hw/arm/sysbus-fdt.c - qemu - Git at Google

 /*
  * ARM Platform Bus device tree generation helpers
  *
  * Copyright (c) 2014 Linaro Limited
  *
  * Authors:
  *  Alex Graf <agraf@suse.de>
  *  Eric Auger <eric.auger@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2 or later, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope 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 "qemu/osdep.h"
 #include "qapi/error.h"
 #include <libfdt.h>
 #include "qemu-common.h"
 #ifdef CONFIG_LINUX
 #include <linux/vfio.h>
 #endif
 #include "hw/arm/sysbus-fdt.h"
 #include "qemu/error-report.h"
 #include "sysemu/device_tree.h"
 #include "hw/platform-bus.h"
 #include "sysemu/sysemu.h"
 #include "hw/vfio/vfio-platform.h"
 #include "hw/vfio/vfio-calxeda-xgmac.h"
 #include "hw/vfio/vfio-amd-xgbe.h"
 #include "hw/arm/fdt.h"

 /*
  * internal struct that contains the information to create dynamic
  * sysbus device node
  */
 typedef struct PlatformBusFDTData {
     void *fdt; /* device tree handle */
     int irq_start; /* index of the first IRQ usable by platform bus devices */
     const char *pbus_node_name; /* name of the platform bus node */
     PlatformBusDevice *pbus;
 } PlatformBusFDTData;

 /*
  * struct used when calling the machine init done notifier
  * that constructs the fdt nodes of platform bus devices
  */
 typedef struct PlatformBusFDTNotifierParams {
     Notifier notifier;
     ARMPlatformBusFDTParams *fdt_params;
 } PlatformBusFDTNotifierParams;

 /* struct that associates a device type name and a node creation function */
 typedef struct NodeCreationPair {
     const char *typename;
     int (*add_fdt_node_fn)(SysBusDevice *sbdev, void *opaque);
 } NodeCreationPair;

 /* helpers */

 typedef struct HostProperty {
     const char *name;
     bool optional;
 } HostProperty;

 #ifdef CONFIG_LINUX

 /**
  * copy_properties_from_host
  *
  * copies properties listed in an array from host device tree to
  * guest device tree. If a non optional property is not found, the
  * function asserts. An optional property is ignored if not found
  * in the host device tree.
  * @props: array of HostProperty to copy
  * @nb_props: number of properties in the array
  * @host_dt: host device tree blob
  * @guest_dt: guest device tree blob
  * @node_path: host dt node path where the property is supposed to be
               found
  * @nodename: guest node name the properties should be added to
  */
 static void copy_properties_from_host(HostProperty *props, int nb_props,
                                       void *host_fdt, void *guest_fdt,
                                       char *node_path, char *nodename)
 {
     int i, prop_len;
     const void *r;
     Error *err = NULL;

     for (i = 0; i < nb_props; i++) {
         r = qemu_fdt_getprop(host_fdt, node_path,
                              props[i].name,
                              &prop_len,
                              props[i].optional ? &err : &error_fatal);
         if (r) {
             qemu_fdt_setprop(guest_fdt, nodename,
                              props[i].name, r, prop_len);
         } else {
             if (prop_len != -FDT_ERR_NOTFOUND) {
                 /* optional property not returned although property exists */
                 error_report_err(err);
             } else {
                 error_free(err);
             }
         }
     }
 }

 /* clock properties whose values are copied/pasted from host */
 static HostProperty clock_copied_properties[] = {
     {"compatible", false},
     {"#clock-cells", false},
     {"clock-frequency", true},
     {"clock-output-names", true},
 };

 /**
  * fdt_build_clock_node
  *
  * Build a guest clock node, used as a dependency from a passthrough'ed
  * device. Most information are retrieved from the host clock node.
  * Also check the host clock is a fixed one.
  *
  * @host_fdt: host device tree blob from which info are retrieved
  * @guest_fdt: guest device tree blob where the clock node is added
  * @host_phandle: phandle of the clock in host device tree
  * @guest_phandle: phandle to assign to the guest node
  */
 static void fdt_build_clock_node(void *host_fdt, void *guest_fdt,
                                 uint32_t host_phandle,
                                 uint32_t guest_phandle)
 {
     char *node_path = NULL;
     char *nodename;
     const void *r;
     int ret, node_offset, prop_len, path_len = 16;

     node_offset = fdt_node_offset_by_phandle(host_fdt, host_phandle);
     if (node_offset <= 0) {
         error_setg(&error_fatal,
                    "not able to locate clock handle %d in host device tree",
                    host_phandle);
     }
     node_path = g_malloc(path_len);
     while ((ret = fdt_get_path(host_fdt, node_offset, node_path, path_len))
             == -FDT_ERR_NOSPACE) {
         path_len += 16;
         node_path = g_realloc(node_path, path_len);
     }
     if (ret < 0) {
         error_setg(&error_fatal,
                    "not able to retrieve node path for clock handle %d",
                    host_phandle);
     }

