s390/pci: create zPCI bus

The zPCI bus is in charge to handle common zPCI resources for
zPCI devices.

Creating the zPCI bus, the PCI bus, the zPCI devices and the
PCI devices and hotplug slots
done in a specific order:
- PCI hotplug slot creation needs a PCI bus
- PCI bus needs a PCI domain
  which is reported by the pci_domain_nr() when setting up the
  host bridge
- PCI domain is set from the zPCI with devfn 0
  this is necessary to have a reproducible enumeration

Therefore we can not create devices or hotplug slots for any PCI
device associated with a zPCI device before having discovered
the function zero of the bus.

The discovery and initialization of devices can be done at several
points in the code:
- On Events, serialized in a thread context
- On initialization, in the kernel init thread context
- When powering on the hotplug slot, in a user thread context

The removal of devices and their parent bus may also be done on
events or for devices when powering down the slot.

To guarantee the existence of the bus and devices until they are
no more needed we use kref in zPCI bus and introduce a reference
count in the zPCI devices.

In this patch the zPCI bus still only accept a device with
a devfn 0.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index 8d6ee4af4230..d39e9299e133 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -14,6 +14,8 @@
 #include <asm/pci_debug.h>
 #include <asm/sclp.h>
 
+#include "pci_bus.h"
+
 /* Content Code Description for PCI Function Error */
 struct zpci_ccdf_err {
 	u32 reserved1;
@@ -53,7 +55,7 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 	zpci_err_hex(ccdf, sizeof(*ccdf));
 
 	if (zdev)
-		pdev = pci_get_slot(zdev->bus, ZPCI_DEVFN);
+		pdev = pci_get_slot(zdev->zbus->bus, ZPCI_DEVFN);
 
 	pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
 	       pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
@@ -78,11 +80,9 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 	enum zpci_state state;
 	int ret;
 
-	if (zdev)
-		pdev = pci_get_slot(zdev->bus, ZPCI_DEVFN);
+	if (zdev && zdev->zbus && zdev->zbus->bus)
+		pdev = pci_get_slot(zdev->zbus->bus, ZPCI_DEVFN);
 
-	pr_info("%s: Event 0x%x reconfigured PCI function 0x%x\n",
-		pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
 	zpci_err("avail CCDF:\n");
 	zpci_err_hex(ccdf, sizeof(*ccdf));
 
@@ -102,7 +102,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 		if (ret)
 			break;
 		pci_lock_rescan_remove();
-		pci_rescan_bus(zdev->bus);
+		pci_rescan_bus(zdev->zbus->bus);
 		pci_unlock_rescan_remove();
 		break;
 	case 0x0302: /* Reserved -> Standby */
@@ -140,7 +140,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 		zdev->state = ZPCI_FN_STATE_STANDBY;
 		if (!clp_get_state(ccdf->fid, &state) &&
 		    state == ZPCI_FN_STATE_RESERVED) {
-			zpci_remove_device(zdev);
+			zpci_zdev_put(zdev);
 		}
 		break;
 	case 0x0306: /* 0x308 or 0x302 for multiple devices */
@@ -149,12 +149,11 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 	case 0x0308: /* Standby -> Reserved */
 		if (!zdev)
 			break;
-		zpci_remove_device(zdev);
+		zpci_zdev_put(zdev);
 		break;
 	default:
 		break;
 	}
-	pci_dev_put(pdev);
 }
 
 void zpci_event_availability(void *data)