Date:	Wed, 25 May 2016 10:38:33 -0400
From:	agustinv@...eaurora.org
To:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>
Cc:	timur@...eaurora.org, cov@...eaurora.org, agross@...eaurora.org,
	harba@...eaurora.org, jcm@...hat.com, msalter@...hat.com,
	mlangsdo@...hat.com, ahs3@...hat.com, astone@...hat.com,
	graeme.gregory@...aro.org, guohanjun@...wei.com,
	charles.garcia-tobin@....com
Subject: Re: [PATCH V3 2/2] irqchip: qcom: Add IRQ combiner driver

Adding linux-arm-kernel and linux-acpi

On 2016-05-13 12:16, Agustin Vega-Frias wrote:
> Driver for interrupt combiners in the Top-level Control and Status
> Registers (TCSR) hardware block in Qualcomm Technologies chips.
> 
> An interrupt combiner in this block combines a set of interrupts by
> OR'ing the individual interrupt signals into a summary interrupt
> signal routed to a parent interrupt controller, and provides read-
> only, 32-bit registers to query the status of individual interrupts.
> The status bit for IRQ n is bit (n % 32) within register (n / 32)
> of the given combiner. Thus, each combiner can be described as a set
> of register offsets and the number of IRQs managed.
> 
> Signed-off-by: Agustin Vega-Frias <agustinv@...eaurora.org>
> ---
>  drivers/irqchip/Kconfig             |   8 +
>  drivers/irqchip/Makefile            |   1 +
>  drivers/irqchip/qcom-irq-combiner.c | 344 
> ++++++++++++++++++++++++++++++++++++
>  3 files changed, 353 insertions(+)
>  create mode 100644 drivers/irqchip/qcom-irq-combiner.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index f582e0d..609ff28 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -245,3 +245,11 @@ config IRQ_MXS
>  config MVEBU_ODMI
>  	bool
>  	select GENERIC_MSI_IRQ_DOMAIN
> +
> +config QCOM_IRQ_COMBINER
> +	bool "QCOM IRQ combiner support"
> +	depends on ARCH_QCOM
> +	select IRQ_DOMAIN
> +	help
> +	  Say yes here to add support for the IRQ combiner devices embedded
> +	  in Qualcomm Technologies chips.
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index b03cfcb..05c688b 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -65,3 +65,4 @@ obj-$(CONFIG_INGENIC_IRQ)		+= irq-ingenic.o
>  obj-$(CONFIG_IMX_GPCV2)			+= irq-imx-gpcv2.o
>  obj-$(CONFIG_PIC32_EVIC)		+= irq-pic32-evic.o
>  obj-$(CONFIG_MVEBU_ODMI)		+= irq-mvebu-odmi.o
> +obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
> diff --git a/drivers/irqchip/qcom-irq-combiner.c
> b/drivers/irqchip/qcom-irq-combiner.c
> new file mode 100644
> index 0000000..b4f767c
> --- /dev/null
> +++ b/drivers/irqchip/qcom-irq-combiner.c
> @@ -0,0 +1,344 @@
> +/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or 
> modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only 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.
> + */
> +
> +/*
> + * Driver for interrupt combiners in the Top-level Control and Status
> + * Registers (TCSR) hardware block in Qualcomm Technologies chips.
> + * An interrupt combiner in this block combines a set of interrupts by
> + * OR'ing the individual interrupt signals into a summary interrupt
> + * signal routed to a parent interrupt controller, and provides read-
> + * only, 32-bit registers to query the status of individual 
> interrupts.
> + * The status bit for IRQ n is bit (n % 32) within register (n / 32)
> + * of the given combiner. Thus, each combiner can be described as a 
> set
> + * of register offsets and the number of IRQs managed.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +
> +#define REG_SIZE 32
> +
> +struct combiner_reg {
> +	void __iomem *addr;
> +	unsigned long mask;
> +};
> +
> +struct combiner {
> +	struct irq_chip     irq_chip;
> +	struct irq_domain   *domain;
> +	int                 parent_irq;
> +	u32                 nirqs;
> +	u32                 nregs;
> +	struct combiner_reg regs[0];
> +};
> +
> +static inline u32 irq_register(int irq)
> +{
> +	return irq / REG_SIZE;
> +}
> +
> +static inline u32 irq_bit(int irq)
> +{
> +	return irq % REG_SIZE;
> +
> +}
> +
> +static inline int irq_nr(u32 reg, u32 bit)
> +{
> +	return reg * REG_SIZE + bit;
> +}
> +
> +/*
> + * Handler for the cascaded IRQ.
