PCI: dwc: Support multiple ATU memory regions

The current ATU setup only supports a single memory resource which
isn't sufficient if there are also prefetchable memory regions. In order
to support multiple memory regions, we need to move away from fixed ATU
slots and rework the assignment. As there's always an ATU entry for
config space, let's assign index 0 to config space. Then we assign
memory resources to index 1 and up. Finally, if we have an I/O region
and slots remaining, we assign the I/O region last. If there aren't
remaining slots, we keep the same config and I/O space sharing.

Link: https://lore.kernel.org/r/20201026181652.418729-1-robh@kernel.orgTested-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Vidya Sagar <vidyas@nvidia.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Cc: Vidya Sagar <vidyas@nvidia.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>

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

@@ -464,9 +464,7 @@ static void __iomem *dw_pcie_other_conf_map_bus(struct pci_bus *bus,
 		type = PCIE_ATU_TYPE_CFG1;
 
 
-	dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX1,
-				  type, pp->cfg0_base,
-				  busdev, pp->cfg0_size);
+	dw_pcie_prog_outbound_atu(pci, 0, type, pp->cfg0_base, busdev, pp->cfg0_size);
 
 	return pp->va_cfg0_base + where;
 }
@@ -480,9 +478,8 @@ static int dw_pcie_rd_other_conf(struct pci_bus *bus, unsigned int devfn,
 
 	ret = pci_generic_config_read(bus, devfn, where, size, val);
 
-	if (!ret && pci->num_viewport <= 2)
-		dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX1,
-					  PCIE_ATU_TYPE_IO, pp->io_base,
+	if (!ret && pci->io_cfg_atu_shared)
+		dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO, pp->io_base,
 					  pp->io_bus_addr, pp->io_size);
 
 	return ret;
@@ -497,9 +494,8 @@ static int dw_pcie_wr_other_conf(struct pci_bus *bus, unsigned int devfn,
 
 	ret = pci_generic_config_write(bus, devfn, where, size, val);
 
-	if (!ret && pci->num_viewport <= 2)
-		dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX1,
-					  PCIE_ATU_TYPE_IO, pp->io_base,
+	if (!ret && pci->io_cfg_atu_shared)
+		dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO, pp->io_base,
 					  pp->io_bus_addr, pp->io_size);
 
 	return ret;
@@ -586,21 +582,35 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 	 * ATU, so we should not program the ATU here.
 	 */
 	if (pp->bridge->child_ops == &dw_child_pcie_ops) {
-		struct resource_entry *tmp, *entry = NULL;
+		int atu_idx = 0;
+		struct resource_entry *entry;
 
 		/* Get last memory resource entry */
-		resource_list_for_each_entry(tmp, &pp->bridge->windows)
-			if (resource_type(tmp->res) == IORESOURCE_MEM)
-				entry = tmp;
+		resource_list_for_each_entry(entry, &pp->bridge->windows) {
+			if (resource_type(entry->res) != IORESOURCE_MEM)
+				continue;
+
+			if (pci->num_viewport <= ++atu_idx)
+				break;
 
-		dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX0,
+			dw_pcie_prog_outbound_atu(pci, atu_idx,
 						  PCIE_ATU_TYPE_MEM, entry->res->start,
 						  entry->res->start - entry->offset,
 						  resource_size(entry->res));
-		if (pci->num_viewport > 2)
-			dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX2,
+		}
+
+		if (pp->io_size) {
+			if (pci->num_viewport > ++atu_idx)
+				dw_pcie_prog_outbound_atu(pci, atu_idx,
 							  PCIE_ATU_TYPE_IO, pp->io_base,
 							  pp->io_bus_addr, pp->io_size);
+			else
+				pci->io_cfg_atu_shared = true;
+		}
+
+		if (pci->num_viewport <= atu_idx)
+			dev_warn(pci->dev, "Resources exceed number of ATU entries (%d)",
+				 pci->num_viewport);
 	}
 
 	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);

drivers/pci/controller/dwc/pcie-designware.h

@@ -80,9 +80,6 @@
 #define PCIE_ATU_VIEWPORT		0x900
 #define PCIE_ATU_REGION_INBOUND		BIT(31)
 #define PCIE_ATU_REGION_OUTBOUND	0
-#define PCIE_ATU_REGION_INDEX2		0x2
-#define PCIE_ATU_REGION_INDEX1		0x1
-#define PCIE_ATU_REGION_INDEX0		0x0
 #define PCIE_ATU_CR1			0x904
 #define PCIE_ATU_TYPE_MEM		0x0
 #define PCIE_ATU_TYPE_IO		0x2
@@ -266,7 +263,6 @@ struct dw_pcie {
 	/* Used when iatu_unroll_enabled is true */
 	void __iomem		*atu_base;
 	u32			num_viewport;
-	u8			iatu_unroll_enabled;
 	struct pcie_port	pp;
 	struct dw_pcie_ep	ep;
 	const struct dw_pcie_ops *ops;
@@ -274,6 +270,8 @@ struct dw_pcie {
 	int			num_lanes;
 	int			link_gen;
 	u8			n_fts[2];
+	bool			iatu_unroll_enabled: 1;
+	bool			io_cfg_atu_shared: 1;
 };
 
 #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)