PCI: Enable ATS at the device state restore

During S3 or S4 resume or PCI reset, ATS regs aren't restored correctly.
This patch enables ATS at the device state restore if PCI device has ATS
capability.

Signed-off-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index e11ebafaf774..a4a1b369853b 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -128,6 +128,23 @@ void pci_disable_ats(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_disable_ats);
 
+void pci_restore_ats_state(struct pci_dev *dev)
+{
+        u16 ctrl;
+
+        if (!pci_ats_enabled(dev))
+                return;
+        if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS))
+                BUG();
+
+        ctrl = PCI_ATS_CTRL_ENABLE;
+        if (!dev->is_virtfn)
+                ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU);
+
+        pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
+}
+EXPORT_SYMBOL_GPL(pci_restore_ats_state);
+
 /**
  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
  * @dev: the PCI device