From 4ff116d0d5fd8a025604b0802d93a2d5f4e465d1 Mon Sep 17 00:00:00 2001 From: Vidya Sagar Date: Tue, 13 Sep 2022 18:48:22 +0530 Subject: [PATCH] PCI/ASPM: Save L1 PM Substates Capability for suspend/resume Previously the L1 PM Substates Control Registers (CTL1 and CTL2) weren't saved and restored during suspend/resume leading to the L1 PM Substates configuration being lost post-resume. Save the L1 PM Substates Control Registers so that the configuration is retained post-resume. [bhelgaas: drop pci_is_pcie() testing; we can rely on pci_configure_ltr() having already done that] Link: https://lore.kernel.org/r/20220913131822.16557-3-vidyas@nvidia.com Signed-off-by: Vidya Sagar Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 7 +++++++ drivers/pci/pci.h | 4 ++++ drivers/pci/pcie/aspm.c | 37 +++++++++++++++++++++++++++++++++++++ 3 files changed, 48 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 95bc329..68a49fb 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1663,6 +1663,7 @@ int pci_save_state(struct pci_dev *dev) return i; pci_save_ltr_state(dev); + pci_save_aspm_l1ss_state(dev); pci_save_dpc_state(dev); pci_save_aer_state(dev); pci_save_ptm_state(dev); @@ -1769,6 +1770,7 @@ void pci_restore_state(struct pci_dev *dev) * LTR itself (in the PCIe capability). */ pci_restore_ltr_state(dev); + pci_restore_aspm_l1ss_state(dev); pci_restore_pcie_state(dev); pci_restore_pasid_state(dev); @@ -3485,6 +3487,11 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev) if (error) pci_err(dev, "unable to allocate suspend buffer for LTR\n"); + error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_L1SS, + 2 * sizeof(u32)); + if (error) + pci_err(dev, "unable to allocate suspend buffer for ASPM-L1SS\n"); + pci_allocate_vc_save_buffers(dev); } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 785f310..365a844 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -561,10 +561,14 @@ bool pcie_wait_for_link(struct pci_dev *pdev, bool active); void pcie_aspm_init_link_state(struct pci_dev *pdev); void pcie_aspm_exit_link_state(struct pci_dev *pdev); void pcie_aspm_powersave_config_link(struct pci_dev *pdev); +void pci_save_aspm_l1ss_state(struct pci_dev *dev); +void pci_restore_aspm_l1ss_state(struct pci_dev *dev); #else static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { } static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { } static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { } +static inline void pci_save_aspm_l1ss_state(struct pci_dev *dev) { } +static inline void pci_restore_aspm_l1ss_state(struct pci_dev *dev) { } #endif #ifdef CONFIG_PCIE_ECRC diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index b4bdadc..016d222 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -732,6 +732,43 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state) PCI_L1SS_CTL1_L1SS_MASK, val); } +void pci_save_aspm_l1ss_state(struct pci_dev *dev) +{ + struct pci_cap_saved_state *save_state; + u16 l1ss = dev->l1ss; + u32 *cap; + + if (!l1ss) + return; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS); + if (!save_state) + return; + + cap = (u32 *)&save_state->cap.data[0]; + pci_read_config_dword(dev, l1ss + PCI_L1SS_CTL2, cap++); + pci_read_config_dword(dev, l1ss + PCI_L1SS_CTL1, cap++); +} + +void pci_restore_aspm_l1ss_state(struct pci_dev *dev) +{ + struct pci_cap_saved_state *save_state; + u32 *cap, ctl1, ctl2; + u16 l1ss = dev->l1ss; + + if (!l1ss) + return; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS); + if (!save_state) + return; + + cap = (u32 *)&save_state->cap.data[0]; + ctl2 = *cap++; + ctl1 = *cap; + aspm_program_l1ss(dev, ctl1, ctl2); +} + static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val) { pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL, -- 2.7.4