     r = qemu_fdt_getprop(host_fdt, node_path, "compatible", &prop_len,
                          &error_fatal);
     if (strcmp(r, "fixed-clock")) {
         error_setg(&error_fatal,
                    "clock handle %d is not a fixed clock", host_phandle);
     }

     nodename = strrchr(node_path, '/');
     qemu_fdt_add_subnode(guest_fdt, nodename);

     copy_properties_from_host(clock_copied_properties,
                               ARRAY_SIZE(clock_copied_properties),
                               host_fdt, guest_fdt,
                               node_path, nodename);

     qemu_fdt_setprop_cell(guest_fdt, nodename, "phandle", guest_phandle);

     g_free(node_path);
 }

 /**
  * sysfs_to_dt_name: convert the name found in sysfs into the node name
  * for instance e0900000.xgmac is converted into xgmac@e0900000
  * @sysfs_name: directory name in sysfs
  *
  * returns the device tree name upon success or NULL in case the sysfs name
  * does not match the expected format
  */
 static char *sysfs_to_dt_name(const char *sysfs_name)
 {
     gchar **substrings =  g_strsplit(sysfs_name, ".", 2);
     char *dt_name = NULL;

     if (!substrings || !substrings[0] || !substrings[1]) {
         goto out;
     }
     dt_name = g_strdup_printf("%s@%s", substrings[1], substrings[0]);
 out:
     g_strfreev(substrings);
     return dt_name;
 }

 /* Device Specific Code */

 /**
  * add_calxeda_midway_xgmac_fdt_node
  *
  * Generates a simple node with following properties:
  * compatible string, regs, interrupts, dma-coherent
  */
 static int add_calxeda_midway_xgmac_fdt_node(SysBusDevice *sbdev, void *opaque)
 {
     PlatformBusFDTData *data = opaque;
     PlatformBusDevice *pbus = data->pbus;
     void *fdt = data->fdt;
     const char *parent_node = data->pbus_node_name;
     int compat_str_len, i;
     char *nodename;
     uint32_t *irq_attr, *reg_attr;
     uint64_t mmio_base, irq_number;
     VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
     VFIODevice *vbasedev = &vdev->vbasedev;

     mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
     nodename = g_strdup_printf("%s/%s@%" PRIx64, parent_node,
                                vbasedev->name, mmio_base);
     qemu_fdt_add_subnode(fdt, nodename);

     compat_str_len = strlen(vdev->compat) + 1;
     qemu_fdt_setprop(fdt, nodename, "compatible",
                           vdev->compat, compat_str_len);

     qemu_fdt_setprop(fdt, nodename, "dma-coherent", "", 0);

     reg_attr = g_new(uint32_t, vbasedev->num_regions * 2);
     for (i = 0; i < vbasedev->num_regions; i++) {
         mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, i);
         reg_attr[2 * i] = cpu_to_be32(mmio_base);
         reg_attr[2 * i + 1] = cpu_to_be32(
                                 memory_region_size(vdev->regions[i]->mem));
     }
     qemu_fdt_setprop(fdt, nodename, "reg", reg_attr,
                      vbasedev->num_regions * 2 * sizeof(uint32_t));

     irq_attr = g_new(uint32_t, vbasedev->num_irqs * 3);
     for (i = 0; i < vbasedev->num_irqs; i++) {
         irq_number = platform_bus_get_irqn(pbus, sbdev , i)
                          + data->irq_start;
         irq_attr[3 * i] = cpu_to_be32(GIC_FDT_IRQ_TYPE_SPI);
         irq_attr[3 * i + 1] = cpu_to_be32(irq_number);
         irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_LEVEL_HI);
     }
     qemu_fdt_setprop(fdt, nodename, "interrupts",
                      irq_attr, vbasedev->num_irqs * 3 * sizeof(uint32_t));
     g_free(irq_attr);
     g_free(reg_attr);
     g_free(nodename);
     return 0;
 }

 /* AMD xgbe properties whose values are copied/pasted from host */
 static HostProperty amd_xgbe_copied_properties[] = {
     {"compatible", false},
     {"dma-coherent", true},
     {"amd,per-channel-interrupt", true},
     {"phy-mode", false},
     {"mac-address", true},
     {"amd,speed-set", false},
     {"amd,serdes-blwc", true},
     {"amd,serdes-cdr-rate", true},
     {"amd,serdes-pq-skew", true},
     {"amd,serdes-tx-amp", true},
     {"amd,serdes-dfe-tap-config", true},
     {"amd,serdes-dfe-tap-enable", true},
     {"clock-names", false},
 };

 /**
  * add_amd_xgbe_fdt_node
  *
  * Generates the combined xgbe/phy node following kernel >=4.2
  * binding documentation:
  * Documentation/devicetree/bindings/net/amd-xgbe.txt:
  * Also 2 clock nodes are created (dma and ptp)
  *
  * Asserts in case of error
  */
 static int add_amd_xgbe_fdt_node(SysBusDevice *sbdev, void *opaque)
 {
     PlatformBusFDTData *data = opaque;
     PlatformBusDevice *pbus = data->pbus;
     VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
     VFIODevice *vbasedev = &vdev->vbasedev;
     VFIOINTp *intp;
     const char *parent_node = data->pbus_node_name;
     char **node_path, *nodename, *dt_name;
     void *guest_fdt = data->fdt, *host_fdt;
     const void *r;
     int i, prop_len;
     uint32_t *irq_attr, *reg_attr, *host_clock_phandles;
     uint64_t mmio_base, irq_number;
     uint32_t guest_clock_phandles[2];

     host_fdt = load_device_tree_from_sysfs();

     dt_name = sysfs_to_dt_name(vbasedev->name);
     if (!dt_name) {
         error_setg(&error_fatal, "%s incorrect sysfs device name %s",
                     __func__, vbasedev->name);
     }
     node_path = qemu_fdt_node_path(host_fdt, dt_name, vdev->compat,
                                    &error_fatal);
     if (!node_path || !node_path[0]) {
         error_setg(&error_fatal, "%s unable to retrieve node path for %s/%s",
                    __func__, dt_name, vdev->compat);
     }

     if (node_path[1]) {
         error_setg(&error_fatal, "%s more than one node matching %s/%s!",
                    __func__, dt_name, vdev->compat);
     }

     g_free(dt_name);

     if (vbasedev->num_regions != 5) {
         error_setg(&error_fatal, "%s Does the host dt node combine XGBE/PHY?",
                    __func__);
     }

     /* generate nodes for DMA_CLK and PTP_CLK */
     r = qemu_fdt_getprop(host_fdt, node_path[0], "clocks",
                          &prop_len, &error_fatal);
     if (prop_len != 8) {
         error_setg(&error_fatal, "%s clocks property should contain 2 handles",
                    __func__);
     }
     host_clock_phandles = (uint32_t *)r;
     guest_clock_phandles[0] = qemu_fdt_alloc_phandle(guest_fdt);
     guest_clock_phandles[1] = qemu_fdt_alloc_phandle(guest_fdt);

     /**
      * clock handles fetched from host dt are in be32 layout whereas
      * rest of the code uses cpu layout. Also guest clock handles are
      * in cpu layout.
      */
     fdt_build_clock_node(host_fdt, guest_fdt,
                          be32_to_cpu(host_clock_phandles[0]),
                          guest_clock_phandles[0]);

     fdt_build_clock_node(host_fdt, guest_fdt,
                          be32_to_cpu(host_clock_phandles[1]),
                          guest_clock_phandles[1]);

     /* combined XGBE/PHY node */
     mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
     nodename = g_strdup_printf("%s/%s@%" PRIx64, parent_node,
                                vbasedev->name, mmio_base);
     qemu_fdt_add_subnode(guest_fdt, nodename);

     copy_properties_from_host(amd_xgbe_copied_properties,
                        ARRAY_SIZE(amd_xgbe_copied_properties),
                        host_fdt, guest_fdt,
                        node_path[0], nodename);

     qemu_fdt_setprop_cells(guest_fdt, nodename, "clocks",
                            guest_clock_phandles[0],
                            guest_clock_phandles[1]);

     reg_attr = g_new(uint32_t, vbasedev->num_regions * 2);
     for (i = 0; i < vbasedev->num_regions; i++) {
         mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, i);
         reg_attr[2 * i] = cpu_to_be32(mmio_base);
         reg_attr[2 * i + 1] = cpu_to_be32(
                                 memory_region_size(vdev->regions[i]->mem));
     }
     qemu_fdt_setprop(guest_fdt, nodename, "reg", reg_attr,
                      vbasedev->num_regions * 2 * sizeof(uint32_t));

     irq_attr = g_new(uint32_t, vbasedev->num_irqs * 3);
     for (i = 0; i < vbasedev->num_irqs; i++) {
         irq_number = platform_bus_get_irqn(pbus, sbdev , i)
                          + data->irq_start;
         irq_attr[3 * i] = cpu_to_be32(GIC_FDT_IRQ_TYPE_SPI);
         irq_attr[3 * i + 1] = cpu_to_be32(irq_number);
         /*
           * General device interrupt and PCS auto-negotiation interrupts are
           * level-sensitive while the 4 per-channel interrupts are edge
           * sensitive
           */
         QLIST_FOREACH(intp, &vdev->intp_list, next) {
             if (intp->pin == i) {
                 break;
             }
         }
         if (intp->flags & VFIO_IRQ_INFO_AUTOMASKED) {
             irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_LEVEL_HI);
         } else {
             irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_EDGE_LO_HI);
         }
     }
     qemu_fdt_setprop(guest_fdt, nodename, "interrupts",
                      irq_attr, vbasedev->num_irqs * 3 * sizeof(uint32_t));

     g_free(host_fdt);
     g_strfreev(node_path);
     g_free(irq_attr);
     g_free(reg_attr);
     g_free(nodename);
     return 0;
 }

