diff options
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/cxl/pci.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index 3a5f9801640d..6ac6b05f41a4 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -1426,6 +1426,43 @@ static int cxl_slot_is_switched(struct pci_dev *dev) return (depth > CXL_MAX_PCIEX_PARENT); } +bool cxl_slot_is_supported(struct pci_dev *dev, int flags) +{ + if (!cpu_has_feature(CPU_FTR_HVMODE)) + return false; + + if ((flags & CXL_SLOT_FLAG_DMA) && (!pvr_version_is(PVR_POWER8NVL))) { + /* + * CAPP DMA mode is technically supported on regular P8, but + * will EEH if the card attempts to access memory < 4GB, which + * we cannot realistically avoid. We might be able to work + * around the issue, but until then return unsupported: + */ + return false; + } + + if (cxl_slot_is_switched(dev)) + return false; + + /* + * XXX: This gets a little tricky on regular P8 (not POWER8NVL) since + * the CAPP can be connected to PHB 0, 1 or 2 on a first come first + * served basis, which is racy to check from here. If we need to + * support this in future we might need to consider having this + * function effectively reserve it ahead of time. + * + * Currently, the only user of this API is the Mellanox CX4, which is + * only supported on P8NVL due to the above mentioned limitation of + * CAPP DMA mode and therefore does not need to worry about this. If the + * issue with CAPP DMA mode is later worked around on P8 we might need + * to revisit this. + */ + + return true; +} +EXPORT_SYMBOL_GPL(cxl_slot_is_supported); + + static int cxl_probe(struct pci_dev *dev, const struct pci_device_id *id) { struct cxl *adapter; |