Message-ID: <cae2ec7d-5f57-3e4f-7688-5a1523c66b82@arm.com>
Date:   Mon, 7 Aug 2017 11:43:50 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] irqchip: uniphier-aidet: add UniPhier AIDET irqchip
 driver

On 03/08/17 12:15, Masahiro Yamada wrote:
> UniPhier SoCs contain AIDET (ARM Interrupt Detector).  This is intended
> to provide additional features that are not covered by GIC.  The main
> purpose is to provide logic inverter to support low level and falling
> edge trigger type for interrupt lines from on-board devices.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
> ---
> 
>  .../socionext,uniphier-aidet.txt                   |  32 +++
>  MAINTAINERS                                        |   1 +
>  drivers/irqchip/Kconfig                            |   5 +
>  drivers/irqchip/Makefile                           |   1 +
>  drivers/irqchip/irq-uniphier-aidet.c               | 252 +++++++++++++++++++++
>  5 files changed, 291 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/socionext,uniphier-aidet.txt
>  create mode 100644 drivers/irqchip/irq-uniphier-aidet.c
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/socionext,uniphier-aidet.txt b/Documentation/devicetree/bindings/interrupt-controller/socionext,uniphier-aidet.txt
> new file mode 100644
> index 000000000000..af57fbccd234
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/socionext,uniphier-aidet.txt
> @@ -0,0 +1,32 @@
> +UniPhier AIDET
> +
> +UniPhier AIDET (ARM Interrupt Detector) is an add-on block for ARM GIC (Generic
> +Interrupt Controller).  GIC itself can handle only high level and rising edge
> +interrupts.  The AIDET provides logic inverter to support low level and falling
> +edge interrupts.
> +
> +Required properties:
> +- compatible: Should be one of the following:
> +    "socionext,uniphier-ld4-aidet"  - for LD4 SoC
> +    "socionext,uniphier-pro4-aidet" - for Pro4 SoC
> +    "socionext,uniphier-sld8-aidet" - for sLD8 SoC
> +    "socionext,uniphier-pro5-aidet" - for Pro5 SoC
> +    "socionext,uniphier-pxs2-aidet" - for PXs2/LD6b SoC
> +    "socionext,uniphier-ld11-aidet" - for LD11 SoC
> +    "socionext,uniphier-ld20-aidet" - for LD20 SoC
> +    "socionext,uniphier-pxs3-aidet" - for PXs3 SoC
> +- reg: Specifies offset and length of the register set for the device.
> +- interrupt-controller: Identifies the node as an interrupt controller
> +- #interrupt-cells : Specifies the number of cells needed to encode an interrupt
> +  source.  The value should be 2.  The first cell defines the interrupt number.
> +  The second cell specifies the trigger type as defined in interrupts.txt in
> +  this directory.

"interrupt number" is a pretty vague concept. You probably want to
explain how it relates to the GIC (is that the INTID? or the SPI number?
What about PPIs?).

> +
> +Example:
> +
> +	aidet: aidet@...20000 {
> +		compatible = "socionext,uniphier-pro4-aidet";
> +		reg = <0x5fc20000 0x200>;
> +		interrupt-controller;
> +		#interrupt-cells = <2>;
> +	};
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 567343b8ffaa..26b3d10b7344 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1993,6 +1993,7 @@ F:	arch/arm64/boot/dts/socionext/
>  F:	drivers/bus/uniphier-system-bus.c
>  F:	drivers/clk/uniphier/
>  F:	drivers/i2c/busses/i2c-uniphier*
> +F:	drivers/irqchip/irq-uniphier-aidet.c
>  F:	drivers/pinctrl/uniphier/
>  F:	drivers/reset/reset-uniphier.c
>  F:	drivers/tty/serial/8250/8250_uniphier.c
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index f1fd5f44d1d4..a0d7218a1677 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -306,3 +306,8 @@ config QCOM_IRQ_COMBINER
>  	help
>  	  Say yes here to add support for the IRQ combiner devices embedded
>  	  in Qualcomm Technologies chips.
> +
> +config IRQ_UNIPHIER_AIDET
> +	def_bool y
> +	depends on ARCH_UNIPHIER || COMPILE_TEST
> +	select IRQ_DOMAIN_HIERARCHY
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index e88d856cc09c..2c630574986f 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -78,3 +78,4 @@ obj-$(CONFIG_EZNPS_GIC)			+= irq-eznps.o
>  obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o irq-aspeed-i2c-ic.o
>  obj-$(CONFIG_STM32_EXTI) 		+= irq-stm32-exti.o
>  obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
> +obj-$(CONFIG_IRQ_UNIPHIER_AIDET)	+= irq-uniphier-aidet.o
> diff --git a/drivers/irqchip/irq-uniphier-aidet.c b/drivers/irqchip/irq-uniphier-aidet.c
> new file mode 100644
> index 000000000000..8ceed5070e77
> --- /dev/null
> +++ b/drivers/irqchip/irq-uniphier-aidet.c
> @@ -0,0 +1,252 @@
> +/*
> + * Driver for UniPhier AIDET (ARM Interrupt Detector)
> + *
> + * Copyright (C) 2017 Socionext Inc.
> + *   Author: Masahiro Yamada <yamada.masahiro@...ionext.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/init.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +
> +#define UNIPHIER_AIDET_NR_IRQS		256
> +
> +#define UNIPHIER_AIDET_DETCONF		0x00
> +
> +struct uniphier_aidet_priv {
> +	struct irq_chip chip;
> +	struct irq_domain *domain;
> +	void __iomem *reg_base;
> +	spinlock_t lock;
> +	u32 saved_vals[UNIPHIER_AIDET_NR_IRQS / 32];
> +};
> +
> +static void uniphier_aidet_reg_update(struct uniphier_aidet_priv *priv,
> +				      unsigned int reg, u32 mask, u32 val)
> +{
> +	unsigned long flags;
> +	u32 tmp;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	tmp = readl(priv->reg_base + reg);
> +	tmp &= ~mask;
> +	tmp |= mask & val;
> +	writel(tmp, priv->reg_base + reg);

