1 files changed, 330 insertions, 0 deletions
diff --git a/arch/mips/sgi-ip30/ip30-irq.c b/arch/mips/sgi-ip30/ip30-irq.c
new file mode 100644
index 000000000..423c32cb6
--- /dev/null
+++ b/arch/mips/sgi-ip30/ip30-irq.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip30-irq.c: Highlevel interrupt handling for IP30 architecture.
+ */
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/percpu.h>
+#include <linux/spinlock.h>
+#include <linux/tick.h>
+#include <linux/types.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/sgi/heart.h>
+
+#include "ip30-common.h"
+
+struct heart_irq_data {
+	u64	*irq_mask;
+	int	cpu;
+};
+
+static DECLARE_BITMAP(heart_irq_map, HEART_NUM_IRQS);
+
+static DEFINE_PER_CPU(unsigned long, irq_enable_mask);
+
+static inline int heart_alloc_int(void)
+{
+	int bit;
+
+again:
+	bit = find_first_zero_bit(heart_irq_map, HEART_NUM_IRQS);
+	if (bit >= HEART_NUM_IRQS)
+		return -ENOSPC;
+
+	if (test_and_set_bit(bit, heart_irq_map))
+		goto again;
+
+	return bit;
+}
+
+static void ip30_error_irq(struct irq_desc *desc)
+{
+	u64 pending, mask, cause, error_irqs, err_reg;
+	int cpu = smp_processor_id();
+	int i;
+
+	pending = heart_read(&heart_regs->isr);
+	mask = heart_read(&heart_regs->imr[cpu]);
+	cause = heart_read(&heart_regs->cause);
+	error_irqs = (pending & HEART_L4_INT_MASK & mask);
+
+	/* Bail if there's nothing to process (how did we get here, then?) */
+	if (unlikely(!error_irqs))
+		return;
+
+	/* Prevent any of the error IRQs from firing again. */
+	heart_write(mask & ~(pending), &heart_regs->imr[cpu]);
+
+	/* Ack all error IRQs. */
+	heart_write(HEART_L4_INT_MASK, &heart_regs->clear_isr);
+
+	/*
+	 * If we also have a cause value, then something happened, so loop
+	 * through the error IRQs and report a "heart attack" for each one
+	 * and print the value of the HEART cause register.  This is really
+	 * primitive right now, but it should hopefully work until a more
+	 * robust error handling routine can be put together.
+	 *
+	 * Refer to heart.h for the HC_* macros to work out the cause
+	 * that got us here.
+	 */
+	if (cause) {
+		pr_alert("IP30: CPU%d: HEART ATTACK! ISR = 0x%.16llx, IMR = 0x%.16llx, CAUSE = 0x%.16llx\n",
+			 cpu, pending, mask, cause);
+
+		if (cause & HC_COR_MEM_ERR) {
+			err_reg = heart_read(&heart_regs->mem_err_addr);
+			pr_alert("  HEART_MEMERR_ADDR = 0x%.16llx\n", err_reg);
+		}
+
+		/* i = 63; i >= 51; i-- */
+		for (i = HEART_ERR_MASK_END; i >= HEART_ERR_MASK_START; i--)
+			if ((pending >> i) & 1)
+				pr_alert("  HEART Error IRQ #%d\n", i);
+
+		/* XXX: Seems possible to loop forever here, so panic(). */
+		panic("IP30: Fatal Error !\n");
+	}
+
+	/* Unmask the error IRQs. */
+	heart_write(mask, &heart_regs->imr[cpu]);
+}
+
+static void ip30_normal_irq(struct irq_desc *desc)
+{
+	int cpu = smp_processor_id();
+	struct irq_domain *domain;
+	u64 pend, mask;
+	int ret;
+
+	pend = heart_read(&heart_regs->isr);
+	mask = (heart_read(&heart_regs->imr[cpu]) &
+		(HEART_L0_INT_MASK | HEART_L1_INT_MASK | HEART_L2_INT_MASK));
+
+	pend &= mask;
+	if (unlikely(!pend))
+		return;
+
+#ifdef CONFIG_SMP
