Commit 9481cf2e authored by Eric Auger's avatar Eric Auger Committed by Alex Williamson
Browse files

hw/arm/sysbus-fdt: helpers for clock node generation 



Some passthrough'ed devices depend on clock nodes. Those need to be
generated in the guest device tree. This patch introduces some helpers
to build a clock node from information retrieved in the host device tree.

- copy_properties_from_host copies properties from a host device tree
  node to a guest device tree node
- fdt_build_clock_node builds a guest clock node and checks the host
  fellow clock is a fixed one.

fdt_build_clock_node will become static as soon as it gets used. A
dummy pre-declaration is needed for compilation of this patch.

Signed-off-by: default avatarEric Auger <eric.auger@linaro.org>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 58e71097

hw/arm/sysbus-fdt.c

+120 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
 */



#include "qemu/osdep.h"

#include <libfdt.h>

#include "hw/arm/sysbus-fdt.h"

#include "qemu/error-report.h"

#include "sysemu/device_tree.h"
@@ -57,6 +58,125 @@ typedef struct NodeCreationPair { 
    int (*add_fdt_node_fn)(SysBusDevice *sbdev, void *opaque);

} NodeCreationPair;



/* helpers */



typedef struct HostProperty {

    const char *name;

    bool optional;

} HostProperty;



/**

 * 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

 */

void fdt_build_clock_node(void *host_fdt, void *guest_fdt,

                         uint32_t host_phandle,

                         uint32_t guest_phandle);

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);

}



/* Device Specific Code */



/**