xen/arm: Add support for Xilinx ZynqMP PCI host controller

Add support for Xilinx ZynqMP PCI host controller to map the PCI config
space to the XEN memory.

Patch helps to understand how the generic infrastructure for PCI
host-bridge discovery will be used for future references.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/pci/Makefile

@@ -3,3 +3,4 @@ obj-y += pci-access.o
 obj-y += pci-host-generic.o
 obj-y += pci-host-common.o
 obj-y += ecam.o
+obj-y += pci-host-zynqmp.o

xen/arch/arm/pci/pci-host-zynqmp.c

@@ -0,0 +1,65 @@
+/*
+ * Based on Linux drivers/pci/controller/pci-host-common.c
+ * Based on Linux drivers/pci/controller/pci-host-generic.c
+ * Based on xen/arch/arm/pci/pci-host-generic.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/init.h>
+#include <xen/pci.h>
+#include <asm/device.h>
+#include <asm/pci.h>
+
+static int __init nwl_cfg_reg_index(struct dt_device_node *np)
+{
+    return dt_property_match_string(np, "reg-names", "cfg");
+}
+
+/* ECAM ops */
+const struct pci_ecam_ops nwl_pcie_ops = {
+    .bus_shift  = 20,
+    .cfg_reg_index = nwl_cfg_reg_index,
+    .pci_ops    = {
+        .map_bus                = pci_ecam_map_bus,
+        .read                   = pci_generic_config_read,
+        .write                  = pci_generic_config_write,
+    }
+};
+
+static const struct dt_device_match __initconstrel nwl_pcie_dt_match[] =
+{
+    { .compatible = "xlnx,nwl-pcie-2.11" },
+    { },
+};
+
+static int __init pci_host_generic_probe(struct dt_device_node *dev,
+                                         const void *data)
+{
+    return pci_host_common_probe(dev, &nwl_pcie_ops);
+}
+
+DT_DEVICE_START(pci_gen, "PCI HOST ZYNQMP", DEVICE_PCI)
+.dt_match = nwl_pcie_dt_match,
+.init = pci_host_generic_probe,
+DT_DEVICE_END
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */