Re: [PATCH v8 09/16] irqchip: Add RISC-V incoming MSI controller early driver

Emil Renner Berthing
2023-09-13T10:33:28Z

Anup Patel wrote:
> The RISC-V advanced interrupt architecture (AIA) specification
> defines a new MSI controller called incoming message signalled
> interrupt controller (IMSIC) which manages MSI on per-HART (or
> per-CPU) basis. It also supports IPIs as software injected MSIs.
> (For more details refer https://github.com/riscv/riscv-aia)
>
> Let us add an early irqchip driver for RISC-V IMSIC which sets
> up the IMSIC state and provide IPIs.
>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
> drivers/irqchip/Kconfig | 7 +-
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-riscv-imsic-early.c | 258 ++++++++++++
> drivers/irqchip/irq-riscv-imsic-state.c | 523 ++++++++++++++++++++++++
> drivers/irqchip/irq-riscv-imsic-state.h | 66 +++
> include/linux/irqchip/riscv-imsic.h | 86 ++++
> 6 files changed, 940 insertions(+), 1 deletion(-)
> create mode 100644 drivers/irqchip/irq-riscv-imsic-early.c
> create mode 100644 drivers/irqchip/irq-riscv-imsic-state.c
> create mode 100644 drivers/irqchip/irq-riscv-imsic-state.h
> create mode 100644 include/linux/irqchip/riscv-imsic.h
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index f7149d0f3d45..ee99aacbefcc 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -30,7 +30,6 @@ config ARM_GIC_V2M
>
> config GIC_NON_BANKED
> bool
> -

Hi Anup,

This change looks like a mistake to me.

/Emil

> config ARM_GIC_V3
> bool
> select IRQ_DOMAIN_HIERARCHY
> @@ -546,6 +545,12 @@ config SIFIVE_PLIC
> select IRQ_DOMAIN_HIERARCHY
> select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
>
> +config RISCV_IMSIC
> + bool
> + depends on RISCV
> + select IRQ_DOMAIN_HIERARCHY
> + select GENERIC_MSI_IRQ
> +
> 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 ffd945fe71aa..d714724387ce 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -95,6 +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_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-early.c b/drivers/irqchip/irq-riscv-imsic-early.c
> new file mode 100644
> index 000000000000..1de89ce1ec2f
> --- /dev/null
> +++ b/drivers/irqchip/irq-riscv-imsic-early.c
> @@ -0,0 +1,258 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + * Copyright (C) 2022 Ventana Micro Systems Inc.
> + */
> +
> +#define pr_fmt(fmt) "riscv-imsic: " 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/spinlock.h>
> +#include <linux/smp.h>
> +
> +#include "irq-riscv-imsic-state.h"
> +
> +/*
> + * The IMSIC driver uses 1 IPI for ID synchronization and
> + * arch/riscv/kernel/smp.c require 6 IPIs so we fix the
> + * total number of IPIs to 8.
> + */
> +#define IMSIC_NR_IPI 8
> +
> +static int imsic_parent_irq;
> +
> +#ifdef CONFIG_SMP
> +static irqreturn_t imsic_ids_sync_handler(int irq, void *data)
> +{
> + imsic_ids_local_sync();
> + return IRQ_HANDLED;
> +}
> +
> +void imsic_ids_remote_sync(void)
> +{
> + struct cpumask amask;
> +
> + /*
> + * We simply inject ID synchronization IPI to all target CPUs
> + * except current CPU. The ipi_send_mask() implementation of
> + * IPI mux will inject ID synchronization IPI only for CPUs
> + * that have enabled it so offline CPUs won't receive IPI.
> + * An offline CPU will unconditionally synchronize IDs through
> + * imsic_starting_cpu() when the CPU is brought up.
> + */
> + cpumask_andnot(&amask, cpu_online_mask, cpumask_of(smp_processor_id()));
> + __ipi_send_mask(imsic->ipi_lsync_desc, &amask);
> +}
> +
> +static void imsic_ipi_send(unsigned int cpu)
> +{
> + struct imsic_local_config *local =
> + per_cpu_ptr(imsic->global.local, cpu);
> +
> + writel(imsic->ipi_id, local->msi_va);
> +}
> +
> +static void imsic_ipi_starting_cpu(void)
> +{
> + /* Enable IPIs for current CPU. */
> + __imsic_id_enable(imsic->ipi_id);
> +
> + /* Enable virtual IPI used for IMSIC ID synchronization */
> + enable_percpu_irq(imsic->ipi_virq, 0);
> +}
> +
> +static void imsic_ipi_dying_cpu(void)
> +{
> + /*
> + * Disable virtual IPI used for IMSIC ID synchronization so
> + * that we don't receive ID synchronization requests.
