PCI: cadence: Use AXI region 0 to signal interrupts from EP

[ Upstream commit 0652d4b6 ]

The IRQ physical address is allocated from region 0, rather than
the highest region. Update the driver to reserve this region in
the bitmap and to use region 0 for all types of interrupt.

This corrects a problem which prevents the interrupt being
signalled correctly if using the first address in the AXI region,
since an offset of zero will always be mapped to region 0.

Fixes: 37dddf14 ("PCI: cadence: Add EndPoint Controller driver for Cadence PCIe controller")
Signed-off-by: Alan Douglas <adouglas@cadence.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pci/controller/pcie-cadence-ep.c

@@ -258,7 +258,6 @@ static void cdns_pcie_ep_assert_intx(struct cdns_pcie_ep *ep, u8 fn,
 				     u8 intx, bool is_asserted)
 {
 	struct cdns_pcie *pcie = &ep->pcie;
-	u32 r = ep->max_regions - 1;
 	u32 offset;
 	u16 status;
 	u8 msg_code;
@@ -268,8 +267,8 @@ static void cdns_pcie_ep_assert_intx(struct cdns_pcie_ep *ep, u8 fn,
 	/* Set the outbound region if needed. */
 	if (unlikely(ep->irq_pci_addr != CDNS_PCIE_EP_IRQ_PCI_ADDR_LEGACY ||
 		     ep->irq_pci_fn != fn)) {
-		/* Last region was reserved for IRQ writes. */
-		cdns_pcie_set_outbound_region_for_normal_msg(pcie, fn, r,
+		/* First region was reserved for IRQ writes. */
+		cdns_pcie_set_outbound_region_for_normal_msg(pcie, fn, 0,
 							     ep->irq_phys_addr);
 		ep->irq_pci_addr = CDNS_PCIE_EP_IRQ_PCI_ADDR_LEGACY;
 		ep->irq_pci_fn = fn;
@@ -347,8 +346,8 @@ static int cdns_pcie_ep_send_msi_irq(struct cdns_pcie_ep *ep, u8 fn,
 	/* Set the outbound region if needed. */
 	if (unlikely(ep->irq_pci_addr != (pci_addr & ~pci_addr_mask) ||
 		     ep->irq_pci_fn != fn)) {
-		/* Last region was reserved for IRQ writes. */
-		cdns_pcie_set_outbound_region(pcie, fn, ep->max_regions - 1,
+		/* First region was reserved for IRQ writes. */
+		cdns_pcie_set_outbound_region(pcie, fn, 0,
 					      false,
 					      ep->irq_phys_addr,
 					      pci_addr & ~pci_addr_mask,
@@ -517,6 +516,8 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
 		goto free_epc_mem;
 	}
 	ep->irq_pci_addr = CDNS_PCIE_EP_IRQ_PCI_ADDR_NONE;
+	/* Reserve region 0 for IRQs */
+	set_bit(0, &ep->ob_region_map);
 
 	return 0;