On Wed, Jan 06, 2016 at 03:13:23PM +0000, Eric Auger wrote: > 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. > > - inherit_properties copies properties from a host device tree node to > a guest device tree node
I dislike the name, since the first thing I think when I see "inherit" is that it's about a node inheriting a property from an ancestor node, not the guest inheriting properties from the host. Maybe "passthrough_properties()"? > - 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: Eric Auger <eric.au...@linaro.org> > > --- > > v1 -> v2: > - inherit properties now outputs an error message in case > qemu_fdt_getprop fails for an existing optional property > - no hardcoded fixed buffer length > - fdt_build_clock_node becomes void and auto-asserts on error > - use boolean values when defining the clock properties > > RFC -> v1: > - use the new proto of qemu_fdt_getprop > - remove newline in error_report > - fix some style issues > --- > hw/arm/sysbus-fdt.c | 120 > ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 120 insertions(+) > > diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c > index 9d28797..a1cf57b 100644 > --- a/hw/arm/sysbus-fdt.c > +++ b/hw/arm/sysbus-fdt.c > @@ -21,6 +21,7 @@ > * > */ > > +#include <libfdt.h> > #include "hw/arm/sysbus-fdt.h" > #include "qemu/error-report.h" > #include "sysemu/device_tree.h" > @@ -56,6 +57,125 @@ typedef struct NodeCreationPair { > int (*add_fdt_node_fn)(SysBusDevice *sbdev, void *opaque); > } NodeCreationPair; > > +/* helpers */ > + > +typedef struct HostProperty { > + const char *name; > + bool optional; > +} HostProperty; > + > +/** > + * inherit_properties > + * > + * copies properties listed in an array from host device tree to > + * guest device tree. If a non optional property is not found, the > + * function self-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 inherit_properties(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_inherited_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); > + > + inherit_properties(clock_inherited_properties, > + ARRAY_SIZE(clock_inherited_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 */ > > /** -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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