This is the root interrupt controller used on Apple ARM SoCs such as the M1. This irqchip driver performs multiple functions: * Handles both IRQs and FIQs * Drives the AIC peripheral itself (which handles IRQs) * Dispatches FIQs to downstream hard-wired clients (currently the ARM timer). * Implements a virtual IPI multiplexer to funnel multiple Linux IPIs into a single hardware IPI Signed-off-by: Hector Martin <marcan@xxxxxxxxx> --- MAINTAINERS | 2 + drivers/irqchip/Kconfig | 8 + drivers/irqchip/Makefile | 1 + drivers/irqchip/irq-apple-aic.c | 837 ++++++++++++++++++++++++++++++++ include/linux/cpuhotplug.h | 1 + 5 files changed, 849 insertions(+) create mode 100644 drivers/irqchip/irq-apple-aic.c diff --git a/MAINTAINERS b/MAINTAINERS index b26a7e23c512..e27332ec1f12 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1647,6 +1647,8 @@ C: irc://chat.freenode.net/asahi-dev T: git https://github.com/AsahiLinux/linux.git F: Documentation/devicetree/bindings/arm/apple.yaml F: Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml +F: drivers/irqchip/irq-apple-aic.c +F: include/dt-bindings/interrupt-controller/apple-aic.h ARM/ARTPEC MACHINE SUPPORT M: Jesper Nilsson <jesper.nilsson@xxxxxxxx> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig index 15536e321df5..d3a14f304ec8 100644 --- a/drivers/irqchip/Kconfig +++ b/drivers/irqchip/Kconfig @@ -577,4 +577,12 @@ config MST_IRQ help Support MStar Interrupt Controller. +config APPLE_AIC + bool "Apple Interrupt Controller (AIC)" + depends on ARM64 + default ARCH_APPLE + help + Support for the Apple Interrupt Controller found on Apple Silicon SoCs, + such as the M1. + endmenu diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index c59b95a0532c..eb6a515f0f64 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -113,3 +113,4 @@ obj-$(CONFIG_LOONGSON_PCH_MSI) += irq-loongson-pch-msi.o obj-$(CONFIG_MST_IRQ) += irq-mst-intc.o obj-$(CONFIG_SL28CPLD_INTC) += irq-sl28cpld.o obj-$(CONFIG_MACH_REALTEK_RTL) += irq-realtek-rtl.o +obj-$(CONFIG_APPLE_AIC) += irq-apple-aic.o diff --git a/drivers/irqchip/irq-apple-aic.c b/drivers/irqchip/irq-apple-aic.c new file mode 100644 index 000000000000..ed16b6cc00d7 --- /dev/null +++ b/drivers/irqchip/irq-apple-aic.c @@ -0,0 +1,837 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright The Asahi Linux Contributors + * + * Based on irq-lpc32xx: + * Copyright 2015-2016 Vladimir Zapolskiy <vz@xxxxxxxxx> + * Based on irq-bcm2836: + * Copyright 2015 Broadcom + */ + +/* + * AIC is a fairly simple interrupt controller with the following features: + * + * - 896 level-triggered hardware IRQs + * - Single mask bit per IRQ + * - Per-IRQ affinity setting + * - Automatic masking on event delivery (auto-ack) + * - Software triggering (ORed with hw line) + * - 2 per-CPU IPIs (meant as "self" and "other", but they are + * interchangeable if not symmetric) + * - Automatic prioritization (single event/ack register per CPU, lower IRQs = + * higher priority) + * - Automatic masking on ack + * - Default "this CPU" register view and explicit per-CPU views + * + * In addition, this driver also handles FIQs, as these are routed to the same + * IRQ vector. These are used for Fast IPIs (TODO), the ARMv8 timer IRQs, and + * performance counters (TODO). + * + * Implementation notes: + * + * - This driver creates two IRQ domains, one for HW IRQs and internal FIQs, + * and one for IPIs. + * - Since Linux needs more than 2 IPIs, we implement a software IRQ controller + * and funnel all IPIs into one per-CPU IPI (the second "self" IPI is unused). + * - FIQ hwirq numbers are assigned after true hwirqs, and are per-cpu. + * - DT bindings use 3-cell form (like GIC): + * - <0 nr flags> - hwirq #nr + * - <1 nr flags> - FIQ #nr + * - nr=0 Physical HV timer + * - nr=1 Virtual HV timer + * - nr=2 Physical guest timer + * - nr=3 Virtual guest timer + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/bits.h> +#include <linux/bitfield.h> +#include <linux/cpuhotplug.h> +#include <linux/io.h> +#include <linux/irqchip.h> +#include <linux/irqdomain.h> +#include <linux/limits.h> +#include <linux/of_address.h> +#include <linux/slab.h> +#include <asm/exception.h> +#include <asm/sysreg.h> +#include <asm/virt.h> + +#include <dt-bindings/interrupt-controller/apple-aic.h> + +/* + * AIC registers (MMIO) + */ + +#define AIC_INFO 0x0004 +#define AIC_INFO_NR_HW GENMASK(15, 0) + +#define AIC_CONFIG 0x0010 + +#define AIC_WHOAMI 0x2000 +#define AIC_EVENT 0x2004 +#define AIC_EVENT_TYPE GENMASK(31, 16) +#define AIC_EVENT_NUM GENMASK(15, 0) + +#define AIC_EVENT_TYPE_HW 1 +#define AIC_EVENT_TYPE_IPI 4 +#define AIC_EVENT_IPI_OTHER 1 +#define AIC_EVENT_IPI_SELF 2 + +#define AIC_IPI_SEND 0x2008 +#define AIC_IPI_ACK 0x200c +#define AIC_IPI_MASK_SET 0x2024 +#define AIC_IPI_MASK_CLR 0x2028 + +#define AIC_IPI_SEND_CPU(cpu) BIT(cpu) + +#define AIC_IPI_OTHER BIT(0) +#define AIC_IPI_SELF BIT(31) + +#define AIC_TARGET_CPU 0x3000 +#define AIC_SW_SET 0x4000 +#define AIC_SW_CLR 0x4080 +#define AIC_MASK_SET 0x4100 +#define AIC_MASK_CLR 0x4180 + +#define AIC_CPU_IPI_SET(cpu) (0x5008 + ((cpu) << 7)) +#define AIC_CPU_IPI_CLR(cpu) (0x500c + ((cpu) << 7)) +#define AIC_CPU_IPI_MASK_SET(cpu) (0x5024 + ((cpu) << 7)) +#define AIC_CPU_IPI_MASK_CLR(cpu) (0x5028 + ((cpu) << 7)) + +#define MASK_REG(x) (4 * ((x) >> 5)) +#define MASK_BIT(x) BIT((x) & GENMASK(4, 0)) + +/* + * IMP-DEF sysregs that control FIQ sources + * Note: sysreg-based IPIs are not supported yet. + */ + +/* Core PMC control register */ +#define SYS_IMP_APL_PMCR0_EL1 sys_reg(3, 1, 15, 0, 0) +#define PMCR0_IMODE GENMASK(10, 8) +#define PMCR0_IMODE_OFF 0 +#define PMCR0_IMODE_PMI 1 +#define PMCR0_IMODE_AIC 2 +#define PMCR0_IMODE_HALT 3 +#define PMCR0_IMODE_FIQ 4 +#define PMCR0_IACT BIT(11) + +/* IPI request registers */ +#define SYS_IMP_APL_IPI_RR_LOCAL_EL1 sys_reg(3, 5, 15, 0, 0) +#define SYS_IMP_APL_IPI_RR_GLOBAL_EL1 sys_reg(3, 5, 15, 0, 1) +#define IPI_RR_CPU GENMASK(7, 0) +/* Cluster only used for the GLOBAL register */ +#define IPI_RR_CLUSTER GENMASK(23, 16) +#define IPI_RR_TYPE GENMASK(29, 28) +#define IPI_RR_IMMEDIATE 0 +#define IPI_RR_RETRACT 1 +#define IPI_RR_DEFERRED 2 +#define IPI_RR_NOWAKE 3 + +/* IPI status register */ +#define SYS_IMP_APL_IPI_SR_EL1 sys_reg(3, 5, 15, 1, 1) +#define IPI_SR_PENDING BIT(0) + +/* Guest timer FIQ enable register */ +#define SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2 sys_reg(3, 5, 15, 1, 3) +#define VM_TMR_FIQ_ENABLE_V BIT(0) +#define VM_TMR_FIQ_ENABLE_P BIT(1) + +/* Deferred IPI countdown register */ +#define SYS_IMP_APL_IPI_CR_EL1 sys_reg(3, 5, 15, 3, 1) + +/* Uncore PMC control register */ +#define SYS_IMP_APL_UPMCR0_EL1 sys_reg(3, 7, 15, 0, 4) +#define UPMCR0_IMODE GENMASK(18, 16) +#define UPMCR0_IMODE_OFF 0 +#define UPMCR0_IMODE_AIC 2 +#define UPMCR0_IMODE_HALT 3 +#define UPMCR0_IMODE_FIQ 4 + +/* Uncore PMC status register */ +#define SYS_IMP_APL_UPMSR_EL1 sys_reg(3, 7, 15, 6, 4) +#define UPMSR_IACT BIT(0) + +#define AIC_NR_FIQ 4 +#define AIC_NR_SWIPI 32 + +struct aic_irq_chip { + void __iomem *base; + struct irq_domain *hw_domain; + struct irq_domain *ipi_domain; + int nr_hw; + int ipi_hwirq; +}; + +static DEFINE_PER_CPU(uint32_t, aic_fiq_unmasked); + +static DEFINE_PER_CPU(atomic_t, aic_vipi_flag); +static DEFINE_PER_CPU(atomic_t, aic_vipi_enable); + +static struct aic_irq_chip *aic_irqc; + +static void aic_handle_ipi(struct pt_regs *regs); + +static u32 aic_ic_read(struct aic_irq_chip *ic, u32 reg) +{ + return readl_relaxed(ic->base + reg); +} + +static void aic_ic_write(struct aic_irq_chip *ic, u32 reg, u32 val) +{ + writel_relaxed(val, ic->base + reg); +} + +/* + * IRQ irqchip + */ + +static void aic_irq_mask(struct irq_data *d) +{ + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + + aic_ic_write(ic, AIC_MASK_SET + MASK_REG(irqd_to_hwirq(d)), + MASK_BIT(irqd_to_hwirq(d))); +} + +static void aic_irq_unmask(struct irq_data *d) +{ + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + + aic_ic_write(ic, AIC_MASK_CLR + MASK_REG(d->hwirq), + MASK_BIT(irqd_to_hwirq(d))); +} + +static void aic_irq_eoi(struct irq_data *d) +{ + /* + * Reading the interrupt reason automatically acknowledges and masks + * the IRQ, so we just unmask it here if needed. + */ + if (!irqd_irq_disabled(d) && !irqd_irq_masked(d)) + aic_irq_unmask(d); +} + +static void __exception_irq_entry aic_handle_irq(struct pt_regs *regs) +{ + struct aic_irq_chip *ic = aic_irqc; + u32 event, type, irq; + + do { + /* + * We cannot use a relaxed read here, as reads from DMA buffers + * need to be ordered after the IRQ fires. + */ + event = readl(ic->base + AIC_EVENT); + type = FIELD_GET(AIC_EVENT_TYPE, event); + irq = FIELD_GET(AIC_EVENT_NUM, event); + + if (type == AIC_EVENT_TYPE_HW) + handle_domain_irq(aic_irqc->hw_domain, irq, regs); + else if (type == AIC_EVENT_TYPE_IPI && irq == 1) + aic_handle_ipi(regs); + else if (event != 0) + pr_err_ratelimited("Unknown IRQ event %d, %d\n", type, irq); + } while (event); + + /* + * vGIC maintenance interrupts end up here too, so we need to check + * for them separately. This should never trigger if KVM is working + * properly, because it will have already taken care of clearing it + * on guest exit before this handler runs. + */ + if (is_kernel_in_hyp_mode() && (read_sysreg_s(SYS_ICH_HCR_EL2) & ICH_HCR_EN) && + read_sysreg_s(SYS_ICH_MISR_EL2) != 0) { + pr_err_ratelimited("vGIC IRQ fired and not handled by KVM, disabling.