> + */
> + disable_percpu_irq(imsic->ipi_virq);
> +}
> +
> +static int __init imsic_ipi_domain_init(void)
> +{
> + int virq;
> +
> + /* Allocate interrupt identity for IPIs */
> + virq = imsic_ids_alloc(get_count_order(1));
> + if (virq < 0)
> + return virq;
> + imsic->ipi_id = virq;
> +
> + /* Create IMSIC IPI multiplexing */
> + virq = ipi_mux_create(IMSIC_NR_IPI, imsic_ipi_send);
> + if (virq <= 0) {
> + imsic_ids_free(imsic->ipi_id, get_count_order(1));
> + return (virq < 0) ? virq : -ENOMEM;
> + }
> + imsic->ipi_virq = virq;
> +
> + /* First vIRQ is used for IMSIC ID synchronization */
> + virq = request_percpu_irq(imsic->ipi_virq, imsic_ids_sync_handler,
> + "riscv-imsic-lsync", imsic->global.local);
> + if (virq) {
> + imsic_ids_free(imsic->ipi_id, get_count_order(1));
> + return virq;
> + }
> + irq_set_status_flags(imsic->ipi_virq, IRQ_HIDDEN);
> + imsic->ipi_lsync_desc = irq_to_desc(imsic->ipi_virq);
> +
> + /* Set vIRQ range */
> + riscv_ipi_set_virq_range(imsic->ipi_virq + 1, IMSIC_NR_IPI - 1, true);
> +
> + /* Announce that IMSIC is providing IPIs */
> + pr_info("%pfwP: providing IPIs using interrupt %d\n",
> + imsic->fwnode, imsic->ipi_id);
> +
> + return 0;
> +}
> +#else
> +static void imsic_ipi_starting_cpu(void)
> +{
> +}
> +
> +static void imsic_ipi_dying_cpu(void)
> +{
> +}
> +
> +static int __init imsic_ipi_domain_init(void)
> +{
> + /* Clear the IPI id because we are not using IPIs */
> + imsic->ipi_id = 0;
> + return 0;
> +}
> +#endif
> +
> +/*
> + * To handle an interrupt, we read the TOPEI CSR and write zero in one
> + * instruction. If TOPEI CSR is non-zero then we translate TOPEI.ID to
> + * Linux interrupt number and let Linux IRQ subsystem handle it.
> + */
> +static void imsic_handle_irq(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + irq_hw_number_t hwirq;
> + int err;
> +
> + chained_irq_enter(chip, desc);
> +
> + while ((hwirq = csr_swap(CSR_TOPEI, 0))) {
> + hwirq = hwirq >> TOPEI_ID_SHIFT;
> +
> + if (hwirq == imsic->ipi_id) {
> +#ifdef CONFIG_SMP
> + ipi_mux_process();
> +#endif
> + continue;
> + }
> +
> + if (unlikely(!imsic->base_domain))
> + continue;
> +
> + err = generic_handle_domain_irq(imsic->base_domain, hwirq);
> + if (unlikely(err))
> + pr_warn_ratelimited(
> + "hwirq %lu mapping not found\n", hwirq);
> + }
> +
> + chained_irq_exit(chip, desc);
> +}
> +
> +static int imsic_starting_cpu(unsigned int cpu)
> +{
> + /* Enable per-CPU parent interrupt */
> + enable_percpu_irq(imsic_parent_irq,
> + irq_get_trigger_type(imsic_parent_irq));
> +
> + /* Setup IPIs */
> + imsic_ipi_starting_cpu();
> +
> + /*
> + * Interrupts identities might have been enabled/disabled while
> + * this CPU was not running so sync-up local enable/disable state.
