1 files changed, 443 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
new file mode 100644
index 000000000000..445c5a01b766
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -0,0 +1,443 @@
+/*
+ * Copyright 2011 IBM Corporation.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+#include <linux/types.h>
+#include <linux/threads.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/debugfs.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/irq.h>
+#include <asm/errno.h>
+#include <asm/rtas.h>
+#include <asm/xics.h>
+#include <asm/firmware.h>
+
+/* Globals common to all ICP/ICS implementations */
+const struct icp_ops	*icp_ops;
+
+unsigned int xics_default_server		= 0xff;
+unsigned int xics_default_distrib_server	= 0;
+unsigned int xics_interrupt_server_size		= 8;
+
+DEFINE_PER_CPU(struct xics_cppr, xics_cppr);
+
+struct irq_host *xics_host;
+
+static LIST_HEAD(ics_list);
+
+void xics_update_irq_servers(void)
+{
+	int i, j;
+	struct device_node *np;
+	u32 ilen;
+	const u32 *ireg;
+	u32 hcpuid;
+
+	/* Find the server numbers for the boot cpu. */
+	np = of_get_cpu_node(boot_cpuid, NULL);
+	BUG_ON(!np);
+
+	hcpuid = get_hard_smp_processor_id(boot_cpuid);
+	xics_default_server = xics_default_distrib_server = hcpuid;
+
+	pr_devel("xics: xics_default_server = 0x%x\n", xics_default_server);
+
+	ireg = of_get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
+	if (!ireg) {
+		of_node_put(np);
+		return;
+	}
+
+	i = ilen / sizeof(int);
+
+	/* Global interrupt distribution server is specified in the last
+	 * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
+	 * entry fom this property for current boot cpu id and use it as
+	 * default distribution server
+	 */
+	for (j = 0; j < i; j += 2) {
+		if (ireg[j] == hcpuid) {
+			xics_default_distrib_server = ireg[j+1];
+			break;
+		}
+	}
+	pr_devel("xics: xics_default_distrib_server = 0x%x\n",
+		 xics_default_distrib_server);
+	of_node_put(np);
+}
+
+/* GIQ stuff, currently only supported on RTAS setups, will have
+ * to be sorted properly for bare metal
+ */
+void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
+{
+#ifdef CONFIG_PPC_RTAS
+	int index;
+	int status;
+
+	if (!rtas_indicator_present(GLOBAL_INTERRUPT_QUEUE, NULL))
+		return;
+
+	index = (1UL << xics_interrupt_server_size) - 1 - gserver;
+
+	status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE, index, join);
+
+	WARN(status < 0, "set-indicator(%d, %d, %u) returned %d\n",
+	     GLOBAL_INTERRUPT_QUEUE, index, join, status);
+#endif
+}
+
+void xics_setup_cpu(void)
+{
+	icp_ops->set_priority(LOWEST_PRIORITY);
+
+	xics_set_cpu_giq(xics_default_distrib_server, 1);
+}
+
+void xics_mask_unknown_vec(unsigned int vec)
+{
+	struct ics *ics;
+
+	pr_err("Interrupt 0x%x (real) is invalid, disabling it.\n", vec);
+
+	list_for_each_entry(ics, &ics_list, link)
+		ics->mask_unknown(ics, vec);
+}
+
+
+#ifdef CONFIG_SMP
+
+static void xics_request_ipi(void)
+{
+	unsigned int ipi;
+
+	ipi = irq_create_mapping(xics_host, XICS_IPI);
+	BUG_ON(ipi == NO_IRQ);
+
+	/*
+	 * IPIs are marked IRQF_DISABLED as they must run with irqs
+	 * disabled, and PERCPU.  The handler was set in map.
+	 */
+	BUG_ON(request_irq(ipi, icp_ops->ipi_action,
+			   IRQF_DISABLED|IRQF_PERCPU, "IPI", NULL));
+}
+
+int __init xics_smp_probe(void)
+{
+	/* Setup cause_ipi callback  based on which ICP is used */
+	smp_ops->cause_ipi = icp_ops->cause_ipi;
+
+	/* Register all the IPIs */
+	xics_request_ipi();
+
+	return cpumask_weight(cpu_possible_mask);
+}
+
+#endif /* CONFIG_SMP */
+
+void xics_teardown_cpu(void)
+{
+	struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+	/*
+	 * we have to reset the cppr index to 0 because we're
+	 * not going to return from the IPI
+	 */
+	os_cppr->index = 0;
+	icp_ops->set_priority(0);
+	icp_ops->teardown_cpu();
+}
+
+void xics_kexec_teardown_cpu(int secondary)
+{
+	xics_teardown_cpu();
+
+	icp_ops->flush_ipi();
+
+	/*
+	 * Some machines need to have at least one cpu in the GIQ,
+	 * so leave the master cpu in the group.
