1 files changed, 314 insertions, 0 deletions
diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
new file mode 100644
index 000000000..42df9fafa
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
+ *
+ * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 1999 - 2001 Kanoj Sarcar
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/sched.h>
+
+#include <asm/io.h>
+#include <asm/irq_cpu.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/intr.h>
+#include <asm/sn/irq_alloc.h>
+
+struct hub_irq_data {
+	u64	*irq_mask[2];
+	cpuid_t	cpu;
+};
+
+static DECLARE_BITMAP(hub_irq_map, IP27_HUB_IRQ_COUNT);
+
+static DEFINE_PER_CPU(unsigned long [2], irq_enable_mask);
+
+static inline int alloc_level(void)
+{
+	int level;
+
+again:
+	level = find_first_zero_bit(hub_irq_map, IP27_HUB_IRQ_COUNT);
+	if (level >= IP27_HUB_IRQ_COUNT)
+		return -ENOSPC;
+
+	if (test_and_set_bit(level, hub_irq_map))
+		goto again;
+
+	return level;
+}
+
+static void enable_hub_irq(struct irq_data *d)
+{
+	struct hub_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);
+	__raw_writeq(mask[0], hd->irq_mask[0]);
+	__raw_writeq(mask[1], hd->irq_mask[1]);
+}
+
+static void disable_hub_irq(struct irq_data *d)
+{
+	struct hub_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);
+	__raw_writeq(mask[0], hd->irq_mask[0]);
+	__raw_writeq(mask[1], hd->irq_mask[1]);
+}
+
+static void setup_hub_mask(struct hub_irq_data *hd, const struct cpumask *mask)
+{
+	nasid_t nasid;
+	int cpu;
+
+	cpu = cpumask_first_and(mask, cpu_online_mask);
+	if (cpu >= nr_cpu_ids)
+		cpu = cpumask_any(cpu_online_mask);
+
+	nasid = cpu_to_node(cpu);
+	hd->cpu = cpu;
+	if (!cputoslice(cpu)) {
+		hd->irq_mask[0] = REMOTE_HUB_PTR(nasid, PI_INT_MASK0_A);
+		hd->irq_mask[1] = REMOTE_HUB_PTR(nasid, PI_INT_MASK1_A);
+	} else {
+		hd->irq_mask[0] = REMOTE_HUB_PTR(nasid, PI_INT_MASK0_B);
+		hd->irq_mask[1] = REMOTE_HUB_PTR(nasid, PI_INT_MASK1_B);
+	}
+}
+
+static int set_affinity_hub_irq(struct irq_data *d, const struct cpumask *mask,
+				bool force)
+{
+	struct hub_irq_data *hd = irq_data_get_irq_chip_data(d);
+
+	if (!hd)
+		return -EINVAL;
+
+	if (irqd_is_started(d))
+		disable_hub_irq(d);
+
+	setup_hub_mask(hd, mask);
+
+	if (irqd_is_started(d))
+		enable_hub_irq(d);
+
+	irq_data_update_effective_affinity(d, cpumask_of(hd->cpu));
+
+	return 0;
+}
+
+static struct irq_chip hub_irq_type = {
+	.name		  = "HUB",
+	.irq_mask	  = disable_hub_irq,
+	.irq_unmask	  = enable_hub_irq,
+	.irq_set_affinity = set_affinity_hub_irq,
+};
+
+static int hub_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			    unsigned int nr_irqs, void *arg)
+{
+	struct irq_alloc_info *info = arg;
+	struct hub_irq_data *hd;
+	struct hub_data *hub;
+	struct irq_desc *desc;
+	int swlevel;
+
+	if (nr_irqs > 1 || !info)
+		return -EINVAL;
+
+	hd = kzalloc(sizeof(*hd), GFP_KERNEL);
+	if (!hd)
+		return -ENOMEM;
+
+	swlevel = alloc_level();
+	if (unlikely(swlevel < 0)) {
+		kfree(hd);
+		return -EAGAIN;
+	}
+	irq_domain_set_info(domain, virq, swlevel, &hub_irq_type, hd,
+			    handle_level_irq, NULL, NULL);
+
+	/* use CPU connected to nearest hub */
+	hub = hub_data(info->nasid);
+	setup_hub_mask(hd, &hub->h_cpus);
+	info->nasid = cpu_to_node(hd->cpu);
+
+	/* Make sure it's not already pending when we connect it. */
+	REMOTE_HUB_CLR_INTR(info->nasid, swlevel);
+
+	desc = irq_to_desc(virq);
+	desc->irq_common_data.node = info->nasid;
+	cpumask_copy(desc->irq_common_data.affinity, &hub->h_cpus);
+
+	return 0;
+}
+
+static void hub_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 && irqd->chip_data)
+		kfree(irqd->chip_data);
+}
+
+static const struct irq_domain_ops hub_domain_ops = {
+	.alloc = hub_domain_alloc,
+	.free  = hub_domain_free,
+};
+
+/*
+ * This code is unnecessarily complex, because we do
+ * intr enabling. Basically, once we grab the set of intrs we need
+ * to service, we must mask _all_ these interrupts; firstly, to make
+ * sure the same intr does not intr again, causing recursion that
+ * can lead to stack overflow. Secondly, we can not just mask the
+ * one intr we are do_IRQing, because the non-masked intrs in the
+ * first set might intr again, causing multiple servicings of the
+ * same intr. This effect is mostly seen for intercpu intrs.
