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linux/arch/s390/pci/pci_bus.h

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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>
2020-03-23 09:45:43 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright IBM Corp. 2020
*
* Author(s):
* Pierre Morel <pmorel@linux.ibm.com>
*
*/
int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops);
void zpci_bus_device_unregister(struct zpci_dev *zdev);
s390/pci: separate zbus creation from scanning In the existing code the creation of the PCI bus and the scanning of function zero all happens in zpci_scan_bus(). This in turn requires functions to be enabled and their resources to be available before the PCI bus is even created. This not only means that functions are enabled long before they are actually made available to the common PCI subsystem. In case of functions with non-zero devfn which appeared before the function with devfn zero they can wait arbitrarily long in this enabled but not scanned state. Fix this by separating the creation of the PCI bus from scanning it and only prepare, that is enable and setup MMIO bus resources, functions just before they are scanned. As they may be scanned multiple times track if we already created resources in the zdev. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-02-12 13:19:31 +00:00
int zpci_bus_scan_bus(struct zpci_bus *zbus);
s390/pci: separate zbus registration from scanning Now that the zbus can be created without being scanned we can go one step further and make registering a device to a zbus independent from scanning it. This way the zbus handling becomes much more natural in that functions can be registered on the zbus to be scanned later more closely resembling the handling of both real PCI hardware and other virtual PCI busses like Hyper-V's virtual PCI bus (see for example drivers/pci/controller/pci-hyperv.c:create_root_hv_pci_bus()). Having zbus registration separate from scanning allows us to return fully initialized but still disabled zdevs from zpci_create_device() which can then be configured just as we would configure a zdev from standby (minus the SCLP Configure already done by the platform). There is still the exception that a PCI function with non-zero devfn can be plugged before its PCI bus, which depends on the function with zero devfn, is created. In this case the zdev returend from zpci_create_device() is still missing its bus, hotplug slot, and resources which need to be created later but at least it doesn't wait in the enabled state and can otherwise be treated as initialized. With this we also separate the initial PCI scan using CLP List PCI Functions into two phases. In the CLP loop's callback we only register each function with a virtual zbus creating the latter as needed. Then, after we have built this virtual PCI topology based on our list of zbusses, we can make use of the common code functionality to scan each complete zbus as a separate child bus. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-02-12 10:57:58 +00:00
void zpci_bus_scan_busses(void);
s390/pci: separate zbus creation from scanning In the existing code the creation of the PCI bus and the scanning of function zero all happens in zpci_scan_bus(). This in turn requires functions to be enabled and their resources to be available before the PCI bus is even created. This not only means that functions are enabled long before they are actually made available to the common PCI subsystem. In case of functions with non-zero devfn which appeared before the function with devfn zero they can wait arbitrarily long in this enabled but not scanned state. Fix this by separating the creation of the PCI bus from scanning it and only prepare, that is enable and setup MMIO bus resources, functions just before they are scanned. As they may be scanned multiple times track if we already created resources in the zdev. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-02-12 13:19:31 +00:00
s390/pci: introduce zpci_bus_scan_device() To match zpci_bus_scan_device() and the PCI common code terminology and to remove some code duplication, we pull the multiple uses of pci_scan_single_device() into a function. For now this has the side effect of adding each device to the PCI bus separately and locking and unlocking the rescan/remove lock for each instead of just once per bus. This is clearly less efficient but provides a correct intermediate behavior until a follow on change does both the adding and scanning only once per bus. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-02-11 13:20:03 +00:00
int zpci_bus_scan_device(struct zpci_dev *zdev);
s390/pci: move zpci_remove_device() to bus code The zpci_remove_device() function removes the device from the PCI common code core which is an operation dealing primarily with the zbus and PCI bus code. With that and to match an upcoming refactoring of the symmetric scanning part move it to the bus code. Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-01-26 12:58:28 +00:00
void zpci_bus_remove_device(struct zpci_dev *zdev, bool set_error);
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>
2020-03-23 09:45:43 +00:00
void zpci_release_device(struct kref *kref);
static inline void zpci_zdev_put(struct zpci_dev *zdev)
{
kref_put(&zdev->kref, zpci_release_device);
}
int zpci_alloc_domain(int domain);
void zpci_free_domain(int domain);
int zpci_setup_bus_resources(struct zpci_dev *zdev,
struct list_head *resources);
s390/pci: Handling multifunctions We allow multiple functions on a single bus. We suppress the ZPCI_DEVFN definition and replace its occurences with zpci->devfn. We verify the number of device during the registration. There can never be more domains in use than existing devices, so we do not need to verify the count of domain after having verified the count of devices. 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>
2020-04-22 13:15:23 +00:00
static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus,
unsigned int devfn)
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>
2020-03-23 09:45:43 +00:00
{
struct zpci_bus *zbus = bus->sysdata;
s390/pci: Handling multifunctions We allow multiple functions on a single bus. We suppress the ZPCI_DEVFN definition and replace its occurences with zpci->devfn. We verify the number of device during the registration. There can never be more domains in use than existing devices, so we do not need to verify the count of domain after having verified the count of devices. 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>
2020-04-22 13:15:23 +00:00
return (devfn >= ZPCI_FUNCTIONS_PER_BUS) ? NULL : zbus->function[devfn];
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>
2020-03-23 09:45:43 +00:00
}
s390/pci: fix PF/VF linking on hot plug Currently there are four places in which a PCI function is scanned and made available to drivers: 1. In pci_scan_root_bus() as part of the initial zbus creation. 2. In zpci_bus_add_devices() when registering a device in configured state on a zbus that has already been scanned. 3. When a function is already known to zPCI (in reserved/standby state) and configuration is triggered through firmware by PEC 0x301. 4. When a device is already known to zPCI (in standby/reserved state) and configuration is triggered from within Linux using enable_slot(). The PF/VF linking step and setting of pdev->is_virtfn introduced with commit e5794cf1a270 ("s390/pci: create links between PFs and VFs") was only triggered for the second case, which is where VFs created through sriov_numvfs usually land. However unlike some other platforms but like POWER VFs can be individually enabled/disabled through /sys/bus/pci/slots. Fix this by doing VF setup as part of pcibios_bus_add_device() which is called in all of the above cases. Finally to remove the PF/VF links call the common code pci_iov_remove_virtfn() function to remove linked VFs. This takes care of the necessary sysfs cleanup. Fixes: e5794cf1a270 ("s390/pci: create links between PFs and VFs") Cc: <stable@vger.kernel.org> # 5.8: 2f0230b2f2d5: s390/pci: re-introduce zpci_remove_device() Cc: <stable@vger.kernel.org> # 5.8 Acked-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-08-03 15:58:10 +00:00
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