+	 */
+	if (secondary)
+		xics_set_cpu_giq(xics_default_distrib_server, 0);
+}
+
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/* Interrupts are disabled. */
+void xics_migrate_irqs_away(void)
+{
+	int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
+	unsigned int irq, virq;
+
+	/* If we used to be the default server, move to the new "boot_cpuid" */
+	if (hw_cpu == xics_default_server)
+		xics_update_irq_servers();
+
+	/* Reject any interrupt that was queued to us... */
+	icp_ops->set_priority(0);
+
+	/* Remove ourselves from the global interrupt queue */
+	xics_set_cpu_giq(xics_default_distrib_server, 0);
+
+	/* Allow IPIs again... */
+	icp_ops->set_priority(DEFAULT_PRIORITY);
+
+	for_each_irq(virq) {
+		struct irq_desc *desc;
+		struct irq_chip *chip;
+		long server;
+		unsigned long flags;
+		struct ics *ics;
+
+		/* We can't set affinity on ISA interrupts */
+		if (virq < NUM_ISA_INTERRUPTS)
+			continue;
+		if (!virq_is_host(virq, xics_host))
+			continue;
+		irq = (unsigned int)virq_to_hw(virq);
+		/* We need to get IPIs still. */
+		if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
+			continue;
+		desc = irq_to_desc(virq);
+		/* We only need to migrate enabled IRQS */
+		if (!desc || !desc->action)
+			continue;
+		chip = irq_desc_get_chip(desc);
+		if (!chip || !chip->irq_set_affinity)
+			continue;
+
+		raw_spin_lock_irqsave(&desc->lock, flags);
+
+		/* Locate interrupt server */
+		server = -1;
+		ics = irq_get_chip_data(virq);
+		if (ics)
+			server = ics->get_server(ics, irq);
+		if (server < 0) {
+			printk(KERN_ERR "%s: Can't find server for irq %d\n",
+			       __func__, irq);
+			goto unlock;
+		}
+
+		/* We only support delivery to all cpus or to one cpu.
+		 * The irq has to be migrated only in the single cpu
+		 * case.
+		 */
+		if (server != hw_cpu)
+			goto unlock;
+
+		/* This is expected during cpu offline. */
+		if (cpu_online(cpu))
+			pr_warning("IRQ %u affinity broken off cpu %u\n",
+			       virq, cpu);
+
+		/* Reset affinity to all cpus */
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+		irq_set_affinity(virq, cpu_all_mask);
+		continue;
+unlock:
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+	}
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+#ifdef CONFIG_SMP
+/*
+ * For the moment we only implement delivery to all cpus or one cpu.
+ *
+ * If the requested affinity is cpu_all_mask, we set global affinity.
+ * If not we set it to the first cpu in the mask, even if multiple cpus
+ * are set. This is so things like irqbalance (which set core and package
+ * wide affinities) do the right thing.
+ *
+ * We need to fix this to implement support for the links
+ */
+int xics_get_irq_server(unsigned int virq, const struct cpumask *cpumask,
+			unsigned int strict_check)
+{
+
+	if (!distribute_irqs)
+		return xics_default_server;
+
+	if (!cpumask_subset(cpu_possible_mask, cpumask)) {
+		int server = cpumask_first_and(cpu_online_mask, cpumask);
+
+		if (server < nr_cpu_ids)
+			return get_hard_smp_processor_id(server);
+
+		if (strict_check)
+			return -1;
+	}
+
+	/*
+	 * Workaround issue with some versions of JS20 firmware that
+	 * deliver interrupts to cpus which haven't been started. This
+	 * happens when using the maxcpus= boot option.