> + */
> + imsic_ids_local_sync();
> +
> + /* Enable local interrupt delivery */
> + imsic_ids_local_delivery(true);
> +
> + return 0;
> +}
> +
> +static int imsic_dying_cpu(unsigned int cpu)
> +{
> + /* Cleanup IPIs */
> + imsic_ipi_dying_cpu();
> +
> + return 0;
> +}
> +
> +static int __init imsic_early_probe(struct fwnode_handle *fwnode)
> +{
> + int rc;
> + struct irq_domain *domain;
> +
> + /* Setup IMSIC state */
> + rc = imsic_setup_state(fwnode);
> + if (rc) {
> + pr_err("%pfwP: failed to setup state (error %d)\n",
> + fwnode, rc);
> + return rc;
> + }
> +
> + /* Find parent domain and register chained handler */
> + 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;
> + }
> + imsic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT);
> + if (!imsic_parent_irq) {
> + pr_err("%pfwP: Failed to create INTC mapping\n", fwnode);
> + return -ENOENT;
> + }
> + irq_set_chained_handler(imsic_parent_irq, imsic_handle_irq);
> +
> + /* Initialize IPI domain */
> + rc = imsic_ipi_domain_init();
> + if (rc) {
> + pr_err("%pfwP: Failed to initialize IPI domain\n", fwnode);
> + return rc;
> + }
> +
> + /*
> + * Setup cpuhp state (must be done after setting imsic_parent_irq)
> + *
> + * Don't disable per-CPU IMSIC file when CPU goes offline
> + * because this affects IPI and the masking/unmasking of
> + * virtual IPIs is done via generic IPI-Mux
> + */
> + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
> + "irqchip/riscv/imsic:starting",
> + imsic_starting_cpu, imsic_dying_cpu);
> +
> + return 0;
> +}
> +
> +static int __init imsic_early_dt_init(struct device_node *node,
> + struct device_node *parent)
> +{
> + int rc;
> +
> + /* Do early setup of IMSIC state and IPIs */
> + rc = imsic_early_probe(&node->fwnode);
> + if (rc)
> + return rc;
> +
> + /* Ensure that OF platform device gets probed */
> + of_node_clear_flag(node, OF_POPULATED);
> + return 0;
> +}
> +IRQCHIP_DECLARE(riscv_imsic, "riscv,imsics", imsic_early_dt_init);
> diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
> new file mode 100644
> index 000000000000..412b5b919dcc
> --- /dev/null
> +++ b/drivers/irqchip/irq-riscv-imsic-state.c
> @@ -0,0 +1,523 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + * Copyright (C) 2022 Ventana Micro Systems Inc.
> + */
> +
> +#define pr_fmt(fmt) "riscv-imsic: " fmt
> +#include <linux/bitmap.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/spinlock.h>
> +#include <linux/smp.h>
> +#include <asm/hwcap.h>
> +
> +#include "irq-riscv-imsic-state.h"
> +
> +#define IMSIC_DISABLE_EIDELIVERY 0
> +#define IMSIC_ENABLE_EIDELIVERY 1
> +#define IMSIC_DISABLE_EITHRESHOLD 1
> +#define IMSIC_ENABLE_EITHRESHOLD 0
> +
> +#define imsic_csr_write(__c, __v) \
> +do { \
> + csr_write(CSR_ISELECT, __c); \
> + csr_write(CSR_IREG, __v); \
> +} while (0)
> +
> +#define imsic_csr_read(__c) \
> +({ \
> + unsigned long __v; \
> + csr_write(CSR_ISELECT, __c); \
> + __v = csr_read(CSR_IREG); \
> + __v; \
> +})
> +
> +#define imsic_csr_set(__c, __v) \
> +do { \
> + csr_write(CSR_ISELECT, __c); \
> + csr_set(CSR_IREG, __v); \
> +} while (0)
> +
> +#define imsic_csr_clear(__c, __v) \
> +do { \
> + csr_write(CSR_ISELECT, __c); \
> + csr_clear(CSR_IREG, __v); \
> +} while (0)
> +
> +struct imsic_priv *imsic;
> +
> +const struct imsic_global_config *imsic_get_global_config(void)
> +{
> + return (imsic) ? &imsic->global : NULL;
> +}
> +EXPORT_SYMBOL_GPL(imsic_get_global_config);
> +
> +void __imsic_eix_update(unsigned long base_id,
> + unsigned long num_id, bool pend, bool val)
> +{
> + unsigned long i, isel, ireg;
> + unsigned long id = base_id, last_id = base_id + num_id;
> +
> + while (id < last_id) {
> + isel = id / BITS_PER_LONG;
> + isel *= BITS_PER_LONG / IMSIC_EIPx_BITS;
> + isel += (pend) ? IMSIC_EIP0 : IMSIC_EIE0;
> +
> + ireg = 0;
> + for (i = id & (__riscv_xlen - 1);
> + (id < last_id) && (i < __riscv_xlen); i++) {
> + ireg |= BIT(i);
> + id++;
> + }
> +
> + /*
> + * The IMSIC EIEx and EIPx registers are indirectly
> + * accessed via using ISELECT and IREG CSRs so we
> + * need to access these CSRs without getting preempted.
> + *
> + * All existing users of this function call this
> + * function with local IRQs disabled so we don't
> + * need to do anything special here.
> + */
> + if (val)
> + imsic_csr_set(isel, ireg);
> + else
> + imsic_csr_clear(isel, ireg);
> + }
> +}
> +
> +void imsic_id_set_target(unsigned int id, unsigned int target_cpu)
> +{
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&imsic->ids_lock, flags);
> + imsic->ids_target_cpu[id] = target_cpu;
> + raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
> +}
> +
> +unsigned int imsic_id_get_target(unsigned int id)
> +{
> + unsigned int ret;
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&imsic->ids_lock, flags);
> + ret = imsic->ids_target_cpu[id];
> + raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
> +
> + return ret;
> +}
> +
> +void imsic_ids_local_sync(void)
> +{
> + int i;
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&imsic->ids_lock, flags);
> + for (i = 1; i <= imsic->global.nr_ids; i++) {
> + if (imsic->ipi_id == i)
> + continue;
> +
> + if (test_bit(i, imsic->ids_enabled_bimap))
> + __imsic_id_enable(i);
> + else
> + __imsic_id_disable(i);
> + }
> + raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
> +}
> +
> +void imsic_ids_local_delivery(bool enable)
> +{
> + if (enable) {
> + imsic_csr_write(IMSIC_EITHRESHOLD, IMSIC_ENABLE_EITHRESHOLD);
> + imsic_csr_write(IMSIC_EIDELIVERY, IMSIC_ENABLE_EIDELIVERY);
> + } else {
> + imsic_csr_write(IMSIC_EIDELIVERY, IMSIC_DISABLE_EIDELIVERY);
> + imsic_csr_write(IMSIC_EITHRESHOLD, IMSIC_DISABLE_EITHRESHOLD);
> + }
> +}
> +
> +int imsic_ids_alloc(unsigned int order)
> +{
> + int ret;
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&imsic->ids_lock, flags);
> + ret = bitmap_find_free_region(imsic->ids_used_bimap,
> + imsic->global.nr_ids + 1, order);
> + raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
> +
> + return ret;
> +}
> +
> +void imsic_ids_free(unsigned int base_id, unsigned int order)
> +{
> + unsigned long flags;
> +
> + raw_spin_lock_irqsave(&imsic->ids_lock, flags);
> + bitmap_release_region(imsic->ids_used_bimap, base_id, order);
> + raw_spin_unlock_irqrestore(&imsic->ids_lock, flags);
> +}
> +
> +static int __init imsic_ids_init(void)
> +{
> + int i;
> + struct imsic_global_config *global = &imsic->global;
> +
> + raw_spin_lock_init(&imsic->ids_lock);
> +
> + /* Allocate used bitmap */
> + imsic->ids_used_bimap = bitmap_zalloc(global->nr_ids + 1, GFP_KERNEL);
> + if (!imsic->ids_used_bimap)
> + return -ENOMEM;
> +
> + /* Allocate enabled bitmap */
> + imsic->ids_enabled_bimap = bitmap_zalloc(global->nr_ids + 1,
> + GFP_KERNEL);
> + if (!imsic->ids_enabled_bimap) {
> + kfree(imsic->ids_used_bimap);
> + return -ENOMEM;
> + }
> +
> + /* Allocate target CPU array */
> + imsic->ids_target_cpu = kcalloc(global->nr_ids + 1,
> + sizeof(unsigned int), GFP_KERNEL);
> + if (!imsic->ids_target_cpu) {
> + bitmap_free(imsic->ids_enabled_bimap);
> + bitmap_free(imsic->ids_used_bimap);
> + return -ENOMEM;
> + }
> + for (i = 0; i <= global->nr_ids; i++)
> + imsic->ids_target_cpu[i] = UINT_MAX;
> +
> + /* Reserve ID#0 because it is special and never implemented */
> + bitmap_set(imsic->ids_used_bimap, 0, 1);
> +
> + return 0;
> +}
> +
> +static void __init imsic_ids_cleanup(void)
> +{
> + kfree(imsic->ids_target_cpu);
> + bitmap_free(imsic->ids_enabled_bimap);
> + bitmap_free(imsic->ids_used_bimap);
> +}
> +
> +static int __init imsic_get_parent_hartid(struct fwnode_handle *fwnode,
> + u32 index, unsigned long *hartid)
> +{
> + int rc;
> + struct fwnode_reference_args parent;
> +
> + rc = fwnode_property_get_reference_args(fwnode,
> + "interrupts-extended", "#interrupt-cells",
> + 0, index, &parent);
> + if (rc)
> + return rc;
> +
> + /*
> + * Skip interrupts other than external interrupts for
> + * current privilege level.
