diff options
author | Niklas Schnelle <schnelle@linux.ibm.com> | 2021-07-01 15:49:11 +0200 |
---|---|---|
committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-11-08 14:17:49 +0100 |
commit | da995d538d3a17610d89fea0f5813cf7921b3c2c (patch) | |
tree | 5004af3a435a6546658bf78ecbc559a355aea055 /arch | |
parent | 4fe204977096e900cb91a3298b05c794ac24f540 (diff) | |
download | linux-da995d538d3a17610d89fea0f5813cf7921b3c2c.tar.bz2 |
s390/pci: implement reset_slot for hotplug slot
This is done by adding a zpci_hot_reset_device() call which does a low
level reset of the PCI function without changing its higher level
function state. This way it can be used while the zPCI function is bound
to a driver and with DMA tables being controlled either through the
IOMMU or DMA APIs which is prohibited when using zpci_disable_device()
as that drop existing DMA translations.
As this reset, unlike a normal FLR, also calls zpci_clear_irq() we need
to implement arch_restore_msi_irqs() and make sure we re-enable IRQs for
the PCI function if they were previously disabled.
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/s390/include/asm/pci.h | 1 | ||||
-rw-r--r-- | arch/s390/pci/pci.c | 59 | ||||
-rw-r--r-- | arch/s390/pci/pci_irq.c | 9 |
3 files changed, 69 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index 35adc0cd0e6a..a47068a73969 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -210,6 +210,7 @@ int zpci_deconfigure_device(struct zpci_dev *zdev); void zpci_device_reserved(struct zpci_dev *zdev); bool zpci_is_device_configured(struct zpci_dev *zdev); +int zpci_hot_reset_device(struct zpci_dev *zdev); int zpci_register_ioat(struct zpci_dev *, u8, u64, u64, u64); int zpci_unregister_ioat(struct zpci_dev *, u8); void zpci_remove_reserved_devices(void); diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index fe01ca3b33fa..e95b08e5cc5b 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -724,6 +724,65 @@ int zpci_disable_device(struct zpci_dev *zdev) } /** + * zpci_hot_reset_device - perform a reset of the given zPCI function + * @zdev: the slot which should be reset + * + * Performs a low level reset of the zPCI function. The reset is low level in + * the sense that the zPCI function can be reset without detaching it from the + * common PCI subsystem. The reset may be performed while under control of + * either DMA or IOMMU APIs in which case the existing DMA/IOMMU translation + * table is reinstated at the end of the reset. + * + * After the reset the functions internal state is reset to an initial state + * equivalent to its state during boot when first probing a driver. + * Consequently after reset the PCI function requires re-initialization via the + * common PCI code including re-enabling IRQs via pci_alloc_irq_vectors() + * and enabling the function via e.g.pci_enablde_device_flags().The caller + * must guard against concurrent reset attempts. + * + * In most cases this function should not be called directly but through + * pci_reset_function() or pci_reset_bus() which handle the save/restore and + * locking. + * + * Return: 0 on success and an error value otherwise + */ +int zpci_hot_reset_device(struct zpci_dev *zdev) +{ + int rc; + + zpci_dbg(3, "rst fid:%x, fh:%x\n", zdev->fid, zdev->fh); + if (zdev_enabled(zdev)) { + /* Disables device access, DMAs and IRQs (reset state) */ + rc = zpci_disable_device(zdev); + /* + * Due to a z/VM vs LPAR inconsistency in the error state the + * FH may indicate an enabled device but disable says the + * device is already disabled don't treat it as an error here. + */ + if (rc == -EINVAL) + rc = 0; + if (rc) + return rc; + } + + rc = zpci_enable_device(zdev); + if (rc) + return rc; + + if (zdev->dma_table) + rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, + (u64)zdev->dma_table); + else + rc = zpci_dma_init_device(zdev); + if (rc) { + zpci_disable_device(zdev); + return rc; + } + + return 0; +} + +/** * zpci_create_device() - Create a new zpci_dev and add it to the zbus * @fid: Function ID of the device to be created * @fh: Current Function Handle of the device to be created diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c index 3823e159bf74..954bb7a83124 100644 --- a/arch/s390/pci/pci_irq.c +++ b/arch/s390/pci/pci_irq.c @@ -387,6 +387,15 @@ void arch_teardown_msi_irqs(struct pci_dev *pdev) airq_iv_free(zpci_ibv[0], zdev->msi_first_bit, zdev->msi_nr_irqs); } +void arch_restore_msi_irqs(struct pci_dev *pdev) +{ + struct zpci_dev *zdev = to_zpci(pdev); + + if (!zdev->irqs_registered) + zpci_set_irq(zdev); + default_restore_msi_irqs(pdev); +} + static struct airq_struct zpci_airq = { .handler = zpci_floating_irq_handler, .isc = PCI_ISC, |