Given that these accesses do not seem to rely on anything making it into
memory before the access, consider using the _relaxed accessors (no need
for two DSBs here).

> +	spin_unlock_irqrestore(&priv->lock, flags);
> +}
> +
> +static void uniphier_aidet_detconf_update(struct uniphier_aidet_priv *priv,
> +					  unsigned long index, unsigned int val)
> +{
> +	unsigned int reg;
> +	u32 mask;
> +
> +	reg = UNIPHIER_AIDET_DETCONF + index / 32 * 4;

What is the purpose of UNIPHIER_AIDET_DETCONF here, which is always 0?

> +	mask = BIT(index % 32);
> +
> +	uniphier_aidet_reg_update(priv, reg, mask, val ? mask : 0);
> +}
> +
> +static int uniphier_aidet_irq_set_type(struct irq_data *data, unsigned int type)
> +{
> +	struct uniphier_aidet_priv *priv = data->chip_data;
> +	unsigned int val = 0;
> +
> +	/* enable inverter for active low triggers */
> +	switch (type) {
> +	case IRQ_TYPE_EDGE_RISING:
> +	case IRQ_TYPE_LEVEL_HIGH:

Nit: consider moving the "val" assignment here so that the symmetry
between the two cases becomes obvious.

> +		break;
> +	case IRQ_TYPE_EDGE_FALLING:
> +		val = 1;
> +		type = IRQ_TYPE_EDGE_RISING;
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		val = 1;
> +		type = IRQ_TYPE_LEVEL_HIGH;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	uniphier_aidet_detconf_update(priv, data->hwirq, val);
> +
> +	return irq_chip_set_type_parent(data, type);
> +}
> +
> +static int uniphier_aidet_domain_translate(struct irq_domain *domain,
> +					   struct irq_fwspec *fwspec,
> +					   unsigned long *out_hwirq,
> +					   unsigned int *out_type)
> +{
> +	if (WARN_ON(fwspec->param_count < 2))
> +		return -EINVAL;
> +
> +	*out_hwirq = fwspec->param[0];
> +	*out_type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> +
> +	return 0;
> +}
> +
> +static int uniphier_aidet_domain_alloc(struct irq_domain *domain,
> +				       unsigned int virq, unsigned int nr_irqs,
> +				       void *arg)
> +{
> +	struct uniphier_aidet_priv *priv = domain->host_data;
> +	irq_hw_number_t hwirq;
> +	unsigned int type;
> +	int i, ret;
> +
> +	ret = uniphier_aidet_domain_translate(domain, arg, &hwirq, &type);
> +	if (ret)
> +		return ret;
> +
> +	if (hwirq >= UNIPHIER_AIDET_NR_IRQS)
> +		return -ENXIO;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		struct irq_fwspec parent_fwspec;
> +
> +		ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
> +						    &priv->chip, priv);
> +		if (ret)
> +			return ret;
> +
> +		/* parent is GIC */
> +		parent_fwspec.fwnode = domain->parent->fwnode;
> +		parent_fwspec.param_count = 3;
> +		parent_fwspec.param[0] = 0;		/* SPI */
> +		parent_fwspec.param[1] = hwirq - 32;
> +		parent_fwspec.param[2] = IRQ_TYPE_LEVEL_HIGH;

So this is SPI only? And your first line starts at 32? So what is in the
32bit register?

