7 files changed, 337 insertions, 1 deletions

diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 3bbfd6a9c475..8d9498e51585 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -108,4 +108,15 @@ config SPARSE_IRQ
 
           If you don't know what to do here, say N.
 
+config GENERIC_IRQ_DEBUGFS
+        bool "Expose irq internals in debugfs"
+        depends on DEBUG_FS
+        default n
+        ---help---
+
+          Exposes internal state information through debugfs. Mostly for
+          developers and debugging of hard to diagnose interrupt problems.
+
+          If you don't know what to do here, say N.
+
 endmenu
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 1d3ee3169202..c61fc9c2d1f7 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_PM_SLEEP) += pm.o
 obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
 obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o
 obj-$(CONFIG_SMP) += affinity.o
+obj-$(CONFIG_GENERIC_IRQ_DEBUGFS) += debugfs.o
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
new file mode 100644
index 000000000000..50ee2f6593e8
--- /dev/null
+++ b/kernel/irq/debugfs.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright 2017 Thomas Gleixner <tglx@linutronix.de>
+ *
+ * This file is licensed under the GPL V2.
+ */
+#include <linux/debugfs.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+
+#include "internals.h"
+
+static struct dentry *irq_dir;
+
+struct irq_bit_descr {
+        unsigned int    mask;
+        char            *name;
+};
+#define BIT_MASK_DESCR(m)       { .mask = m, .name = #m }
+
+static void irq_debug_show_bits(struct seq_file *m, int ind, unsigned int state,
+                                const struct irq_bit_descr *sd, int size)
+{
+        int i;
+
+        for (i = 0; i < size; i++, sd++) {
+                if (state & sd->mask)
+                        seq_printf(m, "%*s%s\n", ind + 12, "", sd->name);
+        }
+}
+
+#ifdef CONFIG_SMP
+static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc)
+{
+        struct irq_data *data = irq_desc_get_irq_data(desc);
+        struct cpumask *msk;
+
+        msk = irq_data_get_affinity_mask(data);
+        seq_printf(m, "affinity: %*pbl\n", cpumask_pr_args(msk));
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+        msk = desc->pending_mask;
+        seq_printf(m, "pending:  %*pbl\n", cpumask_pr_args(msk));
+#endif
+}
+#else
+static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc) { }
+#endif
+
+static const struct irq_bit_descr irqchip_flags[] = {
+        BIT_MASK_DESCR(IRQCHIP_SET_TYPE_MASKED),
+        BIT_MASK_DESCR(IRQCHIP_EOI_IF_HANDLED),
+        BIT_MASK_DESCR(IRQCHIP_MASK_ON_SUSPEND),
+        BIT_MASK_DESCR(IRQCHIP_ONOFFLINE_ENABLED),
+        BIT_MASK_DESCR(IRQCHIP_SKIP_SET_WAKE),
+        BIT_MASK_DESCR(IRQCHIP_ONESHOT_SAFE),
+        BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
+};
+
+static void
+irq_debug_show_chip(struct seq_file *m, struct irq_data *data, int ind)
+{
+        struct irq_chip *chip = data->chip;
+
+        if (!chip) {
+                seq_printf(m, "chip: None\n");
+                return;
+        }
+        seq_printf(m, "%*schip:    %s\n", ind, "", chip->name);
+        seq_printf(m, "%*sflags:   0x%lx\n", ind + 1, "", chip->flags);
+        irq_debug_show_bits(m, ind, chip->flags, irqchip_flags,
+                            ARRAY_SIZE(irqchip_flags));
+}
+
+static void
+irq_debug_show_data(struct seq_file *m, struct irq_data *data, int ind)
+{
+        seq_printf(m, "%*sdomain:  %s\n", ind, "",
+                   data->domain ? data->domain->name : "");
+        seq_printf(m, "%*shwirq:   0x%lx\n", ind + 1, "", data->hwirq);
+        irq_debug_show_chip(m, data, ind + 1);
+#ifdef  CONFIG_IRQ_DOMAIN_HIERARCHY
+        if (!data->parent_data)
+                return;
+        seq_printf(m, "%*sparent:\n", ind + 1, "");
+        irq_debug_show_data(m, data->parent_data, ind + 4);
+#endif
+}
+
+static const struct irq_bit_descr irqdata_states[] = {
+        BIT_MASK_DESCR(IRQ_TYPE_EDGE_RISING),
+        BIT_MASK_DESCR(IRQ_TYPE_EDGE_FALLING),
+        BIT_MASK_DESCR(IRQ_TYPE_LEVEL_HIGH),
+        BIT_MASK_DESCR(IRQ_TYPE_LEVEL_LOW),