 #endif /* CONFIG_LINUX */

 /* list of supported dynamic sysbus devices */
 static const NodeCreationPair add_fdt_node_functions[] = {
 #ifdef CONFIG_LINUX
     {TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node},
     {TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node},
 #endif
     {"", NULL}, /* last element */
 };

 /* Generic Code */

 /**
  * add_fdt_node - add the device tree node of a dynamic sysbus device
  *
  * @sbdev: handle to the sysbus device
  * @opaque: handle to the PlatformBusFDTData
  *
  * Checks the sysbus type belongs to the list of device types that
  * are dynamically instantiable and if so call the node creation
  * function.
  */
 static int add_fdt_node(SysBusDevice *sbdev, void *opaque)
 {
     int i, ret;

     for (i = 0; i < ARRAY_SIZE(add_fdt_node_functions); i++) {
         if (!strcmp(object_get_typename(OBJECT(sbdev)),
                     add_fdt_node_functions[i].typename)) {
             ret = add_fdt_node_functions[i].add_fdt_node_fn(sbdev, opaque);
             assert(!ret);
             return 0;
         }
     }
     error_report("Device %s can not be dynamically instantiated",
                      qdev_fw_name(DEVICE(sbdev)));
     exit(1);
 }

 /**
  * add_all_platform_bus_fdt_nodes - create all the platform bus nodes
  *
  * builds the parent platform bus node and all the nodes of dynamic
  * sysbus devices attached to it.
  */
 static void add_all_platform_bus_fdt_nodes(ARMPlatformBusFDTParams *fdt_params)
 {
     const char platcomp[] = "qemu,platform\0simple-bus";
     PlatformBusDevice *pbus;
     DeviceState *dev;
     gchar *node;
     uint64_t addr, size;
     int irq_start, dtb_size;
     struct arm_boot_info *info = fdt_params->binfo;
     const ARMPlatformBusSystemParams *params = fdt_params->system_params;
     const char *intc = fdt_params->intc;
     void *fdt = info->get_dtb(info, &dtb_size);

     /*
      * If the user provided a dtb, we assume the dynamic sysbus nodes
      * already are integrated there. This corresponds to a use case where
      * the dynamic sysbus nodes are complex and their generation is not yet
      * supported. In that case the user can take charge of the guest dt
      * while qemu takes charge of the qom stuff.
      */
     if (info->dtb_filename) {
         return;
     }

     assert(fdt);

     node = g_strdup_printf("/platform@%"PRIx64, params->platform_bus_base);
     addr = params->platform_bus_base;
     size = params->platform_bus_size;
     irq_start = params->platform_bus_first_irq;

     /* Create a /platform node that we can put all devices into */
     qemu_fdt_add_subnode(fdt, node);
     qemu_fdt_setprop(fdt, node, "compatible", platcomp, sizeof(platcomp));

     /* Our platform bus region is less than 32bits, so 1 cell is enough for
      * address and size
      */
     qemu_fdt_setprop_cells(fdt, node, "#size-cells", 1);
     qemu_fdt_setprop_cells(fdt, node, "#address-cells", 1);
     qemu_fdt_setprop_cells(fdt, node, "ranges", 0, addr >> 32, addr, size);

     qemu_fdt_setprop_phandle(fdt, node, "interrupt-parent", intc);

     dev = qdev_find_recursive(sysbus_get_default(), TYPE_PLATFORM_BUS_DEVICE);
     pbus = PLATFORM_BUS_DEVICE(dev);

     /* We can only create dt nodes for dynamic devices when they're ready */
     assert(pbus->done_gathering);

     PlatformBusFDTData data = {
         .fdt = fdt,
         .irq_start = irq_start,
         .pbus_node_name = node,
         .pbus = pbus,
     };

     /* Loop through all dynamic sysbus devices and create their node */
     foreach_dynamic_sysbus_device(add_fdt_node, &data);

     g_free(node);
 }

 static void platform_bus_fdt_notify(Notifier *notifier, void *data)
 {
     PlatformBusFDTNotifierParams *p = DO_UPCAST(PlatformBusFDTNotifierParams,
                                                 notifier, notifier);

     add_all_platform_bus_fdt_nodes(p->fdt_params);
     g_free(p->fdt_params);
     g_free(p);
 }

 void arm_register_platform_bus_fdt_creator(ARMPlatformBusFDTParams *fdt_params)
 {
     PlatformBusFDTNotifierParams *p = g_new(PlatformBusFDTNotifierParams, 1);

