On Sun, Oct 25, 2020 at 12:34:42AM +0530, Vidya Sagar wrote:
> Previously ASPM L1-Sub-States control registers (CTL1 and CTL2) weren't
> saved and restored during suspend/resume leading to ASPM-L1SS
> configuration being lost post resume.
>
> Save the ASPM-L1SS control registers so that the configuration is retained
> post resume.
>
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
Applied to pci/aspm for v5.11, thanks!
I tidied up pci_restore_aspm_l1ss_state() so it does the checking the
same way as pci_save_aspm_l1ss_state().
> ---
> v1:
> * It would be really good if someone can verify it on a non tegra194 platform
>
> drivers/pci/pci.c | 7 +++++++
> drivers/pci/pci.h | 4 ++++
> drivers/pci/pcie/aspm.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 52 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index a458c46d7e39..034497264bde 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1551,6 +1551,7 @@ 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);
> return pci_save_vc_state(dev);
> @@ -1656,6 +1657,7 @@ 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);
> @@ -3319,6 +3321,11 @@ 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 fa12f7cbc1a0..8d2135f61e36 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -565,11 +565,15 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev);
> void pcie_aspm_exit_link_state(struct pci_dev *pdev);
> void pcie_aspm_pm_state_change(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_pm_state_change(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 253c30cc1967..d965bbc563ed 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -742,6 +742,47 @@ 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;
> + int aspm_l1ss;
> + u32 *cap;
> +
> + if (!pci_is_pcie(dev))
> + return;
> +
> + aspm_l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
> + if (!aspm_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, aspm_l1ss + PCI_L1SS_CTL1, cap++);
> + pci_read_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL2, cap++);
> +}
> +
> +void pci_restore_aspm_l1ss_state(struct pci_dev *dev)
> +{
> + struct pci_cap_saved_state *save_state;
> + int aspm_l1ss;
> + u32 *cap;
> +
> + if (!pci_is_pcie(dev))
> + return;
> +
> + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_L1SS);
> + aspm_l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
> + if (!save_state || !aspm_l1ss)
> + return;
> +
> + cap = (u32 *)&save_state->cap.data[0];
> + pci_write_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL1, *cap++);
> + pci_write_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL2, *cap++);
> +}
> +
> static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
> {
> pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
> --
> 2.17.1
>