+        BIT_MASK_DESCR(IRQD_LEVEL),
+
+        BIT_MASK_DESCR(IRQD_ACTIVATED),
+        BIT_MASK_DESCR(IRQD_IRQ_STARTED),
+        BIT_MASK_DESCR(IRQD_IRQ_DISABLED),
+        BIT_MASK_DESCR(IRQD_IRQ_MASKED),
+        BIT_MASK_DESCR(IRQD_IRQ_INPROGRESS),
+
+        BIT_MASK_DESCR(IRQD_PER_CPU),
+        BIT_MASK_DESCR(IRQD_NO_BALANCING),
+
+        BIT_MASK_DESCR(IRQD_MOVE_PCNTXT),
+        BIT_MASK_DESCR(IRQD_AFFINITY_SET),
+        BIT_MASK_DESCR(IRQD_SETAFFINITY_PENDING),
+        BIT_MASK_DESCR(IRQD_AFFINITY_MANAGED),
+        BIT_MASK_DESCR(IRQD_MANAGED_SHUTDOWN),
+
+        BIT_MASK_DESCR(IRQD_FORWARDED_TO_VCPU),
+
+        BIT_MASK_DESCR(IRQD_WAKEUP_STATE),
+        BIT_MASK_DESCR(IRQD_WAKEUP_ARMED),
+};
+
+static const struct irq_bit_descr irqdesc_states[] = {
+        BIT_MASK_DESCR(_IRQ_NOPROBE),
+        BIT_MASK_DESCR(_IRQ_NOREQUEST),
+        BIT_MASK_DESCR(_IRQ_NOTHREAD),
+        BIT_MASK_DESCR(_IRQ_NOAUTOEN),
+        BIT_MASK_DESCR(_IRQ_NESTED_THREAD),
+        BIT_MASK_DESCR(_IRQ_PER_CPU_DEVID),
+        BIT_MASK_DESCR(_IRQ_IS_POLLED),
+        BIT_MASK_DESCR(_IRQ_DISABLE_UNLAZY),
+};
+
+static const struct irq_bit_descr irqdesc_istates[] = {
+        BIT_MASK_DESCR(IRQS_AUTODETECT),
+        BIT_MASK_DESCR(IRQS_SPURIOUS_DISABLED),
+        BIT_MASK_DESCR(IRQS_POLL_INPROGRESS),
+        BIT_MASK_DESCR(IRQS_ONESHOT),
+        BIT_MASK_DESCR(IRQS_REPLAY),
+        BIT_MASK_DESCR(IRQS_WAITING),
+        BIT_MASK_DESCR(IRQS_PENDING),
+        BIT_MASK_DESCR(IRQS_SUSPENDED),
+};
+
+
+static int irq_debug_show(struct seq_file *m, void *p)
+{
+        struct irq_desc *desc = m->private;
+        struct irq_data *data;
+
+        raw_spin_lock_irq(&desc->lock);
+        data = irq_desc_get_irq_data(desc);
+        seq_printf(m, "handler:  %pf\n", desc->handle_irq);
+        seq_printf(m, "status:   0x%08x\n", desc->status_use_accessors);
+        irq_debug_show_bits(m, 0, desc->status_use_accessors, irqdesc_states,
+                            ARRAY_SIZE(irqdesc_states));
+        seq_printf(m, "istate:   0x%08x\n", desc->istate);
+        irq_debug_show_bits(m, 0, desc->istate, irqdesc_istates,
+                            ARRAY_SIZE(irqdesc_istates));
+        seq_printf(m, "ddepth:   %u\n", desc->depth);
+        seq_printf(m, "wdepth:   %u\n", desc->wake_depth);
+        seq_printf(m, "dstate:   0x%08x\n", irqd_get(data));
+        irq_debug_show_bits(m, 0, irqd_get(data), irqdata_states,
+                            ARRAY_SIZE(irqdata_states));
+        seq_printf(m, "node:     %d\n", irq_data_get_node(data));
+        irq_debug_show_masks(m, desc);
+        irq_debug_show_data(m, data, 0);
+        raw_spin_unlock_irq(&desc->lock);
+        return 0;
+}
+
+static int irq_debug_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, irq_debug_show, inode->i_private);
+}
+
+static const struct file_operations dfs_irq_ops = {
+        .open           = irq_debug_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc)
+{
+        char name [10];
+
+        if (!irq_dir || !desc || desc->debugfs_file)
+                return;
+
+        sprintf(name, "%d", irq);
+        desc->debugfs_file = debugfs_create_file(name, 0444, irq_dir, desc,
+                                                 &dfs_irq_ops);
+}
+
+void irq_remove_debugfs_entry(struct irq_desc *desc)
+{
+        if (desc->debugfs_file)
+                debugfs_remove(desc->debugfs_file);
+}
+
+static int __init irq_debugfs_init(void)
+{
+        struct dentry *root_dir;
+        int irq;
+
+        root_dir = debugfs_create_dir("irq", NULL);
+        if (!root_dir)
+                return -ENOMEM;
+
+        irq_domain_debugfs_init(root_dir);
+
+        irq_dir = debugfs_create_dir("irqs", root_dir);
+
+        irq_lock_sparse();
+        for_each_active_irq(irq)
+                irq_add_debugfs_entry(irq, irq_to_desc(irq));
+        irq_unlock_sparse();
+
+        return 0;
+}
+__initcall(irq_debugfs_init);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 921a2419720c..094db5bfb83f 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -169,6 +169,11 @@ irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags)
 