     p->fdt_params = fdt_params;
     p->notifier.notify = platform_bus_fdt_notify;
     qemu_add_machine_init_done_notifier(&p->notifier);
 }
	/*
	* ARM Platform Bus device tree generation helpers
	*
	* Copyright (c) 2014 Linaro Limited
	*
	* Authors:
	* Alex Graf <agraf@suse.de>
	* Eric Auger <eric.auger@linaro.org>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2 or later, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope 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 "qemu/osdep.h"
	#include "qapi/error.h"
	#include <libfdt.h>
	#include "qemu-common.h"
	#ifdef CONFIG_LINUX
	#include <linux/vfio.h>
	#endif
	#include "hw/arm/sysbus-fdt.h"
	#include "qemu/error-report.h"
	#include "sysemu/device_tree.h"
	#include "hw/platform-bus.h"
	#include "sysemu/sysemu.h"
	#include "hw/vfio/vfio-platform.h"
	#include "hw/vfio/vfio-calxeda-xgmac.h"
	#include "hw/vfio/vfio-amd-xgbe.h"
	#include "hw/arm/fdt.h"

	/*
	* internal struct that contains the information to create dynamic
	* sysbus device node
	*/
	typedef struct PlatformBusFDTData {
	void fdt; / device tree handle */
	int irq_start; /* index of the first IRQ usable by platform bus devices */
	const char pbus_node_name; / name of the platform bus node */
	PlatformBusDevice *pbus;
	} PlatformBusFDTData;

	/*
	* struct used when calling the machine init done notifier
	* that constructs the fdt nodes of platform bus devices
	*/
	typedef struct PlatformBusFDTNotifierParams {
	Notifier notifier;
	ARMPlatformBusFDTParams *fdt_params;
	} PlatformBusFDTNotifierParams;

	/* struct that associates a device type name and a node creation function */
	typedef struct NodeCreationPair {
	const char *typename;
	int (add_fdt_node_fn)(SysBusDevice sbdev, void *opaque);
	} NodeCreationPair;

	/* helpers */

	typedef struct HostProperty {
	const char *name;
	bool optional;
	} HostProperty;

	#ifdef CONFIG_LINUX

	/**
	* copy_properties_from_host
	*
	* copies properties listed in an array from host device tree to
	* guest device tree. If a non optional property is not found, the
	* function asserts. An optional property is ignored if not found
	* in the host device tree.
	* @props: array of HostProperty to copy
	* @nb_props: number of properties in the array
	* @host_dt: host device tree blob
	* @guest_dt: guest device tree blob
	* @node_path: host dt node path where the property is supposed to be
	found
	* @nodename: guest node name the properties should be added to
	*/
	static void copy_properties_from_host(HostProperty *props, int nb_props,
	void host_fdt, void guest_fdt,
	char node_path, char nodename)
	{
	int i, prop_len;
	const void *r;
	Error *err = NULL;

	for (i = 0; i < nb_props; i++) {
	r = qemu_fdt_getprop(host_fdt, node_path,
	props[i].name,
	&prop_len,
	props[i].optional ? &err : &error_fatal);
	if (r) {
	qemu_fdt_setprop(guest_fdt, nodename,
	props[i].name, r, prop_len);
	} else {
	if (prop_len != -FDT_ERR_NOTFOUND) {
	/* optional property not returned although property exists */
	error_report_err(err);
	} else {
	error_free(err);
	}
	}
	}
	}

	/* clock properties whose values are copied/pasted from host */
	static HostProperty clock_copied_properties[] = {
	{"compatible", false},
	{"#clock-cells", false},
	{"clock-frequency", true},
	{"clock-output-names", true},
	};

	/**
	* fdt_build_clock_node
	*
	* Build a guest clock node, used as a dependency from a passthrough'ed
	* device. Most information are retrieved from the host clock node.
	* Also check the host clock is a fixed one.
	*
	* @host_fdt: host device tree blob from which info are retrieved
	* @guest_fdt: guest device tree blob where the clock node is added
	* @host_phandle: phandle of the clock in host device tree
	* @guest_phandle: phandle to assign to the guest node
	*/
	static void fdt_build_clock_node(void host_fdt, void guest_fdt,
	uint32_t host_phandle,
	uint32_t guest_phandle)
	{
	char *node_path = NULL;
	char *nodename;
	const void *r;
	int ret, node_offset, prop_len, path_len = 16;

	node_offset = fdt_node_offset_by_phandle(host_fdt, host_phandle);
	if (node_offset <= 0) {
	error_setg(&error_fatal,
	"not able to locate clock handle %d in host device tree",
	host_phandle);
	}
	node_path = g_malloc(path_len);
	while ((ret = fdt_get_path(host_fdt, node_offset, node_path, path_len))
	== -FDT_ERR_NOSPACE) {
	path_len += 16;
	node_path = g_realloc(node_path, path_len);
	}
	if (ret < 0) {
	error_setg(&error_fatal,
	"not able to retrieve node path for clock handle %d",
	host_phandle);
	}