> + */
> + if (parent.args[0] != RV_IRQ_EXT)
> + return -EINVAL;
> +
> + return riscv_get_intc_hartid(parent.fwnode, hartid);
> +}
> +
> +static int __init imsic_get_mmio_resource(struct fwnode_handle *fwnode,
> + u32 index, struct resource *res)
> +{
> + /*
> + * Currently, only OF fwnode is support so extend this function
> + * for other types of fwnode for ACPI support.
> + */
> + if (!is_of_node(fwnode))
> + return -EINVAL;
> + return of_address_to_resource(to_of_node(fwnode), index, res);
> +}
> +
> +int __init imsic_setup_state(struct fwnode_handle *fwnode)
> +{
> + int rc, cpu;
> + phys_addr_t base_addr;
> + void __iomem **mmios_va = NULL;
> + struct resource res, *mmios = NULL;
> + struct imsic_local_config *local;
> + struct imsic_global_config *global;
> + unsigned long reloff, hartid;
> + u32 i, j, index, nr_parent_irqs, nr_handlers = 0, num_mmios = 0;
> +
> + /*
> + * Only one IMSIC instance allowed in a platform for clean
> + * implementation of SMP IRQ affinity and per-CPU IPIs.
> + *
> + * This means on a multi-socket (or multi-die) platform we
> + * will have multiple MMIO regions for one IMSIC instance.
> + */
> + if (imsic) {
> + pr_err("%pfwP: already initialized hence ignoring\n",
> + fwnode);
> + return -EALREADY;
> + }
> +
> + if (!riscv_isa_extension_available(NULL, SxAIA)) {
> + pr_err("%pfwP: AIA support not available\n", fwnode);
> + return -ENODEV;
> + }
> +
> + imsic = kzalloc(sizeof(*imsic), GFP_KERNEL);
> + if (!imsic)
> + return -ENOMEM;
> + imsic->fwnode = fwnode;
> + global = &imsic->global;
> +
> + global->local = alloc_percpu(typeof(*(global->local)));
> + if (!global->local) {
> + rc = -ENOMEM;
> + goto out_free_priv;
> + }
> +
> + /* Find number of parent interrupts */
> + nr_parent_irqs = 0;
> + while (!imsic_get_parent_hartid(fwnode, nr_parent_irqs, &hartid))
> + nr_parent_irqs++;
> + if (!nr_parent_irqs) {
> + pr_err("%pfwP: no parent irqs available\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Find number of guest index bits in MSI address */
> + rc = fwnode_property_read_u32_array(fwnode, "riscv,guest-index-bits",
> + &global->guest_index_bits, 1);
> + if (rc)
> + global->guest_index_bits = 0;
> + i = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT;
> + if (i < global->guest_index_bits) {
> + pr_err("%pfwP: guest index bits too big\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Find number of HART index bits */
> + rc = fwnode_property_read_u32_array(fwnode, "riscv,hart-index-bits",
> + &global->hart_index_bits, 1);
> + if (rc) {
> + /* Assume default value */
> + global->hart_index_bits = __fls(nr_parent_irqs);
> + if (BIT(global->hart_index_bits) < nr_parent_irqs)
> + global->hart_index_bits++;
> + }
> + i = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT - global->guest_index_bits;
> + if (i < global->hart_index_bits) {
> + pr_err("%pfwP: HART index bits too big\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Find number of group index bits */
> + rc = fwnode_property_read_u32_array(fwnode, "riscv,group-index-bits",
> + &global->group_index_bits, 1);
> + if (rc)
> + global->group_index_bits = 0;
> + i = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT -
> + global->guest_index_bits - global->hart_index_bits;
> + if (i < global->group_index_bits) {
> + pr_err("%pfwP: group index bits too big\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /*
> + * Find first bit position of group index.
