Re: [PATCH v5 2/5] irqchip/irq-goldfish-pic: Add Goldfish PIC driver

[Marc Zyngier <marc.zyngier@arm.com>]

On Fri, Oct 20 2017 at  4:33:35 pm BST, Aleksandar Markovic <aleksandar.markovic@rt-rk.com> wrote:
> From: Miodrag Dinic <miodrag.dinic@mips.com>
>
> Add device driver for a virtual programmable interrupt controller
>
> The virtual PIC is designed as a device tree-based interrupt controller.
>
> The compatible string used by OS for binding the driver is
> "google,goldfish-pic".
>
> Signed-off-by: Miodrag Dinic <miodrag.dinic@mips.com>
> Signed-off-by: Goran Ferenc <goran.ferenc@mips.com>
> Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
> ---
>  MAINTAINERS                        |   1 +
>  drivers/irqchip/Kconfig            |   8 +++
>  drivers/irqchip/Makefile           |   1 +
>  drivers/irqchip/irq-goldfish-pic.c | 131 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 141 insertions(+)
>  create mode 100644 drivers/irqchip/irq-goldfish-pic.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 4d5108f..f1be016 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -876,6 +876,7 @@ ANDROID GOLDFISH PIC DRIVER
>  M:	Miodrag Dinic <miodrag.dinic@mips.com>
>  S:	Supported
>  F:	Documentation/devicetree/bindings/interrupt-controller/google,goldfish-pic.txt
> +F:	drivers/irqchip/irq-goldfish-pic.c
>  
>  ANDROID GOLDFISH RTC DRIVER
>  M:	Miodrag Dinic <miodrag.dinic@mips.com>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 9d8a1dd..712b561 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -321,3 +321,11 @@ config IRQ_UNIPHIER_AIDET
>  	select IRQ_DOMAIN_HIERARCHY
>  	help
>  	  Support for the UniPhier AIDET (ARM Interrupt Detector).
> +
> +config GOLDFISH_PIC
> +	bool "Goldfish programmable interrupt controller"
> +	depends on MIPS && (GOLDFISH || COMPILE_TEST)
> +	select IRQ_DOMAIN
> +	help
> +	  Say yes here to enable Goldfish interrupt controller driver used
> +	  for Goldfish based virtual platforms.
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 845abc1..0e7a224 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -79,3 +79,4 @@ 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
> +obj-$(CONFIG_GOLDFISH_PIC) 		+= irq-goldfish-pic.o
> diff --git a/drivers/irqchip/irq-goldfish-pic.c b/drivers/irqchip/irq-goldfish-pic.c
> new file mode 100644
> index 0000000..d8b5277
> --- /dev/null
> +++ b/drivers/irqchip/irq-goldfish-pic.c
> @@ -0,0 +1,131 @@
> +/*
> + * Copyright (C) 2017 Imagination Technologies Ltd.	All rights reserved
> + *	Author: Miodrag Dinic <miodrag.dinic@imgtec.com>
> + *
> + * This file implements interrupt controller driver for MIPS Goldfish PIC.
> + *
> + * This program is free software; you can redistribute	it and/or modify it
> + * under  the terms of	the GNU General	 Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +
> +#define GFPIC_NR_IRQS			32
> +
> +/* 8..39 Cascaded Goldfish PIC interrupts */
> +#define GFPIC_IRQ_BASE			8
> +
> +#define GFPIC_REG_IRQ_PENDING		0x04
> +#define GFPIC_REG_IRQ_DISABLE_ALL	0x08
> +#define GFPIC_REG_IRQ_DISABLE		0x0c
> +#define GFPIC_REG_IRQ_ENABLE		0x10
> +
> +struct goldfish_pic_data {
> +	void __iomem *base;
> +	struct irq_domain *irq_domain;
> +};
> +
> +static irqreturn_t goldfish_pic_cascade(int irq, void *data)
> +{
> +	struct goldfish_pic_data *gfpic = irq_get_handler_data(irq);
> +	u32 hwirq;
> +	u32 virq;
> +
> +	hwirq = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
> +
> +	virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
> +	generic_handle_irq(virq);
> +
> +	return IRQ_HANDLED;
> +}

This is not how we implement cascaded (chained) interrupt
controllers. See existing examples everywhere in the irqchip directory.

> +
> +static const struct irq_domain_ops goldfish_irq_domain_ops = {
> +	.xlate = irq_domain_xlate_onecell,
> +};
> +
> +static struct irqaction cascade = {
> +	.handler	= goldfish_pic_cascade,
> +	.name		= "Goldfish PIC cascade",
> +};
> +
> +static int __init goldfish_pic_of_init(struct device_node *of_node,
> +				       struct device_node *parent)
> +{
> +	struct goldfish_pic_data *gfpic;
> +	struct irq_chip_generic *gc;
> +	struct irq_chip_type *ct;
> +	unsigned int parent_irq;
> +	int ret = 0;
> +
> +	gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
> +	if (!gfpic) {
> +		ret = -ENOMEM;
> +		goto out_err;
> +	}
> +
> +	parent_irq = irq_of_parse_and_map(of_node, 0);
> +	if (!parent_irq) {
> +		pr_err("Failed to map Goldfish PIC parent IRQ\n");
> +		ret = -EINVAL;
> +		goto out_free;
> +	}
> +
> +	ret = irq_set_handler_data(parent_irq, gfpic);
> +	if (ret)
> +		goto out_unmap_irq;
> +
> +	gfpic->base = of_iomap(of_node, 0);
> +	if (!gfpic->base) {
> +		pr_err("Failed to map Goldfish PIC base\n");
> +		ret = -ENOMEM;
> +		goto out_unmap_irq;
> +	}
> +
> +	/* Mask interrupts. */
> +	writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
> +
> +	gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
> +				    handle_level_irq);
> +
> +	ct = gc->chip_types;
> +	ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
> +	ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
> +	ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
> +	ct->chip.irq_mask = irq_gc_mask_disable_reg;
> +
> +	irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0, 0,
> +			       IRQ_NOPROBE | IRQ_LEVEL);
> +
> +	gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
> +						  GFPIC_IRQ_BASE, 0,
> +						  &goldfish_irq_domain_ops,
> +						  NULL);
> +	if (!gfpic->irq_domain) {
> +		pr_err("Failed to add irqdomain for Goldfish PIC\n");
> +		ret = -EINVAL;
> +		goto out_iounmap;
> +	}
> +
> +	setup_irq(parent_irq, &cascade);
> +
> +	pr_info("Successfully registered Goldfish PIC\n");
> +	return 0;
> +
> +out_iounmap:
> +	iounmap(gfpic->base);
> +out_unmap_irq:
> +	irq_dispose_mapping(parent_irq);
> +out_free:
> +	kfree(gfpic);
> +out_err:
> +	return ret;
> +}
> +
> +IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);

It otherwise looks much better than the previous versions.

Thanks,

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