> + */
> +static void combiner_handle_irq(struct irq_desc *desc)
> +{
> +	struct combiner *combiner = irq_desc_get_handler_data(desc);
> +	struct irq_chip *chip = irq_desc_get_chip(desc);
> +	u32 reg;
> +
> +	chained_irq_enter(chip, desc);
> +
> +	for (reg = 0; reg < combiner->nregs; reg++) {
> +		int virq;
> +		int hwirq;
> +		u32 bit;
> +		u32 status;
> +
> +		if (combiner->regs[reg].mask == 0)
> +			continue;
> +
> +		status = readl_relaxed(combiner->regs[reg].addr);
> +		status &= combiner->regs[reg].mask;
> +
> +		while (status) {
> +			bit = __ffs(status);
> +			status &= ~(1 << bit);
> +			hwirq = irq_nr(reg, bit);
> +			virq = irq_find_mapping(combiner->domain, hwirq);
> +			if (virq >= 0)
> +				generic_handle_irq(virq);
> +
> +		}
> +	}
> +
> +	chained_irq_exit(chip, desc);
> +}
> +
> +/*
> + * irqchip callbacks
> + */
> +
> +static void combiner_irq_chip_mask_irq(struct irq_data *data)
> +{
> +	struct combiner *combiner = irq_data_get_irq_chip_data(data);
> +	struct combiner_reg *reg = combiner->regs + 
> irq_register(data->hwirq);
> +
> +	clear_bit(irq_bit(data->hwirq), &reg->mask);
> +}
> +
> +static void combiner_irq_chip_unmask_irq(struct irq_data *data)
> +{
> +	struct combiner *combiner = irq_data_get_irq_chip_data(data);
> +	struct combiner_reg *reg = combiner->regs + 
> irq_register(data->hwirq);
> +
> +	set_bit(irq_bit(data->hwirq), &reg->mask);
> +}
> +
> +#ifdef CONFIG_SMP
> +static int combiner_irq_chip_set_affinity(struct irq_data *data,
> +					 const struct cpumask *mask, bool force)
> +{
> +	struct combiner *combiner = irq_data_get_irq_chip_data(data);
> +	struct irq_data *pdata = irq_get_irq_data(combiner->parent_irq);
> +
> +	if (pdata->chip && pdata->chip->irq_set_affinity)
> +		return pdata->chip->irq_set_affinity(pdata, mask, force);
> +	else
> +		return -EINVAL;
> +}
> +#endif
> +
> +/*
> + * domain callbacks
> + */
> +
> +static int combiner_irq_map(struct irq_domain *domain, unsigned int 
> irq,
> +				   irq_hw_number_t hwirq)
> +{
> +	struct combiner *combiner = domain->host_data;
> +
> +	if (hwirq >= combiner->nirqs)
> +		return -EINVAL;
> +
> +	irq_set_chip_and_handler(irq, &combiner->irq_chip, handle_level_irq);
> +	irq_set_chip_data(irq, combiner);
> +	irq_set_parent(irq, combiner->parent_irq);
> +	irq_set_noprobe(irq);
> +	return 0;
> +}
> +
> +static void combiner_irq_unmap(struct irq_domain *domain, unsigned int 
> irq)
> +{
> +	irq_set_chip_and_handler(irq, NULL, NULL);
> +	irq_set_chip_data(irq, NULL);
> +	irq_set_parent(irq, -1);
> +}
> +
> +static struct irq_domain_ops domain_ops = {
> +	.map = combiner_irq_map,
> +	.unmap = combiner_irq_unmap
> +};
> +
> +/*
> + * Probing and initialization.
> + *
> + * Combiner devices reside inside the TCSR block so the resulting DSDT
> + * topology is:
> + *
> + * Device (TCS0)
> + * {
> + *         Name (_HID, "QCOM80B0") // Qualcomm TCSR controller
> + *         Name (_UID, 0)
> + *
> + *         Method (_CRS, 0x0, Serialized) {
> + *                 Name (RBUF, ResourceTemplate ()
> + *                 {
> + *                         Memory32Fixed (ReadWrite, 0x2E10000, 
> 0x00001000)
> + *                 })
> + *                 Return (RBUF)
> + *         }
> + *
> + *         Device (QIC0)
> + *         {
> + *                 Name(_HID,"QCOM80B1") // Qualcomm TCSR IRQ combiner
> + *                 ...
> + *         } // end Device QIC0
> + *         ...
> + * }
> + *
> + * Thus all combiner devices same the same memory mapping from the 
> parent
> + * device.
