Date:	Wed, 27 Feb 2013 17:40:14 +0900
From:	Simon Horman <horms@...ge.net.au>
To:	Magnus Damm <magnus.damm@...il.com>
Cc:	linux-kernel@...r.kernel.org, linux-sh@...r.kernel.org,
	benh@...nel.crashing.org, grant.likely@...retlab.ca,
	tglx@...utronix.de
Subject: Re: [PATCH] irqchip: Renesas IRQC driver

On Wed, Feb 27, 2013 at 05:15:01PM +0900, Magnus Damm wrote:
> From: Magnus Damm <damm@...nsource.se>
> 
> This patch adds a driver for external IRQ pins connected
> to the IRQC hardware block on recent SoCs from Renesas.
> 
> The IRQC hardware block is used together with more
> recent ARM based SoCs using the GIC. As usual the GIC
> requires external IRQ trigger setup somewhere else
> which in this particular case happens to be IRQC.
> 
> This driver implements the glue code needed to configure
> IRQ trigger and also handle mask/unmask and demux of
> external IRQ pins hooked up from the IRQC to the GIC.
> 
> Tested on r8a73a4 but is designed to work with a wide
> range of SoCs. The driver requires one GIC SPI per
> external IRQ pin to operate.  Each driver instance
> will handle up to 32 external IRQ pins.

s/will/may/

> The SoCs using this driver are currently mainly used
> together with regular platform devices so this driver
> allows configuration via platform data to support things
> like static interrupt base address. DT support will
> be added incrementally in the not so distant future.
> 
> Signed-off-by: Magnus Damm <damm@...nsource.se>
> ---
> 
>  drivers/irqchip/Kconfig                        |    4 
>  drivers/irqchip/Makefile                       |    1 
>  drivers/irqchip/irq-renesas-irqc.c             |  298 ++++++++++++++++++++++++
>  include/linux/platform_data/irq-renesas-irqc.h |   27 ++
>  4 files changed, 330 insertions(+)
> 
> --- 0002/drivers/irqchip/Kconfig
> +++ work/drivers/irqchip/Kconfig	2013-02-27 16:00:08.000000000 +0900
> @@ -29,6 +29,10 @@ config RENESAS_INTC_IRQPIN
>  	bool
>  	select IRQ_DOMAIN
>  
> +config RENESAS_IRQC
> +	bool
> +	select IRQ_DOMAIN
> +
>  config VERSATILE_FPGA_IRQ
>  	bool
>  	select IRQ_DOMAIN
> --- 0002/drivers/irqchip/Makefile
> +++ work/drivers/irqchip/Makefile	2013-02-27 16:00:08.000000000 +0900
> @@ -6,4 +6,5 @@ obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-sh
>  obj-$(CONFIG_ARM_GIC)			+= irq-gic.o
>  obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
>  obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
> +obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
>  obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
> --- /dev/null
> +++ work/drivers/irqchip/irq-renesas-irqc.c	2013-02-27 17:04:02.000000000 +0900
> @@ -0,0 +1,298 @@
> +/*
> + * Renesas IRQC Driver
> + *
> + *  Copyright (C) 2013 Magnus Damm
> + *
> + * 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
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + */
> +
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/interrupt.h>
> +#include <linux/ioport.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/platform_data/irq-renesas-irqc.h>
> +
> +#define IRQC_IRQ_MAX 32 /* maximum 32 interrupts per driver instance */
> +
> +#define IRQC_REQ_STS 0x00
> +#define IRQC_EN_STS 0x04
> +#define IRQC_EN_SET 0x08
> +#define IRQC_INT_CPU_BASE(n) (0x000 + ((n) * 0x10))
> +#define DETECT_STATUS 0x100
> +#define IRQC_CONFIG(n) (0x180 + ((n) * 0x04))
> +
> +struct irqc_irq {
> +	int hw_irq;
> +	int requested_irq;
> +	int domain_irq;
> +	struct irqc_priv *p;
> +};
> +
> +struct irqc_priv {
> +	void __iomem *iomem;
> +	void __iomem *cpu_int_base;
> +	struct irqc_irq irq[IRQC_IRQ_MAX];
> +	struct renesas_irqc_config config;
> +	unsigned int number_of_irqs;
