diff options
Diffstat (limited to 'hw/pci/pcie.c')
| -rw-r--r-- | hw/pci/pcie.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c index aef84c665b..6891deb711 100644 --- a/hw/pci/pcie.c +++ b/hw/pci/pcie.c @@ -741,6 +741,45 @@ void pcie_add_capability(PCIDevice *dev, memset(dev->cmask + offset, 0xFF, size); } +/* + * Sync the PCIe Link Status negotiated speed and width of a bridge with the + * downstream device. If downstream device is not present, re-write with the + * Link Capability fields. Limit width and speed to bridge capabilities for + * compatibility. Use config_read to access the downstream device since it + * could be an assigned device with volatile link information. + */ +void pcie_sync_bridge_lnk(PCIDevice *bridge_dev) +{ + PCIBridge *br = PCI_BRIDGE(bridge_dev); + PCIBus *bus = pci_bridge_get_sec_bus(br); + PCIDevice *target = bus->devices[0]; + uint8_t *exp_cap = bridge_dev->config + bridge_dev->exp.exp_cap; + uint16_t lnksta, lnkcap = pci_get_word(exp_cap + PCI_EXP_LNKCAP); + + if (!target || !target->exp.exp_cap) { + lnksta = lnkcap; + } else { + lnksta = target->config_read(target, + target->exp.exp_cap + PCI_EXP_LNKSTA, + sizeof(lnksta)); + + if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) { + lnksta &= ~PCI_EXP_LNKSTA_NLW; + lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW; + } + + if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) { + lnksta &= ~PCI_EXP_LNKSTA_CLS; + lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS; + } + } + + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA, + PCI_EXP_LNKSTA_CLS | PCI_EXP_LNKSTA_NLW); + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, lnksta & + (PCI_EXP_LNKSTA_CLS | PCI_EXP_LNKSTA_NLW)); +} + /************************************************************************** * pci express extended capability helper functions */ |