +{
> +	struct irq_domain *parent_domain = NULL;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct device_node *gic_node;
> +	struct mchp_eic *eic;
> +	int ret, i;
> +
> +	eic = devm_kzalloc(dev, sizeof(*eic), GFP_KERNEL);
> +	if (!eic)
> +		return -ENOMEM;
> +
> +	eic->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
> +	if (IS_ERR(eic->base))
> +		return PTR_ERR(eic->base);
> +
> +	gic_node = of_irq_find_parent(np);
> +	if (gic_node)
> +		parent_domain = irq_find_host(gic_node);
> +	of_node_put(gic_node);
> +	if (!parent_domain)
> +		return -ENODEV;
> +
> +	eic->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(eic->clk))
> +		return PTR_ERR(eic->clk);
> +
> +	ret = clk_prepare_enable(eic->clk);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < MCHP_EIC_NIRQ; i++) {
> +		struct of_phandle_args irq;
> +
> +		/* Disable it, if any. */
> +		writel_relaxed(0UL, eic->base + MCHP_EIC_SCFG(i));
> +
> +		ret = of_irq_parse_one(np, i, &irq);
> +		if (ret)
> +			goto clk_unprepare;
> +
> +		if (WARN_ON(irq.args_count != 3)) {
> +			ret = -EINVAL;
> +			goto clk_unprepare;
> +		}
> +
> +		eic->irqs[i] = irq.args[1];
> +	}
> +
> +	eic->domain = irq_domain_add_hierarchy(parent_domain, 0, MCHP_EIC_NIRQ,
> +					       np, &mchp_eic_domain_ops, eic);
> +	if (!eic->domain) {
> +		ret = dev_err_probe(dev, -ENOMEM, "Failed to add domain\n");
> +		goto clk_unprepare;
> +	}
> +
> +	eic->dev = dev;
> +	platform_set_drvdata(pdev, eic);
> +
> +	dev_info(dev, "EIC registered, nr_irqs %u\n", MCHP_EIC_NIRQ);
> +
> +	return 0;
> +
> +clk_unprepare:
> +	clk_disable_unprepare(eic->clk);
> +	return ret;
> +}
> +
> +static int __maybe_unused mchp_eic_suspend(struct device *dev)
> +{
> +	struct mchp_eic *eic = dev_get_drvdata(dev);
> +	unsigned int hwirq;
> +
> +	for (hwirq = 0; hwirq < MCHP_EIC_NIRQ; hwirq++)
> +		eic->scfg[hwirq] = readl_relaxed(eic->base +
> +						 MCHP_EIC_SCFG(hwirq));
> +
> +	if (!eic->wakeup_source)
> +		clk_disable_unprepare(eic->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused mchp_eic_resume(struct device *dev)
> +{
> +	struct mchp_eic *eic = dev_get_drvdata(dev);
> +	unsigned int hwirq;
> +
> +	if (!eic->wakeup_source)
> +		clk_prepare_enable(eic->clk);
> +
> +	for (hwirq = 0; hwirq < MCHP_EIC_NIRQ; hwirq++)
> +		writel_relaxed(eic->scfg[hwirq], eic->base +
> +			       MCHP_EIC_SCFG(hwirq));
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops mchp_eic_pm_ops = {
> +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mchp_eic_suspend, mchp_eic_resume)
> +};
> +
> +static const struct of_device_id mchp_eic_dt_ids[] = {
> +	{ .compatible = "microchip,sama7g5-eic", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, mchp_eic_dt_ids);
> +
> +static struct platform_driver mchp_eic_device_driver = {
> +	.probe		= mchp_eic_probe,
> +	.driver		= {
> +		.name = "mchp-eic",
> +		.of_match_table = of_match_ptr(mchp_eic_dt_ids),
> +		.pm = pm_ptr(&mchp_eic_pm_ops),
> +	},
> +};
> +builtin_platform_driver(mchp_eic_device_driver);

Please use the

IRQCHIP_PLATFORM_DRIVER_BEGIN()
IRQCHIP_MATCH()
IRQCHIP_PLATFORM_DRIVER_END()

construct instead. See drivers/irqchip/qcom-pdc.c for an example. It
will at the very least avoid exposing the unbind attribute that will
lead to an explosion if touched.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

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