> +	struct platform_device *pdev;
> +	struct irq_chip irq_chip;
> +	struct irq_domain *irq_domain;
> +};
> +
> +static void irqc_dbg(struct irqc_irq *i, char *str)
> +{
> +	dev_dbg(&i->p->pdev->dev, "%s (%d:%d:%d)\n",
> +		str, i->requested_irq, i->hw_irq, i->domain_irq);
> +}
> +
> +static void irqc_irq_enable(struct irq_data *d)
> +{
> +	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
> +	int hw_irq = irqd_to_hwirq(d);
> +
> +	irqc_dbg(&p->irq[hw_irq], "enable");
> +	iowrite32(BIT(hw_irq), p->cpu_int_base + IRQC_EN_SET);
> +}
> +
> +static void irqc_irq_disable(struct irq_data *d)
> +{
> +	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
> +	int hw_irq = irqd_to_hwirq(d);
> +
> +	irqc_dbg(&p->irq[hw_irq], "disable");
> +	iowrite32(BIT(hw_irq), p->cpu_int_base + IRQC_EN_STS);
> +}
> +
> +#define INTC_IRQ_SENSE_VALID 0x10
> +#define INTC_IRQ_SENSE(x) (x + INTC_IRQ_SENSE_VALID)
> +
> +static unsigned char irqc_sense[IRQ_TYPE_SENSE_MASK + 1] = {
> +	[IRQ_TYPE_LEVEL_LOW] = INTC_IRQ_SENSE(0x01),
> +	[IRQ_TYPE_LEVEL_HIGH] = INTC_IRQ_SENSE(0x02),
> +	[IRQ_TYPE_EDGE_FALLING] = INTC_IRQ_SENSE(0x04), /* Synchronous */
> +	[IRQ_TYPE_EDGE_RISING] = INTC_IRQ_SENSE(0x08), /* Synchronous */
> +	[IRQ_TYPE_EDGE_BOTH] = INTC_IRQ_SENSE(0x0c),  /* Synchronous */
> +};
> +
> +static int irqc_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
> +	int hw_irq = irqd_to_hwirq(d);
> +	unsigned char value = irqc_sense[type & IRQ_TYPE_SENSE_MASK];
> +	unsigned long tmp;
> +
> +	irqc_dbg(&p->irq[hw_irq], "sense");
> +
> +	if (!(value & INTC_IRQ_SENSE_VALID))
> +		return -EINVAL;
> +
> +	tmp = ioread32(p->iomem + IRQC_CONFIG(hw_irq));
> +	tmp &= ~0x3f;
> +	tmp |= value ^ INTC_IRQ_SENSE_VALID;
> +	iowrite32(tmp, p->iomem + IRQC_CONFIG(hw_irq));
> +	return 0;
> +}
> +
> +static irqreturn_t irqc_irq_handler(int irq, void *dev_id)
> +{
> +	struct irqc_irq *i = dev_id;
> +	struct irqc_priv *p = i->p;
> +	unsigned long bit = BIT(i->hw_irq);
> +
> +	irqc_dbg(i, "demux1");
> +
> +	if (ioread32(p->iomem + DETECT_STATUS) & bit) {
> +		iowrite32(bit, p->iomem + DETECT_STATUS);
> +		irqc_dbg(i, "demux2");
> +		generic_handle_irq(i->domain_irq);
> +		return IRQ_HANDLED;
> +	}
> +	return IRQ_NONE;
> +}
> +
> +static int irqc_irq_domain_map(struct irq_domain *h, unsigned int virq,
> +			       irq_hw_number_t hw)
> +{
> +	struct irqc_priv *p = h->host_data;
> +
> +	p->irq[hw].domain_irq = virq;
> +	p->irq[hw].hw_irq = hw;
> +
> +	irqc_dbg(&p->irq[hw], "map");
> +	irq_set_chip_data(virq, h->host_data);
> +	irq_set_chip_and_handler(virq, &p->irq_chip, handle_level_irq);
> +	set_irq_flags(virq, IRQF_VALID); /* kill me now */
> +	return 0;
> +}
> +
> +static struct irq_domain_ops irqc_irq_domain_ops = {
> +	.map	= irqc_irq_domain_map,
> +};
> +
> +static int irqc_probe(struct platform_device *pdev)
> +{
> +	struct renesas_irqc_config *pdata = pdev->dev.platform_data;
> +	struct irqc_priv *p;
> +	struct resource *io;
> +	struct resource *irq;
> +	struct irq_chip *irq_chip;
> +	const char *name = dev_name(&pdev->dev);
> +	int ret;
> +	int k;
> +
> +	p = kzalloc(sizeof(*p), GFP_KERNEL);
> +	if (!p) {
> +		dev_err(&pdev->dev, "failed to allocate driver data\n");
> +		ret = -ENOMEM;
> +		goto err0;
> +	}
> +
> +	/* deal with driver instance configuration */
> +	if (pdata)
> +		memcpy(&p->config, pdata, sizeof(*pdata));
> +
> +	p->pdev = pdev;
> +	platform_set_drvdata(pdev, p);
> +
> +	/* get hold of manadatory IOMEM */
> +	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!io) {
> +		dev_err(&pdev->dev, "not enough IOMEM resources\n");
> +		ret = -EINVAL;
> +		goto err1;
> +	}
> +
> +	/* allow any number of IRQs between 1 and IRQC_IRQ_MAX */