> + */
> +
> +static int __init combiner_probe(struct platform_device *pdev)
> +{
> +	struct platform_device *tcsr_pdev;
> +	struct combiner *combiner;
> +	void __iomem *tcsr_base;
> +	size_t alloc_sz;
> +	u32 nregs;
> +	u32 nirqs;
> +
> +	tcsr_pdev = to_platform_device(pdev->dev.parent);
> +	tcsr_base = platform_get_drvdata(tcsr_pdev);
> +	if (!tcsr_base)
> +		return -ENODEV;
> +
> +	if (device_property_read_u32(&pdev->dev, "qcom,combiner-nr-irqs",
> +				     &nirqs)) {
> +		dev_err(&pdev->dev, "Error reading number of IRQs\n");
> +		return -EINVAL;
> +	}
> +
> +	nregs = device_property_read_u32_array(&pdev->dev, 
> "qcom,combiner-regs",
> +					       NULL, 0);
> +	if (nregs < DIV_ROUND_UP(nirqs, REG_SIZE)) {
> +		dev_err(&pdev->dev, "Error reading regs property\n");
> +		return -EINVAL;
> +	}
> +
> +	alloc_sz = sizeof(*combiner) + sizeof(struct combiner_reg) * nregs;
> +	combiner = devm_kzalloc(&pdev->dev, alloc_sz, GFP_KERNEL);
> +	if (combiner) {
> +		int i;
> +		u32 regs[nregs];
> +
> +		if (device_property_read_u32_array(&pdev->dev,
> +						   "qcom,combiner-regs",
> +						   regs, nregs)) {
> +			dev_err(&pdev->dev, "Error reading regs property\n");
> +			return -EINVAL;
> +		}
> +
> +		combiner->nirqs = nirqs;
> +		combiner->nregs = nregs;
> +		for (i = 0; i < nregs; i++) {
> +			combiner->regs[i].addr = tcsr_base + regs[i];
> +			combiner->regs[i].mask = 0;
> +		}
> +	} else {
> +		return -ENOMEM;
> +	}
> +
> +	combiner->irq_chip.irq_mask   = combiner_irq_chip_mask_irq;
> +	combiner->irq_chip.irq_unmask = combiner_irq_chip_unmask_irq;
> +#ifdef CONFIG_SMP
> +	combiner->irq_chip.irq_set_affinity = combiner_irq_chip_set_affinity;
> +#endif
> +
> +	combiner->parent_irq = platform_get_irq(pdev, 0);
> +	if (combiner->parent_irq <= 0) {
> +		dev_err(&pdev->dev, "Error getting IRQ resource\n");
> +		return -EINVAL;
> +	}
> +
> +	combiner->domain = irq_domain_create_linear(pdev->dev.fwnode, nirqs,
> +						    &domain_ops, combiner);
> +	if (!combiner->domain)
> +		/* Errors printed by irq_domain_create_linear */
> +		return -ENODEV;
> +
> +	irq_set_chained_handler_and_data(combiner->parent_irq,
> +					 combiner_handle_irq, combiner);
> +
> +	if (device_property_read_string(&pdev->dev, "qcom,combiner-name",
> +					&combiner->irq_chip.name) != 0)
> +		combiner->irq_chip.name = "qcom-irq-combiner";
> +
> +	dev_info(&pdev->dev, "Initialized with [p=%d,n=%d,r=%p]\n",
> +		 combiner->parent_irq, nirqs, combiner->regs[0].addr);
> +	return 0;
> +}
> +
> +static const struct acpi_device_id qcom_irq_combiner_acpi_match[] = {
> +	{ "QCOM80B1", },
> +	{ }
> +};
> +
> +static struct platform_driver qcom_irq_combiner_probe = {
> +	.driver = {
> +		.name = "qcom-irq-combiner",
> +		.owner = THIS_MODULE,
> +		.acpi_match_table = ACPI_PTR(qcom_irq_combiner_acpi_match),
> +	},
> +	.probe = combiner_probe,
> +};
> +
> +static int __init register_qcom_irq_combiner(void)
> +{
> +	return platform_driver_register(&qcom_irq_combiner_probe);
> +}
> +arch_initcall(register_qcom_irq_combiner);
> +
> +static int __init tcsr_probe(struct platform_device *pdev)
> +{
> +	struct resource *mr;
> +	void __iomem *tcsr_base;
> +
> +	mr = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (mr == NULL) {
> +		dev_err(&pdev->dev, "Error getting memory resource\n");
> +		return -EINVAL;
> +	}
> +
> +	tcsr_base = devm_ioremap_resource(&pdev->dev, mr);
> +	if (IS_ERR(tcsr_base)) {
> +		dev_err(&pdev->dev, "Error mapping memory resource\n");
> +		return PTR_ERR(tcsr_base);
> +	}
> +
> +	dev_info(&pdev->dev, "Initialized TCSR block @%pa\n", &mr->start);
> +	platform_set_drvdata(pdev, tcsr_base);
> +	return 0;
> +}
> +
> +static const struct acpi_device_id qcom_tcsr_acpi_match[] = {
> +	{ "QCOM80B0", },
> +	{ }
> +};
> +
> +static struct platform_driver qcom_tcsr_probe = {
> +	.driver = {
> +		.name = "qcom-tcsr",
> +		.owner = THIS_MODULE,
> +		.acpi_match_table = ACPI_PTR(qcom_tcsr_acpi_match),
> +	},
> +	.probe = tcsr_probe,
> +};
> +
> +static int __init register_qcom_tcsr(void)
> +{
> +	return platform_driver_register(&qcom_tcsr_probe);
> +}
> +arch_initcall(register_qcom_tcsr);
> --
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
> Forum,
> a Linux Foundation Collaborative Project.

-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
Forum,
a Linux Foundation Collaborative Project.

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