1 files changed, 394 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
new file mode 100644
index 000000000000..70290b35b317
--- /dev/null
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -0,0 +1,394 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017-2018 SiFive
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#define pr_fmt(fmt) "riscv-intc: " fmt
+#include <linux/acpi.h>
+#include <linux/atomic.h>
+#include <linux/bits.h>
+#include <linux/cpu.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/smp.h>
+#include <linux/soc/andes/irq.h>
+
+#include <asm/hwcap.h>
+
+static struct irq_domain *intc_domain;
+static unsigned int riscv_intc_nr_irqs __ro_after_init = BITS_PER_LONG;
+static unsigned int riscv_intc_custom_base __ro_after_init = BITS_PER_LONG;
+static unsigned int riscv_intc_custom_nr_irqs __ro_after_init;
+
+static void riscv_intc_irq(struct pt_regs *regs)
+{
+	unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
+
+	if (generic_handle_domain_irq(intc_domain, cause))
+		pr_warn_ratelimited("Failed to handle interrupt (cause: %ld)\n", cause);
+}
+
+static void riscv_intc_aia_irq(struct pt_regs *regs)
+{
+	unsigned long topi;
+
+	while ((topi = csr_read(CSR_TOPI)))
+		generic_handle_domain_irq(intc_domain, topi >> TOPI_IID_SHIFT);
+}
+
+/*
+ * On RISC-V systems local interrupts are masked or unmasked by writing
+ * the SIE (Supervisor Interrupt Enable) CSR.  As CSRs can only be written
+ * on the local hart, these functions can only be called on the hart that
+ * corresponds to the IRQ chip.
+ */
+
+static void riscv_intc_irq_mask(struct irq_data *d)
+{
+	if (IS_ENABLED(CONFIG_32BIT) && d->hwirq >= BITS_PER_LONG)
+		csr_clear(CSR_IEH, BIT(d->hwirq - BITS_PER_LONG));
+	else
+		csr_clear(CSR_IE, BIT(d->hwirq));
+}
+
+static void riscv_intc_irq_unmask(struct irq_data *d)
+{
+	if (IS_ENABLED(CONFIG_32BIT) && d->hwirq >= BITS_PER_LONG)
+		csr_set(CSR_IEH, BIT(d->hwirq - BITS_PER_LONG));
+	else
+		csr_set(CSR_IE, BIT(d->hwirq));
+}
+
+static void andes_intc_irq_mask(struct irq_data *d)
+{
+	/*
+	 * Andes specific S-mode local interrupt causes (hwirq)
+	 * are defined as (256 + n) and controlled by n-th bit
+	 * of SLIE.
+	 */
+	unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
+
+	if (d->hwirq < ANDES_SLI_CAUSE_BASE)
+		csr_clear(CSR_IE, mask);
+	else
+		csr_clear(ANDES_CSR_SLIE, mask);
+}
+
+static void andes_intc_irq_unmask(struct irq_data *d)
+{
+	unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
+
+	if (d->hwirq < ANDES_SLI_CAUSE_BASE)
+		csr_set(CSR_IE, mask);
+	else
+		csr_set(ANDES_CSR_SLIE, mask);
+}
+
+static void riscv_intc_irq_eoi(struct irq_data *d)
+{
+	/*
+	 * The RISC-V INTC driver uses handle_percpu_devid_irq() flow
+	 * for the per-HART local interrupts and child irqchip drivers
+	 * (such as PLIC, SBI IPI, CLINT, APLIC, IMSIC, etc) implement
+	 * chained handlers for the per-HART local interrupts.
+	 *
+	 * In the absence of irq_eoi(), the chained_irq_enter() and
+	 * chained_irq_exit() functions (used by child irqchip drivers)
+	 * will do unnecessary mask/unmask of per-HART local interrupts
+	 * at the time of handling interrupts. To avoid this, we provide
+	 * an empty irq_eoi() callback for RISC-V INTC irqchip.
+	 */
+}
+
+static struct irq_chip riscv_intc_chip = {
+	.name = "RISC-V INTC",
+	.irq_mask = riscv_intc_irq_mask,
+	.irq_unmask = riscv_intc_irq_unmask,
+	.irq_eoi = riscv_intc_irq_eoi,
+};
+
+static struct irq_chip andes_intc_chip = {
+	.name		= "RISC-V INTC",
+	.irq_mask	= andes_intc_irq_mask,
+	.irq_unmask	= andes_intc_irq_unmask,
+	.irq_eoi	= riscv_intc_irq_eoi,
+};
+
+static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
+				 irq_hw_number_t hwirq)
+{
+	struct irq_chip *chip = d->host_data;
+
+	irq_set_percpu_devid(irq);
+	irq_domain_set_info(d, irq, hwirq, chip, NULL, handle_percpu_devid_irq,
+			    NULL, NULL);
+
+	return 0;
+}
+
+static int riscv_intc_domain_alloc(struct irq_domain *domain,
+				   unsigned int virq, unsigned int nr_irqs,
+				   void *arg)
+{
+	int i, ret;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	struct irq_fwspec *fwspec = arg;
+
+	ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	/*
+	 * Only allow hwirq for which we have corresponding standard or
+	 * custom interrupt enable register.
+	 */
+	if (hwirq >= riscv_intc_nr_irqs &&
+	    (hwirq < riscv_intc_custom_base ||
+	     hwirq >= riscv_intc_custom_base + riscv_intc_custom_nr_irqs))
+		return -EINVAL;
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = riscv_intc_domain_map(domain, virq + i, hwirq + i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct irq_domain_ops riscv_intc_domain_ops = {
+	.map	= riscv_intc_domain_map,
+	.xlate	= irq_domain_xlate_onecell,
+	.alloc	= riscv_intc_domain_alloc,
+	.free	= irq_domain_free_irqs_top,
+};
+
+static struct fwnode_handle *riscv_intc_hwnode(void)
+{
+	return intc_domain->fwnode;
+}
+
+static int __init riscv_intc_init_common(struct fwnode_handle *fn, struct irq_chip *chip)
+{
+	int rc;
+
+	intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, chip);
+	if (!intc_domain) {
+		pr_err("unable to add IRQ domain\n");
+		return -ENXIO;
+	}
+
+	if (riscv_isa_extension_available(NULL, SxAIA)) {
+		riscv_intc_nr_irqs = 64;
+		rc = set_handle_irq(&riscv_intc_aia_irq);
+	} else {
+		rc = set_handle_irq(&riscv_intc_irq);
+	}
+	if (rc) {
+		pr_err("failed to set irq handler\n");
+		return rc;
+	}
+
+	riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
+
+	pr_info("%d local interrupts mapped%s\n",
+		riscv_intc_nr_irqs,
+		riscv_isa_extension_available(NULL, SxAIA) ? " using AIA" : "");
+	if (riscv_intc_custom_nr_irqs)
+		pr_info("%d custom local interrupts mapped\n", riscv_intc_custom_nr_irqs);
+
+	return 0;
+}
+
+static int __init riscv_intc_init(struct device_node *node,
+				  struct device_node *parent)
+{
+	struct irq_chip *chip = &riscv_intc_chip;
+	unsigned long hartid;
+	int rc;
+
+	rc = riscv_of_parent_hartid(node, &hartid);
+	if (rc < 0) {
+		pr_warn("unable to find hart id for %pOF\n", node);
+		return 0;
+	}
+
+	/*
+	 * The DT will have one INTC DT node under each CPU (or HART)
+	 * DT node so riscv_intc_init() function will be called once
+	 * for each INTC DT node. We only need to do INTC initialization
+	 * for the INTC DT node belonging to boot CPU (or boot HART).
+	 */
+	if (riscv_hartid_to_cpuid(hartid) != smp_processor_id()) {
+		/*
+		 * The INTC nodes of each CPU are suppliers for downstream
+		 * interrupt controllers (such as PLIC, IMSIC and APLIC
+		 * direct-mode) so we should mark an INTC node as initialized
+		 * if we are not creating IRQ domain for it.
