RE: [PATCH v3 2/2] irqchip: Add support for Renesas RZ/N1 GPIO interrupt multiplexer

[Phil Edworthy]

Hello,

Any comments on this patch?

Thanks
Phil

> -----Original Message-----
> From: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> Sent: 13 November 2018 13:09
> To: Marc Zyngier <marc.zyngier@xxxxxxx>; Thomas Gleixner
> <tglx@xxxxxxxxxxxxx>; Jason Cooper <jason@xxxxxxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>; linux-renesas-
> soc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Phil Edworthy
> <phil.edworthy@xxxxxxxxxxx>
> Subject: [PATCH v3 2/2] irqchip: Add support for Renesas RZ/N1 GPIO
> interrupt multiplexer
> 
> On RZ/N1 devices, there are 3 Synopsys DesignWare GPIO blocks each
> configured to have 32 interrupt outputs, so we have a total of 96 GPIO
> interrupts. All of these are passed to the GPIO IRQ Muxer, which selects
> 8 of the GPIO interrupts to pass onto the GIC. The interrupt signals aren't
> latched, so there is nothing to do in this driver when an interrupt is received,
> other than tell the corresponding GPIO block.
> 
> Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> ---
> v3:
>  - Use 'interrupt-map' DT property to map the interrupts, this is very similar
>    to PCIe MSI. The only difference is that we need to get hold of the interrupt
>    specifier for the interupts coming into the irqmux.
>  - Do not use a chained interrupt controller.
> v2:
>  - Use interrupt-map to allow the GPIO controller info to be specified
>    as part of the irq.
>  - Renamed struct and funcs from 'girq' to a more comprehenisble 'irqmux'.
> ---
>  drivers/irqchip/Kconfig        |   9 ++
>  drivers/irqchip/Makefile       |   1 +
>  drivers/irqchip/rzn1-irq-mux.c | 205
> +++++++++++++++++++++++++++++++++
>  3 files changed, 215 insertions(+)
>  create mode 100644 drivers/irqchip/rzn1-irq-mux.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index
> 96451b581452..53c54bba1dd8 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -204,6 +204,15 @@ config RENESAS_IRQC
>  	select GENERIC_IRQ_CHIP
>  	select IRQ_DOMAIN
> 
> +config RENESAS_RZN1_IRQ_MUX
> +	bool "Renesas RZ/N1 GPIO IRQ multiplexer support"
> +	depends on ARCH_RZN1
> +	select IRQ_DOMAIN
> +	help
> +	  Say yes here to add support for the GPIO IRQ multiplexer
> embedded
> +	  in Renesas RZ/N1 SoC devices. The GPIO IRQ Muxer selects which of
> +	  the interrupts coming from the GPIO controllers are used.
> +
>  config ST_IRQCHIP
>  	bool
>  	select REGMAP
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index
> b822199445ff..b090f84dd42e 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -45,6 +45,7 @@ obj-$(CONFIG_SIRF_IRQ)			+= irq-
> sirfsoc.o
>  obj-$(CONFIG_JCORE_AIC)			+= irq-jcore-aic.o
>  obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
>  obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
> +obj-$(CONFIG_RENESAS_RZN1_IRQ_MUX)	+= rzn1-irq-mux.o
>  obj-$(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/rzn1-irq-mux.c b/drivers/irqchip/rzn1-irq-mux.c
> new file mode 100644 index 000000000000..ee7810b9b3f3
> --- /dev/null
> +++ b/drivers/irqchip/rzn1-irq-mux.c
> @@ -0,0 +1,205 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RZ/N1 GPIO Interrupt Multiplexer
> + *
> + * Copyright (C) 2018 Renesas Electronics Europe Limited
> + *
> + * On RZ/N1 devices, there are 3 Synopsys DesignWare GPIO blocks each
> +configured
> + * to have 32 interrupt outputs, so we have a total of 96 GPIO interrupts.
> + * All of these are passed to the GPIO IRQ Muxer, which selects 8 of
> +the GPIO
> + * interrupts to pass onto the GIC.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +
> +#define MAX_NR_INPUT_IRQS	96
> +#define MAX_NR_OUTPUT_IRQS	8
> +
> +/*
> + * "interrupt-map" consists of 1 interrupt cell, 0 address cells,
> +phandle to
> + * interrupt parent, and parent interrupt specifier (3 cells for GIC),
> +giving
> + * a total of 5 cells.
> + */
> +#define IMAP_LENGTH		5
> +
> +struct irqmux_priv;
> +struct irqmux_one {
> +	unsigned int irq;
> +	unsigned int src_hwirq;
> +	struct irqmux_priv *priv;
> +};
> +
