acpi: add build_append_namestring() helper

Use build_append_namestring() instead of build_append_nameseg()
So user won't have to care whether name is NameSeg, NamePath or
NameString.

See for reference ACPI 5.0: 20.2.2 Name Objects Encoding

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/acpi/aml-build.c

@@ -23,6 +23,7 @@
 #include <stdarg.h>
 #include <assert.h>
 #include <stdbool.h>
+#include <string.h>
 #include "hw/acpi/aml-build.h"
 
 GArray *build_alloc_array(void)
@@ -52,25 +53,102 @@ void build_append_array(GArray *array, GArray *val)
 
 #define ACPI_NAMESEG_LEN 4
 
-void GCC_FMT_ATTR(2, 3)
+static void
-build_append_nameseg(GArray *array, const char *format, ...)
+build_append_nameseg(GArray *array, const char *seg)
 {
     /* It would be nicer to use g_string_vprintf but it's only there in 2.22 */
-    char s[] = "XXXX";
     int len;
-    va_list args;
-
-    va_start(args, format);
-    len = vsnprintf(s, sizeof s, format, args);
-    va_end(args);
 
+    len = strlen(seg);
     assert(len <= ACPI_NAMESEG_LEN);
 
-    g_array_append_vals(array, s, len);
+    g_array_append_vals(array, seg, len);
     /* Pad up to ACPI_NAMESEG_LEN characters if necessary. */
     g_array_append_vals(array, "____", ACPI_NAMESEG_LEN - len);
 }
 
+static void
+build_append_namestringv(GArray *array, const char *format, va_list ap)
+{
+    /* It would be nicer to use g_string_vprintf but it's only there in 2.22 */
+    char *s;
+    int len;
+    va_list va_len;
+    char **segs;
+    char **segs_iter;
+    int seg_count = 0;
+
+    va_copy(va_len, ap);
+    len = vsnprintf(NULL, 0, format, va_len);
+    va_end(va_len);
+    len += 1;
+    s = g_new(typeof(*s), len);
+
+    len = vsnprintf(s, len, format, ap);
+
+    segs = g_strsplit(s, ".", 0);
+    g_free(s);
+
+    /* count segments */
+    segs_iter = segs;
+    while (*segs_iter) {
+        ++segs_iter;
+        ++seg_count;
+    }
+    /*
+     * ACPI 5.0 spec: 20.2.2 Name Objects Encoding:
+     * "SegCount can be from 1 to 255"
+     */
+    assert(seg_count > 0 && seg_count <= 255);
+
+    /* handle RootPath || PrefixPath */
+    s = *segs;
+    while (*s == '\\' || *s == '^') {
+        build_append_byte(array, *s);
+        ++s;
+    }
+
+    switch (seg_count) {
+    case 1:
+        if (!*s) {
+            build_append_byte(array, 0x0); /* NullName */
+        } else {
+            build_append_nameseg(array, s);
+        }
+        break;
+
+    case 2:
+        build_append_byte(array, 0x2E); /* DualNamePrefix */
+        build_append_nameseg(array, s);
+        build_append_nameseg(array, segs[1]);
+        break;
+    default:
+        build_append_byte(array, 0x2F); /* MultiNamePrefix */
+        build_append_byte(array, seg_count);
+
+        /* handle the 1st segment manually due to prefix/root path */
+        build_append_nameseg(array, s);
+
+        /* add the rest of segments */
+        segs_iter = segs + 1;
+        while (*segs_iter) {
+            build_append_nameseg(array, *segs_iter);
+            ++segs_iter;
+        }
+        break;
+    }
+    g_strfreev(segs);
+}
+
+void build_append_namestring(GArray *array, const char *format, ...)
+{
+    va_list ap;
+
+    va_start(ap, format);
+    build_append_namestringv(array, format, ap);
+    va_end(ap);
+}
+
 /* 5.4 Definition Block Encoding */
 enum {
     PACKAGE_LENGTH_1BYTE_SHIFT = 6, /* Up to 63 - use extra 2 bits. */

hw/i386/acpi-build.c

@@ -286,7 +286,7 @@ static GArray *build_alloc_method(const char *name, uint8_t arg_count)
 {
     GArray *method = build_alloc_array();
 
