This patch adds a driver that manages the local interrupts on each RISC-V hart, as specifiec by the RISC-V supervisor level ISA manual. The local interrupt controller manages software interrupts, timer interrupts, and hardware interrupts (which are routed via the platform level interrupt controller). Per-hart local interrupt controllers are found on all RISC-V systems. Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxx> --- drivers/irqchip/Kconfig | 14 +++ drivers/irqchip/Makefile | 1 + drivers/irqchip/irq-riscv-intc.c | 210 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 225 insertions(+) create mode 100644 drivers/irqchip/irq-riscv-intc.c diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index f1fd5f44d1d4..7923d3fa8fae 100644 --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -306,3 +306,17 @@ config QCOM_IRQ_COMBINER help Say yes here to add support for the IRQ combiner devices embedded in Qualcomm Technologies chips. + +config RISCV_INTC + def_bool y if RISCV + #bool "RISC-V Interrupt Controller" + depends on RISCV + default y + help + This enables support for the local interrupt controller found in + standard RISC-V systems. The local interrupt controller handles + timer interrupts, software interrupts, and hardware interrupts. + Without a local interrupt controller the system will be unable to + handle any interrupts, including those passed via the PLIC. + + If you don't know what to do here, say Y. diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index e88d856cc09c..b1aa9114afc4 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -78,3 +78,4 @@ obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o irq-aspeed-i2c-ic.o obj-$(CONFIG_STM32_EXTI) += irq-stm32-exti.o obj-$(CONFIG_QCOM_IRQ_COMBINER) += qcom-irq-combiner.o +obj-$(CONFIG_RISCV_INTC) += irq-riscv-intc.o diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c new file mode 100644 index 000000000000..d019bd3a4ae3 --- /dev/null +++ b/drivers/irqchip/irq-riscv-intc.c @@ -0,0 +1,210 @@ +/* + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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. + */ + +#include <linux/irq.h> +#include <linux/irqchip.h> +#include <linux/irqdomain.h> +#include <linux/interrupt.h> +#include <linux/ftrace.h> +#include <linux/of.h> +#include <linux/seq_file.h> + +#include <asm/ptrace.h> +#include <asm/sbi.h> +#include <asm/smp.h> + +#define PTR_BITS (8 * sizeof(uintptr_t)) + +struct riscv_irq_data { + struct irq_chip chip; + struct irq_domain *domain; + int hart; + char name[20]; +}; +DEFINE_PER_CPU(struct riscv_irq_data, riscv_irq_data); + +static void riscv_software_interrupt(void) +{ +#ifdef CONFIG_SMP + irqreturn_t ret; + + ret = handle_ipi(); + + WARN_ON(ret == IRQ_NONE); +#else + /* + * We currently only use software interrupts to pass inter-processor + * interrupts, so if a non-SMP system gets a software interrupt then we + * don't know what to do. + */ + pr_warning("Software Interrupt without CONFIG_SMP\n"); +#endif +} + +asmlinkage void __irq_entry do_IRQ(unsigned int cause, struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + struct irq_domain *domain; + + irq_enter(); + + /* + * There are three classes of interrupt: timer, software, and + * external devices. We dispatch between them here. External + * device interrupts use the generic IRQ mechanisms. + */ + switch (cause) { + case INTERRUPT_CAUSE_TIMER: + riscv_timer_interrupt(); + break; + case INTERRUPT_CAUSE_SOFTWARE: + riscv_software_interrupt(); + break; + default: + domain = per_cpu(riscv_irq_data, smp_processor_id()).domain; + generic_handle_irq(irq_find_mapping(domain, cause)); + break; + } + + irq_exit(); + set_irq_regs(old_regs); +} + +static int riscv_irqdomain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) +{ + struct riscv_irq_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); + irq_set_affinity(irq, cpumask_of(data->hart)); + + return 0; +} + +static const struct irq_domain_ops riscv_irqdomain_ops = { + .map = riscv_irqdomain_map, + .xlate = irq_domain_xlate_onecell, +}; + +/* + * On RISC-V systems local interrupts are masked or unmasked by writing the SIE + * (Supervisor Interrupt Enable) CSR. As CSRs can only be written on the local + * hart, these functions can only be called on the hart that corresponds to the + * IRQ chip. They are only called internally to this module, so they BUG_ON if + * this condition is violated rather than attempting to handle the error by + * forwarding to the target hart, as that's already expected to have been done. + */ +static void riscv_irq_mask(struct irq_data *d) +{ + struct riscv_irq_data *data = irq_data_get_irq_chip_data(d); + + BUG_ON(smp_processor_id() != data->hart); + csr_clear(sie, 1 << (long)d->hwirq); +} + +static void riscv_irq_unmask(struct irq_data *d) +{ + struct riscv_irq_data *data = irq_data_get_irq_chip_data(d); + + BUG_ON(smp_processor_id() != data->hart); + csr_set(sie, 1 << (long)d->hwirq); +} + +/* Callbacks for twiddling SIE on another hart. */ +static void riscv_irq_enable_helper(void *d) +{ + riscv_irq_unmask(d); +} + +static void riscv_irq_disable_helper(void *d) +{ + riscv_irq_mask(d); +} + +static void riscv_remote_ctrl(unsigned int cpu, void (*fn)(void *d), + struct irq_data *data) +{ + smp_call_function_single(cpu, fn, data, true); +} + +static void riscv_irq_enable(struct irq_data *d) +{ + struct riscv_irq_data *data = irq_data_get_irq_chip_data(d); + + /* + * It's only possible to write SIE on the current hart. This jumps + * over to the target hart if it's not the current one. It's invalid + * to write SIE on a hart that's not currently running. + */ + if (data->hart == smp_processor_id()) + riscv_irq_unmask(d); + else if (cpu_online(data->hart)) + riscv_remote_ctrl(data->hart, riscv_irq_enable_helper, d); + else + WARN_ON_ONCE(1); +} + +static void riscv_irq_disable(struct irq_data *d) +{ + struct riscv_irq_data *data = irq_data_get_irq_chip_data(d); + + /* + * It's only possible to write SIE on the current hart. This jumps + * over to the target hart if it's not the current one. It's invalid + * to write SIE on a hart that's not currently running. + */ + if (data->hart == smp_processor_id()) + riscv_irq_mask(d); + else if (cpu_online(data->hart)) + riscv_remote_ctrl(data->hart, riscv_irq_disable_helper, d); + else + WARN_ON_ONCE(1); +} + +static int riscv_intc_init(struct device_node *node, struct device_node *parent) +{ + int hart; + struct riscv_irq_data *data; + + if (parent) + return 0; + + hart = riscv_of_processor_hart(node->parent); + if (hart < 0) + return -EIO; + + data = &per_cpu(riscv_irq_data, hart); + snprintf(data->name, sizeof(data->name), "riscv,cpu_intc,%d", hart); + data->hart = hart; + data->chip.name = data->name; + data->chip.irq_mask = riscv_irq_mask; + data->chip.irq_unmask = riscv_irq_unmask; + data->chip.irq_enable = riscv_irq_enable; + data->chip.irq_disable = riscv_irq_disable; + data->domain = irq_domain_add_linear(node, PTR_BITS, + &riscv_irqdomain_ops, data); + if (!data->domain) + goto error_add_linear; + pr_info("%s: %d local interrupts mapped\n", data->name, PTR_BITS); + return 0; + +error_add_linear: + pr_warning("%s: unable to add IRQ domain\n", + data->name); + return -ENXIO; +} + +IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init); -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html