Date:   Fri, 24 Mar 2017 16:22:11 +0000
From:   Marc Zyngier <marc.zyngier@....com>
To:     Youlin Pei <youlin.pei@...iatek.com>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        hongkun.cao@...iatek.com, yong.wu@...iatek.com,
        erin.lo@...iatek.com
Subject: Re: [PATCH v3 2/3] irqchip: mtk-cirq: Add mediatek mtk-cirq implement

On 14/02/17 02:56, Youlin Pei wrote:
> In Mediatek SOCs, the CIRQ is a low power interrupt controller
> designed to works outside MCUSYS which comprises with Cortex-Ax
> cores,CCI and GIC.
> 
> The CIRQ controller is integrated in between MCUSYS( include
> Cortex-Ax, CCI and GIC ) and interrupt sources as the second
> level interrupt controller. The external interrupts which outside
> MCUSYS will feed through CIRQ then bypass to GIC. CIRQ can monitors
> all edge trigger interupts. When an edge interrupt is triggered,
> CIRQ can record the status and generate a pulse signal to GIC when
> flush command executed.
> 
> When system enters sleep mode, MCUSYS will be turned off to improve
> power consumption, also GIC is power down. The edge trigger interrupts
> will be lost in this scenario without CIRQ.
> 
> This commit provides the CIRQ irqchip implement.
> 
> Signed-off-by: Youlin Pei <youlin.pei@...iatek.com>
> ---
>  drivers/irqchip/Makefile       |    2 +-
>  drivers/irqchip/irq-mtk-cirq.c |  288 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 289 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/irqchip/irq-mtk-cirq.c
> 
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 0e55d94..db9acd1 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -61,7 +61,7 @@ obj-$(CONFIG_BCM7120_L2_IRQ)		+= irq-bcm7120-l2.o
>  obj-$(CONFIG_BRCMSTB_L2_IRQ)		+= irq-brcmstb-l2.o
>  obj-$(CONFIG_KEYSTONE_IRQ)		+= irq-keystone.o
>  obj-$(CONFIG_MIPS_GIC)			+= irq-mips-gic.o
> -obj-$(CONFIG_ARCH_MEDIATEK)		+= irq-mtk-sysirq.o
> +obj-$(CONFIG_ARCH_MEDIATEK)		+= irq-mtk-sysirq.o irq-mtk-cirq.o
>  obj-$(CONFIG_ARCH_DIGICOLOR)		+= irq-digicolor.o
>  obj-$(CONFIG_RENESAS_H8300H_INTC)	+= irq-renesas-h8300h.o
>  obj-$(CONFIG_RENESAS_H8S_INTC)		+= irq-renesas-h8s.o
> diff --git a/drivers/irqchip/irq-mtk-cirq.c b/drivers/irqchip/irq-mtk-cirq.c
> new file mode 100644
> index 0000000..b5cf506
> --- /dev/null
> +++ b/drivers/irqchip/irq-mtk-cirq.c
> @@ -0,0 +1,288 @@
> +/*
> + * Copyright (c) 2016 MediaTek Inc.
> + * Author: Youlin.Pei <youlin.pei@...iatek.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/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_address.h>
> +#include <linux/slab.h>
> +#include <linux/syscore_ops.h>
> +
> +#define CIRQ_ACK	0x40
> +#define CIRQ_MASK_SET	0xc0
> +#define CIRQ_MASK_CLR	0x100
> +#define CIRQ_SENS_SET	0x180
> +#define CIRQ_SENS_CLR	0x1c0
> +#define CIRQ_POL_SET	0x240
> +#define CIRQ_POL_CLR	0x280
> +#define CIRQ_CONTROL	0x300
> +
> +#define CIRQ_EN	0x1
> +#define CIRQ_EDGE	0x2
> +#define CIRQ_FLUSH	0x4
> +
> +struct mtk_cirq_chip_data {
> +	void __iomem *base;
> +	unsigned int ext_irq_start;
> +	unsigned int ext_irq_end;
> +	struct irq_domain *domain;
> +};
> +
> +static struct mtk_cirq_chip_data *cirq_data;

Question in relation to the sysirq patches that have been queued for
4.12: Are we going to see something similar with this driver, where
you're going to have to support multiple non-contiguous register sets?
I'd rather have this kind of thing from day one, instead of adding that
at a later time...

