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Date: Fri, 26 Aug 2022 18:25:26 +0530
From: Vidya Sagar <vidyas@...dia.com>
To: <bhelgaas@...gle.com>, <lorenzo.pieralisi@....com>,
<refactormyself@...il.com>, <kw@...ux.com>, <rajatja@...gle.com>,
<kenny@...ix.com>, <kai.heng.feng@...onical.com>,
<treding@...dia.com>, <jonathanh@...dia.com>, <abhsahu@...dia.com>,
<sagupta@...dia.com>
CC: <benchuanggli@...il.com>, <linux-pci@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <kthota@...dia.com>,
<mmaddireddy@...dia.com>, <vidyas@...dia.com>, <sagar.tv@...il.com>
Subject: [PATCH V3] 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.
Signed-off-by: Vidya Sagar <vidyas@...dia.com>
---
V3:
* Disabled L1.2 enable fields while restoring Control-1 register
Hi Kai-Heng,
Could you please try this patch on your setup?
Thanks & Regards,
Vidya Sagar
drivers/pci/pci.c | 7 ++++++
drivers/pci/pci.h | 4 ++++
drivers/pci/pcie/aspm.c | 50 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 61 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 95bc329e74c0..68a49fbaabde 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 785f31086313..365a844ec430 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 a8aec190986c..ee1f651bb1af 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -726,6 +726,56 @@ 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_CTL2, cap++);
+ pci_read_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL1, cap++);
+}
+
+void pci_restore_aspm_l1ss_state(struct pci_dev *dev)
+{
+ int aspm_l1ss;
+ struct pci_cap_saved_state *save_state;
+ u32 *cap, l1_2_enable;
+
+ 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_CTL2, *cap++);
+ /* Disable L1.2 while updating. See PCIe r5.0, sec 5.5.4, 7.8.3.3 */
+ l1_2_enable = *cap & PCI_L1SS_CTL1_L1_2_MASK;
+ pci_write_config_dword(dev, aspm_l1ss + PCI_L1SS_CTL1,
+ (*cap & ~PCI_L1SS_CTL1_L1_2_MASK));
+ if (l1_2_enable)
+ pci_clear_and_set_dword(dev, aspm_l1ss + PCI_L1SS_CTL1, 0,
+ l1_2_enable);
+}
+
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
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