+ * Kanoj 05.13.00
+ */
+
+static void ip27_do_irq_mask0(struct irq_desc *desc)
+{
+	cpuid_t cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	struct irq_domain *domain;
+	u64 pend0;
+	int irq;
+
+	/* copied from Irix intpend0() */
+	pend0 = LOCAL_HUB_L(PI_INT_PEND0);
+
+	pend0 &= mask[0];		/* Pick intrs we should look at */
+	if (!pend0)
+		return;
+
+#ifdef CONFIG_SMP
+	if (pend0 & (1UL << CPU_RESCHED_A_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_RESCHED_A_IRQ);
+		scheduler_ipi();
+	} else if (pend0 & (1UL << CPU_RESCHED_B_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_RESCHED_B_IRQ);
+		scheduler_ipi();
+	} else if (pend0 & (1UL << CPU_CALL_A_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ);
+		generic_smp_call_function_interrupt();
+	} else if (pend0 & (1UL << CPU_CALL_B_IRQ)) {
+		LOCAL_HUB_CLR_INTR(CPU_CALL_B_IRQ);
+		generic_smp_call_function_interrupt();
+	} else
+#endif
+	{
+		domain = irq_desc_get_handler_data(desc);
+		irq = irq_linear_revmap(domain, __ffs(pend0));
+		if (irq)
+			generic_handle_irq(irq);
+		else
+			spurious_interrupt();
+	}
+
+	LOCAL_HUB_L(PI_INT_PEND0);
+}
+
+static void ip27_do_irq_mask1(struct irq_desc *desc)
+{
+	cpuid_t cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	struct irq_domain *domain;
+	u64 pend1;
+	int irq;
+
+	/* copied from Irix intpend0() */
+	pend1 = LOCAL_HUB_L(PI_INT_PEND1);
+
+	pend1 &= mask[1];		/* Pick intrs we should look at */
+	if (!pend1)
+		return;
+
+	domain = irq_desc_get_handler_data(desc);
+	irq = irq_linear_revmap(domain, __ffs(pend1) + 64);
+	if (irq)
+		generic_handle_irq(irq);
+	else
+		spurious_interrupt();
+
+	LOCAL_HUB_L(PI_INT_PEND1);
+}
+
+void install_ipi(void)
+{
+	int cpu = smp_processor_id();
+	unsigned long *mask = per_cpu(irq_enable_mask, cpu);
+	int slice = LOCAL_HUB_L(PI_CPU_NUM);
+	int resched, call;
+
+	resched = CPU_RESCHED_A_IRQ + slice;
+	set_bit(resched, mask);
+	LOCAL_HUB_CLR_INTR(resched);
+
+	call = CPU_CALL_A_IRQ + slice;
+	set_bit(call, mask);
+	LOCAL_HUB_CLR_INTR(call);
+
+	if (slice == 0) {
+		LOCAL_HUB_S(PI_INT_MASK0_A, mask[0]);
+		LOCAL_HUB_S(PI_INT_MASK1_A, mask[1]);
+	} else {
+		LOCAL_HUB_S(PI_INT_MASK0_B, mask[0]);
+		LOCAL_HUB_S(PI_INT_MASK1_B, mask[1]);
+	}
+}
+
+void __init arch_init_irq(void)
+{
+	struct irq_domain *domain;
+	struct fwnode_handle *fn;
+	int i;
+
+	mips_cpu_irq_init();
+
+	/*
+	 * Some interrupts are reserved by hardware or by software convention.
+	 * Mark these as reserved right away so they won't be used accidentally
+	 * later.
+	 */
+	for (i = 0; i <= CPU_CALL_B_IRQ; i++)
+		set_bit(i, hub_irq_map);
+
+	for (i = NI_BRDCAST_ERR_A; i <= MSC_PANIC_INTR; i++)
+		set_bit(i, hub_irq_map);
+
+	fn = irq_domain_alloc_named_fwnode("HUB");
+	WARN_ON(fn == NULL);
+	if (!fn)
+		return;
+	domain = irq_domain_create_linear(fn, IP27_HUB_IRQ_COUNT,
+					  &hub_domain_ops, NULL);
+	WARN_ON(domain == NULL);
+	if (!domain)
+		return;
+
+	irq_set_default_host(domain);
+
+	irq_set_percpu_devid(IP27_HUB_PEND0_IRQ);
+	irq_set_chained_handler_and_data(IP27_HUB_PEND0_IRQ, ip27_do_irq_mask0,
+					 domain);
+	irq_set_percpu_devid(IP27_HUB_PEND1_IRQ);
+	irq_set_chained_handler_and_data(IP27_HUB_PEND1_IRQ, ip27_do_irq_mask1,
+					 domain);
+}