\n"); + sysreg_clear_set_s(SYS_ICH_HCR_EL2, ICH_HCR_EN, 0); + } +} + +static int aic_irq_set_affinity(struct irq_data *d, + const struct cpumask *mask_val, bool force) +{ + irq_hw_number_t hwirq = irqd_to_hwirq(d); + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + int cpu; + + if (force) + cpu = cpumask_first(mask_val); + else + cpu = cpumask_any_and(mask_val, cpu_online_mask); + + aic_ic_write(ic, AIC_TARGET_CPU + hwirq * 4, BIT(cpu)); + irq_data_update_effective_affinity(d, cpumask_of(cpu)); + + return IRQ_SET_MASK_OK; +} + +static int aic_irq_set_type(struct irq_data *d, unsigned int type) +{ + /* + * Some IRQs (e.g. MSIs) implicitly have edge semantics, and we don't + * have a way to find out the type of any given IRQ, so just allow both. + */ + return (type == IRQ_TYPE_LEVEL_HIGH || type == IRQ_TYPE_EDGE_RISING) ? 0 : -EINVAL; +} + +static struct irq_chip aic_chip = { + .name = "AIC", + .irq_mask = aic_irq_mask, + .irq_unmask = aic_irq_unmask, + .irq_eoi = aic_irq_eoi, + .irq_set_affinity = aic_irq_set_affinity, + .irq_set_type = aic_irq_set_type, +}; + +/* + * FIQ irqchip + */ + +static unsigned long aic_fiq_get_idx(struct irq_data *d) +{ + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + + return irqd_to_hwirq(d) - ic->nr_hw; +} + +static void aic_fiq_set_mask(struct irq_data *d) +{ + /* Only the guest timers have real mask bits, unfortunately. */ + switch (aic_fiq_get_idx(d)) { + case AIC_TMR_GUEST_PHYS: + sysreg_clear_set_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2, VM_TMR_FIQ_ENABLE_P, 0); + isb(); + break; + case AIC_TMR_GUEST_VIRT: + sysreg_clear_set_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2, VM_TMR_FIQ_ENABLE_V, 0); + isb(); + break; + default: + break; + } +} + +static void aic_fiq_clear_mask(struct irq_data *d) +{ + switch (aic_fiq_get_idx(d)) { + case AIC_TMR_GUEST_PHYS: + sysreg_clear_set_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2, 0, VM_TMR_FIQ_ENABLE_P); + isb(); + break; + case AIC_TMR_GUEST_VIRT: + sysreg_clear_set_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2, 0, VM_TMR_FIQ_ENABLE_V); + isb(); + break; + default: + break; + } +} + +static void aic_fiq_mask(struct irq_data *d) +{ + aic_fiq_set_mask(d); + __this_cpu_and(aic_fiq_unmasked, ~BIT(aic_fiq_get_idx(d))); +} + +static void aic_fiq_unmask(struct irq_data *d) +{ + aic_fiq_clear_mask(d); + __this_cpu_or(aic_fiq_unmasked, BIT(aic_fiq_get_idx(d))); +} + +static void aic_fiq_eoi(struct irq_data *d) +{ + /* We mask to ack (where we can), so we need to unmask at EOI. */ + if (__this_cpu_read(aic_fiq_unmasked) & BIT(aic_fiq_get_idx(d))) + aic_fiq_clear_mask(d); +} + +#define TIMER_FIRING(x) \ + (((x) & (ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_MASK | \ + ARCH_TIMER_CTRL_IT_STAT)) == \ + (ARCH_TIMER_CTRL_ENABLE | ARCH_TIMER_CTRL_IT_STAT)) + +static void __exception_irq_entry aic_handle_fiq(struct pt_regs *regs) +{ + /* + * It would be really nice if we had a system register that lets us get + * the FIQ source state without having to peek down into sources... + * but such a register does not seem to exist. + * + * So, we have these potential sources to test for: + * - Fast IPIs (not yet used) + * - The 4 timers (CNTP, CNTV for each of HV and guest) + * - Per-core PMCs (not yet supported) + * - Per-cluster uncore PMCs (not yet supported) + * + * Since not dealing with any of these results in a FIQ storm, + * we check for everything here, even things we don't support yet. + */ + + if (read_sysreg_s(SYS_IMP_APL_IPI_SR_EL1) & IPI_SR_PENDING) { + pr_err_ratelimited("Fast IPI fired. Acking.