+	if (pend & BIT_ULL(HEART_L2_INT_RESCHED_CPU_0)) {
+		heart_write(BIT_ULL(HEART_L2_INT_RESCHED_CPU_0),
+			    &heart_regs->clear_isr);
+		scheduler_ipi();
+	} else if (pend & BIT_ULL(HEART_L2_INT_RESCHED_CPU_1)) {
+		heart_write(BIT_ULL(HEART_L2_INT_RESCHED_CPU_1),
+			    &heart_regs->clear_isr);
+		scheduler_ipi();
+	} else if (pend & BIT_ULL(HEART_L2_INT_CALL_CPU_0)) {
+		heart_write(BIT_ULL(HEART_L2_INT_CALL_CPU_0),
+			    &heart_regs->clear_isr);
+		generic_smp_call_function_interrupt();
+	} else if (pend & BIT_ULL(HEART_L2_INT_CALL_CPU_1)) {
+		heart_write(BIT_ULL(HEART_L2_INT_CALL_CPU_1),
+			    &heart_regs->clear_isr);
+		generic_smp_call_function_interrupt();
+	} else
+#endif
+	{
+		domain = irq_desc_get_handler_data(desc);
+		ret = generic_handle_domain_irq(domain, __ffs(pend));
+		if (ret)
+			spurious_interrupt();
+	}
+}
+
+static void ip30_ack_heart_irq(struct irq_data *d)
+{
+	heart_write(BIT_ULL(d->hwirq), &heart_regs->clear_isr);
+}
+
+static void ip30_mask_heart_irq(struct irq_data *d)
+{
+	struct heart_irq_data *hd = irq_data_get_irq_chip_data(d);
+	unsigned long *mask = &per_cpu(irq_enable_mask, hd->cpu);
+
+	clear_bit(d->hwirq, mask);
+	heart_write(*mask, &heart_regs->imr[hd->cpu]);
+}
+
+static void ip30_mask_and_ack_heart_irq(struct irq_data *d)
+{
+	struct heart_irq_data *hd = irq_data_get_irq_chip_data(d);
+	unsigned long *mask = &per_cpu(irq_enable_mask, hd->cpu);
+
+	clear_bit(d->hwirq, mask);
+	heart_write(*mask, &heart_regs->imr[hd->cpu]);
+	heart_write(BIT_ULL(d->hwirq), &heart_regs->clear_isr);
+}
+
+static void ip30_unmask_heart_irq(struct irq_data *d)
+{
+	struct heart_irq_data *hd = irq_data_get_irq_chip_data(d);
+	unsigned long *mask = &per_cpu(irq_enable_mask, hd->cpu);
+
+	set_bit(d->hwirq, mask);
+	heart_write(*mask, &heart_regs->imr[hd->cpu]);
+}
+
+static int ip30_set_heart_irq_affinity(struct irq_data *d,
+				       const struct cpumask *mask, bool force)
+{
+	struct heart_irq_data *hd = irq_data_get_irq_chip_data(d);
+
+	if (!hd)
+		return -EINVAL;
+
+	if (irqd_is_started(d))
+		ip30_mask_and_ack_heart_irq(d);
+
+	hd->cpu = cpumask_first_and(mask, cpu_online_mask);
+
+	if (irqd_is_started(d))
+		ip30_unmask_heart_irq(d);
+
+	irq_data_update_effective_affinity(d, cpumask_of(hd->cpu));
+
+	return 0;
+}
+
+static struct irq_chip heart_irq_chip = {
+	.name			= "HEART",
+	.irq_ack		= ip30_ack_heart_irq,
+	.irq_mask		= ip30_mask_heart_irq,
+	.irq_mask_ack		= ip30_mask_and_ack_heart_irq,
+	.irq_unmask		= ip30_unmask_heart_irq,
+	.irq_set_affinity	= ip30_set_heart_irq_affinity,
+};
+
+static int heart_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	struct irq_alloc_info *info = arg;
+	struct heart_irq_data *hd;
+	int hwirq;
+
+	if (nr_irqs > 1 || !info)
+		return -EINVAL;
+
+	hd = kzalloc(sizeof(*hd), GFP_KERNEL);
+	if (!hd)
+		return -ENOMEM;
+
+	hwirq = heart_alloc_int();
+	if (hwirq < 0) {
+		kfree(hd);
+		return -EAGAIN;
+	}
+	irq_domain_set_info(domain, virq, hwirq, &heart_irq_chip, hd,
+			    handle_level_irq, NULL, NULL);
+
+	return 0;
+}
+
+static void heart_domain_free(struct irq_domain *domain,