Specially given that the platform that is using this driver does also
have a sysirq controller.

> +
> +static void mtk_cirq_write_mask(struct irq_data *data, unsigned int offset)
> +{
> +	struct mtk_cirq_chip_data *chip_data = data->chip_data;
> +	unsigned int cirq_num = data->hwirq;
> +	u32 mask = 1 << (cirq_num % 32);
> +
> +	writel_relaxed(mask, chip_data->base + offset + (cirq_num / 32) * 4);
> +}
> +
> +static void mtk_cirq_mask(struct irq_data *data)
> +{
> +	mtk_cirq_write_mask(data, CIRQ_MASK_SET);
> +	irq_chip_mask_parent(data);
> +}
> +
> +static void mtk_cirq_unmask(struct irq_data *data)
> +{
> +	mtk_cirq_write_mask(data, CIRQ_MASK_CLR);
> +	irq_chip_unmask_parent(data);
> +}
> +
> +static int mtk_cirq_set_type(struct irq_data *data, unsigned int type)
> +{
> +	int ret;
> +
> +	switch (type & IRQ_TYPE_SENSE_MASK) {
> +	case IRQ_TYPE_EDGE_FALLING:
> +		mtk_cirq_write_mask(data, CIRQ_POL_CLR);
> +		mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
> +		break;
> +	case IRQ_TYPE_EDGE_RISING:
> +		mtk_cirq_write_mask(data, CIRQ_POL_SET);
> +		mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		mtk_cirq_write_mask(data, CIRQ_POL_CLR);
> +		mtk_cirq_write_mask(data, CIRQ_SENS_SET);
> +		break;
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		mtk_cirq_write_mask(data, CIRQ_POL_SET);
> +		mtk_cirq_write_mask(data, CIRQ_SENS_SET);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	data = data->parent_data;
> +	ret = data->chip->irq_set_type(data, type);
> +	return ret;
> +}
> +
> +static struct irq_chip mtk_cirq_chip = {
> +	.name			= "MT_CIRQ",
> +	.irq_mask		= mtk_cirq_mask,
> +	.irq_unmask		= mtk_cirq_unmask,
> +	.irq_eoi		= irq_chip_eoi_parent,
> +	.irq_set_type		= mtk_cirq_set_type,
> +	.irq_retrigger		= irq_chip_retrigger_hierarchy,
> +#ifdef CONFIG_SMP
> +	.irq_set_affinity	= irq_chip_set_affinity_parent,
> +#endif
> +};
> +
> +static int mtk_cirq_domain_translate(struct irq_domain *d,
> +				     struct irq_fwspec *fwspec,
> +				     unsigned long *hwirq,
> +				     unsigned int *type)
> +{
> +	if (is_of_node(fwspec->fwnode)) {
> +		if (fwspec->param_count != 3)
> +			return -EINVAL;
> +
> +		/* No PPI should point to this domain */
> +		if (fwspec->param[0] != 0)
> +			return -EINVAL;
> +
> +		/* cirq support irq number check */
> +		if (fwspec->param[1] < cirq_data->ext_irq_start ||
> +		    fwspec->param[1] > cirq_data->ext_irq_end)
> +			return -EINVAL;
> +
> +		*hwirq = fwspec->param[1] - cirq_data->ext_irq_start;
> +		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
> +		return 0;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int mtk_cirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +				 unsigned int nr_irqs, void *arg)
> +{
> +	int ret;
> +	irq_hw_number_t hwirq;
> +	unsigned int type;
> +	struct irq_fwspec *fwspec = arg;
> +	struct irq_fwspec parent_fwspec = *fwspec;
> +
> +	ret = mtk_cirq_domain_translate(domain, fwspec, &hwirq, &type);
> +	if (ret)
> +		return ret;
> +
> +	if (WARN_ON(nr_irqs != 1))
> +		return -EINVAL;
> +
> +	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
> +				      &mtk_cirq_chip,
> +				      domain->host_data);
> +
> +	parent_fwspec.fwnode = domain->parent->fwnode;
> +	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
> +					    &parent_fwspec);
> +}
> +
> +static const struct irq_domain_ops cirq_domain_ops = {
> +	.translate	= mtk_cirq_domain_translate,
> +	.alloc		= mtk_cirq_domain_alloc,
> +	.free		= irq_domain_free_irqs_common,
> +};
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int mtk_cirq_suspend(void)
> +{
> +	u32 value, mask;
> +	unsigned int irq, hwirq_num;
> +	bool pending, masked;
> +	int i, pendret, maskret;
> +
> +	hwirq_num = cirq_data->ext_irq_end - cirq_data->ext_irq_start + 1;
> +	for (i = 0; i < hwirq_num; i++) {
> +		irq = irq_find_mapping(cirq_data->domain, i);
> +		if (irq) {
> +			pendret = irq_get_irqchip_state(irq,
> +							IRQCHIP_STATE_PENDING,
> +							&pending);
> +
> +			maskret = irq_get_irqchip_state(irq,
> +							IRQCHIP_STATE_MASKED,
> +							&masked);
> +
> +			if (pendret == 0 && maskret == 0 &&
> +			    (pending && !masked))
> +				continue;
> +		}
> +
> +		mask = 1 << (i % 32);
> +		writel_relaxed(mask, cirq_data->base + CIRQ_ACK + (i / 32) * 4);
> +	}

