From patchwork Mon Apr 18 10:53:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anup Patel X-Patchwork-Id: 12816475 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BB3D6C433F5 for ; Mon, 18 Apr 2022 10:54:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yaiSP9qTHDedih9EB7iLLFmvi42elO6O0w1oAMfjQkc=; b=ZxHvXE67pCM0DJ X7rWI9dhymXt7JyrcfsSFKaDnzBCNXcKmMCLINUd3qvSUn9mv6RamPye7yc24PC/iGLIZf8fZ6SJT OgkqkWbS9Rpjo+jrMUs9qJgZNEwyLzagAj2MNLcbqcfte9G006o1L5sxfXJkZG/G6zHdApNuce6fb TNKqWBiKpeGV5xUrrTO7cZBs1FiiAfFSedmPdN61Wr5QMawwBLANHZBajPsvY/oyeOgN93B0IX0xk K/+gI0PSrrstxcC4R9ukpa2HSbMXxTJBbmYOBAT5nQuPsn8cXLF+2z2eaOIMHf8misAvwSLGWvpa2 RzoXCLMKDrogFpoGO77w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngP19-00GNSk-Iq; Mon, 18 Apr 2022 10:54:03 +0000 Received: from mail-pl1-x629.google.com ([2607:f8b0:4864:20::629]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ngP16-00GNQm-Du for linux-riscv@lists.infradead.org; Mon, 18 Apr 2022 10:54:02 +0000 Received: by mail-pl1-x629.google.com with SMTP id n8so12068654plh.1 for ; Mon, 18 Apr 2022 03:53:58 -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=CYq3mBdDGawHXMT5SWWslUUS5hK4Hd8Wp59zi1ahbDM=; b=iCXsMVhfd51rdcRl3b57Duylzu1GmgkumWHlPeTBZKXHBtRt68RdZeK++cfogcZY6j TqAWj0gfWcisq86nDMNWa59Vka4ZhZMIIjEkRGKhuoki0KulqsIQTLcF7goIBMYVbZxI kXSACMZjIb3DhDhRdHffqsjgKrHuq5KFNzVnPVsDKEnfox+pTTsx2oCdOlA3QGfjyZIs f9ED7+3gwcM3XyQz9lrcG3DyNNU09zjkd7WBOBJy8juTB0U49Py43MU0BAoMw0CcEXnc t1zN5AWmjeyyO/a8cLEt3SWLDCx0O2/dz2+bQwLLOrLg0dadpWiAPOULGAizxolQq1Vz U3sQ== 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=CYq3mBdDGawHXMT5SWWslUUS5hK4Hd8Wp59zi1ahbDM=; b=BBLs2qyQcpCq6ZdD+ukN1MXMCSFDuHpTYQzM3E/iKZYX3Vwf3oZSa5haeitYYPydNq MlaFIfhmBg4asQcDQ839/2HAkKbadJarm3qtoUEHkZxzL7UbYbuVjb/NFi8hglqVb1ou ucOrSms+EyPKaO38FLH92NtczFWfHt7uy+aAlSaZ1fXzLlBcv0JsTBb/z52GWwG8JxtC Aba3n8XqASTAN9TBa+T1rvbcYIaQTGKF+2BbX4rIdrQpkg+6YyYgj96prOeyiktyzIIV JIc7MBraFQJNwwFdeCj+iSxNnsiAZHaVFa8xv5mXXs6TiiTC2KgqlwZC7bgPp4ZPi098 Tf0Q== X-Gm-Message-State: AOAM5327roZ9+WmuTMNKHWFn+4Q2zuaesD3L+z4ATED1VmViN2amK66x b5W1Pb6ZsvvAzTxyf/U3rGR9Mw== X-Google-Smtp-Source: ABdhPJyWiuVi87QXzpcK6qoq7Jhkmm8t2eggIhC2fF87vumJCb0MSKo4/zNY32/9Z654u9S1DB3XOQ== X-Received: by 2002:a17:902:a60f:b0:155:efbf:1291 with SMTP id u15-20020a170902a60f00b00155efbf1291mr10403061plq.152.1650279237488; Mon, 18 Apr 2022 03:53:57 -0700 (PDT) Received: from localhost.localdomain ([122.172.241.223]) by smtp.gmail.com with ESMTPSA id j13-20020a056a00130d00b004f1025a4361sm12986278pfu.202.2022.04.18.03.53.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Apr 2022 03:53:56 -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 v6 3/7] genirq: Add mechanism to multiplex a single HW IPI Date: Mon, 18 Apr 2022 16:23:01 +0530 Message-Id: <20220418105305.1196665-4-apatel@ventanamicro.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220418105305.1196665-1-apatel@ventanamicro.com> References: <20220418105305.1196665-1-apatel@ventanamicro.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220418_035400_512741_D7EEBCA2 X-CRM114-Status: GOOD ( 25.06 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.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 add a generic IPI multiplexing mechanism which help us create multiple virtual IPIs using a single HW IPI. This generic IPI multiplexing is shared among various RISC-V irqchip drivers. Signed-off-by: Anup Patel --- include/linux/irq.h | 11 +++ kernel/irq/Kconfig | 4 + kernel/irq/Makefile | 1 + kernel/irq/ipi-mux.c | 197 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 213 insertions(+) create mode 100644 kernel/irq/ipi-mux.c diff --git a/include/linux/irq.h b/include/linux/irq.h index f92788ccdba2..5bb4e2db63d7 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -1247,6 +1247,17 @@ 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); +}; + +void ipi_mux_process(void); +int ipi_mux_create(unsigned int parent_virq, const struct ipi_mux_ops *ops); + #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..1a1fcfe3ac54 --- /dev/null +++ b/kernel/irq/ipi-mux.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Multiplex several virtual 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 = "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) +{ + unsigned int type = IRQ_TYPE_NONE; + struct irq_fwspec *fwspec = arg; + irq_hw_number_t hwirq; + int i, ret; + + 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, +}; + +/** + * ipi_mux_process - Process multiplexed virtual IPIs + */ +void ipi_mux_process(void) +{ + unsigned long irqs, *bits = this_cpu_ptr(&ipi_mux_bits); + irq_hw_number_t hwirq; + int err; + + /* Clear the parent IPI */ + if (ipi_mux_ops->ipi_mux_clear) + ipi_mux_ops->ipi_mux_clear(ipi_mux_parent_virq); + + /* + * Barrier for IPI bits paired with smp_mb__xyz_atomic() + * in ipi_mux_send_mask() + */ + smp_mb(); + + irqs = xchg(bits, 0); + if (!irqs) + return; + + 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) +{ + disable_percpu_irq(ipi_mux_parent_virq); + return 0; +} + +static int ipi_mux_starting_cpu(unsigned int cpu) +{ + enable_percpu_irq(ipi_mux_parent_virq, + irq_get_trigger_type(ipi_mux_parent_virq)); + return 0; +} + +/** + * ipi_mux_create - Create virtual IPIs (total IPI_MUX_NR_IRQS) multiplexed + * on top of a single parent IPI. + * @parent_virq: virq of the parent IPI + * @ops: multiplexing operations for the 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 newly created virutal IPIs upon success + * or <=0 upon failure + */ +int ipi_mux_create(unsigned int parent_virq, const struct ipi_mux_ops *ops) +{ + struct irq_domain *domain; + struct irq_fwspec ipi; + int virq; + + if (ipi_mux_domain || !ops || !ops->ipi_mux_send) + 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; +}