diff options
Diffstat (limited to 'drivers/irqchip/irq-thead-c900-aclint-sswi.c')
| -rw-r--r-- | drivers/irqchip/irq-thead-c900-aclint-sswi.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-thead-c900-aclint-sswi.c b/drivers/irqchip/irq-thead-c900-aclint-sswi.c new file mode 100644 index 000000000000..b0e366ade427 --- /dev/null +++ b/drivers/irqchip/irq-thead-c900-aclint-sswi.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2024 Inochi Amaoto <inochiama@gmail.com> + */ + +#define pr_fmt(fmt) "thead-c900-aclint-sswi: " fmt +#include <linux/cpu.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/irqchip.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/pci.h> +#include <linux/spinlock.h> +#include <linux/smp.h> +#include <linux/string_choices.h> +#include <asm/sbi.h> +#include <asm/vendorid_list.h> + +#define THEAD_ACLINT_xSWI_REGISTER_SIZE 4 + +#define THEAD_C9XX_CSR_SXSTATUS 0x5c0 +#define THEAD_C9XX_SXSTATUS_CLINTEE BIT(17) + +static int sswi_ipi_virq __ro_after_init; +static DEFINE_PER_CPU(void __iomem *, sswi_cpu_regs); + +static void thead_aclint_sswi_ipi_send(unsigned int cpu) +{ + writel_relaxed(0x1, per_cpu(sswi_cpu_regs, cpu)); +} + +static void thead_aclint_sswi_ipi_clear(void) +{ + writel_relaxed(0x0, this_cpu_read(sswi_cpu_regs)); +} + +static void thead_aclint_sswi_ipi_handle(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + + chained_irq_enter(chip, desc); + + csr_clear(CSR_IP, IE_SIE); + thead_aclint_sswi_ipi_clear(); + + ipi_mux_process(); + + chained_irq_exit(chip, desc); +} + +static int thead_aclint_sswi_starting_cpu(unsigned int cpu) +{ + enable_percpu_irq(sswi_ipi_virq, irq_get_trigger_type(sswi_ipi_virq)); + + return 0; +} + +static int thead_aclint_sswi_dying_cpu(unsigned int cpu) +{ + thead_aclint_sswi_ipi_clear(); + + disable_percpu_irq(sswi_ipi_virq); + + return 0; +} + +static int __init thead_aclint_sswi_parse_irq(struct fwnode_handle *fwnode, + void __iomem *reg) +{ + struct of_phandle_args parent; + unsigned long hartid; + u32 contexts, i; + int rc, cpu; + + contexts = of_irq_count(to_of_node(fwnode)); + if (!(contexts)) { + pr_err("%pfwP: no ACLINT SSWI context available\n", fwnode); + return -EINVAL; + } + + for (i = 0; i < contexts; i++) { + rc = of_irq_parse_one(to_of_node(fwnode), i, &parent); + if (rc) + return rc; + + rc = riscv_of_parent_hartid(parent.np, &hartid); + if (rc) + return rc; + + if (parent.args[0] != RV_IRQ_SOFT) + return -ENOTSUPP; + + cpu = riscv_hartid_to_cpuid(hartid); + + per_cpu(sswi_cpu_regs, cpu) = reg + i * THEAD_ACLINT_xSWI_REGISTER_SIZE; + } + + pr_info("%pfwP: register %u CPU%s\n", fwnode, contexts, str_plural(contexts)); + + return 0; +} + +static int __init thead_aclint_sswi_probe(struct fwnode_handle *fwnode) +{ + struct irq_domain *domain; + void __iomem *reg; + int virq, rc; + + /* If it is T-HEAD CPU, check whether SSWI is enabled */ + if (riscv_cached_mvendorid(0) == THEAD_VENDOR_ID && + !(csr_read(THEAD_C9XX_CSR_SXSTATUS) & THEAD_C9XX_SXSTATUS_CLINTEE)) + return -ENOTSUPP; + + if (!is_of_node(fwnode)) + return -EINVAL; + + reg = of_iomap(to_of_node(fwnode), 0); + if (!reg) + return -ENOMEM; + + /* Parse SSWI setting */ + rc = thead_aclint_sswi_parse_irq(fwnode, reg); + if (rc < 0) + return rc; + + /* If mulitple SSWI devices are present, do not register irq again */ + if (sswi_ipi_virq) + return 0; + + /* Find riscv intc domain and create IPI irq mapping */ + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), DOMAIN_BUS_ANY); + if (!domain) { + pr_err("%pfwP: Failed to find INTC domain\n", fwnode); + return -ENOENT; + } + + sswi_ipi_virq = irq_create_mapping(domain, RV_IRQ_SOFT); + if (!sswi_ipi_virq) { + pr_err("unable to create ACLINT SSWI IRQ mapping\n"); + return -ENOMEM; + } + + /* Register SSWI irq and handler */ + virq = ipi_mux_create(BITS_PER_BYTE, thead_aclint_sswi_ipi_send); + if (virq <= 0) { + pr_err("unable to create muxed IPIs\n"); + irq_dispose_mapping(sswi_ipi_virq); + return virq < 0 ? virq : -ENOMEM; + } + + irq_set_chained_handler(sswi_ipi_virq, thead_aclint_sswi_ipi_handle); + + cpuhp_setup_state(CPUHP_AP_IRQ_THEAD_ACLINT_SSWI_STARTING, + "irqchip/thead-aclint-sswi:starting", + thead_aclint_sswi_starting_cpu, + thead_aclint_sswi_dying_cpu); + + riscv_ipi_set_virq_range(virq, BITS_PER_BYTE); + + /* Announce that SSWI is providing IPIs */ + pr_info("providing IPIs using THEAD ACLINT SSWI\n"); + + return 0; +} + +static int __init thead_aclint_sswi_early_probe(struct device_node *node, + struct device_node *parent) +{ + return thead_aclint_sswi_probe(&node->fwnode); +} +IRQCHIP_DECLARE(thead_aclint_sswi, "thead,c900-aclint-sswi", thead_aclint_sswi_early_probe); |