From 4257f7e008ea394fcecc050f1569c3503b8bcc15 Mon Sep 17 00:00:00 2001
From: Vidya Sagar <vidyas@nvidia.com>
Date: Sun, 25 Oct 2020 00:34:42 +0530
Subject: [PATCH] PCI/ASPM: Save/restore L1SS Capability for suspend/resume
Previously ASPM L1 Substates control registers (CTL1 and CTL2) weren't
saved and restored during suspend/resume leading to L1 Substates
configuration being lost post-resume.
Save the L1 Substates control registers so that the configuration is
retained post-resume.
Link: https://lore.kernel.org/r/20201024190442.871-1-vidyas@nvidia.com
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pci.c | 7 +++++++
drivers/pci/pci.h | 4 ++++
drivers/pci/pcie/aspm.c | 44 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 55 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e578d34095e9..eb52c28c3a1a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1564,6 +1564,7 @@ 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);
@@ -1669,6 +1670,7 @@ 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);
@@ -3332,6 +3334,11 @@ 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 f86cae9aa1f4..60308cd1cffc 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -564,11 +564,15 @@ 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 ac0557a305af..a08e7d6dc248 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -734,6 +734,50 @@ 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)
+{
+ int aspm_l1ss;
+ struct pci_cap_saved_state *save_state;
+ 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)
+{
+ int aspm_l1ss;
+ struct pci_cap_saved_state *save_state;
+ 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_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,
--
2.42.0