PCI: dwc: Restore MSI Receiver mask during resume

If a host that uses the IP's integrated MSI Receiver lost power
during suspend, we call dw_pcie_setup_rc() to reinit the RC. But
dw_pcie_setup_rc() always sets pp->irq_mask[ctrl] to ~0, so the mask
register is always set as 0xffffffff incorrectly, thus the MSI can't
work after resume.

Fix this issue by moving pp->irq_mask[ctrl] initialization to
dw_pcie_host_init() so we can correctly set the mask reg during both
boot and resume.

Tested-by: Richard Zhu <hongxing.zhu@nxp.com>
Link: https://lore.kernel.org/r/20211226074019.2556-1-jszhang@kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -362,6 +362,12 @@ int dw_pcie_host_init(struct pcie_port *pp)
 			if (ret < 0)
 				return ret;
 		} else if (pp->has_msi_ctrl) {
+			u32 ctrl, num_ctrls;
+
+			num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+			for (ctrl = 0; ctrl < num_ctrls; ctrl++)
+				pp->irq_mask[ctrl] = ~0;
+
 			if (!pp->msi_irq) {
 				pp->msi_irq = platform_get_irq_byname_optional(pdev, "msi");
 				if (pp->msi_irq < 0) {
@@ -541,7 +547,6 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 
 		/* Initialize IRQ Status array */
 		for (ctrl = 0; ctrl < num_ctrls; ctrl++) {
-			pp->irq_mask[ctrl] = ~0;
 			dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK +
 					    (ctrl * MSI_REG_CTRL_BLOCK_SIZE),
 					    pp->irq_mask[ctrl]);