[PATCH v8 10/16] irqchip/riscv-imsic: Add support for platform MSI irqdomain

Anup Patel
2023-09-12T17:51:31Z

The Linux platform MSI support requires a platform MSI irqdomain so
let us add a platform irqchip driver for RISC-V IMSIC which provides
a base IRQ domain and platform MSI domain. This driver assumes that
the IMSIC state is already initialized by the IMSIC early driver.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
drivers/irqchip/Makefile | 2 +-
drivers/irqchip/irq-riscv-imsic-platform.c | 280 +++++++++++++++++++++
2 files changed, 281 insertions(+), 1 deletion(-)
create mode 100644 drivers/irqchip/irq-riscv-imsic-platform.c

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index d714724387ce..abca445a3229 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -95,7 +95,7 @@ obj-$(CONFIG_QCOM_MPM) += irq-qcom-mpm.o
obj-$(CONFIG_CSKY_MPINTC) += irq-csky-mpintc.o
obj-$(CONFIG_CSKY_APB_INTC) += irq-csky-apb-intc.o
obj-$(CONFIG_RISCV_INTC) += irq-riscv-intc.o
-obj-$(CONFIG_RISCV_IMSIC) += irq-riscv-imsic-state.o irq-riscv-imsic-early.o
+obj-$(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_IMX_IRQSTEER) += irq-imx-irqsteer.o
obj-$(CONFIG_IMX_INTMUX) += irq-imx-intmux.o
diff --git a/drivers/irqchip/irq-riscv-imsic-platform.c b/drivers/irqchip/irq-riscv-imsic-platform.c
new file mode 100644
index 000000000000..b78f1b2ee3dc
--- /dev/null
+++ b/drivers/irqchip/irq-riscv-imsic-platform.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ * Copyright (C) 2022 Ventana Micro Systems Inc.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/cpu.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+
+#include "irq-riscv-imsic-state.h"
+
+static int imsic_cpu_page_phys(unsigned int cpu,
+ unsigned int guest_index,
+ phys_addr_t *out_msi_pa)
+{
+ struct imsic_global_config *global;
+ struct imsic_local_config *local;
+
+ global = &imsic->global;
+ local = per_cpu_ptr(global->local, cpu);
+
+ if (BIT(global->guest_index_bits) <= guest_index)
+ return -EINVAL;
+
+ if (out_msi_pa)
+ *out_msi_pa = local->msi_pa +
+ (guest_index * IMSIC_MMIO_PAGE_SZ);
+
+ return 0;
+}
+
+static int imsic_get_cpu(const struct cpumask *mask_val, bool force,
+ unsigned int *out_target_cpu)
+{
+ unsigned int cpu;
+
+ if (force)
+ cpu = cpumask_first(mask_val);
+ else
+ cpu = cpumask_any_and(mask_val, cpu_online_mask);
+
+ if (cpu >= nr_cpu_ids)
+ return -EINVAL;
+
+ if (out_target_cpu)
+ *out_target_cpu = cpu;
+
+ return 0;
+}
+
+static void imsic_irq_mask(struct irq_data *d)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&imsic->ids_lock, flags);
+ bitmap_clear(imsic->ids_enabled_bimap, d->hwirq, 1);
+ __imsic_id_disable(d->hwirq);
+ raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
+
+ imsic_ids_remote_sync();
+}
+
+static void imsic_irq_unmask(struct irq_data *d)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&imsic->ids_lock, flags);
+ bitmap_set(imsic->ids_enabled_bimap, d->hwirq, 1);
+ __imsic_id_enable(d->hwirq);
+ raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
+
+ imsic_ids_remote_sync();
+}
+
+static void imsic_irq_compose_msi_msg(struct irq_data *d,
+ struct msi_msg *msg)
+{
+ phys_addr_t msi_addr;
+ unsigned int cpu;
+ int err;
+
+ cpu = imsic_id_get_target(d->hwirq);
+ if (WARN_ON(cpu == UINT_MAX))
+ return;
+
+ err = imsic_cpu_page_phys(cpu, 0, &msi_addr);
+ if (WARN_ON(err))
+ return;
+
+ msg->address_hi = upper_32_bits(msi_addr);
+ msg->address_lo = lower_32_bits(msi_addr);
+ msg->data = d->hwirq;
+}
+
+#ifdef CONFIG_SMP
+static int imsic_irq_set_affinity(struct irq_data *d,
+ const struct cpumask *mask_val,
+ bool force)
+{
+ unsigned int target_cpu;
+ int rc;
+
+ rc = imsic_get_cpu(mask_val, force, &target_cpu);
+ if (rc)
+ return rc;
+
+ imsic_id_set_target(d->hwirq, target_cpu);
+ irq_data_update_effective_affinity(d, cpumask_of(target_cpu));
+
+ return IRQ_SET_MASK_OK;
+}
+#endif
+
+static struct irq_chip imsic_irq_base_chip = {
+ .name = "IMSIC-BASE",
+ .irq_mask = imsic_irq_mask,
+ .irq_unmask = imsic_irq_unmask,
