x86, irq: Introduce helper functions to release IOAPIC pin

Introduce function mp_unmap_irq() to release IOAPIC IRQ when IRQ is not
used any more, which will typically called by pcibios_disabled_irq.

And function mp_irqdomain_unmap() is a common implementation of
irq_domain_ops.unmap for IOAPIC.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1402302011-23642-38-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 64 insertions, 0 deletions

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index af6f9d4309bf..0aeed5ca356e 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -187,10 +187,12 @@ extern int mp_find_ioapic(u32 gsi);
 extern int mp_find_ioapic_pin(int ioapic, u32 gsi);
 extern u32 mp_pin_to_gsi(int ioapic, int pin);
 extern int mp_map_gsi_to_irq(u32 gsi, unsigned int flags);
+extern void mp_unmap_irq(int irq);
 extern void __init mp_register_ioapic(int id, u32 address, u32 gsi_base,
                                       struct ioapic_domain_cfg *cfg);
 extern int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
                             irq_hw_number_t hwirq);
+extern void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq);
 extern int mp_set_gsi_attr(u32 gsi, int trigger, int polarity, int node);
 extern void __init pre_init_apic_IRQ0(void);
 
@@ -234,6 +236,7 @@ static inline void ioapic_insert_resources(void) { }
 static inline int mp_find_ioapic(u32 gsi) { return 0; }
 static inline u32 mp_pin_to_gsi(int ioapic, int pin) { return UINT_MAX; }
 static inline int mp_map_gsi_to_irq(u32 gsi, unsigned int flags) { return gsi; }
+static inline void mp_unmap_irq(int irq) { }
 
 static inline int save_ioapic_entries(void)
 {
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 8485d904b653..8d80a8f1d670 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -467,6 +467,21 @@ static int __add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pi
         return 0;
 }
 
+static void __remove_pin_from_irq(struct irq_cfg *cfg, int apic, int pin)
+{
+        struct irq_pin_list **last, *entry;
+
+        last = &cfg->irq_2_pin;
+        for_each_irq_pin(entry, cfg->irq_2_pin)
+                if (entry->apic == apic && entry->pin == pin) {
+                        *last = entry->next;
+                        kfree(entry);
+                        return;
+                } else {
+                        last = &entry->next;
+                }
+}
+
 static void add_pin_to_irq_node(struct irq_cfg *cfg, int node, int apic, int pin)
 {
         if (__add_pin_to_irq_node(cfg, node, apic, pin))
@@ -1119,6 +1134,31 @@ int mp_map_gsi_to_irq(u32 gsi, unsigned int flags)
         return mp_map_pin_to_irq(gsi, idx, ioapic, pin, flags);
 }
 
+void mp_unmap_irq(int irq)
+{
+        struct irq_data *data = irq_get_irq_data(irq);
+        struct mp_pin_info *info;
+        int ioapic, pin;
+
+        if (!data || !data->domain)
+                return;
+
+        ioapic = (int)(long)data->domain->host_data;
+        pin = (int)data->hwirq;
+        info = mp_pin_info(ioapic, pin);
+
+        mutex_lock(&ioapic_mutex);
+        if (--info->count == 0) {
+                info->set = 0;
+                if (irq < nr_legacy_irqs() &&
+                    ioapics[ioapic].irqdomain_cfg.type == IOAPIC_DOMAIN_LEGACY)
+                        mp_irqdomain_unmap(data->domain, irq);
+                else
+                        irq_dispose_mapping(irq);
+        }
+        mutex_unlock(&ioapic_mutex);
+}
+
 /*
  * Find a specific PCI IRQ entry.
  * Not an __init, possibly needed by modules
@@ -3878,6 +3918,27 @@ int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
         return io_apic_setup_irq_pin(virq, info->node, &attr);
 }
 
+void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq)
+{
+        struct irq_data *data = irq_get_irq_data(virq);
+        struct irq_cfg *cfg = irq_cfg(virq);
+        int ioapic = (int)(long)domain->host_data;
+        int pin = (int)data->hwirq;
+
+        /*
+         * Skip the timer IRQ if there's a quirk handler installed and if it
+         * returns 1:
+         */
+        if (apic->multi_timer_check &&
+            apic->multi_timer_check(ioapic, virq))
+                return;
+
+        ioapic_mask_entry(ioapic, pin);
+        __remove_pin_from_irq(cfg, ioapic, pin);
+        WARN_ON(cfg->irq_2_pin != NULL);
+        arch_teardown_hwirq(virq);
+}
+
 int mp_set_gsi_attr(u32 gsi, int trigger, int polarity, int node)
 {
         int ret = 0;