+	 */
+	if (cpumask_equal(cpu_online_mask, cpu_present_mask))
+		return xics_default_distrib_server;
+
+	return xics_default_server;
+}
+#endif /* CONFIG_SMP */
+
+static int xics_host_match(struct irq_host *h, struct device_node *node)
+{
+	struct ics *ics;
+
+	list_for_each_entry(ics, &ics_list, link)
+		if (ics->host_match(ics, node))
+			return 1;
+
+	return 0;
+}
+
+/* Dummies */
+static void xics_ipi_unmask(struct irq_data *d) { }
+static void xics_ipi_mask(struct irq_data *d) { }
+
+static struct irq_chip xics_ipi_chip = {
+	.name = "XICS",
+	.irq_eoi = NULL, /* Patched at init time */
+	.irq_mask = xics_ipi_mask,
+	.irq_unmask = xics_ipi_unmask,
+};
+
+static int xics_host_map(struct irq_host *h, unsigned int virq,
+			 irq_hw_number_t hw)
+{
+	struct ics *ics;
+
+	pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hw);
+
+	/* Insert the interrupt mapping into the radix tree for fast lookup */
+	irq_radix_revmap_insert(xics_host, virq, hw);
+
+	/* They aren't all level sensitive but we just don't really know */
+	irq_set_status_flags(virq, IRQ_LEVEL);
+
+	/* Don't call into ICS for IPIs */
+	if (hw == XICS_IPI) {
+		irq_set_chip_and_handler(virq, &xics_ipi_chip,
+					 handle_percpu_irq);
+		return 0;
+	}
+
+	/* Let the ICS setup the chip data */
+	list_for_each_entry(ics, &ics_list, link)
+		if (ics->map(ics, virq) == 0)
+			return 0;
+
+	return -EINVAL;
+}
+
+static int xics_host_xlate(struct irq_host *h, struct device_node *ct,
+			   const u32 *intspec, unsigned int intsize,
+			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+
+{
+	/* Current xics implementation translates everything
+	 * to level. It is not technically right for MSIs but this
+	 * is irrelevant at this point. We might get smarter in the future
+	 */
+	*out_hwirq = intspec[0];
+	*out_flags = IRQ_TYPE_LEVEL_LOW;
+
+	return 0;
+}
+
+static struct irq_host_ops xics_host_ops = {
+	.match = xics_host_match,
+	.map = xics_host_map,
+	.xlate = xics_host_xlate,
+};
+
+static void __init xics_init_host(void)
+{
+	xics_host = irq_alloc_host(NULL, IRQ_HOST_MAP_TREE, 0, &xics_host_ops,
+				   XICS_IRQ_SPURIOUS);
+	BUG_ON(xics_host == NULL);
+	irq_set_default_host(xics_host);
+}
+
+void __init xics_register_ics(struct ics *ics)
+{
+	list_add(&ics->link, &ics_list);
+}
+
+static void __init xics_get_server_size(void)
+{
+	struct device_node *np;
+	const u32 *isize;
+
+	/* We fetch the interrupt server size from the first ICS node
+	 * we find if any
+	 */
+	np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xics");
+	if (!np)
+		return;
+	isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);
+	if (!isize)
+		return;
+	xics_interrupt_server_size = *isize;
+	of_node_put(np);
+}
+
+void __init xics_init(void)
+{
+	int rc = -1;
+
+	/* Fist locate ICP */
+#ifdef CONFIG_PPC_ICP_HV
+	if (firmware_has_feature(FW_FEATURE_LPAR))
+		rc = icp_hv_init();
+#endif
+#ifdef CONFIG_PPC_ICP_NATIVE
+	if (rc < 0)
+		rc = icp_native_init();
+#endif
+	if (rc < 0) {
+		pr_warning("XICS: Cannot find a Presentation Controller !\n");
+		return;
+	}
+
+	/* Copy get_irq callback over to ppc_md */
+	ppc_md.get_irq = icp_ops->get_irq;
+
+	/* Patch up IPI chip EOI */
+	xics_ipi_chip.irq_eoi = icp_ops->eoi;
+
+	/* Now locate ICS */
+#ifdef CONFIG_PPC_ICS_RTAS
+	rc = ics_rtas_init();
+#endif
+	if (rc < 0)
+		pr_warning("XICS: Cannot find a Source Controller !\n");
+
+	/* Initialize common bits */
+	xics_get_server_size();
+	xics_update_irq_servers();
+	xics_init_host();
+	xics_setup_cpu();
+}