	r = qemu_fdt_getprop(host_fdt, node_path, "compatible", &prop_len,
	&error_fatal);
	if (strcmp(r, "fixed-clock")) {
	error_setg(&error_fatal,
	"clock handle %d is not a fixed clock", host_phandle);
	}

	nodename = strrchr(node_path, '/');
	qemu_fdt_add_subnode(guest_fdt, nodename);

	copy_properties_from_host(clock_copied_properties,
	ARRAY_SIZE(clock_copied_properties),
	host_fdt, guest_fdt,
	node_path, nodename);

	qemu_fdt_setprop_cell(guest_fdt, nodename, "phandle", guest_phandle);

	g_free(node_path);
	}

	/**
	* sysfs_to_dt_name: convert the name found in sysfs into the node name
	* for instance e0900000.xgmac is converted into xgmac@e0900000
	* @sysfs_name: directory name in sysfs
	*
	* returns the device tree name upon success or NULL in case the sysfs name
	* does not match the expected format
	*/
	static char sysfs_to_dt_name(const char sysfs_name)
	{
	gchar **substrings = g_strsplit(sysfs_name, ".", 2);
	char *dt_name = NULL;

	if (!substrings \|\| !substrings[0] \|\| !substrings[1]) {
	goto out;
	}
	dt_name = g_strdup_printf("%s@%s", substrings[1], substrings[0]);
	out:
	g_strfreev(substrings);
	return dt_name;
	}

	/* Device Specific Code */

	/**
	* add_calxeda_midway_xgmac_fdt_node
	*
	* Generates a simple node with following properties:
	* compatible string, regs, interrupts, dma-coherent
	*/
	static int add_calxeda_midway_xgmac_fdt_node(SysBusDevice sbdev, void opaque)
	{
	PlatformBusFDTData *data = opaque;
	PlatformBusDevice *pbus = data->pbus;
	void *fdt = data->fdt;
	const char *parent_node = data->pbus_node_name;
	int compat_str_len, i;
	char *nodename;
	uint32_t irq_attr, reg_attr;
	uint64_t mmio_base, irq_number;
	VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
	VFIODevice *vbasedev = &vdev->vbasedev;

	mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
	nodename = g_strdup_printf("%s/%s@%" PRIx64, parent_node,
	vbasedev->name, mmio_base);
	qemu_fdt_add_subnode(fdt, nodename);

	compat_str_len = strlen(vdev->compat) + 1;
	qemu_fdt_setprop(fdt, nodename, "compatible",
	vdev->compat, compat_str_len);

	qemu_fdt_setprop(fdt, nodename, "dma-coherent", "", 0);

	reg_attr = g_new(uint32_t, vbasedev->num_regions * 2);
	for (i = 0; i < vbasedev->num_regions; i++) {
	mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, i);
	reg_attr[2 * i] = cpu_to_be32(mmio_base);
	reg_attr[2 * i + 1] = cpu_to_be32(
	memory_region_size(vdev->regions[i]->mem));
	}
	qemu_fdt_setprop(fdt, nodename, "reg", reg_attr,
	vbasedev->num_regions * 2 * sizeof(uint32_t));

	irq_attr = g_new(uint32_t, vbasedev->num_irqs * 3);
	for (i = 0; i < vbasedev->num_irqs; i++) {
	irq_number = platform_bus_get_irqn(pbus, sbdev , i)
	+ data->irq_start;
	irq_attr[3 * i] = cpu_to_be32(GIC_FDT_IRQ_TYPE_SPI);
	irq_attr[3 * i + 1] = cpu_to_be32(irq_number);
	irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_LEVEL_HI);
	}
	qemu_fdt_setprop(fdt, nodename, "interrupts",
	irq_attr, vbasedev->num_irqs * 3 * sizeof(uint32_t));
	g_free(irq_attr);
	g_free(reg_attr);
	g_free(nodename);
	return 0;
	}

	/* AMD xgbe properties whose values are copied/pasted from host */
	static HostProperty amd_xgbe_copied_properties[] = {
	{"compatible", false},
	{"dma-coherent", true},
	{"amd,per-channel-interrupt", true},
	{"phy-mode", false},
	{"mac-address", true},
	{"amd,speed-set", false},
	{"amd,serdes-blwc", true},
	{"amd,serdes-cdr-rate", true},
	{"amd,serdes-pq-skew", true},
	{"amd,serdes-tx-amp", true},
	{"amd,serdes-dfe-tap-config", true},
	{"amd,serdes-dfe-tap-enable", true},
	{"clock-names", false},
	};

