Add a driver for the T-HEAD C900 ACLINT SSWI device, which is an
enhanced implementation of the RISC-V ACLINT SSWI specification.
This device allows the system to send ipi via fast device interface.
Signed-off-by: Inochi Amaoto <inochiama@xxxxxxxxx>
---
drivers/irqchip/Kconfig | 12 ++
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-thead-c900-aclint-sswi.c | 176 +++++++++++++++++++
include/linux/cpuhotplug.h | 1 +
4 files changed, 190 insertions(+)
create mode 100644 drivers/irqchip/irq-thead-c900-aclint-sswi.c
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 341cd9ca5a05..b6e8411f28d3 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -611,6 +611,18 @@ config STARFIVE_JH8100_INTC
If you don't know what to do here, say Y.
+config THEAD_C900_ACLINT_SSWI
+ bool "THEAD C9XX ACLINT S-mode IPI Interrupt Controller"
+ depends on RISCV
+ depends on SMP
+ select IRQ_DOMAIN_HIERARCHY
+ select GENERIC_IRQ_IPI_MUX
+ help
+ This enables support for T-HEAD specific ACLINT SSWI device
+ support.
+
+ If you don't know what to do here, say Y.
+
config EXYNOS_IRQ_COMBINER
bool "Samsung Exynos IRQ combiner support" if COMPILE_TEST
depends on (ARCH_EXYNOS && ARM) || COMPILE_TEST
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e3679ec2b9f7..583418261253 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_RISCV_APLIC_MSI) += irq-riscv-aplic-msi.o
obj-$(CONFIG_RISCV_IMSIC) += irq-riscv-imsic-state.o irq-riscv-imsic-early.o irq-riscv-imsic-platform.o
obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
obj-$(CONFIG_STARFIVE_JH8100_INTC) += irq-starfive-jh8100-intc.o
+obj-$(CONFIG_THEAD_C900_ACLINT_SSWI) += irq-thead-c900-aclint-sswi.o
obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
obj-$(CONFIG_IMX_INTMUX) += irq-imx-intmux.o
obj-$(CONFIG_IMX_MU_MSI) += irq-imx-mu-msi.o
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..e1051869a7ab
--- /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@xxxxxxxxx>
+ */
+
+#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 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 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 * ACLINT_xSWI_REGISTER_SIZE;
+ }
+
+ pr_info("%pfwP: register %u CPU%s\n", fwnode, contexts, str_plural(contexts));
+
+ return 0;
+}
+
+static int __init 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 = 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 aclint_sswi_early_probe(struct device_node *node,
+ struct device_node *parent)
+{
+ return aclint_sswi_probe(&node->fwnode);
+}
+IRQCHIP_DECLARE(thead_aclint_sswi, "thead,c900-aclint-sswi", aclint_sswi_early_probe);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 2361ed4d2b15..799052249c7b 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -147,6 +147,7 @@ enum cpuhp_state {
CPUHP_AP_IRQ_EIOINTC_STARTING,
CPUHP_AP_IRQ_AVECINTC_STARTING,
CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
+ CPUHP_AP_IRQ_THEAD_ACLINT_SSWI_STARTING,
CPUHP_AP_IRQ_RISCV_IMSIC_STARTING,
CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
CPUHP_AP_ARM_MVEBU_COHERENCY,
--
2.47.0
