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[209.132.180.67]) by mx.google.com with ESMTP id r59-v6si12508078plb.187.2018.07.25.02.38.22; Wed, 25 Jul 2018 02:38:37 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=ez0KWJko; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728887AbeGYKsF (ORCPT + 99 others); Wed, 25 Jul 2018 06:48:05 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:43090 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728768AbeGYKsF (ORCPT ); Wed, 25 Jul 2018 06:48:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=liX0BELlvsA0Dl8YJdUznS8FTBnVlY6yzne8y+ydW6w=; b=ez0KWJkoMHw8gAaFFqg3fYe1m sXS29p+3DBPm/qTcNz7kQ2WD1vjo+nUN4jUFXs10cIB6ld/10YIEirUybqaBg5EvDLQm/5+B5nJue cbmOUWOwEPLFcs8FqQNhte1oe2m9UPKUfiGSGMWS8M9tJfp/0bvAjmXlcExK4E7c0t4gXGkNFJDuE LYNoS7HBnxazVDDz7X5EJYTDCIhTxMRNZloYZbTX/gx1oMB4buP+9afdcAxl0aXNzn472mfLNn6Jz DJ5HCO64aYDAFakyE1sKX/+XJa9LN/90ZQHlp6jfkhD2gfL1YB9+IDCKva7pvcfaMGZMBxtXokhNz 2RMIUpn+g==; Received: from [91.112.108.175] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fiGEG-0005K8-TI; Wed, 25 Jul 2018 09:37:09 +0000 From: Christoph Hellwig To: tglx@linutronix.de, palmer@sifive.com, jason@lakedaemon.net, marc.zyngier@arm.com, robh+dt@kernel.org, mark.rutland@arm.com Cc: devicetree@vger.kernel.org, aou@eecs.berkeley.edu, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, shorne@gmail.com, Palmer Dabbelt Subject: [PATCH 5/6] irqchip: New RISC-V PLIC Driver Date: Wed, 25 Jul 2018 11:36:48 +0200 Message-Id: <20180725093649.32332-6-hch@lst.de> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180725093649.32332-1-hch@lst.de> References: <20180725093649.32332-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Palmer Dabbelt This patch adds a driver for the Platform Level Interrupt Controller (PLIC) specified as part of the RISC-V supervisor level ISA manual. The PLIC connects global interrupt sources to the local interrupt controller on each hart. Signed-off-by: Palmer Dabbelt [hch: various cleanups, fixed typos, added SPDX tag] Signed-off-by: Christoph Hellwig --- drivers/irqchip/Kconfig | 13 ++ drivers/irqchip/Makefile | 1 + drivers/irqchip/irq-riscv-plic.c | 295 +++++++++++++++++++++++++++++++ 3 files changed, 309 insertions(+) create mode 100644 drivers/irqchip/irq-riscv-plic.c diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index 8460fdcecc2c..d1afac8829ae 100644 --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -376,3 +376,16 @@ endmenu config RISCV_INTC def_bool y depends on RISCV + +config RISCV_PLIC + bool "Platform-Level Interrupt Controller" + depends on RISCV + default y + help + This enables support for the PLIC chip found in standard RISC-V + systems. The PLIC controls devices interrupts and connects them to + each core's local interrupt controller. Aside from timer and + software interrupts, all other interrupt sources (MSI, GPIO, etc) + are subordinate to the PLIC. + + If you don't know what to do here, say Y. diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index 74e333cc274c..7954f4c4a629 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -88,3 +88,4 @@ obj-$(CONFIG_GOLDFISH_PIC) += irq-goldfish-pic.o obj-$(CONFIG_NDS32) += irq-ativic32.o obj-$(CONFIG_QCOM_PDC) += qcom-pdc.o obj-$(CONFIG_RISCV_INTC) += irq-riscv-intc.o +obj-$(CONFIG_RISCV_PLIC) += irq-riscv-plic.o diff --git a/drivers/irqchip/irq-riscv-plic.c b/drivers/irqchip/irq-riscv-plic.c new file mode 100644 index 000000000000..7b80b73c28a0 --- /dev/null +++ b/drivers/irqchip/irq-riscv-plic.c @@ -0,0 +1,295 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017 SiFive + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * From the RISC-V Priviledged Spec v1.10: + * + * Global interrupt sources