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Code Issues Releases Wiki Activity

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 <vidyas@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Vidya Sagar 2022-09-13 18:48:22 +05:30 committed by Bjorn Helgaas
parent 5e85eba6f5
commit 4ff116d0d5
3 changed files with 48 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/pci/pci.c
View File

@ -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);
}

4
drivers/pci/pci.h
View File

@ -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

37
drivers/pci/pcie/aspm.c
View File

@ -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,