[RFC,7/7] irqchip: [Example] dummy wired interrupt/MSI bridge driver

Message ID	1444923568-17413-8-git-send-email-marc.zyngier@arm.com (mailing list archive)
State	New, archived
Delegated to:	Bjorn Helgaas
Headers	show Return-Path: <linux-pci-owner@kernel.org> From: Marc Zyngier <marc.zyngier@arm.com> To: Thomas Gleixner <tglx@linutronix.de>, Jiang Liu <jiang.liu@linux.intel.com>, Jason Cooper <jason@lakedaemon.net> Cc: Ma Jun <majun258@huawei.com>, <linux-arm-kernel@lists.infradead.org>, <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org> Subject: [PATCH RFC 7/7] irqchip: [Example] dummy wired interrupt/MSI bridge driver Date: Thu, 15 Oct 2015 16:39:28 +0100 Message-Id: <1444923568-17413-8-git-send-email-marc.zyngier@arm.com> In-Reply-To: <1444923568-17413-1-git-send-email-marc.zyngier@arm.com> References: <1444923568-17413-1-git-send-email-marc.zyngier@arm.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index 4d7294e..73e38e6 100644 --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -193,3 +193,10 @@ config IRQ_MXS def_bool y if MACH_ASM9260 || ARCH_MXS select IRQ_DOMAIN select STMP_DEVICE + +config DUMMY_MSICHIP + bool "Dummy irqchip on MSI" + depends on GENERIC_MSI_IRQ_DOMAIN + help + Dummy stacked irqchip on top of platform MSI + diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index 177f78f..682e7dc 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -55,3 +55,4 @@ obj-$(CONFIG_RENESAS_H8S_INTC) += irq-renesas-h8s.o obj-$(CONFIG_ARCH_SA1100) += irq-sa11x0.o obj-$(CONFIG_INGENIC_IRQ) += irq-ingenic.o obj-$(CONFIG_IMX_GPCV2) += irq-imx-gpcv2.o +obj-$(CONFIG_DUMMY_MSICHIP) += irq-msichip.o diff --git a/drivers/irqchip/irq-msichip.c b/drivers/irqchip/irq-msichip.c new file mode 100644 index 0000000..82b283b --- /dev/null +++ b/drivers/irqchip/irq-msichip.c @@ -0,0 +1,271 @@ +/* + * Non-functionnal example for a wired irq <-> MSI bridge + * + * Copyright (C) 2015 ARM Limited, All Rights Reserved. + * Author: Marc Zyngier <marc.zyngier@arm.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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * DT fragment to represent the MSI bridge: + + intc: msichip { + compatible = "dummy,msichip"; + num-msis = 32; + interrupt-controller; + interrupt-parent = <&gic>; + #interrupt-cells = <0x2>; + msi-parent = <&its 1234>; + }; + + * DT fragment to represent the device connected to the bridge: + + dummy-dev { + compatible = "dummy,device"; + interrupt-parent = <intc>; + interrupts = <0x5 0x1>; + }; + + * When "dummy,device" gets probed, it dumps the hierarchy for the + * interrupt it has allocated: + + dummydev dummy-dev: Allocated IRQ35 + dummydev dummy-dev: Probing OK + dummydev dummy-dev: IRQ35 hwirq 5 domain msichip_domain_ops + dummydev dummy-dev: IRQ35 hwirq 0 domain msi_domain_ops + dummydev dummy-dev: IRQ35 hwirq 8192 domain its_domain_ops + dummydev dummy-dev: IRQ35 hwirq 8192 domain gic_irq_domain_ops + */ + +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/irqchip.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/msi.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/slab.h> +#include <linux/spinlock.h> + +static void msichip_mask(struct irq_data *data) +{ + /* Do something */ +} + +static void msichip_unmask(struct irq_data *data) +{ + /* Do something */ +} + +static void msichip_eoi(struct irq_data *data) +{ + /* Do something */ +} + +static int msichip_set_type(struct irq_data *data, unsigned int type) +{ + /* Do something */ + return 0; +} + +static int msichip_retrigger(struct irq_data *data) +{ + /* Do something */ + return 0; +} + +static int msichip_set_affinity(struct irq_data *data, + const struct cpumask *dest, bool force) +{ + /* Do something */ + return 0; +} + +static struct irq_chip msichip_chip = { + .name = "MSICHIP", + .irq_mask = msichip_mask, + .irq_unmask = msichip_unmask, + .irq_eoi = msichip_eoi, + .irq_set_type = msichip_set_type, + .irq_retrigger = msichip_retrigger, + .irq_set_affinity = msichip_set_affinity, +}; + +static int msichip_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 != 2) + return -EINVAL; + + *hwirq = fwspec->param[0]; + *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK; + return 0; + } + + return -EINVAL; +} + +static int msichip_domain_alloc(struct irq_domain *domain, unsigned int virq, + unsigned int nr_irqs, void *arg) +{ + int i, err; + irq_hw_number_t hwirq; + unsigned int type; + struct irq_fwspec *fwspec = arg; + void *data; + + err = msichip_domain_translate(domain, fwspec, &hwirq, &type); + if (err) + return err; + + err = platform_msi_domain_alloc(domain, virq, nr_irqs); + if (err) + return err; + + data = platform_msi_get_host_data(domain); + for (i = 0; i < nr_irqs; i++) + irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i, + &msichip_chip, data); + + return 0; +} + +static const struct irq_domain_ops msichip_domain_ops = { + .translate = msichip_domain_translate, + .alloc = msichip_domain_alloc, + .free = irq_domain_free_irqs_common, +}; + +struct msichip_data { + /* Add whatever you fancy here */ + struct platform_device *pdev; +}; + +static void msichip_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg) +{ + /* Do the right thing */ +} + +static int msichip_probe(struct platform_device *pdev) +{ + struct irq_domain *domain; + struct msichip_data *msichip_data; + u32 num_msis; + + dev_info(&pdev->dev, "Probing\n"); + msichip_data = kzalloc(sizeof(*msichip_data), GFP_KERNEL); + if (!msichip_data) + return -ENOMEM; + + msichip_data->pdev = pdev; + + /* If there is no "num-msi" property, assume 64... */ + if (of_property_read_u32(pdev->dev.of_node, "num-msis", &num_msis) < 0) + num_msis = 64; + + dev_info(&pdev->dev, "allocating %d MSIs\n", num_msis); + + domain = platform_msi_create_device_domain(&pdev->dev, num_msis, + msichip_write_msi_msg, + &msichip_domain_ops, + msichip_data); + + if (!domain){ + kfree(msichip_data); + return -ENOMEM; + } + + dev_info(&pdev->dev, "Probing OK\n"); + return 0; +} + +static const struct of_device_id msichip_of_match[] = { + { .compatible = "dummy,msichip", }, + { }, +}; +MODULE_DEVICE_TABLE(of, msichip_of_match); + +static struct platform_driver msichip_driver = { + .driver = { + .name = "msichip", + .of_match_table = msichip_of_match, + }, + .probe = msichip_probe, +}; +/* Do not define this as an irqchip */ +module_platform_driver(msichip_driver); + + + +/* Driver for a dummy device connected to the MSI bridge */ +static irqreturn_t dummydev_handler(int irq, void *dummy) +{ + return IRQ_HANDLED; +} + +static void dummydev_dump_hierarchy(struct device *dev, int irq) +{ + struct irq_data *data = irq_get_irq_data(irq); + + while(data) { + dev_info(dev, "IRQ%d hwirq %d domain %ps\n", + data->irq, (int)data->hwirq, data->domain->ops); + data = data->parent_data; + } +} + +static int dummydev_probe(struct platform_device *pdev) +{ + int irq; + + dev_info(&pdev->dev, "Probing\n"); + irq = irq_of_parse_and_map(pdev->dev.of_node, 0); + if (!irq) { + dev_err(&pdev->dev, "irq allocation failed, defering\n"); + return -EPROBE_DEFER; + } + + dev_info(&pdev->dev, "Allocated IRQ%d\n", irq); + + if (request_irq(irq, dummydev_handler, 0, "dummydev", pdev)) + return -EINVAL; + + dev_info(&pdev->dev, "Probing OK\n"); + + dummydev_dump_hierarchy(&pdev->dev, irq); + return 0; +} + +static const struct of_device_id dummydev_of_match[] = { + { .compatible = "dummy,device", }, + { }, +}; +MODULE_DEVICE_TABLE(of, dummydev_of_match); + +static struct platform_driver dummydev_driver = { + .driver = { + .name = "dummydev", + .of_match_table = dummydev_of_match, + }, + .probe = dummydev_probe, +}; + +module_platform_driver(dummydev_driver);

[RFC,7/7] irqchip: [Example] dummy wired interrupt/MSI bridge driver

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