> +
> +		ret = irq_domain_alloc_irqs_parent(domain, virq, 1,
> +						   &parent_fwspec);
> +		if (ret)
> +			return ret;
> +
> +		virq++;
> +		hwirq++;
> +	}

Two things here: is there any case where you actually have nr_irqs not
being 1? As far as I know, this is only used for Multi-MSI, and nothing
else. And if you do need it, then you should probably have a slightly
better error handling (you're leaking interrupts on error here).

> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops uniphier_aidet_domain_ops = {
> +	.alloc = uniphier_aidet_domain_alloc,
> +	.free = irq_domain_free_irqs_common,
> +	.translate = uniphier_aidet_domain_translate,
> +};
> +
> +static int uniphier_aidet_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *parent_np;
> +	struct irq_domain *parent_domain;
> +	struct uniphier_aidet_priv *priv;
> +	struct resource *res;
> +
> +	parent_np = of_irq_find_parent(dev->of_node);
> +	if (!parent_np)
> +		return -ENXIO;
> +
> +	parent_domain = irq_find_host(parent_np);
> +	of_node_put(parent_np);
> +	if (!parent_domain)
> +		return -EPROBE_DEFER;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	priv->reg_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(priv->reg_base))
> +		return PTR_ERR(priv->reg_base);
> +
> +	spin_lock_init(&priv->lock);
> +
> +	priv->chip.name = dev_name(dev);
> +	priv->chip.irq_mask = irq_chip_mask_parent;
> +	priv->chip.irq_unmask = irq_chip_unmask_parent;
> +	priv->chip.irq_eoi = irq_chip_eoi_parent;
> +	priv->chip.irq_set_type = uniphier_aidet_irq_set_type;
> +
> +	priv->domain = irq_domain_add_hierarchy(parent_domain, 0,
> +						UNIPHIER_AIDET_NR_IRQS,
> +						dev->of_node,
> +						&uniphier_aidet_domain_ops,
> +						priv);

You seem to be able to handle multiple AIDET devices, and yet your DT
description doesn't specify a base/span for the interrupt lines that are
covered by this device. Is that something you intend to support?

> +	if (!priv->domain)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused uniphier_aidet_suspend(struct device *dev)
> +{
> +	struct uniphier_aidet_priv *priv = dev_get_drvdata(dev);
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(priv->saved_vals); i++)
> +		priv->saved_vals[i] = readl(priv->reg_base +

readl_relaxed

> +					    UNIPHIER_AIDET_DETCONF + i * 4);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused uniphier_aidet_resume(struct device *dev)
> +{
> +	struct uniphier_aidet_priv *priv = dev_get_drvdata(dev);
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(priv->saved_vals); i++)
> +		writel(priv->saved_vals[i],

writel_relaxed

> +		       priv->reg_base + UNIPHIER_AIDET_DETCONF + i * 4);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops uniphier_aidet_pm_ops = {
> +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(uniphier_aidet_suspend,
> +				      uniphier_aidet_resume)
> +};
> +
> +static const struct of_device_id uniphier_aidet_match[] = {
> +	{ .compatible = "socionext,uniphier-ld4-aidet" },
> +	{ .compatible = "socionext,uniphier-pro4-aidet" },
> +	{ .compatible = "socionext,uniphier-sld8-aidet" },
> +	{ .compatible = "socionext,uniphier-pro5-aidet" },
> +	{ .compatible = "socionext,uniphier-pxs2-aidet" },
> +	{ .compatible = "socionext,uniphier-ld11-aidet" },
> +	{ .compatible = "socionext,uniphier-ld20-aidet" },
> +	{ .compatible = "socionext,uniphier-pxs3-aidet" },
> +	{ /* sentinel */ }
> +};
> +
> +static struct platform_driver uniphier_aidet_driver = {
> +	.probe = uniphier_aidet_probe,
> +	.driver = {
> +		.name = "uniphier-aidet",
> +		.of_match_table = uniphier_aidet_match,
> +		.pm = &uniphier_aidet_pm_ops,
> +	},
> +};
> +builtin_platform_driver(uniphier_aidet_driver);
> 

Thanks,

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

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