+		 */
+		fwnode_dev_initialized(of_fwnode_handle(node), true);
+		return 0;
+	}
+
+	if (of_device_is_compatible(node, "andestech,cpu-intc")) {
+		riscv_intc_custom_base = ANDES_SLI_CAUSE_BASE;
+		riscv_intc_custom_nr_irqs = ANDES_RV_IRQ_LAST;
+		chip = &andes_intc_chip;
+	}
+
+	return riscv_intc_init_common(of_fwnode_handle(node), chip);
+}
+
+IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);
+IRQCHIP_DECLARE(andes, "andestech,cpu-intc", riscv_intc_init);
+
+#ifdef CONFIG_ACPI
+
+struct rintc_data {
+	union {
+		u32		ext_intc_id;
+		struct {
+			u32	context_id	: 16,
+				reserved	:  8,
+				aplic_plic_id	:  8;
+		};
+	};
+	unsigned long		hart_id;
+	u64			imsic_addr;
+	u32			imsic_size;
+};
+
+static u32 nr_rintc;
+static struct rintc_data **rintc_acpi_data;
+
+#define for_each_matching_plic(_plic_id)				\
+	unsigned int _plic;						\
+									\
+	for (_plic = 0; _plic < nr_rintc; _plic++)			\
+		if (rintc_acpi_data[_plic]->aplic_plic_id != _plic_id)	\
+			continue;					\
+		else
+
+unsigned int acpi_rintc_get_plic_nr_contexts(unsigned int plic_id)
+{
+	unsigned int nctx = 0;
+
+	for_each_matching_plic(plic_id)
+		nctx++;
+
+	return nctx;
+}
+
+static struct rintc_data *get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	unsigned int ctxt = 0;
+
+	for_each_matching_plic(plic_id) {
+		if (ctxt == ctxt_idx)
+			return rintc_acpi_data[_plic];
+
+		ctxt++;
+	}
+
+	return NULL;
+}
+
+unsigned long acpi_rintc_ext_parent_to_hartid(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	struct rintc_data *data = get_plic_context(plic_id, ctxt_idx);
+
+	return data ? data->hart_id : INVALID_HARTID;
+}
+
+unsigned int acpi_rintc_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	struct rintc_data *data = get_plic_context(plic_id, ctxt_idx);
+
+	return data ? data->context_id : INVALID_CONTEXT;
+}
+
+unsigned long acpi_rintc_index_to_hartid(u32 index)
+{
+	return index >= nr_rintc ? INVALID_HARTID : rintc_acpi_data[index]->hart_id;
+}
+
+int acpi_rintc_get_imsic_mmio_info(u32 index, struct resource *res)
+{
+	if (index >= nr_rintc)
+		return -1;
+
+	res->start = rintc_acpi_data[index]->imsic_addr;
+	res->end = res->start + rintc_acpi_data[index]->imsic_size - 1;
+	res->flags = IORESOURCE_MEM;
+	return 0;
+}
+
+static int __init riscv_intc_acpi_match(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	return 0;
+}
+
+static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
+				       const unsigned long end)
+{
+	struct acpi_madt_rintc *rintc;
+	struct fwnode_handle *fn;
+	int count;
+	int rc;
+
+	if (!rintc_acpi_data) {
+		count = acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, riscv_intc_acpi_match, 0);
+		if (count <= 0)
+			return -EINVAL;
+
+		rintc_acpi_data = kcalloc(count, sizeof(*rintc_acpi_data), GFP_KERNEL);
+		if (!rintc_acpi_data)
+			return -ENOMEM;
+	}
+
+	rintc = (struct acpi_madt_rintc *)header;
+	rintc_acpi_data[nr_rintc] = kzalloc(sizeof(*rintc_acpi_data[0]), GFP_KERNEL);
+	if (!rintc_acpi_data[nr_rintc])
+		return -ENOMEM;
+
+	rintc_acpi_data[nr_rintc]->ext_intc_id = rintc->ext_intc_id;
+	rintc_acpi_data[nr_rintc]->hart_id = rintc->hart_id;
+	rintc_acpi_data[nr_rintc]->imsic_addr = rintc->imsic_addr;
+	rintc_acpi_data[nr_rintc]->imsic_size = rintc->imsic_size;
+	nr_rintc++;
+
+	/*
+	 * The ACPI MADT will have one INTC for each CPU (or HART)
+	 * so riscv_intc_acpi_init() function will be called once
+	 * for each INTC. We only do INTC initialization
+	 * for the INTC belonging to the boot CPU (or boot HART).
+	 */
+	if (riscv_hartid_to_cpuid(rintc->hart_id) != smp_processor_id())
+		return 0;
+
+	fn = irq_domain_alloc_named_fwnode("RISCV-INTC");
+	if (!fn) {
+		pr_err("unable to allocate INTC FW node\n");
+		return -ENOMEM;
+	}
+
+	rc = riscv_intc_init_common(fn, &riscv_intc_chip);
+	if (rc)
+		irq_domain_free_fwnode(fn);
+	else
+		acpi_set_irq_model(ACPI_IRQ_MODEL_RINTC, riscv_acpi_get_gsi_domain_id);
+
+	return rc;
+}
+
+IRQCHIP_ACPI_DECLARE(riscv_intc, ACPI_MADT_TYPE_RINTC, NULL,
+		     ACPI_MADT_RINTC_VERSION_V1, riscv_intc_acpi_init);
+#endif