From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83947C433F5 for ; Thu, 24 Mar 2022 15:14:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351263AbiCXPPy (ORCPT ); Thu, 24 Mar 2022 11:15:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351242AbiCXPPt (ORCPT ); Thu, 24 Mar 2022 11:15:49 -0400 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 614AC6D1AF for ; Thu, 24 Mar 2022 08:14:17 -0700 (PDT) Received: by mail-pj1-x102d.google.com with SMTP id o68-20020a17090a0a4a00b001c686a48263so5627339pjo.1 for ; Thu, 24 Mar 2022 08:14:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ventanamicro.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WcwCMxaX9JGeZSa3WsYbeDt7zeQSVMsZQFsPlTBgjwI=; b=ao50hYAHeoP2jOTtUXeOZTknJ0f/Xmi+TM8O+7ruznhPlZUUNFR/nPHJyOzqTF/4bu hgwBKOkZHh/d4al26PR6q08WHmoxCHxcmv6CqKT4V405CIgeaGz8xKl4PnkyRmY/EB18 35E03LRxNQ/k+FRG+jC3FI6EjgHul4IQcSksnDXgKtL2ElVRhzqALMkplvpeWqJbsxbG xk3Qg//fGkigrRJ0cYwRld6OOMJwhOF9V5/dqho46dMPyPHB9Kxh8ulzRXhip9vaTEy2 dat1+1BsABy+1YJurT6rlaKhEMoF8klJ2VhY4NDxgzCLBZLNfac+jkC/ZAY9boxbbBxH lmEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WcwCMxaX9JGeZSa3WsYbeDt7zeQSVMsZQFsPlTBgjwI=; b=jzyUMfMB07oLbLLHrDmpjDntABRwjnfKx9RiA+qJm9TupsbQ8q2SQvokdrhcdGZ4MR CTIAiZIYJtuga8KeI5grFsvwRMHWVf8VxLj8uLs4nyDCs2UDG2uoYydSw4iqiqNkWMRP sOi9NHpLA7z/geS6fPQrhJJfsiwPuIE9LzIydjFGMtA7aRPEV7SwD1HKyhM/dpG7DRvD JslBKsaWgiTruJ8O1c90KLiyyAUOCeAF8xv8XNkM0pnj/a6rW7Ol00jJoMO6Uzrdg3tC 0UqYq6xRbR492+31S0mD8IiF01Bl5KtX7ctsA2PdilqtLCCpLk1AwpKgrbwRjp+hatt8 iIkw== X-Gm-Message-State: AOAM532xrXC09jXb454Ym0Pli1MlYEV9+qjz8tDoJ+mqZIscHwaM4Zsc 9eKeDldKEhiQpoJy9DDZmibWxA== X-Google-Smtp-Source: ABdhPJzSVlFuesIy3ozcbs1Ya9/BR2hqxQl/oz2eLEJWztKwhCuJJPBlm/wUz0WWxO8nsUrReBdutQ== X-Received: by 2002:a17:902:8491:b0:14e:dad4:5ce5 with SMTP id c17-20020a170902849100b0014edad45ce5mr6156464plo.76.1648134856759; Thu, 24 Mar 2022 08:14:16 -0700 (PDT) Received: from localhost.localdomain ([122.171.187.87]) by smtp.gmail.com with ESMTPSA id f16-20020a056a00239000b004fa7103e13csm4166065pfc.41.2022.03.24.08.14.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Mar 2022 08:14:16 -0700 (PDT) From: Anup Patel To: Palmer Dabbelt , Paul Walmsley , Thomas Gleixner , Marc Zyngier , Daniel Lezcano Cc: Atish Patra , Alistair Francis , Anup Patel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel Subject: [PATCH v5 3/7] genirq: Add mechanism to multiplex a single HW IPI Date: Thu, 24 Mar 2022 20:42:54 +0530 Message-Id: <20220324151258.943896-4-apatel@ventanamicro.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220324151258.943896-1-apatel@ventanamicro.com> References: <20220324151258.943896-1-apatel@ventanamicro.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org All RISC-V platforms have a single HW IPI provided by the INTC local interrupt controller. The HW method to trigger INTC IPI can be through external irqchip (e.g. RISC-V AIA), through platform specific device (e.g. SiFive CLINT timer), or through firmware (e.g. SBI IPI call). To support multiple IPIs on RISC-V, we need a generic mechanism to create multiple per-CPU vIRQs using a single HW IPI hence this patch. The generic IPI multiplex mechanism added by this patch can also be useful to other architectures. Signed-off-by: Anup Patel --- include/linux/irq.h | 28 +++++++ kernel/irq/Kconfig | 4 + kernel/irq/Makefile | 1 + kernel/irq/ipi-mux.c | 190 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 223 insertions(+) create mode 100644 kernel/irq/ipi-mux.c diff --git a/include/linux/irq.h b/include/linux/irq.h index 848e1e12c5c6..cdce7eae2f37 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -1248,6 +1248,34 @@ int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest); int ipi_send_single(unsigned int virq, unsigned int cpu); int ipi_send_mask(unsigned int virq, const struct cpumask *dest); +#define IPI_MUX_NR_IRQS BITS_PER_LONG +struct ipi_mux_ops { + void (*ipi_mux_clear)(unsigned int parent_virq); + void (*ipi_mux_send)(unsigned int parent_virq, + const struct cpumask *mask); +}; + +/* Process multiplexed IPIs */ +void ipi_mux_process(void); + +/* + * Create multiple IPIs (total IPI_MUX_NR_IRQS) multiplexed on top of a + * single parent IPI. + * + * If the parent IPI > 0 then ipi_mux_process() will be automatically + * called via chained handler. + * + * If the parent IPI <= 0 then it is responsiblity of irqchip drivers + * to explicitly call ipi_mux_process() for processing muxed + * IPIs. + * + * Returns first virq of the muxed IPIs upon success or <=0 upon failure + */ +int ipi_mux_create(unsigned int parent_virq, const struct ipi_mux_ops *ops); + +/* Destroy multiplexed IPIs */ +void ipi_mux_destroy(void); + #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER /* * Registers a generic IRQ handling function as the top-level IRQ handler in diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 10929eda9825..2388e7d40ed3 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -84,6 +84,10 @@ config GENERIC_IRQ_IPI bool select IRQ_DOMAIN_HIERARCHY +# Generic IRQ IPI Mux support +config GENERIC_IRQ_IPI_MUX + bool + # Generic MSI interrupt support config GENERIC_MSI_IRQ bool diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index b4f53717d143..f19d3080bf11 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o obj-$(CONFIG_PM_SLEEP) += pm.o obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o +obj-$(CONFIG_GENERIC_IRQ_IPI_MUX) += ipi-mux.o obj-$(CONFIG_SMP) += affinity.o obj-$(CONFIG_GENERIC_IRQ_DEBUGFS) += debugfs.o obj-$(CONFIG_GENERIC_IRQ_MATRIX_ALLOCATOR) += matrix.o diff --git a/kernel/irq/ipi-mux.c b/kernel/irq/ipi-mux.c new file mode 100644 index 000000000000..7bf3d007b1e6 --- /dev/null +++ b/kernel/irq/ipi-mux.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Multiplex several IPIs over a single HW IPI. + * + * Copyright (c) 2022 Ventana Micro Systems Inc. + */ + +#define pr_fmt(fmt) "ipi-mux: " fmt +#include +#include +#include +#include +#include +#include +#include + +static unsigned int ipi_mux_parent_virq; +static struct irq_domain *ipi_mux_domain; +static const struct ipi_mux_ops *ipi_mux_ops; +static DEFINE_PER_CPU(unsigned long, ipi_mux_bits); + +static void ipi_mux_dummy(struct irq_data *d) +{ +} + +static void ipi_mux_send_mask(struct irq_data *d, const struct cpumask *mask) +{ + int cpu; + + /* Barrier before doing atomic bit update to IPI bits */ + smp_mb__before_atomic(); + + for_each_cpu(cpu, mask) + set_bit(d->hwirq, per_cpu_ptr(&ipi_mux_bits, cpu)); + + /* Barrier after doing atomic bit update to IPI bits */ + smp_mb__after_atomic(); + + /* Trigger the parent IPI */ + ipi_mux_ops->ipi_mux_send(ipi_mux_parent_virq, mask); +} + +static struct irq_chip ipi_mux_chip = { + .name = "RISC-V IPI Mux", + .irq_mask = ipi_mux_dummy, + .irq_unmask = ipi_mux_dummy, + .ipi_send_mask = ipi_mux_send_mask, +}; + +static int ipi_mux_domain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) +{ + irq_set_percpu_devid(irq); + irq_domain_set_info(d, irq, hwirq, &ipi_mux_chip, d->host_data, + handle_percpu_devid_irq, NULL, NULL); + + return 0; +} + +static int ipi_mux_domain_alloc(struct irq_domain *d, unsigned int virq, + unsigned int nr_irqs, void *arg) +{ + int i, ret; + irq_hw_number_t hwirq; + unsigned int type = IRQ_TYPE_NONE; + struct irq_fwspec *fwspec = arg; + + ret = irq_domain_translate_onecell(d, fwspec, &hwirq, &type); + if (ret) + return ret; + + for (i = 0; i < nr_irqs; i++) { + ret = ipi_mux_domain_map(d, virq + i, hwirq + i); + if (ret) + return ret; + } + + return 0; +} + +static const struct irq_domain_ops ipi_mux_domain_ops = { + .translate = irq_domain_translate_onecell, + .alloc = ipi_mux_domain_alloc, + .free = irq_domain_free_irqs_top, +}; + +void ipi_mux_process(void) +{ + int err; + unsigned long irqs, *bits = this_cpu_ptr(&ipi_mux_bits); + irq_hw_number_t hwirq; + + while (true) { + /* Clear the parent IPI */ + ipi_mux_ops->ipi_mux_clear(ipi_mux_parent_virq); + + /* Order bit clearing and data access. */ + mb(); + + irqs = xchg(bits, 0); + if (!irqs) + break; + + for_each_set_bit(hwirq, &irqs, IPI_MUX_NR_IRQS) { + err = generic_handle_domain_irq(ipi_mux_domain, + hwirq); + if (unlikely(err)) + pr_warn_ratelimited( + "can't find mapping for hwirq %lu\n", + hwirq); + } + } +} + +static void ipi_mux_handler(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + + chained_irq_enter(chip, desc); + ipi_mux_process(); + chained_irq_exit(chip, desc); +} + +static int ipi_mux_dying_cpu(unsigned int cpu) +{ + if (ipi_mux_parent_virq > 0) + disable_percpu_irq(ipi_mux_parent_virq); + return 0; +} + +static int ipi_mux_starting_cpu(unsigned int cpu) +{ + if (ipi_mux_parent_virq > 0) + enable_percpu_irq(ipi_mux_parent_virq, + irq_get_trigger_type(ipi_mux_parent_virq)); + return 0; +} + +int ipi_mux_create(unsigned int parent_virq, const struct ipi_mux_ops *ops) +{ + int virq; + struct irq_fwspec ipi; + struct irq_domain *domain; + + if (ipi_mux_domain || + !ops || !ops->ipi_mux_send || !ops->ipi_mux_clear) + return 0; + + domain = irq_domain_add_linear(NULL, IPI_MUX_NR_IRQS, + &ipi_mux_domain_ops, NULL); + if (!domain) { + pr_err("unable to add IPI Mux domain\n"); + return 0; + } + + ipi.fwnode = domain->fwnode; + ipi.param_count = 1; + ipi.param[0] = 0; + virq = __irq_domain_alloc_irqs(domain, -1, IPI_MUX_NR_IRQS, + NUMA_NO_NODE, &ipi, false, NULL); + if (virq <= 0) { + pr_err("unable to alloc IRQs from IPI Mux domain\n"); + irq_domain_remove(domain); + return virq; + } + + ipi_mux_domain = domain; + ipi_mux_parent_virq = parent_virq; + ipi_mux_ops = ops; + + if (parent_virq > 0) { + irq_set_chained_handler(parent_virq, ipi_mux_handler); + + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + "irqchip/ipi-mux:starting", + ipi_mux_starting_cpu, ipi_mux_dying_cpu); + } + + return virq; +} + +void ipi_mux_destroy(void) +{ + if (!ipi_mux_domain) + return; + + irq_domain_remove(ipi_mux_domain); + ipi_mux_domain = NULL; + ipi_mux_parent_virq = 0; +} -- 2.25.1