are assigned small unsigned integer identifiers, + * beginning at the value 1. An interrupt ID of 0 is reserved to mean "no + * interrupt". Interrupt identifiers are also used to break ties when two or + * more interrupt sources have the same assigned priority. Smaller values of + * interrupt ID take precedence over larger values of interrupt ID. + * + * While the RISC-V supervisor spec doesn't define the maximum number of + * devices supported by the PLIC, the largest number supported by devices + * marked as 'riscv,plic0' (which is the only device type this driver supports, + * and is the only extant PLIC as of now) is 1024. As mentioned above, device + * 0 is defined to be non-existent so this device really only supports 1023 + * devices. + */ +#define MAX_DEVICES 1024 +#define MAX_CONTEXTS 15872 + +struct plic_handler { + bool present; + int contextid; + struct plic_data *data; +}; + +/* + * PLIC devices are named like 'riscv,plic0,%llx', this is enough space to + * store that name. + */ +#define PLIC_DATA_NAME_SIZE 30 + +struct plic_data { + struct irq_chip chip; + struct irq_domain *domain; + u32 ndev; + void __iomem *reg; + int handlers; + struct plic_handler *handler; + char name[PLIC_DATA_NAME_SIZE]; + spinlock_t lock; +}; + +/* + * Each interrupt source has a priority register associated with it. + * We always hardwire it to one in Linux. + */ +static inline u32 __iomem *plic_priority(struct plic_data *data, int hwirq) +{ + return data->reg + hwirq * 0x04; +} + +/* + * Each hart context has a vector of interrupt enable bits associated with it. + * There is one bit for each interrupt source. + */ +static inline u32 __iomem *plic_enable_vector(struct plic_data *data, + int contextid) +{ + return data->reg + (1 << 13) + contextid * 0x80; +} + +/* + * Each hart context has a set of control registers associated with it. Right + * now there's only two: a source priority threshold over which the hart will + * take an interrupt, and a register to claim interrupts. + */ +#define CONTEXT_THRESHOLD 0 +#define CONTEXT_CLAIM 4 + +static inline u32 __iomem *plic_hart_data(struct plic_data *data, + int contextid) +{ + return data->reg + (1 << 21) + contextid * 0x1000; +} + +/* Explicit interrupt masking. */ +static void plic_disable(struct plic_data *data, int contextid, int hwirq) +{ + u32 __iomem *reg = plic_enable_vector(data, contextid) + (hwirq / 32); + u32 mask = ~(1 << (hwirq % 32)); + + spin_lock(&data->lock); + writel(readl(reg) & mask, reg); + spin_unlock(&data->lock); +} + +static void plic_enable(struct plic_data *data, int contextid, int hwirq) +{ + u32 __iomem *reg = plic_enable_vector(data, contextid) + (hwirq / 32); + u32 bit = 1 << (hwirq % 32); + + spin_lock(&data->lock); + writel(readl(reg) | bit, reg); + spin_unlock(&data->lock); +} + +/* + * There is no need to mask/unmask PLIC interrupts + * They are "masked" by reading claim and "unmasked" when writing it back. + */ +static void plic_irq_mask(struct irq_data *d) +{ +} + +static void plic_irq_unmask(struct irq_data *d) +{ +} + +static void plic_irq_enable(struct irq_data *d) +{ + struct plic_data *data = irq_data_get_irq_chip_data(d); + int i; + + writel(1, plic_priority(data, d->hwirq)); + for (i = 0; i < data->handlers; ++i) + if (data->handler[i].present) + plic_enable(data, i, d->hwirq); +} + +static void plic_irq_disable(struct irq_data *d) +{ + struct plic_data *data = irq_data_get_irq_chip_data(d); + int i; + + writel(0, plic_priority(data, d->hwirq)); + for (i = 0; i < data->handlers; ++i) + if (data->handler[i].present) + plic_disable(data, i, d->hwirq); +} + +static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) +{ + struct plic_data *data = d->host_data; + + irq_set_chip_and_handler(irq, &data->chip, handle_simple_irq); + irq_set_chip_data(irq, data); + irq_set_noprobe(irq); + return 0; +} + +static const struct irq_domain_ops plic_irqdomain_ops = { + .map = plic_irqdomain_map, + .xlate = irq_domain_xlate_onecell, +}; + +/* + * Handling an interrupt is a two-step process: first you claim the interrupt + * by reading the claim register, then you complete the interrupt by writing + * that source ID back to the same claim register. This automatically enables + * and disables the interrupt, so there's nothing else to do. + */ +static void plic_chained_handle_irq(struct irq_desc *desc) +{ + struct plic_handler *handler = irq_desc_get_handler_data(desc); + struct irq_chip *chip = irq_desc_get_chip(desc); + struct irq_domain *domain = handler->data->domain; + void __iomem *ph = plic_hart_data(handler->data, handler->contextid); + u32 what; + + chained_irq_enter(chip, desc); + while ((what = readl(ph + CONTEXT_CLAIM))) { + int irq = irq_find_mapping(domain, what); + + if (irq > 0) + generic_handle_irq(irq); + else + handle_bad_irq(desc); + writel(what, ph + CONTEXT_CLAIM); + } + chained_irq_exit(chip, desc); +} + +static int plic_init(struct device_node *node, struct device_node *parent) +{ + struct plic_data *data; + struct resource resource; + int i, ok = 0; + int out = -1; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (WARN_ON(!data)) + return -ENOMEM; + + spin_lock_init(&data->lock); + + data->reg = of_iomap(node, 0); + if (WARN_ON(!data->reg)) { + out = -EIO; + goto free_data; + } + + of_property_read_u32(node, "riscv,ndev", &data->ndev); + if (WARN_ON(!data->ndev)) { + out = -EINVAL; + goto free_reg; + } + + data->handlers = of_irq_count(node); + if (WARN_ON(!data->handlers)) { + out = -EINVAL; + goto free_reg; + } + + data->handler = + kcalloc(data->handlers, sizeof(*data->handler), GFP_KERNEL); + if (WARN_ON(!data->handler)) { + out = -ENOMEM; + goto free_reg; + } + + data->domain = irq_domain_add_linear(node, data->ndev + 1, + &plic_irqdomain_ops, data); + if (WARN_ON(!data->domain)) { + out = -ENOMEM; + goto free_handler; + } + + of_address_to_resource(node, 0, &resource); + snprintf(data->name, sizeof(data->name), + "riscv,plic0,%llx", resource.start); + data->chip.name = data->name; + data->chip.irq_mask = plic_irq_mask; + data->chip.irq_unmask = plic_irq_unmask; + data->chip.irq_enable = plic_irq_enable; + data->chip.irq_disable = plic_irq_disable; + + for (i = 0; i < data->handlers; ++i) { + struct plic_handler *handler = &data->handler[i]; + struct of_phandle_args parent; + int parent_irq, hwirq; + + handler->present = false; + + if (of_irq_parse_one(node, i, &parent)) + continue; + /* skip context holes */ + if (parent.args[0] == -1) + continue; + + /* skip any contexts that lead to inactive harts */ + if (of_device_is_compatible(parent.np, "riscv,cpu-intc") && + parent.np->parent && + riscv_of_processor_hart(parent.np->parent) < 0) + continue; + + parent_irq = irq_create_of_mapping(&parent); + if (!parent_irq) + continue; + + handler->present = true; + handler->contextid = i; + handler->data = data; + /* hwirq prio must be > this to trigger an interrupt */ + writel(0, plic_hart_data(data, i) + CONTEXT_THRESHOLD); + + for (hwirq = 1; hwirq <= data->ndev; ++hwirq) + plic_disable(data, i, hwirq); + irq_set_chained_handler_and_data(parent_irq, + plic_chained_handle_irq, handler); + ++ok; + } + + pr_info("%s: mapped %d interrupts to %d/%d handlers\n", + data->name, data->ndev, ok, data->handlers); + WARN_ON(!ok); + return 0; + +free_handler: + kfree(data->handler); +free_reg: + iounmap(data->reg); +free_data: + kfree(data); + return out; +} + +IRQCHIP_DECLARE(plic0, "riscv,plic0", plic_init); -- 2.18.0