+#ifdef CONFIG_SMP
+ .irq_set_affinity = imsic_irq_set_affinity,
+#endif
+ .irq_compose_msi_msg = imsic_irq_compose_msi_msg,
+ .flags = IRQCHIP_SKIP_SET_WAKE |
+ IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int imsic_irq_domain_alloc(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs,
+ void *args)
+{
+ int i, hwirq, err = 0;
+ unsigned int cpu;
+
+ err = imsic_get_cpu(cpu_online_mask, false, &cpu);
+ if (err)
+ return err;
+
+ hwirq = imsic_ids_alloc(get_count_order(nr_irqs));
+ if (hwirq < 0)
+ return hwirq;
+
+ for (i = 0; i < nr_irqs; i++) {
+ imsic_id_set_target(hwirq + i, cpu);
+ irq_domain_set_info(domain, virq + i, hwirq + i,
+ &imsic_irq_base_chip, imsic,
+ handle_simple_irq, NULL, NULL);
+ irq_set_noprobe(virq + i);
+ irq_set_affinity(virq + i, cpu_online_mask);
+ /*
+ * IMSIC does not implement irq_disable() so Linux interrupt
+ * subsystem will take a lazy approach for disabling an IMSIC
+ * interrupt. This means IMSIC interrupts are left unmasked
+ * upon system suspend and interrupts are not processed
+ * immediately upon system wake up. To tackle this, we disable
+ * the lazy approach for all IMSIC interrupts.
+ */
+ irq_set_status_flags(virq + i, IRQ_DISABLE_UNLAZY);
+ }
+
+ return 0;
+}
+
+static void imsic_irq_domain_free(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs)
+{
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+
+ imsic_ids_free(d->hwirq, get_count_order(nr_irqs));
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops imsic_base_domain_ops = {
+ .alloc = imsic_irq_domain_alloc,
+ .free = imsic_irq_domain_free,
+};
+
+static struct irq_chip imsic_plat_irq_chip = {
+ .name = "IMSIC-PLAT",
+};
+
+static struct msi_domain_ops imsic_plat_domain_ops = {
+};
+
+static struct msi_domain_info imsic_plat_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+ .ops = &imsic_plat_domain_ops,
+ .chip = &imsic_plat_irq_chip,
+};
+
+static int imsic_irq_domains_init(struct device *dev)
+{
+ /* Create Base IRQ domain */
+ imsic->base_domain = irq_domain_create_tree(dev->fwnode,
+ &imsic_base_domain_ops, imsic);
+ if (!imsic->base_domain) {
+ dev_err(dev, "failed to create IMSIC base domain\n");
+ return -ENOMEM;
+ }
+ irq_domain_update_bus_token(imsic->base_domain, DOMAIN_BUS_NEXUS);
+
+ /* Create Platform MSI domain */
+ imsic->plat_domain = platform_msi_create_irq_domain(dev->fwnode,
+ &imsic_plat_domain_info,
+ imsic->base_domain);
+ if (!imsic->plat_domain) {
+ dev_err(dev, "failed to create IMSIC platform domain\n");
+ irq_domain_remove(imsic->base_domain);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int imsic_platform_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct imsic_global_config *global;
+ int rc;
+
+ if (!imsic) {
+ dev_err(dev, "early driver not probed\n");
+ return -ENODEV;
+ }
+
+ if (imsic->base_domain) {
+ dev_err(dev, "irq domain already created\n");
+ return -ENODEV;
+ }
+
+ global = &imsic->global;
+
+ /* Initialize IRQ and MSI domains */
+ rc = imsic_irq_domains_init(dev);
+ if (rc) {
+ dev_err(dev, "failed to initialize IRQ and MSI domains\n");
+ return rc;
+ }
+
+ dev_info(dev, " hart-index-bits: %d, guest-index-bits: %d\n",
+ global->hart_index_bits, global->guest_index_bits);
+ dev_info(dev, " group-index-bits: %d, group-index-shift: %d\n",
+ global->group_index_bits, global->group_index_shift);
+ dev_info(dev, " mapped %d interrupts at base PPN %pa\n",
+ global->nr_ids, &global->base_addr);
+
+ return 0;
+}
+
+static const struct of_device_id imsic_platform_match[] = {
+ { .compatible = "riscv,imsics" },
+ {}
+};
+
+static struct platform_driver imsic_platform_driver = {
+ .driver = {
+ .name = "riscv-imsic",
+ .of_match_table = imsic_platform_match,
+ },
+ .probe = imsic_platform_probe,
+};
+
+static int __init imsic_platform_init(void)
+{
+ /*
+ * Register IMSIC driver as early as possible so that IMSIC
+ * platform device is probed as soon as it is created.
+ */
+ return platform_driver_register(&imsic_platform_driver);
+}
+core_initcall(imsic_platform_init);