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path: root/drivers/pci/pci.c
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Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r--drivers/pci/pci.c53
1 files changed, 51 insertions, 2 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c9d8e3c837de..13d65991c77b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1233,7 +1233,6 @@ static void pci_restore_pcie_state(struct pci_dev *dev)
pcie_capability_write_word(dev, PCI_EXP_SLTCTL2, cap[i++]);
}
-
static int pci_save_pcix_state(struct pci_dev *dev)
{
int pos;
@@ -1270,6 +1269,45 @@ static void pci_restore_pcix_state(struct pci_dev *dev)
pci_write_config_word(dev, pos + PCI_X_CMD, cap[i++]);
}
+static void pci_save_ltr_state(struct pci_dev *dev)
+{
+ int ltr;
+ struct pci_cap_saved_state *save_state;
+ u16 *cap;
+
+ if (!pci_is_pcie(dev))
+ return;
+
+ ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
+ if (!ltr)
+ return;
+
+ save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
+ if (!save_state) {
+ pci_err(dev, "no suspend buffer for LTR; ASPM issues possible after resume\n");
+ return;
+ }
+
+ cap = (u16 *)&save_state->cap.data[0];
+ pci_read_config_word(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, cap++);
+ pci_read_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, cap++);
+}
+
+static void pci_restore_ltr_state(struct pci_dev *dev)
+{
+ struct pci_cap_saved_state *save_state;
+ int ltr;
+ u16 *cap;
+
+ save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
+ ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
+ if (!save_state || !ltr)
+ return;
+
+ cap = (u16 *)&save_state->cap.data[0];
+ pci_write_config_word(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap++);
+ pci_write_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, *cap++);
+}
/**
* pci_save_state - save the PCI configuration space of a device before suspending
@@ -1291,6 +1329,7 @@ int pci_save_state(struct pci_dev *dev)
if (i != 0)
return i;
+ pci_save_ltr_state(dev);
pci_save_dpc_state(dev);
return pci_save_vc_state(dev);
}
@@ -1390,7 +1429,12 @@ void pci_restore_state(struct pci_dev *dev)
if (!dev->state_saved)
return;
- /* PCI Express register must be restored first */
+ /*
+ * Restore max latencies (in the LTR capability) before enabling
+ * LTR itself (in the PCIe capability).
+ */
+ pci_restore_ltr_state(dev);
+
pci_restore_pcie_state(dev);
pci_restore_pasid_state(dev);
pci_restore_pri_state(dev);
@@ -2998,6 +3042,11 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev)
if (error)
pci_err(dev, "unable to preallocate PCI-X save buffer\n");
+ error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_LTR,
+ 2 * sizeof(u16));
+ if (error)
+ pci_err(dev, "unable to allocate suspend buffer for LTR\n");
+
pci_allocate_vc_save_buffers(dev);
}