-    build_append_nameseg(method, "%s", name);
+    build_append_namestring(method, "%s", name);
     build_append_byte(method, arg_count); /* MethodFlags: ArgCount */
 
     return method;
@@ -578,7 +578,7 @@ build_append_notify_method(GArray *device, const char *name,
 
     for (i = 0; i < count; i++) {
         GArray *target = build_alloc_array();
-        build_append_nameseg(target, format, i);
+        build_append_namestring(target, format, i);
         assert(i < 256); /* Fits in 1 byte */
         build_append_notify_target_ifequal(method, target, i, 1);
         build_free_array(target);
@@ -709,24 +709,24 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state)
 
     if (bus->parent_dev) {
         op = 0x82; /* DeviceOp */
-        build_append_nameseg(bus_table, "S%.02X",
+        build_append_namestring(bus_table, "S%.02X",
                              bus->parent_dev->devfn);
         build_append_byte(bus_table, 0x08); /* NameOp */
-        build_append_nameseg(bus_table, "_SUN");
+        build_append_namestring(bus_table, "_SUN");
         build_append_value(bus_table, PCI_SLOT(bus->parent_dev->devfn), 1);
         build_append_byte(bus_table, 0x08); /* NameOp */
-        build_append_nameseg(bus_table, "_ADR");
+        build_append_namestring(bus_table, "_ADR");
         build_append_value(bus_table, (PCI_SLOT(bus->parent_dev->devfn) << 16) |
                            PCI_FUNC(bus->parent_dev->devfn), 4);
     } else {
         op = 0x10; /* ScopeOp */;
-        build_append_nameseg(bus_table, "PCI0");
+        build_append_namestring(bus_table, "PCI0");
     }
 
     bsel = object_property_get_qobject(OBJECT(bus), ACPI_PCIHP_PROP_BSEL, NULL);
     if (bsel) {
         build_append_byte(bus_table, 0x08); /* NameOp */
-        build_append_nameseg(bus_table, "BSEL");
+        build_append_namestring(bus_table, "BSEL");
         build_append_int(bus_table, qint_get_int(qobject_to_qint(bsel)));
         memset(slot_hotplug_enable, 0xff, sizeof slot_hotplug_enable);
     } else {
@@ -829,7 +829,7 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state)
             build_append_int(notify, 0x1U << i);
             build_append_byte(notify, 0x00); /* NullName */
             build_append_byte(notify, 0x86); /* NotifyOp */
-            build_append_nameseg(notify, "S%.02X", PCI_DEVFN(i, 0));
+            build_append_namestring(notify, "S%.02X", PCI_DEVFN(i, 0));
             build_append_byte(notify, 0x69); /* Arg1Op */
 
             /* Pack it up */
@@ -853,12 +853,12 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state)
         if (bsel) {
             build_append_byte(method, 0x70); /* StoreOp */
             build_append_int(method, qint_get_int(qobject_to_qint(bsel)));
-            build_append_nameseg(method, "BNUM");
+            build_append_namestring(method, "BNUM");
-            build_append_nameseg(method, "DVNT");
+            build_append_namestring(method, "DVNT");
-            build_append_nameseg(method, "PCIU");
+            build_append_namestring(method, "PCIU");
             build_append_int(method, 1); /* Device Check */
-            build_append_nameseg(method, "DVNT");
+            build_append_namestring(method, "DVNT");
-            build_append_nameseg(method, "PCID");
+            build_append_namestring(method, "PCID");
             build_append_int(method, 3); /* Eject Request */
         }
 
@@ -884,11 +884,8 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state)
          * At the moment this is not needed for root as we have a single root.
          */
         if (bus->parent_dev) {
-            build_append_byte(parent->notify_table, '^'); /* ParentPrefixChar */
+            build_append_namestring(parent->notify_table, "^PCNT.S%.02X",
-            build_append_byte(parent->notify_table, 0x2E); /* DualNamePrefix */
-            build_append_nameseg(parent->notify_table, "S%.02X",
                                     bus->parent_dev->devfn);
-            build_append_nameseg(parent->notify_table, "PCNT");
         }
     }
 
@@ -956,7 +953,7 @@ build_ssdt(GArray *table_data, GArray *linker,
         GArray *sb_scope = build_alloc_array();
         uint8_t op = 0x10; /* ScopeOp */
 
-        build_append_nameseg(sb_scope, "_SB");
+        build_append_namestring(sb_scope, "_SB");
 
         /* build Processor object for each processor */
         for (i = 0; i < acpi_cpus; i++) {
@@ -976,7 +973,7 @@ build_ssdt(GArray *table_data, GArray *linker,
 
         /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })" */
         build_append_byte(sb_scope, 0x08); /* NameOp */
-        build_append_nameseg(sb_scope, "CPON");
+        build_append_namestring(sb_scope, "CPON");
 
         {
             GArray *package = build_alloc_array();

include/hw/acpi/aml-build.h

@@ -12,7 +12,7 @@ void build_append_byte(GArray *array, uint8_t val);
 void build_append_array(GArray *array, GArray *val);
 
 void GCC_FMT_ATTR(2, 3)
-build_append_nameseg(GArray *array, const char *format, ...);
+build_append_namestring(GArray *array, const char *format, ...);
 
 void build_prepend_package_length(GArray *package, unsigned min_bytes);
 void build_package(GArray *package, uint8_t op, unsigned min_bytes);