> + * If not specified assumed the default APLIC-IMSIC configuration.
> + */
> + rc = fwnode_property_read_u32_array(fwnode, "riscv,group-index-shift",
> + &global->group_index_shift, 1);
> + if (rc)
> + global->group_index_shift = IMSIC_MMIO_PAGE_SHIFT * 2;
> + i = global->group_index_bits + global->group_index_shift - 1;
> + if (i >= BITS_PER_LONG) {
> + pr_err("%pfwP: group index shift too big\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Find number of interrupt identities */
> + rc = fwnode_property_read_u32_array(fwnode, "riscv,num-ids",
> + &global->nr_ids, 1);
> + if (rc) {
> + pr_err("%pfwP: number of interrupt identities not found\n",
> + fwnode);
> + goto out_free_local;
> + }
> + if ((global->nr_ids < IMSIC_MIN_ID) ||
> + (global->nr_ids >= IMSIC_MAX_ID) ||
> + ((global->nr_ids & IMSIC_MIN_ID) != IMSIC_MIN_ID)) {
> + pr_err("%pfwP: invalid number of interrupt identities\n",
> + fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Find number of guest interrupt identities */
> + if (fwnode_property_read_u32_array(fwnode, "riscv,num-guest-ids",
> + &global->nr_guest_ids, 1))
> + global->nr_guest_ids = global->nr_ids;
> + if ((global->nr_guest_ids < IMSIC_MIN_ID) ||
> + (global->nr_guest_ids >= IMSIC_MAX_ID) ||
> + ((global->nr_guest_ids & IMSIC_MIN_ID) != IMSIC_MIN_ID)) {
> + pr_err("%pfwP: invalid number of guest interrupt identities\n",
> + fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> +
> + /* Compute base address */
> + rc = imsic_get_mmio_resource(fwnode, 0, &res);
> + if (rc) {
> + pr_err("%pfwP: first MMIO resource not found\n", fwnode);
> + rc = -EINVAL;
> + goto out_free_local;
> + }
> + global->base_addr = res.start;
> + global->base_addr &= ~(BIT(global->guest_index_bits +
> + global->hart_index_bits +
> + IMSIC_MMIO_PAGE_SHIFT) - 1);
> + global->base_addr &= ~((BIT(global->group_index_bits) - 1) <<
> + global->group_index_shift);
> +
> + /* Find number of MMIO register sets */
> + while (!imsic_get_mmio_resource(fwnode, num_mmios, &res))
> + num_mmios++;
> +
> + /* Allocate MMIO resource array */
> + mmios = kcalloc(num_mmios, sizeof(*mmios), GFP_KERNEL);
> + if (!mmios) {
> + rc = -ENOMEM;
> + goto out_free_local;
> + }
> +
> + /* Allocate MMIO virtual address array */
> + mmios_va = kcalloc(num_mmios, sizeof(*mmios_va), GFP_KERNEL);
> + if (!mmios_va) {
> + rc = -ENOMEM;
> + goto out_iounmap;
> + }
> +
> + /* Parse and map MMIO register sets */
> + for (i = 0; i < num_mmios; i++) {
> + rc = imsic_get_mmio_resource(fwnode, i, &mmios[i]);
> + if (rc) {
> + pr_err("%pfwP: unable to parse MMIO regset %d\n",
> + fwnode, i);
> + goto out_iounmap;
> + }
> +
> + base_addr = mmios[i].start;
> + base_addr &= ~(BIT(global->guest_index_bits +
> + global->hart_index_bits +
> + IMSIC_MMIO_PAGE_SHIFT) - 1);
