PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()

To support IOAPIC hotplug, we need to allocate PCI IRQ resources on demand
and free them when not used anymore.

Implement pcibios_alloc_irq() and pcibios_free_irq() to dynamically
allocate and free PCI IRQs.

Remove mp_should_keep_irq(), which is no longer used.

[bhelgaas: changelog]
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/pci_x86.h

@@ -93,8 +93,6 @@ extern raw_spinlock_t pci_config_lock;
 extern int (*pcibios_enable_irq)(struct pci_dev *dev);
 extern void (*pcibios_disable_irq)(struct pci_dev *dev);
 
-extern bool mp_should_keep_irq(struct device *dev);
-
 struct pci_raw_ops {
 	int (*read)(unsigned int domain, unsigned int bus, unsigned int devfn,
 						int reg, int len, u32 *val);

arch/x86/pci/common.c

@@ -673,24 +673,22 @@ int pcibios_add_device(struct pci_dev *dev)
 	return 0;
 }
 
-int pcibios_enable_device(struct pci_dev *dev, int mask)
+int pcibios_alloc_irq(struct pci_dev *dev)
 {
-	int err;
-
-	if ((err = pci_enable_resources(dev, mask)) < 0)
-		return err;
-
-	if (!pci_dev_msi_enabled(dev))
-		return pcibios_enable_irq(dev);
-	return 0;
+	return pcibios_enable_irq(dev);
 }
 
-void pcibios_disable_device (struct pci_dev *dev)
+void pcibios_free_irq(struct pci_dev *dev)
 {
-	if (!pci_dev_msi_enabled(dev) && pcibios_disable_irq)
+	if (pcibios_disable_irq)
 		pcibios_disable_irq(dev);
 }
 
+int pcibios_enable_device(struct pci_dev *dev, int mask)
+{
+	return pci_enable_resources(dev, mask);
+}
+
 int pci_ext_cfg_avail(void)
 {
 	if (raw_pci_ext_ops)

arch/x86/pci/intel_mid_pci.c

@@ -234,10 +234,13 @@ static int intel_mid_pci_irq_enable(struct pci_dev *dev)
 
 static void intel_mid_pci_irq_disable(struct pci_dev *dev)
 {
-	if (!mp_should_keep_irq(&dev->dev) && dev->irq_managed &&
-	    dev->irq > 0) {
+	if (dev->irq_managed && dev->irq > 0) {
 		mp_unmap_irq(dev->irq);
 		dev->irq_managed = 0;
+		/*
+		 * Don't reset dev->irq here, otherwise
+		 * intel_mid_pci_irq_enable() will fail on next call.
+		 */
 	}
 }
 

arch/x86/pci/irq.c

@@ -1257,22 +1257,9 @@ static int pirq_enable_irq(struct pci_dev *dev)
 	return 0;
 }
 
-bool mp_should_keep_irq(struct device *dev)
-{
-	if (dev->power.is_prepared)
-		return true;
-#ifdef CONFIG_PM
-	if (dev->power.runtime_status == RPM_SUSPENDING)
-		return true;
-#endif
-
-	return false;
-}
-
 static void pirq_disable_irq(struct pci_dev *dev)
 {
-	if (io_apic_assign_pci_irqs && !mp_should_keep_irq(&dev->dev) &&
-	    dev->irq_managed && dev->irq) {
+	if (io_apic_assign_pci_irqs && dev->irq_managed && dev->irq) {
 		mp_unmap_irq(dev->irq);
 		dev->irq = 0;
 		dev->irq_managed = 0;

drivers/acpi/pci_irq.c

@@ -484,14 +484,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
 	if (!pin || !dev->irq_managed || dev->irq <= 0)
 		return;
 
-	/* Keep IOAPIC pin configuration when suspending */
-	if (dev->dev.power.is_prepared)
-		return;
-#ifdef	CONFIG_PM
-	if (dev->dev.power.runtime_status == RPM_SUSPENDING)
-		return;
-#endif
-
 	entry = acpi_pci_irq_lookup(dev, pin);
 	if (!entry)
 		return;
@@ -512,5 +504,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
 	if (gsi >= 0) {
 		acpi_unregister_gsi(gsi);
 		dev->irq_managed = 0;
+		dev->irq = 0;
 	}
 }