	/**
	* add_amd_xgbe_fdt_node
	*
	* Generates the combined xgbe/phy node following kernel >=4.2
	* binding documentation:
	* Documentation/devicetree/bindings/net/amd-xgbe.txt:
	* Also 2 clock nodes are created (dma and ptp)
	*
	* Asserts in case of error
	*/
	static int add_amd_xgbe_fdt_node(SysBusDevice sbdev, void opaque)
	{
	PlatformBusFDTData *data = opaque;
	PlatformBusDevice *pbus = data->pbus;
	VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
	VFIODevice *vbasedev = &vdev->vbasedev;
	VFIOINTp *intp;
	const char *parent_node = data->pbus_node_name;
	char *node_path, nodename, *dt_name;
	void guest_fdt = data->fdt, host_fdt;
	const void *r;
	int i, prop_len;
	uint32_t irq_attr, reg_attr, *host_clock_phandles;
	uint64_t mmio_base, irq_number;
	uint32_t guest_clock_phandles[2];

	host_fdt = load_device_tree_from_sysfs();

	dt_name = sysfs_to_dt_name(vbasedev->name);
	if (!dt_name) {
	error_setg(&error_fatal, "%s incorrect sysfs device name %s",
	__func__, vbasedev->name);
	}
	node_path = qemu_fdt_node_path(host_fdt, dt_name, vdev->compat,
	&error_fatal);
	if (!node_path \|\| !node_path[0]) {
	error_setg(&error_fatal, "%s unable to retrieve node path for %s/%s",
	__func__, dt_name, vdev->compat);
	}

	if (node_path[1]) {
	error_setg(&error_fatal, "%s more than one node matching %s/%s!",
	__func__, dt_name, vdev->compat);
	}

	g_free(dt_name);

	if (vbasedev->num_regions != 5) {
	error_setg(&error_fatal, "%s Does the host dt node combine XGBE/PHY?",
	__func__);
	}

	/* generate nodes for DMA_CLK and PTP_CLK */
	r = qemu_fdt_getprop(host_fdt, node_path[0], "clocks",
	&prop_len, &error_fatal);
	if (prop_len != 8) {
	error_setg(&error_fatal, "%s clocks property should contain 2 handles",
	__func__);
	}
	host_clock_phandles = (uint32_t *)r;
	guest_clock_phandles[0] = qemu_fdt_alloc_phandle(guest_fdt);
	guest_clock_phandles[1] = qemu_fdt_alloc_phandle(guest_fdt);

	/**
	* clock handles fetched from host dt are in be32 layout whereas
	* rest of the code uses cpu layout. Also guest clock handles are
	* in cpu layout.
	*/
	fdt_build_clock_node(host_fdt, guest_fdt,
	be32_to_cpu(host_clock_phandles[0]),
	guest_clock_phandles[0]);

	fdt_build_clock_node(host_fdt, guest_fdt,
	be32_to_cpu(host_clock_phandles[1]),
	guest_clock_phandles[1]);

	/* combined XGBE/PHY node */
	mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
	nodename = g_strdup_printf("%s/%s@%" PRIx64, parent_node,
	vbasedev->name, mmio_base);
	qemu_fdt_add_subnode(guest_fdt, nodename);

	copy_properties_from_host(amd_xgbe_copied_properties,
	ARRAY_SIZE(amd_xgbe_copied_properties),
	host_fdt, guest_fdt,
	node_path[0], nodename);

	qemu_fdt_setprop_cells(guest_fdt, nodename, "clocks",
	guest_clock_phandles[0],
	guest_clock_phandles[1]);

	reg_attr = g_new(uint32_t, vbasedev->num_regions * 2);
	for (i = 0; i < vbasedev->num_regions; i++) {
	mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, i);
	reg_attr[2 * i] = cpu_to_be32(mmio_base);
	reg_attr[2 * i + 1] = cpu_to_be32(
	memory_region_size(vdev->regions[i]->mem));
	}
	qemu_fdt_setprop(guest_fdt, nodename, "reg", reg_attr,
	vbasedev->num_regions * 2 * sizeof(uint32_t));

	irq_attr = g_new(uint32_t, vbasedev->num_irqs * 3);
	for (i = 0; i < vbasedev->num_irqs; i++) {
	irq_number = platform_bus_get_irqn(pbus, sbdev , i)
	+ data->irq_start;
	irq_attr[3 * i] = cpu_to_be32(GIC_FDT_IRQ_TYPE_SPI);
	irq_attr[3 * i + 1] = cpu_to_be32(irq_number);
	/*
	* General device interrupt and PCS auto-negotiation interrupts are
	* level-sensitive while the 4 per-channel interrupts are edge
	* sensitive
	*/
	QLIST_FOREACH(intp, &vdev->intp_list, next) {
	if (intp->pin == i) {
	break;
	}
	}
	if (intp->flags & VFIO_IRQ_INFO_AUTOMASKED) {
	irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_LEVEL_HI);
	} else {
	irq_attr[3 * i + 2] = cpu_to_be32(GIC_FDT_IRQ_FLAGS_EDGE_LO_HI);
	}
	}
	qemu_fdt_setprop(guest_fdt, nodename, "interrupts",
	irq_attr, vbasedev->num_irqs * 3 * sizeof(uint32_t));

	g_free(host_fdt);
	g_strfreev(node_path);
	g_free(irq_attr);
	g_free(reg_attr);
	g_free(nodename);
	return 0;
	}