+			      unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *irqd;
+
+	if (nr_irqs > 1)
+		return;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	if (irqd) {
+		clear_bit(irqd->hwirq, heart_irq_map);
+		kfree(irqd->chip_data);
+	}
+}
+
+static const struct irq_domain_ops heart_domain_ops = {
+	.alloc = heart_domain_alloc,
+	.free  = heart_domain_free,
+};
+
+void __init ip30_install_ipi(void)
+{
+	int cpu = smp_processor_id();
+	unsigned long *mask = &per_cpu(irq_enable_mask, cpu);
+
+	set_bit(HEART_L2_INT_RESCHED_CPU_0 + cpu, mask);
+	heart_write(BIT_ULL(HEART_L2_INT_RESCHED_CPU_0 + cpu),
+		    &heart_regs->clear_isr);
+	set_bit(HEART_L2_INT_CALL_CPU_0 + cpu, mask);
+	heart_write(BIT_ULL(HEART_L2_INT_CALL_CPU_0 + cpu),
+		    &heart_regs->clear_isr);
+
+	heart_write(*mask, &heart_regs->imr[cpu]);
+}
+
+void __init arch_init_irq(void)
+{
+	struct irq_domain *domain;
+	struct fwnode_handle *fn;
+	unsigned long *mask;
+	int i;
+
+	mips_cpu_irq_init();
+
+	/* Mask all IRQs. */
+	heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[0]);
+	heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[1]);
+	heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[2]);
+	heart_write(HEART_CLR_ALL_MASK, &heart_regs->imr[3]);
+
+	/* Ack everything. */
+	heart_write(HEART_ACK_ALL_MASK, &heart_regs->clear_isr);
+
+	/* Enable specific HEART error IRQs for each CPU. */
+	mask = &per_cpu(irq_enable_mask, 0);
+	*mask |= HEART_CPU0_ERR_MASK;
+	heart_write(*mask, &heart_regs->imr[0]);
+	mask = &per_cpu(irq_enable_mask, 1);
+	*mask |= HEART_CPU1_ERR_MASK;
+	heart_write(*mask, &heart_regs->imr[1]);
+
+	/*
+	 * Some HEART bits are reserved by hardware or by software convention.
+	 * Mark these as reserved right away so they won't be accidentally
+	 * used later.
+	 */
+	set_bit(HEART_L0_INT_GENERIC, heart_irq_map);
+	set_bit(HEART_L0_INT_FLOW_CTRL_HWTR_0, heart_irq_map);
+	set_bit(HEART_L0_INT_FLOW_CTRL_HWTR_1, heart_irq_map);
+	set_bit(HEART_L2_INT_RESCHED_CPU_0, heart_irq_map);
+	set_bit(HEART_L2_INT_RESCHED_CPU_1, heart_irq_map);
+	set_bit(HEART_L2_INT_CALL_CPU_0, heart_irq_map);
+	set_bit(HEART_L2_INT_CALL_CPU_1, heart_irq_map);
+	set_bit(HEART_L3_INT_TIMER, heart_irq_map);
+
+	/* Reserve the error interrupts (#51 to #63). */
+	for (i = HEART_L4_INT_XWID_ERR_9; i <= HEART_L4_INT_HEART_EXCP; i++)
+		set_bit(i, heart_irq_map);
+
+	fn = irq_domain_alloc_named_fwnode("HEART");
+	WARN_ON(fn == NULL);
+	if (!fn)
+		return;
+	domain = irq_domain_create_linear(fn, HEART_NUM_IRQS,
+					  &heart_domain_ops, NULL);
+	WARN_ON(domain == NULL);
+	if (!domain)
+		return;
+
+	irq_set_default_host(domain);
+
+	irq_set_percpu_devid(IP30_HEART_L0_IRQ);
+	irq_set_chained_handler_and_data(IP30_HEART_L0_IRQ, ip30_normal_irq,
+					 domain);
+	irq_set_percpu_devid(IP30_HEART_L1_IRQ);
+	irq_set_chained_handler_and_data(IP30_HEART_L1_IRQ, ip30_normal_irq,
+					 domain);
+	irq_set_percpu_devid(IP30_HEART_L2_IRQ);
+	irq_set_chained_handler_and_data(IP30_HEART_L2_IRQ, ip30_normal_irq,
+					 domain);
+	irq_set_percpu_devid(IP30_HEART_ERR_IRQ);
+	irq_set_chained_handler_and_data(IP30_HEART_ERR_IRQ, ip30_error_irq,
+					 domain);
+}