PCI: Restore PCI Express capability registers after PM event
Restore PCI Express capability registers after PM event.
This includes maxumum MTU for PCI express and other vital data.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 590f4e6..a544997 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -445,6 +445,51 @@
EXPORT_SYMBOL(pci_choose_state);
+static int pci_save_pcie_state(struct pci_dev *dev)
+{
+ int pos, i = 0;
+ struct pci_cap_saved_state *save_state;
+ u16 *cap;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (pos <= 0)
+ return 0;
+
+ save_state = kzalloc(sizeof(*save_state) + sizeof(u16) * 4, GFP_KERNEL);
+ if (!save_state) {
+ dev_err(&dev->dev, "Out of memory in pci_save_pcie_state\n");
+ return -ENOMEM;
+ }
+ cap = (u16 *)&save_state->data[0];
+
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &cap[i++]);
+ pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
+ pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
+ pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
+ pci_add_saved_cap(dev, save_state);
+ return 0;
+}
+
+static void pci_restore_pcie_state(struct pci_dev *dev)
+{
+ int i = 0, pos;
+ struct pci_cap_saved_state *save_state;
+ u16 *cap;
+
+ save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!save_state || pos <= 0)
+ return;
+ cap = (u16 *)&save_state->data[0];
+
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, cap[i++]);
+ pci_write_config_word(dev, pos + PCI_EXP_LNKCTL, cap[i++]);
+ pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
+ pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
+ pci_remove_saved_cap(save_state);
+ kfree(save_state);
+}
+
/**
* pci_save_state - save the PCI configuration space of a device before suspending
* @dev: - PCI device that we're dealing with
@@ -460,6 +505,8 @@
return i;
if ((i = pci_save_msix_state(dev)) != 0)
return i;
+ if ((i = pci_save_pcie_state(dev)) != 0)
+ return i;
return 0;
}
@@ -473,6 +520,9 @@
int i;
int val;
+ /* PCI Express register must be restored first */
+ pci_restore_pcie_state(dev);
+
/*
* The Base Address register should be programmed before the command
* register(s)