> +	for (k = 0; k < IRQC_IRQ_MAX; k++) {
> +		irq = platform_get_resource(pdev, IORESOURCE_IRQ, k);
> +		if (!irq)
> +			break;
> +
> +		p->irq[k].p = p;
> +		p->irq[k].requested_irq = irq->start;
> +	}
> +
> +	p->number_of_irqs = k;
> +	if (p->number_of_irqs < 1) {
> +		dev_err(&pdev->dev, "not enough IRQ resources\n");
> +		ret = -EINVAL;
> +		goto err1;
> +	}
> +
> +	/* ioremap IOMEM and setup read/write callbacks */
> +	p->iomem = ioremap_nocache(io->start, resource_size(io));
> +	if (!p->iomem) {
> +		dev_err(&pdev->dev, "failed to remap IOMEM\n");
> +		ret = -ENXIO;
> +		goto err2;
> +	}
> +
> +	p->cpu_int_base = p->iomem + IRQC_INT_CPU_BASE(0); /* SYS-SPI */
> +
> +	irq_chip = &p->irq_chip;
> +	irq_chip->name = name;
> +	irq_chip->irq_mask = irqc_irq_disable;
> +	irq_chip->irq_unmask = irqc_irq_enable;
> +	irq_chip->irq_enable = irqc_irq_enable;
> +	irq_chip->irq_disable = irqc_irq_disable;
> +	irq_chip->irq_set_type = irqc_irq_set_type;
> +	irq_chip->flags	= IRQCHIP_SKIP_SET_WAKE;
> +
> +	p->irq_domain = irq_domain_add_simple(pdev->dev.of_node,
> +					      p->number_of_irqs,
> +					      p->config.irq_base,
> +					      &irqc_irq_domain_ops, p);
> +	if (!p->irq_domain) {
> +		ret = -ENXIO;
> +		dev_err(&pdev->dev, "cannot initialize irq domain\n");
> +		goto err2;
> +	}
> +
> +	/* request interrupts one by one */
> +	for (k = 0; k < p->number_of_irqs; k++) {
> +		if (request_irq(p->irq[k].requested_irq, irqc_irq_handler,
> +				0, name, &p->irq[k])) {
> +			dev_err(&pdev->dev, "failed to request IRQ\n");
> +			ret = -ENOENT;
> +			goto err3;
> +		}
> +	}
> +
> +	dev_info(&pdev->dev, "driving %d irqs\n", p->number_of_irqs);
> +
> +	/* warn in case of mismatch if irq base is specified */
> +	if (p->config.irq_base) {
> +		if (p->config.irq_base != p->irq[0].domain_irq)
> +			dev_warn(&pdev->dev, "irq base mismatch (%d/%d)\n",
> +				 p->config.irq_base, p->irq[0].domain_irq);
> +	}
> +
> +	return 0;
> +err3:
> +	for (; k >= 0; k--)
> +		free_irq(p->irq[k - 1].requested_irq, &p->irq[k - 1]);
> +
> +	irq_domain_remove(p->irq_domain);
> +err2:
> +	iounmap(p->iomem);
> +err1:
> +	kfree(p);
> +err0:
> +	return ret;
> +}
> +
> +static int irqc_remove(struct platform_device *pdev)
> +{
> +	struct irqc_priv *p = platform_get_drvdata(pdev);
> +	int k;
> +
> +	for (k = 0; k < p->number_of_irqs; k++)
> +		free_irq(p->irq[k].requested_irq, &p->irq[k]);
> +
> +	irq_domain_remove(p->irq_domain);
> +	iounmap(p->iomem);
> +	kfree(p);
> +	return 0;
> +}
> +
> +static struct platform_driver irqc_device_driver = {
> +	.probe		= irqc_probe,
> +	.remove		= irqc_remove,
> +	.driver		= {
> +		.name	= "renesas_irqc",
> +	}
> +};
> +
> +static int __init irqc_init(void)
> +{
> +	return platform_driver_register(&irqc_device_driver);
> +}
> +postcore_initcall(irqc_init);
> +
> +static void __exit irqc_exit(void)
> +{
> +	platform_driver_unregister(&irqc_device_driver);
> +}
> +module_exit(irqc_exit);
> +
> +MODULE_AUTHOR("Magnus Damm");
> +MODULE_DESCRIPTION("Renesas IRQC Driver");
> +MODULE_LICENSE("GPL v2");
> --- /dev/null
> +++ work/include/linux/platform_data/irq-renesas-irqc.h	2013-02-27 16:12:09.000000000 +0900
> @@ -0,0 +1,27 @@
> +/*
> + * Renesas IRQC Driver
> + *
> + *  Copyright (C) 2013 Magnus Damm
> + *
> + * 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
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + */
> +
> +#ifndef __IRQ_RENESAS_IRQC_H__
> +#define __IRQ_RENESAS_IRQC_H__
> +
> +struct renesas_irqc_config {
> +	unsigned int irq_base;
> +};
> +
> +#endif /* __IRQ_RENESAS_IRQC_H__ */
> 
--
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