 #define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)
 
+static inline unsigned int irqd_get(struct irq_data *d)
+{
+        return __irqd_to_state(d);
+}
+
 /*
  * Manipulation functions for irq_data.state
  */
@@ -237,3 +242,20 @@ irq_init_generic_chip(struct irq_chip_generic *gc, const char *name,
                       int num_ct, unsigned int irq_base,
                       void __iomem *reg_base, irq_flow_handler_t handler) { }
 #endif /* CONFIG_GENERIC_IRQ_CHIP */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc);
+void irq_remove_debugfs_entry(struct irq_desc *desc);
+# ifdef CONFIG_IRQ_DOMAIN
+void irq_domain_debugfs_init(struct dentry *root);
+# else
+static inline void irq_domain_debugfs_init(struct dentry *root);
+# endif
+#else /* CONFIG_GENERIC_IRQ_DEBUGFS */
+static inline void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *d)
+{
+}
+static inline void irq_remove_debugfs_entry(struct irq_desc *d)
+{
+}
+#endif /* CONFIG_GENERIC_IRQ_DEBUGFS */
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 09abce2ea8f0..feade536b6d1 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -394,6 +394,7 @@ static void free_desc(unsigned int irq)
 {
         struct irq_desc *desc = irq_to_desc(irq);
 
+        irq_remove_debugfs_entry(desc);
         unregister_irq_proc(irq, desc);
 
         /*
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 8d5805c655b6..75e1f0851c33 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -29,9 +29,17 @@ struct irqchip_fwid {
         struct fwnode_handle    fwnode;
         unsigned int            type;
         char                    *name;
-        void                    *data;
+        void *data;
 };
 