> +struct irqmux_priv {
> +	struct device *dev;
> +	struct irq_domain *irq_domain;
> +	unsigned int nr_irqs;
> +	struct irqmux_one mux[MAX_NR_OUTPUT_IRQS]; };
> +
> +static irqreturn_t irqmux_handler(int irq, void *data) {
> +	struct irqmux_one *mux = data;
> +	struct irqmux_priv *priv = mux->priv;
> +	unsigned int virq;
> +
> +	virq = irq_find_mapping(priv->irq_domain, mux->src_hwirq);
> +
> +	generic_handle_irq(virq);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int irqmux_domain_map(struct irq_domain *h, unsigned int irq,
> +			     irq_hw_number_t hwirq)
> +{
> +	irq_set_chip_data(irq, h->host_data);
> +	irq_set_chip_and_handler(irq, &dummy_irq_chip,
> handle_simple_irq);
> +
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops irqmux_domain_ops = {
> +	.map = irqmux_domain_map,
> +};
> +
> +static int irqmux_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct resource *res;
> +	u32 __iomem *regs;
> +	struct irqmux_priv *priv;
> +	unsigned int i;
> +	int nr_irqs;
> +	int ret;
> +	const __be32 *imap;
> +	int imaplen;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = dev;
> +	platform_set_drvdata(pdev, priv);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(regs))
> +		return PTR_ERR(regs);
> +
> +	nr_irqs = of_irq_count(np);
> +	if (nr_irqs < 0)
> +		return nr_irqs;
> +
> +	if (nr_irqs > MAX_NR_OUTPUT_IRQS) {
> +		dev_err(dev, "too many output interrupts\n");
> +		return -ENOENT;
> +	}
> +
> +	priv->nr_irqs = nr_irqs;
> +
> +	/* Look for the interrupt-map */
> +	imap = of_get_property(np, "interrupt-map", &imaplen);
> +	if (!imap)
> +		return -ENOENT;
> +	imaplen /= IMAP_LENGTH * sizeof(__be32);
> +
> +	/* Sometimes not all muxs are used */
> +	if (imaplen < priv->nr_irqs)
> +		priv->nr_irqs = imaplen;
> +
> +	/* Create IRQ domain for the interrupts coming from the GPIO blocks
> */
> +	priv->irq_domain = irq_domain_add_linear(np,
> MAX_NR_INPUT_IRQS,
> +						 &irqmux_domain_ops, priv);
> +	if (!priv->irq_domain)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < MAX_NR_INPUT_IRQS; i++)
> +		irq_create_mapping(priv->irq_domain, i);
> +
> +	for (i = 0; i < priv->nr_irqs; i++) {
> +		struct irqmux_one *mux = &priv->mux[i];
> +
> +		ret = irq_of_parse_and_map(np, i);
> +		if (ret < 0) {
> +			ret = -ENOENT;
> +			goto err;
> +		}
> +
> +		mux->irq = ret;
> +		mux->priv = priv;
> +
> +		/*
> +		 * We need the first cell of the interrupt-map to configure
> +		 * the hardware.
> +		 */
> +		mux->src_hwirq = be32_to_cpu(*imap);
> +		imap += IMAP_LENGTH;
> +
> +		dev_info(dev, "%u: %u mapped irq %u\n", i,  mux-
> >src_hwirq,
> +			 mux->irq);
> +
> +		ret = devm_request_irq(dev, mux->irq, irqmux_handler,
> +				       IRQF_SHARED | IRQF_NO_THREAD,
> +				       "irqmux", mux);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to request IRQ: %d\n", ret);
> +			goto err;
> +		}
> +
> +		/* Set up the hardware to pass the interrupt through */
> +		writel(mux->src_hwirq, &regs[i]);
> +	}
> +
> +	dev_info(dev, "probed, %d gpio interrupts\n", priv->nr_irqs);
> +
> +	return 0;
> +
> +err:
> +	while (i--)
> +		irq_dispose_mapping(priv->mux[i].irq);
> +	irq_domain_remove(priv->irq_domain);
> +
> +	return ret;
> +}
> +
> +static int irqmux_remove(struct platform_device *pdev) {
> +	struct irqmux_priv *priv = platform_get_drvdata(pdev);
> +	unsigned int i;
> +
> +	for (i = 0; i < priv->nr_irqs; i++)
> +		irq_dispose_mapping(priv->mux[i].irq);
> +	irq_domain_remove(priv->irq_domain);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id irqmux_match[] = {
> +	{ .compatible = "renesas,rzn1-gpioirqmux", },
> +	{ /* sentinel */ },
> +};
> +
> +MODULE_DEVICE_TABLE(of, irqmux_match);
> +
> +static struct platform_driver irqmux_driver = {
> +	.driver = {
> +		.name = "gpio_irq_mux",
> +		.owner = THIS_MODULE,
> +		.of_match_table = irqmux_match,
> +	},
> +	.probe = irqmux_probe,
> +	.remove = irqmux_remove,
> +};
> +
> +module_platform_driver(irqmux_driver);
> +
> +MODULE_DESCRIPTION("Renesas RZ/N1 GPIO IRQ Multiplexer Driver");
> +MODULE_AUTHOR("Phil Edworthy <phil.edworthy@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1