PCI: dwc: Set 32-bit DMA mask for MSI target address allocation

Set DMA mask to 32-bit while allocating the MSI target address so that
the address is usable for both 32-bit and 64-bit MSI capable devices.
Throw a warning if it fails to set the mask to 32-bit to alert that
devices that are only 32-bit MSI capable may not work properly.

Link: https://lore.kernel.org/r/20201117165312.25847-1-vidyas@nvidia.com
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 99ef808..516b151 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -396,6 +396,14 @@ int dw_pcie_host_init(struct pcie_port *pp)
                                                            dw_chained_msi_isr,
                                                            pp);
 
+                       ret = dma_set_mask(pci->dev, DMA_BIT_MASK(32));
+                       if (!ret) {
+                               dev_warn(pci->dev,
+                                        "Failed to set DMA mask to 32-bit. "
+                                        "Devices with only 32-bit MSI support"
+                                        " may not work properly\n");
+                       }
+
                        pp->msi_data = dma_map_single_attrs(pci->dev, &pp->msi_msg,
                                                      sizeof(pp->msi_msg),
                                                      DMA_FROM_DEVICE,