	#endif /* CONFIG_LINUX */

	/* list of supported dynamic sysbus devices */
	static const NodeCreationPair add_fdt_node_functions[] = {
	#ifdef CONFIG_LINUX
	{TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node},
	{TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node},
	#endif
	{"", NULL}, /* last element */
	};

	/* Generic Code */

	/**
	* add_fdt_node - add the device tree node of a dynamic sysbus device
	*
	* @sbdev: handle to the sysbus device
	* @opaque: handle to the PlatformBusFDTData
	*
	* Checks the sysbus type belongs to the list of device types that
	* are dynamically instantiable and if so call the node creation
	* function.
	*/
	static int add_fdt_node(SysBusDevice sbdev, void opaque)
	{
	int i, ret;

	for (i = 0; i < ARRAY_SIZE(add_fdt_node_functions); i++) {
	if (!strcmp(object_get_typename(OBJECT(sbdev)),
	add_fdt_node_functions[i].typename)) {
	ret = add_fdt_node_functions[i].add_fdt_node_fn(sbdev, opaque);
	assert(!ret);
	return 0;
	}
	}
	error_report("Device %s can not be dynamically instantiated",
	qdev_fw_name(DEVICE(sbdev)));
	exit(1);
	}

	/**
	* add_all_platform_bus_fdt_nodes - create all the platform bus nodes
	*
	* builds the parent platform bus node and all the nodes of dynamic
	* sysbus devices attached to it.
	*/
	static void add_all_platform_bus_fdt_nodes(ARMPlatformBusFDTParams *fdt_params)
	{
	const char platcomp[] = "qemu,platform\0simple-bus";
	PlatformBusDevice *pbus;
	DeviceState *dev;
	gchar *node;
	uint64_t addr, size;
	int irq_start, dtb_size;
	struct arm_boot_info *info = fdt_params->binfo;
	const ARMPlatformBusSystemParams *params = fdt_params->system_params;
	const char *intc = fdt_params->intc;
	void *fdt = info->get_dtb(info, &dtb_size);

	/*
	* If the user provided a dtb, we assume the dynamic sysbus nodes
	* already are integrated there. This corresponds to a use case where
	* the dynamic sysbus nodes are complex and their generation is not yet
	* supported. In that case the user can take charge of the guest dt
	* while qemu takes charge of the qom stuff.
	*/
	if (info->dtb_filename) {
	return;
	}

	assert(fdt);

	node = g_strdup_printf("/platform@%"PRIx64, params->platform_bus_base);
	addr = params->platform_bus_base;
	size = params->platform_bus_size;
	irq_start = params->platform_bus_first_irq;

	/* Create a /platform node that we can put all devices into */
	qemu_fdt_add_subnode(fdt, node);
	qemu_fdt_setprop(fdt, node, "compatible", platcomp, sizeof(platcomp));

	/* Our platform bus region is less than 32bits, so 1 cell is enough for
	* address and size
	*/
	qemu_fdt_setprop_cells(fdt, node, "#size-cells", 1);
	qemu_fdt_setprop_cells(fdt, node, "#address-cells", 1);
	qemu_fdt_setprop_cells(fdt, node, "ranges", 0, addr >> 32, addr, size);

	qemu_fdt_setprop_phandle(fdt, node, "interrupt-parent", intc);

	dev = qdev_find_recursive(sysbus_get_default(), TYPE_PLATFORM_BUS_DEVICE);
	pbus = PLATFORM_BUS_DEVICE(dev);

	/* We can only create dt nodes for dynamic devices when they're ready */
	assert(pbus->done_gathering);

	PlatformBusFDTData data = {
	.fdt = fdt,
	.irq_start = irq_start,
	.pbus_node_name = node,
	.pbus = pbus,
	};

	/* Loop through all dynamic sysbus devices and create their node */
	foreach_dynamic_sysbus_device(add_fdt_node, &data);

	g_free(node);
	}

	static void platform_bus_fdt_notify(Notifier notifier, void data)
	{
	PlatformBusFDTNotifierParams *p = DO_UPCAST(PlatformBusFDTNotifierParams,
	notifier, notifier);

	add_all_platform_bus_fdt_nodes(p->fdt_params);
	g_free(p->fdt_params);
	g_free(p);
	}

	void arm_register_platform_bus_fdt_creator(ARMPlatformBusFDTParams *fdt_params)
	{
	PlatformBusFDTNotifierParams *p = g_new(PlatformBusFDTNotifierParams, 1);

	p->fdt_params = fdt_params;
	p->notifier.notify = platform_bus_fdt_notify;
	qemu_add_machine_init_done_notifier(&p->notifier);
	}