PCI: Restore resized BAR state on resume

BugLink: https://bugs.launchpad.net/bugs/1825958
Resize BARs after resume to the expected size again.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199959
Fixes: d6895ad39f3b ("drm/amdgpu: resize VRAM BAR for CPU access v6")
Fixes: 276b738deb5b ("PCI: Add resizable BAR infrastructure")
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org      # v4.15+
(cherry picked from commit d3252ace0bc652a1a244455556b6a549f969bf99)
Signed-off-by: You-Sheng Yang <vicamo.yang@canonical.com>
Acked-By: AceLan Kao <acelan.kao@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7e600b75d1865f714da54336e48b4c082d92e4d2..e04b375da9f02e622303c09cb6a9c448dc696e55 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1170,6 +1170,33 @@ static void pci_restore_config_space(struct pci_dev *pdev)
        }
 }
 
+static void pci_restore_rebar_state(struct pci_dev *pdev)
+{
+       unsigned int pos, nbars, i;
+       u32 ctrl;
+
+       pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR);
+       if (!pos)
+               return;
+
+       pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
+       nbars = (ctrl & PCI_REBAR_CTRL_NBAR_MASK) >>
+                   PCI_REBAR_CTRL_NBAR_SHIFT;
+
+       for (i = 0; i < nbars; i++, pos += 8) {
+               struct resource *res;
+               int bar_idx, size;
+
+               pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
+               bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX;
+               res = pdev->resource + bar_idx;
+               size = order_base_2((resource_size(res) >> 20) | 1) - 1;
+               ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
+               ctrl |= size << 8;
+               pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
+       }
+}
+
 /**
  * pci_restore_state - Restore the saved state of a PCI device
  * @dev: - PCI device that we're dealing with
@@ -1185,6 +1212,7 @@ void pci_restore_state(struct pci_dev *dev)
        pci_restore_pri_state(dev);
        pci_restore_ats_state(dev);
        pci_restore_vc_state(dev);
+       pci_restore_rebar_state(dev);
 
        pci_cleanup_aer_error_status_regs(dev);