\n"); + write_sysreg_s(IPI_SR_PENDING, SYS_IMP_APL_IPI_SR_EL1); + } + + if (TIMER_FIRING(read_sysreg(cntp_ctl_el0))) + handle_domain_irq(aic_irqc->hw_domain, + aic_irqc->nr_hw + AIC_TMR_HV_PHYS, regs); + + if (TIMER_FIRING(read_sysreg(cntv_ctl_el0))) + handle_domain_irq(aic_irqc->hw_domain, + aic_irqc->nr_hw + AIC_TMR_HV_VIRT, regs); + + if (is_kernel_in_hyp_mode()) { + uint64_t enabled = read_sysreg_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2); + + if ((enabled & VM_TMR_FIQ_ENABLE_P) && + TIMER_FIRING(read_sysreg_s(SYS_CNTP_CTL_EL02))) + handle_domain_irq(aic_irqc->hw_domain, + aic_irqc->nr_hw + AIC_TMR_GUEST_PHYS, regs); + + if ((enabled & VM_TMR_FIQ_ENABLE_V) && + TIMER_FIRING(read_sysreg_s(SYS_CNTV_CTL_EL02))) + handle_domain_irq(aic_irqc->hw_domain, + aic_irqc->nr_hw + AIC_TMR_GUEST_VIRT, regs); + } + + if ((read_sysreg_s(SYS_IMP_APL_PMCR0_EL1) & (PMCR0_IMODE | PMCR0_IACT)) == + (FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_FIQ) | PMCR0_IACT)) { + /* + * Not supported yet, let's figure out how to handle this when + * we implement these proprietary performance counters. For now, + * just mask it and move on. + */ + pr_err_ratelimited("PMC FIQ fired. Masking.\n"); + sysreg_clear_set_s(SYS_IMP_APL_PMCR0_EL1, PMCR0_IMODE | PMCR0_IACT, + FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_OFF)); + } + + if (FIELD_GET(UPMCR0_IMODE, read_sysreg_s(SYS_IMP_APL_UPMCR0_EL1)) == UPMCR0_IMODE_FIQ && + (read_sysreg_s(SYS_IMP_APL_UPMSR_EL1) & UPMSR_IACT)) { + /* Same story with uncore PMCs */ + pr_err_ratelimited("Uncore PMC FIQ fired. Masking.\n"); + sysreg_clear_set_s(SYS_IMP_APL_UPMCR0_EL1, UPMCR0_IMODE, + FIELD_PREP(UPMCR0_IMODE, UPMCR0_IMODE_OFF)); + } +} + +static int aic_fiq_set_type(struct irq_data *d, unsigned int type) +{ + return (type == IRQ_TYPE_LEVEL_HIGH) ? 0 : -EINVAL; +} + +static struct irq_chip fiq_chip = { + .name = "AIC-FIQ", + .irq_mask = aic_fiq_mask, + .irq_unmask = aic_fiq_unmask, + .irq_ack = aic_fiq_set_mask, + .irq_eoi = aic_fiq_eoi, + .irq_set_type = aic_fiq_set_type, +}; + +/* + * Main IRQ domain + */ + +static int aic_irq_domain_map(struct irq_domain *id, unsigned int irq, + irq_hw_number_t hw) +{ + struct aic_irq_chip *ic = id->host_data; + + if (hw < ic->nr_hw) { + irq_domain_set_info(id, irq, hw, &aic_chip, id->host_data, + handle_fasteoi_irq, NULL, NULL); + irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq))); + } else { + irq_set_percpu_devid(irq); + irq_domain_set_info(id, irq, hw, &fiq_chip, id->host_data, + handle_percpu_devid_irq, NULL, NULL); + } + + return 0; +} + +static int aic_irq_domain_translate(struct irq_domain *id, + struct irq_fwspec *fwspec, + unsigned long *hwirq, + unsigned int *type) +{ + struct aic_irq_chip *ic = id->host_data; + + if (fwspec->param_count != 3 || !is_of_node(fwspec->fwnode)) + return -EINVAL; + + switch (fwspec->param[0]) { + case AIC_IRQ: + if (fwspec->param[1] >= ic->nr_hw) + return -EINVAL; + *hwirq = fwspec->param[1]; + break; + case AIC_FIQ: + if (fwspec->param[1] >= AIC_NR_FIQ) + return -EINVAL; + *hwirq = ic->nr_hw + fwspec->param[1]; + + /* + * In EL1 the non-redirected registers are the guest's, + * not EL2's, so remap the hwirqs to match. + */ + if (!is_kernel_in_hyp_mode()) { + switch (fwspec->param[1]) { + case AIC_TMR_GUEST_PHYS: + *hwirq = ic->nr_hw + AIC_TMR_HV_PHYS; + break; + case AIC_TMR_GUEST_VIRT: + *hwirq = ic->nr_hw + AIC_TMR_HV_VIRT; + break; + case AIC_TMR_HV_PHYS: + case AIC_TMR_HV_VIRT: + return -ENOENT; + default: + break; + } + } + break; + default: + return -EINVAL; + } + + *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK; + + return 0; +} + +static int aic_irq_domain_alloc(struct irq_domain *domain, 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 = aic_irq_domain_translate(domain, fwspec, &hwirq, &type); + if (ret) + return ret; + + for (i = 0; i < nr_irqs; i++) { + ret = aic_irq_domain_map(domain, virq + i, hwirq + i); + if (ret) + return ret; + } + + return 0; +} + +static void aic_irq_domain_free(struct irq_domain *domain, unsigned int virq, + unsigned int nr_irqs) +{ + int i; + + for (i = 0; i < nr_irqs; i++) { + struct irq_data *d = irq_domain_get_irq_data(domain, virq + i); + + irq_set_handler(virq + i, NULL); + irq_domain_reset_irq_data(d); + } +} + +static const struct irq_domain_ops aic_irq_domain_ops = { + .translate = aic_irq_domain_translate, + .alloc = aic_irq_domain_alloc, + .free = aic_irq_domain_free, +}; + +/* + * IPI irqchip + */ + +static void aic_ipi_mask(struct irq_data *d) +{ + u32 irq_bit = BIT(irqd_to_hwirq(d)); + + /* No specific ordering requirements needed here. */ + atomic_andnot(irq_bit, this_cpu_ptr(&aic_vipi_enable)); +} + +static void aic_ipi_unmask(struct irq_data *d) +{ + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + u32 irq_bit = BIT(irqd_to_hwirq(d)); + + atomic_or(irq_bit, this_cpu_ptr(&aic_vipi_enable)); + + /* + * The atomic_or() above must complete before the atomic_read_acquire() below to avoid + * racing aic_ipi_send_mask(). + */ + smp_mb__after_atomic(); + + /* + * If a pending vIPI was unmasked, raise a HW IPI to ourselves. + * No barriers needed here since this is a self-IPI. + */ + if (atomic_read(this_cpu_ptr(&aic_vipi_flag)) & irq_bit) + aic_ic_write(ic, AIC_IPI_SEND, AIC_IPI_SEND_CPU(smp_processor_id())); +} + +static void aic_ipi_send_mask(struct irq_data *d, const struct cpumask *mask) +{ + struct aic_irq_chip *ic = irq_data_get_irq_chip_data(d); + u32 irq_bit = BIT(irqd_to_hwirq(d)); + u32 send = 0; + int cpu; + unsigned long pending; + + for_each_cpu(cpu, mask) { + /* + * This sequence is the mirror of the one in aic_ipi_unmask(); + * see the comment there. Additionally, release semantics + * ensure that the vIPI flag set is ordered after any shared + * memory accesses that precede it. This therefore also pairs + * with the atomic_fetch_andnot in aic_handle_ipi(). + */ + pending = atomic_fetch_or_release(irq_bit, per_cpu_ptr(&aic_vipi_flag, cpu)); + + /* + * The atomic_fetch_or_release() above must complete before the + * atomic_read_acquire() below to avoid racing aic_ipi_unmask(). + */ + smp_mb__after_atomic(); + + if (!