[Qemu-devel] [PATCH v3 2/4] hw/arm/sysbus-fdt: Allow device matching with DT compatible value

[Geert Uytterhoeven <geert+renesas@glider.be>]

From: Auger Eric <eric.auger@redhat.com>

Up to now we have relied on the device type to identify a device tree
node creation function.  Since we would like the vfio-platform device to
be instantiatable with different compatible strings we introduce the
capability to specialize the node creation depending on actual
compatible value.

NodeCreationPair is renamed into BindingEntry. The struct is enhanced
with compat and match_fn() fields.  We introduce a new matching function
adapted to the vfio-platform generic device.

>From now on, the AMD XGBE can be instantiated with either manner, i.e.:

    -device vfio-amd-xgbe,host=e0900000.xgmac

or using the new option line:

    -device vfio-platform,host=e0900000.xgmac

Signed-off-by: Eric Auger <eric.auger@redhat.com>
[geert: Match using compatible values in sysfs instead of user-supplied
	manufacturer/model options, reword]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Not tested with amd-xgbe due to lack of hardware.

v3:
  - Match using the compatible values from sysfs instead of using
    user-supplied manufacturer and model options,
  - Reword patch description,
  - Drop RFC state,

v2:
  - No changes,

v1:
  - No changes,

v0:
  - Original version from Eric.
---
 hw/arm/sysbus-fdt.c | 61 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 47 insertions(+), 14 deletions(-)

diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c
index 43d6a7bb48ddc351..0e24c803a1c2c734 100644
--- a/hw/arm/sysbus-fdt.c
+++ b/hw/arm/sysbus-fdt.c
@@ -50,11 +50,13 @@ typedef struct PlatformBusFDTData {
     PlatformBusDevice *pbus;
 } PlatformBusFDTData;
 
-/* struct that associates a device type name and a node creation function */
-typedef struct NodeCreationPair {
+/* struct that allows to match a device and create its FDT node */
+typedef struct BindingEntry {
     const char *typename;
-    int (*add_fdt_node_fn)(SysBusDevice *sbdev, void *opaque);
-} NodeCreationPair;
+    const char *compat;
+    int  (*add_fn)(SysBusDevice *sbdev, void *opaque);
+    bool (*match_fn)(SysBusDevice *sbdev, const struct BindingEntry *combo);
+} BindingEntry;
 
 /* helpers */
 
@@ -413,6 +415,27 @@ static int add_amd_xgbe_fdt_node(SysBusDevice *sbdev, void *opaque)
     return 0;
 }
 
+/* DT compatible matching */
+static bool vfio_platform_match(SysBusDevice *sbdev,
+                                const BindingEntry *entry)
+{
+    VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
+    const char *compat;
+    unsigned int n;
+
+    for (n = vdev->num_compat, compat = vdev->compat; n > 0;
+         n--, compat += strlen(compat) + 1) {
+        if (!strcmp(entry->compat, compat)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+#define VFIO_PLATFORM_BINDING(compat, add_fn) \
+    {TYPE_VFIO_PLATFORM, (compat), (add_fn), vfio_platform_match}
+
 #endif /* CONFIG_LINUX */
 
 static int no_fdt_node(SysBusDevice *sbdev, void *opaque)
@@ -420,14 +443,23 @@ static int no_fdt_node(SysBusDevice *sbdev, void *opaque)
     return 0;
 }
 
-/* list of supported dynamic sysbus devices */
-static const NodeCreationPair add_fdt_node_functions[] = {
+/* Device type based matching */
+static bool type_match(SysBusDevice *sbdev, const BindingEntry *entry)
+{
+    return !strcmp(object_get_typename(OBJECT(sbdev)), entry->typename);
+}
+
+#define TYPE_BINDING(type, add_fn) {(type), NULL, (add_fn), type_match}
+
+/* list of supported dynamic sysbus bindings */
+static const BindingEntry bindings[] = {
 #ifdef CONFIG_LINUX
-    {TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node},
-    {TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node},
+    TYPE_BINDING(TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node),
+    TYPE_BINDING(TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node),
+    VFIO_PLATFORM_BINDING("amd,xgbe-seattle-v1a", add_amd_xgbe_fdt_node),
 #endif
-    {TYPE_RAMFB_DEVICE, no_fdt_node},
-    {"", NULL}, /* last element */
+    TYPE_BINDING(TYPE_RAMFB_DEVICE, no_fdt_node),
+    TYPE_BINDING("", NULL), /* last element */
 };
 
 /* Generic Code */
@@ -446,10 +478,11 @@ static void add_fdt_node(SysBusDevice *sbdev, void *opaque)
 {
     int i, ret;
 
-    for (i = 0; i < ARRAY_SIZE(add_fdt_node_functions); i++) {
-        if (!strcmp(object_get_typename(OBJECT(sbdev)),
-                    add_fdt_node_functions[i].typename)) {
-            ret = add_fdt_node_functions[i].add_fdt_node_fn(sbdev, opaque);
+    for (i = 0; i < ARRAY_SIZE(bindings); i++) {
+        const BindingEntry *iter = &bindings[i];
+
+        if (iter->match_fn(sbdev, iter)) {
+            ret = iter->add_fn(sbdev, opaque);
             assert(!ret);
             return;
         }
-- 
2.17.1