It would be worth documenting exactly what this is for. I had to go back
to our previous discussion in November to remember it.

> +
> +	/* set edge_only mode, record edge-triggerd interrupts */
> +	/* enable cirq */
> +	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> +	value |= (CIRQ_EDGE | CIRQ_EN);
> +	writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
> +
> +	return 0;
> +}
> +
> +static void mtk_cirq_resume(void)
> +{
> +	u32 value;
> +
> +	/* flush recored interrupts, will send signals to parent controller */
> +	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> +	writel_relaxed(value | CIRQ_FLUSH, cirq_data->base + CIRQ_CONTROL);
> +
> +	/* disable cirq */
> +	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
> +	value &= ~(CIRQ_EDGE | CIRQ_EN);
> +	writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
> +}
> +
> +static struct syscore_ops mtk_cirq_syscore_ops = {
> +	.suspend	= mtk_cirq_suspend,
> +	.resume		= mtk_cirq_resume,
> +};
> +
> +static void mtk_cirq_syscore_init(void)
> +{
> +	register_syscore_ops(&mtk_cirq_syscore_ops);
> +}
> +#else
> +static inline void mtk_cirq_syscore_init(void) {}
> +#endif
> +
> +static int __init mtk_cirq_of_init(struct device_node *node,
> +				   struct device_node *parent)
> +{
> +	struct irq_domain *domain, *domain_parent;
> +	unsigned int irq_num;
> +	int ret;
> +
> +	domain_parent = irq_find_host(parent);
> +	if (!domain_parent) {
> +		pr_err("mtk_cirq: interrupt-parent not found\n");
> +		return -EINVAL;
> +	}
> +
> +	cirq_data = kzalloc(sizeof(*cirq_data), GFP_KERNEL);
> +	if (!cirq_data)
> +		return -ENOMEM;
> +
> +	cirq_data->base = of_iomap(node, 0);
> +	if (!cirq_data->base) {
> +		pr_err("mtk_cirq: unable to map cirq register\n");
> +		ret = -ENXIO;
> +		goto out_free;
> +	}
> +
> +	ret = of_property_read_u32_index(node, "mediatek,ext-irq-range", 0,
> +					 &cirq_data->ext_irq_start);
> +	if (ret)
> +		goto out_unmap;
> +
> +	ret = of_property_read_u32_index(node, "mediatek,ext-irq-range", 1,
> +					 &cirq_data->ext_irq_end);
> +	if (ret)
> +		goto out_unmap;
> +
> +	irq_num = cirq_data->ext_irq_end - cirq_data->ext_irq_start + 1;
> +	domain = irq_domain_add_hierarchy(domain_parent, 0,
> +					  irq_num, node,
> +					  &cirq_domain_ops, cirq_data);
> +	if (!domain) {
> +		ret = -ENOMEM;
> +		goto out_unmap;
> +	}
> +	cirq_data->domain = domain;
> +
> +	mtk_cirq_syscore_init();
> +
> +	return 0;
> +
> +out_unmap:
> +	iounmap(cirq_data->base);
> +out_free:
> +	kfree(cirq_data);
> +	return ret;
> +}
> +
> +IRQCHIP_DECLARE(mtk_cirq, "mediatek,mtk-cirq", mtk_cirq_of_init);
> 

It otherwise looks much better than the previous iteration.

Thanks,

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

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