> + base_addr &= ~((BIT(global->group_index_bits) - 1) <<
> + global->group_index_shift);
> + if (base_addr != global->base_addr) {
> + rc = -EINVAL;
> + pr_err("%pfwP: address mismatch for regset %d\n",
> + fwnode, i);
> + goto out_iounmap;
> + }
> +
> + mmios_va[i] = ioremap(mmios[i].start, resource_size(&mmios[i]));
> + if (!mmios_va[i]) {
> + rc = -EIO;
> + pr_err("%pfwP: unable to map MMIO regset %d\n",
> + fwnode, i);
> + goto out_iounmap;
> + }
> + }
> +
> + /* Initialize interrupt identity management */
> + rc = imsic_ids_init();
> + if (rc) {
> + pr_err("%pfwP: failed to initialize interrupt management\n",
> + fwnode);
> + goto out_iounmap;
> + }
> +
> + /* Configure handlers for target CPUs */
> + for (i = 0; i < nr_parent_irqs; i++) {
> + rc = imsic_get_parent_hartid(fwnode, i, &hartid);
> + if (rc) {
> + pr_warn("%pfwP: hart ID for parent irq%d not found\n",
> + fwnode, i);
> + continue;
> + }
> +
> + cpu = riscv_hartid_to_cpuid(hartid);
> + if (cpu < 0) {
> + pr_warn("%pfwP: invalid cpuid for parent irq%d\n",
> + fwnode, i);
> + continue;
> + }
> +
> + /* Find MMIO location of MSI page */
> + index = num_mmios;
> + reloff = i * BIT(global->guest_index_bits) *
> + IMSIC_MMIO_PAGE_SZ;
> + for (j = 0; num_mmios; j++) {
> + if (reloff < resource_size(&mmios[j])) {
> + index = j;
> + break;
> + }
> +
> + /*
> + * MMIO region size may not be aligned to
> + * BIT(global->guest_index_bits) * IMSIC_MMIO_PAGE_SZ
> + * if holes are present.
> + */
> + reloff -= ALIGN(resource_size(&mmios[j]),
> + BIT(global->guest_index_bits) * IMSIC_MMIO_PAGE_SZ);
> + }
> + if (index >= num_mmios) {
> + pr_warn("%pfwP: MMIO not found for parent irq%d\n",
> + fwnode, i);
> + continue;
> + }
> +
> + local = per_cpu_ptr(global->local, cpu);
> + local->msi_pa = mmios[index].start + reloff;
> + local->msi_va = mmios_va[index] + reloff;
> +
> + nr_handlers++;
> + }
> +
> + /* If no CPU handlers found then can't take interrupts */
> + if (!nr_handlers) {
> + pr_err("%pfwP: No CPU handlers found\n", fwnode);
> + rc = -ENODEV;
> + goto out_ids_cleanup;
> + }
> +
> + /* We don't need MMIO arrays anymore so let's free-up */
> + kfree(mmios_va);
> + kfree(mmios);
> +
> + return 0;
> +
> +out_ids_cleanup:
> + imsic_ids_cleanup();
> +out_iounmap:
> + for (i = 0; i < num_mmios; i++) {
> + if (mmios_va[i])
> + iounmap(mmios_va[i]);
> + }
> + kfree(mmios_va);
> + kfree(mmios);
> +out_free_local:
> + free_percpu(imsic->global.local);
> +out_free_priv:
> + kfree(imsic);
> + imsic = NULL;
> + return rc;
> +}
> diff --git a/drivers/irqchip/irq-riscv-imsic-state.h b/drivers/irqchip/irq-riscv-imsic-state.h
> new file mode 100644
> index 000000000000..3170018949a8
> --- /dev/null
> +++ b/drivers/irqchip/irq-riscv-imsic-state.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + * Copyright (C) 2022 Ventana Micro Systems Inc.
