xen/riscv: implement make_cpus_node()

Implement make_cpus_node() to create cpus node for a guest domain.

This function is going to be use by common dom0less code during
construction domain.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/domain-build.c

@@ -3,8 +3,10 @@
 #include <xen/fdt-domain-build.h>
 #include <xen/fdt-kernel.h>
 #include <xen/init.h>
+#include <xen/libfdt/libfdt.h>
 #include <xen/sched.h>
 
+#include <asm/cpufeature.h>
 #include <asm/current.h>
 #include <asm/guest_access.h>
 
@@ -48,3 +50,107 @@ int __init construct_domain(struct domain *d, struct kernel_info *kinfo)
 
     return 0;
 }
+
+int __init make_cpus_node(const struct domain *d, struct kernel_info *kinfo)
+{
+    int res;
+    const struct dt_device_node *cpus = dt_find_node_by_path("/cpus");
+    uint32_t timebase_frequency;
+    bool frequency_valid;
+    void *fdt = kinfo->fdt;
+
+    dt_dprintk("Create cpus node\n");
+
+    if ( !cpus )
+    {
+        dprintk(XENLOG_ERR, "Missing /cpus node in the device tree?\n");
+        return -ENOENT;
+    }
+
+    frequency_valid = dt_property_read_u32(cpus, "timebase-frequency",
+                                           &timebase_frequency);
+
+    res = fdt_begin_node(fdt, "cpus");
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "#address-cells", 1);
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "#size-cells", 0);
+    if ( res )
+        return res;
+
+    if ( frequency_valid )
+        res = fdt_property_cell(fdt, "timebase-frequency", timebase_frequency);
+
+    for ( unsigned int cpu = 0; cpu < d->max_vcpus; cpu++ )
+    {
+        char buf[64];
+
+        snprintf(buf, ARRAY_SIZE(buf), "cpu@%u", cpu);
+        res = fdt_begin_node(fdt, buf);
+        if ( res )
+            return res;
+
+        res = fdt_property_cell(fdt, "reg", cpu);
+        if ( res )
+            return res;
+
+        res = fdt_property_string(fdt, "status", "okay");
+        if ( res )
+            return res;
+
+        res = fdt_property_string(fdt, "compatible", "riscv");
+        if ( res )
+            return res;
+
+        BUILD_BUG_ON((sizeof("riscv,") +
+                      sizeof_field(struct gstage_mode_desc, name)) >= sizeof(buf));
+        snprintf(buf, ARRAY_SIZE(buf), "riscv,%s", max_gstage_mode->name);
+        res = fdt_property_string(fdt, "mmu-type", buf);
+        if ( res )
+            return res;
+
+        res = fdt_property_string(fdt, "riscv,isa", get_guest_isa_str());
+        if ( res )
+            return res;
+
+        res = fdt_property_string(fdt, "device_type", "cpu");
+        if ( res )
+            return res;
+
+        /* Start of interrupt-controller */
+        res = fdt_begin_node(fdt, "interrupt-controller");
+        if ( res )
+            return res;
+
+        res = fdt_property_string(fdt, "compatible", "riscv,cpu-intc");
+        if ( res )
+            return res;
+
+        res = fdt_property_cell(fdt, "#interrupt-cells", 1);
+        if ( res )
+            return res;
+
+        res = fdt_property(fdt, "interrupt-controller", NULL, 0);
+        if ( res )
+            return res;
+
+        res = fdt_property_u32(fdt, "phandle", alloc_phandle(kinfo));
+        if ( res )
+            return res;
+
+        /* End of interrupt-controller */
+        res = fdt_end_node(fdt);
+        if ( res )
+            return res;
+
+        res = fdt_end_node(fdt);
+        if ( res )
+            return res;
+    }
+
+    return fdt_end_node(fdt);
+}