From 6d4266675279b38c301243f3a4fac4a511b03246 Mon Sep 17 00:00:00 2001 From: Vidya Sagar Date: Fri, 23 Feb 2024 13:36:24 -0600 Subject: PCI/ASPM: Update save_state when configuration changes Many PCIe device drivers save the configuration state of their device during probe and restore it when their .slot_reset() hook is called during PCIe error recovery. If the ASPM configuration is changed after the driver's probe is called and before an error event occurs, .slot_reset() restores the ASPM configuration to what it was at the time of probe, not to what it was just before the occurrence of the error event. This leads to a mismatch in ASPM configuration between the device and its upstream device. Update the saved configuration of the device when the ASPM configuration changes. Link: https://lore.kernel.org/r/20240222174436.3565146-1-vidyas@nvidia.com Signed-off-by: Vidya Sagar [bhelgaas: commit log, rebase to pci/aspm, rename to pci_update_aspm_saved_state() since it updates only LNKCTL, update only ASPMC and CLKREQ_EN in LNKCTL] Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: David E. Box --- drivers/pci/pcie/aspm.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 1379b8decdf1..10160d82c10a 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -301,16 +301,42 @@ static int policy_to_clkpm_state(struct pcie_link_state *link) return 0; } +static void pci_update_aspm_saved_state(struct pci_dev *dev) +{ + struct pci_cap_saved_state *save_state; + u16 *cap, lnkctl, aspm_ctl; + + save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP); + if (!save_state) + return; + + pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnkctl); + + /* + * Update ASPM and CLKREQ bits of LNKCTL in save_state. We only + * write PCI_EXP_LNKCTL_CCC during enumeration, so it shouldn't + * change after being captured in save_state. + */ + aspm_ctl = lnkctl & (PCI_EXP_LNKCTL_ASPMC | PCI_EXP_LNKCTL_CLKREQ_EN); + lnkctl &= ~(PCI_EXP_LNKCTL_ASPMC | PCI_EXP_LNKCTL_CLKREQ_EN); + + /* Depends on pci_save_pcie_state(): cap[1] is LNKCTL */ + cap = (u16 *)&save_state->cap.data[0]; + cap[1] = lnkctl | aspm_ctl; +} + static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable) { struct pci_dev *child; struct pci_bus *linkbus = link->pdev->subordinate; u32 val = enable ? PCI_EXP_LNKCTL_CLKREQ_EN : 0; - list_for_each_entry(child, &linkbus->devices, bus_list) + list_for_each_entry(child, &linkbus->devices, bus_list) { pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_CLKREQ_EN, val); + pci_update_aspm_saved_state(child); + } link->clkpm_enabled = !!enable; } @@ -929,6 +955,12 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) pcie_config_aspm_dev(parent, upstream); link->aspm_enabled = state; + + /* Update latest ASPM configuration in saved context */ + pci_save_aspm_l1ss_state(link->downstream); + pci_update_aspm_saved_state(link->downstream); + pci_save_aspm_l1ss_state(parent); + pci_update_aspm_saved_state(parent); } static void pcie_config_aspm_path(struct pcie_link_state *link) -- cgit