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static void debugfs_add_domain_dir(struct irq_domain *d);
+static void debugfs_remove_domain_dir(struct irq_domain *d);
+#else
+static inline void debugfs_add_domain_dir(struct irq_domain *d) { }
+static inline void debugfs_remove_domain_dir(struct irq_domain *d) { }
+#endif
+
 /**
  * irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for
  *                           identifying an irq domain
@@ -194,6 +202,7 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
         irq_domain_check_hierarchy(domain);
 
         mutex_lock(&irq_domain_mutex);
+        debugfs_add_domain_dir(domain);
         list_add(&domain->link, &irq_domain_list);
         mutex_unlock(&irq_domain_mutex);
 
@@ -213,6 +222,7 @@ EXPORT_SYMBOL_GPL(__irq_domain_add);
 void irq_domain_remove(struct irq_domain *domain)
 {
         mutex_lock(&irq_domain_mutex);
+        debugfs_remove_domain_dir(domain);
 
         WARN_ON(!radix_tree_empty(&domain->revmap_tree));
 
@@ -1599,3 +1609,78 @@ static void irq_domain_check_hierarchy(struct irq_domain *domain)
 {
 }
 #endif  /* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static struct dentry *domain_dir;
+
+static void
+irq_domain_debug_show_one(struct seq_file *m, struct irq_domain *d, int ind)
+{
+        seq_printf(m, "%*sname:   %s\n", ind, "", d->name);
+        seq_printf(m, "%*ssize:   %u\n", ind + 1, "",
+                   d->revmap_size + d->revmap_direct_max_irq);
+        seq_printf(m, "%*smapped: %u\n", ind + 1, "", d->mapcount);
+        seq_printf(m, "%*sflags:  0x%08x\n", ind +1 , "", d->flags);
+#ifdef  CONFIG_IRQ_DOMAIN_HIERARCHY
+        if (!d->parent)
+                return;
+        seq_printf(m, "%*sparent: %s\n", ind + 1, "", d->parent->name);
+        irq_domain_debug_show_one(m, d->parent, ind + 4);
+#endif
+}
+
+static int irq_domain_debug_show(struct seq_file *m, void *p)
+{
+        struct irq_domain *d = m->private;
+
+        /* Default domain? Might be NULL */
+        if (!d) {
+                if (!irq_default_domain)
+                        return 0;
+                d = irq_default_domain;
+        }
+        irq_domain_debug_show_one(m, d, 0);
+        return 0;
+}
+
+static int irq_domain_debug_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, irq_domain_debug_show, inode->i_private);
+}
+
+static const struct file_operations dfs_domain_ops = {
+        .open           = irq_domain_debug_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static void debugfs_add_domain_dir(struct irq_domain *d)
+{
+        if (!d->name || !domain_dir || d->debugfs_file)
+                return;
+        d->debugfs_file = debugfs_create_file(d->name, 0444, domain_dir, d,
+                                              &dfs_domain_ops);
+}
+
+static void debugfs_remove_domain_dir(struct irq_domain *d)
+{
+        if (d->debugfs_file)
+                debugfs_remove(d->debugfs_file);
+}
+
+void __init irq_domain_debugfs_init(struct dentry *root)
+{
+        struct irq_domain *d;
+
+        domain_dir = debugfs_create_dir("domains", root);
+        if (!domain_dir)
+                return;
+
+        debugfs_create_file("default", 0444, domain_dir, NULL, &dfs_domain_ops);
+        mutex_lock(&irq_domain_mutex);
+        list_for_each_entry(d, &irq_domain_list, link)
+                debugfs_add_domain_dir(d);
+        mutex_unlock(&irq_domain_mutex);
+}
+#endif
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4c34696ca575..284f4eb1ffbe 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1398,6 +1398,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                 wake_up_process(new->secondary->thread);
 
         register_irq_proc(irq, desc);
+        irq_add_debugfs_entry(irq, desc);
         new->dir = NULL;
         register_handler_proc(irq, new);
         free_cpumask_var(mask);