> + */
> +
> +#ifndef _IRQ_RISCV_IMSIC_STATE_H
> +#define _IRQ_RISCV_IMSIC_STATE_H
> +
> +#include <linux/irqchip/riscv-imsic.h>
> +#include <linux/irqdomain.h>
> +#include <linux/fwnode.h>
> +
> +struct imsic_priv {
> + /* Device details */
> + struct fwnode_handle *fwnode;
> +
> + /* Global configuration common for all HARTs */
> + struct imsic_global_config global;
> +
> + /* Global state of interrupt identities */
> + raw_spinlock_t ids_lock;
> + unsigned long *ids_used_bimap;
> + unsigned long *ids_enabled_bimap;
> + unsigned int *ids_target_cpu;
> +
> + /* IPI interrupt identity and synchronization */
> + u32 ipi_id;
> + int ipi_virq;
> + struct irq_desc *ipi_lsync_desc;
> +
> + /* IRQ domains (created by platform driver) */
> + struct irq_domain *base_domain;
> + struct irq_domain *plat_domain;
> +};
> +
> +extern struct imsic_priv *imsic;
> +
> +void __imsic_eix_update(unsigned long base_id,
> + unsigned long num_id, bool pend, bool val);
> +
> +#define __imsic_id_enable(__id) \
> + __imsic_eix_update((__id), 1, false, true)
> +#define __imsic_id_disable(__id) \
> + __imsic_eix_update((__id), 1, false, false)
> +
> +void imsic_id_set_target(unsigned int id, unsigned int target_cpu);
> +unsigned int imsic_id_get_target(unsigned int id);
> +
> +void imsic_ids_local_sync(void);
> +void imsic_ids_local_delivery(bool enable);
> +
> +#ifdef CONFIG_SMP
> +void imsic_ids_remote_sync(void);
> +#else
> +static inline void imsic_ids_remote_sync(void)
> +{
> +}
> +#endif
> +
> +int imsic_ids_alloc(unsigned int order);
> +void imsic_ids_free(unsigned int base_id, unsigned int order);
> +
> +int imsic_setup_state(struct fwnode_handle *fwnode);
> +
> +#endif
> diff --git a/include/linux/irqchip/riscv-imsic.h b/include/linux/irqchip/riscv-imsic.h
> new file mode 100644
> index 000000000000..1f6fc9a57218
> --- /dev/null
> +++ b/include/linux/irqchip/riscv-imsic.h
> @@ -0,0 +1,86 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + * Copyright (C) 2022 Ventana Micro Systems Inc.
> + */
> +#ifndef __LINUX_IRQCHIP_RISCV_IMSIC_H
> +#define __LINUX_IRQCHIP_RISCV_IMSIC_H
> +
> +#include <linux/types.h>
> +#include <asm/csr.h>
> +
> +#define IMSIC_MMIO_PAGE_SHIFT 12
> +#define IMSIC_MMIO_PAGE_SZ (1UL << IMSIC_MMIO_PAGE_SHIFT)
> +#define IMSIC_MMIO_PAGE_LE 0x00
> +#define IMSIC_MMIO_PAGE_BE 0x04
> +
> +#define IMSIC_MIN_ID 63
> +#define IMSIC_MAX_ID 2048
> +
> +#define IMSIC_EIDELIVERY 0x70
> +
> +#define IMSIC_EITHRESHOLD 0x72
> +
> +#define IMSIC_EIP0 0x80
> +#define IMSIC_EIP63 0xbf
> +#define IMSIC_EIPx_BITS 32
> +
> +#define IMSIC_EIE0 0xc0
> +#define IMSIC_EIE63 0xff
> +#define IMSIC_EIEx_BITS 32
> +
> +#define IMSIC_FIRST IMSIC_EIDELIVERY
> +#define IMSIC_LAST IMSIC_EIE63
> +
> +#define IMSIC_MMIO_SETIPNUM_LE 0x00
> +#define IMSIC_MMIO_SETIPNUM_BE 0x04
> +
> +struct imsic_local_config {
> + phys_addr_t msi_pa;
> + void __iomem *msi_va;
> +};
> +
> +struct imsic_global_config {
> + /*
> + * MSI Target Address Scheme
> + *
> + * XLEN-1 12 0
> + * | | |
> + * -------------------------------------------------------------
> + * |xxxxxx|Group Index|xxxxxxxxxxx|HART Index|Guest Index| 0 |
> + * -------------------------------------------------------------
> + */
> +
> + /* Bits representing Guest index, HART index, and Group index */
> + u32 guest_index_bits;
> + u32 hart_index_bits;
> + u32 group_index_bits;
> + u32 group_index_shift;
> +
> + /* Global base address matching all target MSI addresses */
> + phys_addr_t base_addr;
> +
> + /* Number of interrupt identities */
> + u32 nr_ids;
> +
> + /* Number of guest interrupt identities */
> + u32 nr_guest_ids;
> +
> + /* Per-CPU IMSIC addresses */
> + struct imsic_local_config __percpu *local;
> +};
> +
> +#ifdef CONFIG_RISCV_IMSIC
> +
> +extern const struct imsic_global_config *imsic_get_global_config(void);
> +
> +#else
> +
> +static inline const struct imsic_global_config *imsic_get_global_config(void)
> +{
> + return NULL;
> +}
> +
> +#endif
> +
> +#endif
> --
> 2.34.1
>
>
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