dsdt: track device hierarchy

Add parent entry to acpi_device struct, set it when parsing sub-devices,
restore it when done.

This allows to track and check for device relationships, for example the
GSIn sub-devices of PCI0.  Known limitation: Establishing relationship
using Scope() does not work.

This also makes the parser process data after sub-devices correctly,
for example find _CRS in this case:

        Device (PCI0)
        {
	    [ ... ]
            Device (GSI0)
	    [ ... ]
            Name (_CRS, ResourceTemplate ()
	    { ... ]
	}

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>.

2 files changed, 16 insertions, 4 deletions

diff --git a/src/fw/dsdt_parser.c b/src/fw/dsdt_parser.c
index 61beeefd..fee3c090 100644
--- a/src/fw/dsdt_parser.c
+++ b/src/fw/dsdt_parser.c
@@ -18,6 +18,7 @@
 
 struct acpi_device {
     struct hlist_node node;
+    struct acpi_device *parent;
     char name[16];
     u8 *hid_aml;
     u8 *sta_aml;
@@ -349,22 +350,25 @@ static int parse_pkg_scope(struct parse_state *s,
 static int parse_pkg_device(struct parse_state *s,
                             u8 *ptr)
 {
+    struct acpi_device *dev;
     int offset, pkglength;
 
     offset = parse_pkg_common(s, ptr, "device", &pkglength);
 
-    s->dev = malloc_tmp(sizeof(struct acpi_device));
-    if (!s->dev) {
+    dev = malloc_tmp(sizeof(struct acpi_device));
+    if (!dev) {
         warn_noalloc();
         s->error = 1;
         return pkglength;
     }
 
-    memset(s->dev, 0, sizeof(struct acpi_device));
+    memset(dev, 0, sizeof(struct acpi_device));
+    dev->parent = s->dev;
+    s->dev = dev;
     hlist_add_head(&s->dev->node, &acpi_devices);
     strtcpy(s->dev->name, s->name, sizeof(s->name));
     parse_termlist(s, ptr, offset, pkglength);
-    s->dev = NULL;
+    s->dev = s->dev->parent;
 
     return pkglength;
 }
@@ -620,6 +624,11 @@ int acpi_dsdt_find_irq(struct acpi_device *dev, u64 *irq)
                          3 /* irq */, irq, &max);
 }
 
+int acpi_dsdt_is_parent(struct acpi_device *dev, struct acpi_device *parent)
+{
+    return dev->parent == parent;
+}
+
 int acpi_dsdt_present_eisaid(u16 eisaid)
 {
     if (!CONFIG_ACPI_PARSE)
@@ -666,6 +675,8 @@ void acpi_dsdt_parse(void)
             dprintf(1, ", sta (0x%x)", dev->sta_aml[0]);
         if (dev->crs_data)
             dprintf(1, ", crs");
+        if (dev->parent)
+            dprintf(1, ", parent %s", acpi_dsdt_name(dev->parent));
         dprintf(1, "\n");
         if (dev->crs_data)
             print_resources("        ", dev->crs_data, dev->crs_size);
diff --git a/src/util.h b/src/util.h
index 0de35229..d4071fc5 100644
--- a/src/util.h
+++ b/src/util.h
@@ -104,6 +104,7 @@ int acpi_dsdt_present_eisaid(u16 eisaid);
 int acpi_dsdt_find_io(struct acpi_device *dev, u64 *min, u64 *max);
 int acpi_dsdt_find_mem(struct acpi_device *dev, u64 *min, u64 *max);
 int acpi_dsdt_find_irq(struct acpi_device *dev, u64 *irq);
+int acpi_dsdt_is_parent(struct acpi_device *dev, struct acpi_device *parent);
 
 // fw/coreboot.c
 extern const char *CBvendor, *CBpart;