(pending & irq_bit) && + (atomic_read(per_cpu_ptr(&aic_vipi_enable, cpu)) & irq_bit)) + send |= AIC_IPI_SEND_CPU(cpu); + } + + /* + * The flag writes must complete before the physical IPI is issued + * to another CPU. This is implied by the control dependency on + * the result of atomic_read_acquire() above, which is itself + * already ordered after the vIPI flag write. + */ + if (send) + aic_ic_write(ic, AIC_IPI_SEND, send); +} + +static struct irq_chip ipi_chip = { + .name = "AIC-IPI", + .irq_mask = aic_ipi_mask, + .irq_unmask = aic_ipi_unmask, + .ipi_send_mask = aic_ipi_send_mask, +}; + +/* + * IPI IRQ domain + */ + +static void aic_handle_ipi(struct pt_regs *regs) +{ + int i; + unsigned long enabled, firing; + + /* + * Ack the IPI. We need to order this after the AIC event read, but + * that is enforced by normal MMIO ordering guarantees. + */ + aic_ic_write(aic_irqc, AIC_IPI_ACK, AIC_IPI_OTHER); + + /* + * The mask read does not need to be ordered. Only we can change + * our own mask anyway, so no races are possible here, as long as + * we are properly in the interrupt handler (which is covered by + * the barrier that is part of the top-level AIC handler's readl()). + */ + enabled = atomic_read(this_cpu_ptr(&aic_vipi_enable)); + + /* + * Clear the IPIs we are about to handle. This pairs with the + * atomic_fetch_or_release() in aic_ipi_send_mask(), and needs to be + * ordered after the aic_ic_write() above (to avoid dropping vIPIs) and + * before IPI handling code (to avoid races handling vIPIs before they + * are signaled). The former is taken care of by the release semantics + * of the write portion, while the latter is taken care of by the + * acquire semantics of the read portion. + */ + firing = atomic_fetch_andnot(enabled, this_cpu_ptr(&aic_vipi_flag)) & enabled; + + for_each_set_bit(i, &firing, AIC_NR_SWIPI) + handle_domain_irq(aic_irqc->ipi_domain, i, regs); + + /* + * No ordering needed here; at worst this just changes the timing of + * when the next IPI will be delivered. + */ + aic_ic_write(aic_irqc, AIC_IPI_MASK_CLR, AIC_IPI_OTHER); +} + +static int aic_ipi_alloc(struct irq_domain *d, unsigned int virq, + unsigned int nr_irqs, void *args) +{ + int i; + + for (i = 0; i < nr_irqs; i++) { + irq_set_percpu_devid(virq + i); + irq_domain_set_info(d, virq + i, i, &ipi_chip, d->host_data, + handle_percpu_devid_irq, NULL, NULL); + } + + return 0; +} + +static void aic_ipi_free(struct irq_domain *d, unsigned int virq, unsigned int nr_irqs) +{ + /* Not freeing IPIs */ +} + +static const struct irq_domain_ops aic_ipi_domain_ops = { + .alloc = aic_ipi_alloc, + .free = aic_ipi_free, +}; + +static int aic_init_smp(struct aic_irq_chip *irqc, struct device_node *node) +{ + struct irq_domain *ipi_domain; + int base_ipi; + + ipi_domain = irq_domain_create_linear(irqc->hw_domain->fwnode, AIC_NR_SWIPI, + &aic_ipi_domain_ops, irqc); + if (WARN_ON(!ipi_domain)) + return -ENODEV; + + ipi_domain->flags |= IRQ_DOMAIN_FLAG_IPI_SINGLE; + irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI); + + base_ipi = __irq_domain_alloc_irqs(ipi_domain, -1, AIC_NR_SWIPI, + NUMA_NO_NODE, NULL, false, NULL); + + if (WARN_ON(!base_ipi)) { + irq_domain_remove(ipi_domain); + return -ENODEV; + } + + set_smp_ipi_range(base_ipi, AIC_NR_SWIPI); + + irqc->ipi_domain = ipi_domain; + + return 0; +} + +static int aic_init_cpu(unsigned int cpu) +{ + /* Mask all hard-wired per-CPU IRQ/FIQ sources */ + + /* Pending Fast IPI FIQs */ + write_sysreg_s(IPI_SR_PENDING, SYS_IMP_APL_IPI_SR_EL1); + + /* Timer FIQs */ + sysreg_clear_set(cntp_ctl_el0, 0, ARCH_TIMER_CTRL_IT_MASK); + sysreg_clear_set(cntv_ctl_el0, 0, ARCH_TIMER_CTRL_IT_MASK); + + /* EL2-only (VHE mode) IRQ sources */ + if (is_kernel_in_hyp_mode()) { + /* Guest timers */ + sysreg_clear_set_s(SYS_IMP_APL_VM_TMR_FIQ_ENA_EL2, + VM_TMR_FIQ_ENABLE_V | VM_TMR_FIQ_ENABLE_P, 0); + + /* vGIC maintenance IRQ */ + sysreg_clear_set_s(SYS_ICH_HCR_EL2, ICH_HCR_EN, 0); + } + + /* PMC FIQ */ + sysreg_clear_set_s(SYS_IMP_APL_PMCR0_EL1, PMCR0_IMODE | PMCR0_IACT, + FIELD_PREP(PMCR0_IMODE, PMCR0_IMODE_OFF)); + + /* Uncore PMC FIQ */ + sysreg_clear_set_s(SYS_IMP_APL_UPMCR0_EL1, UPMCR0_IMODE, + FIELD_PREP(UPMCR0_IMODE, UPMCR0_IMODE_OFF)); + + /* Commit all of the above */ + isb(); + + /* + * Make sure the kernel's idea of logical CPU order is the same as AIC's + * If we ever end up with a mismatch here, we will have to introduce + * a mapping table similar to what other irqchip drivers do. + */ + WARN_ON(aic_ic_read(aic_irqc, AIC_WHOAMI) != smp_processor_id()); + + /* + * Always keep IPIs unmasked at the hardware level (except auto-masking + * by AIC during processing). We manage masks at the vIPI level. + */ + aic_ic_write(aic_irqc, AIC_IPI_ACK, AIC_IPI_SELF | AIC_IPI_OTHER); + aic_ic_write(aic_irqc, AIC_IPI_MASK_SET, AIC_IPI_SELF); + aic_ic_write(aic_irqc, AIC_IPI_MASK_CLR, AIC_IPI_OTHER); + + /* Initialize the local mask state */ + __this_cpu_write(aic_fiq_unmasked, 0); + + return 0; +} + +static int __init aic_of_ic_init(struct device_node *node, struct device_node *parent) +{ + int i; + void __iomem *regs; + u32 info; + struct aic_irq_chip *irqc; + + regs = of_iomap(node, 0); + if (WARN_ON(!regs)) + return -EIO; + + irqc = kzalloc(sizeof(*irqc), GFP_KERNEL); + if (!irqc) + return -ENOMEM; + + aic_irqc = irqc; + irqc->base = regs; + + info = aic_ic_read(irqc, AIC_INFO); + irqc->nr_hw = FIELD_GET(AIC_INFO_NR_HW, info); + + irqc->hw_domain = irq_domain_create_linear(of_node_to_fwnode(node), + irqc->nr_hw + AIC_NR_FIQ, + &aic_irq_domain_ops, irqc); + if (WARN_ON(!irqc->hw_domain)) { + iounmap(irqc->base); + kfree(irqc); + return -ENODEV; + } + + irq_domain_update_bus_token(irqc->hw_domain, DOMAIN_BUS_WIRED); + + if (aic_init_smp(irqc, node)) { + irq_domain_remove(irqc->hw_domain); + iounmap(irqc->base); + kfree(irqc); + return -ENODEV; + } + + set_handle_irq(aic_handle_irq); + set_handle_fiq(aic_handle_fiq); + + for (i = 0; i < BITS_TO_U32(irqc->nr_hw); i++) + aic_ic_write(irqc, AIC_MASK_SET + i * 4, U32_MAX); + for (i = 0; i < BITS_TO_U32(irqc->nr_hw); i++) + aic_ic_write(irqc, AIC_SW_CLR + i * 4, U32_MAX); + for (i = 0; i < irqc->nr_hw; i++) + aic_ic_write(irqc, AIC_TARGET_CPU + i * 4, 1); + + if (!is_kernel_in_hyp_mode()) + pr_info("Kernel running in EL1, mapping interrupts"); + + cpuhp_setup_state(CPUHP_AP_IRQ_APPLE_AIC_STARTING, + "irqchip/apple-aic/ipi:starting", + aic_init_cpu, NULL); + + pr_info("Initialized with %d IRQs, %d FIQs, %d vIPIs\n", + irqc->nr_hw, AIC_NR_FIQ, AIC_NR_SWIPI); + + return 0; +} + +IRQCHIP_DECLARE(apple_m1_aic, "apple,aic", aic_of_ic_init); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f14adb882338..f56eee992c75 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -100,6 +100,7 @@ enum cpuhp_state { CPUHP_AP_CPU_PM_STARTING, CPUHP_AP_IRQ_GIC_STARTING, CPUHP_AP_IRQ_HIP04_STARTING, + CPUHP_AP_IRQ_APPLE_AIC_STARTING, CPUHP_AP_IRQ_ARMADA_XP_STARTING, CPUHP_AP_IRQ_BCM2836_STARTING, CPUHP_AP_IRQ_MIPS_GIC_STARTING, -- 2.30.0
