[PATCH 2/2] Revert "PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()"

[Bjorn Helgaas]

This reverts commit 991de2e59090e55c65a7f59a049142e3c480f7bd.

991de2e59090 ("PCI, x86: Implement pcibios_alloc_irq() and
pcibios_free_irq()") appeared in v4.3 and helps support IOAPIC hotplug.

ÐÐÐÐ reported that the Elcus-1553 TA1-PCI driver worked in v4.2 but not
v4.3 and bisected it to 991de2e59090.  Sunjin reported that the RocketRAID
272x driver worked in v4.2 but not v4.3.  In both cases booting with
"pci=routirq" is a workaround.

I think the problem is that after 991de2e59090, we no longer call
pcibios_enable_irq() for upstream bridges.  Prior to 991de2e59090, when a
driver called pci_enable_device(), we recursively called
pcibios_enable_irq() for upstream bridges via pci_enable_bridge().

After 991de2e59090, we call pcibios_enable_irq() from pci_device_probe()
instead of the pci_enable_device() path, which does *not* call
pcibios_enable_irq() for upstream bridges.

Revert 991de2e59090 to fix these driver regressions.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=111211
Fixes: 991de2e59090 ("PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()")
Reported-and-tested-by: ÐÐÐÐ ÐÐÑÐÐ <oleg.moroz@xxxxxxxxxxxxx>
Reported-by: Sunjin Yang <fan4326@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx	# v4.3
CC: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/pci_x86.h |    2 ++
 arch/x86/pci/common.c          |   20 +++++++++++---------
 arch/x86/pci/intel_mid_pci.c   |    7 ++-----
 arch/x86/pci/irq.c             |   15 ++++++++++++++-
 drivers/acpi/pci_irq.c         |    9 ++++++++-
 5 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index fa1195d..164e3f8 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -93,6 +93,8 @@ 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);
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index dc78a4a..8fd6f44 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -673,20 +673,22 @@ int pcibios_add_device(struct pci_dev *dev)
 	return 0;
 }
 
-int pcibios_alloc_irq(struct pci_dev *dev)
+int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
-	return pcibios_enable_irq(dev);
-}
+	int err;
 
-void pcibios_free_irq(struct pci_dev *dev)
-{
-	if (pcibios_disable_irq)
-		pcibios_disable_irq(dev);
+	if ((err = pci_enable_resources(dev, mask)) < 0)
+		return err;
+
+	if (!pci_dev_msi_enabled(dev))
+		return pcibios_enable_irq(dev);
+	return 0;
 }
 
-int pcibios_enable_device(struct pci_dev *dev, int mask)
+void pcibios_disable_device (struct pci_dev *dev)
 {
-	return pci_enable_resources(dev, mask);
+	if (!pci_dev_msi_enabled(dev) && pcibios_disable_irq)
+		pcibios_disable_irq(dev);
 }
 
 int pci_ext_cfg_avail(void)
diff --git a/arch/x86/pci/intel_mid_pci.c b/arch/x86/pci/intel_mid_pci.c
index 8826ff5..8b93e63 100644
--- a/arch/x86/pci/intel_mid_pci.c
+++ b/arch/x86/pci/intel_mid_pci.c
@@ -256,13 +256,10 @@ static int intel_mid_pci_irq_enable(struct pci_dev *dev)
 
 static void intel_mid_pci_irq_disable(struct pci_dev *dev)
 {
-	if (dev->irq_managed && dev->irq > 0) {
+	if (!mp_should_keep_irq(&dev->dev) && 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.
-		 */
 	}
 }
 
diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 72108f0..9bd1154 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -1257,9 +1257,22 @@ 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 && dev->irq_managed && dev->irq) {
+	if (io_apic_assign_pci_irqs && !mp_should_keep_irq(&dev->dev) &&
+	    dev->irq_managed && dev->irq) {
 		mp_unmap_irq(dev->irq);
 		dev->irq = 0;
 		dev->irq_managed = 0;
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 172b74d..8a10a7a 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -481,6 +481,14 @@ 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;
@@ -501,6 +509,5 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
 	if (gsi >= 0) {
 		acpi_unregister_gsi(gsi);
 		dev->irq_managed = 0;
-		dev->irq = 0;
 	}
 }