[PATCH 2/2] xfree86: Provide backward-compatibilty API for OdevAttributes

[Keith Packard]

This allows drivers to compile using the old OdevAttributes API
against a new server. It generates compiler errors if the caller uses
the wrong or undefined attribute types, or if the caller provides an
incorrect default value for an integer attribute.

Signed-off-by: Keith Packard <keithp at keithp.com>
---
 hw/xfree86/common/xf86platformBus.h | 71 +++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/hw/xfree86/common/xf86platformBus.h b/hw/xfree86/common/xf86platformBus.h
index 823a10c..2a90104 100644
--- a/hw/xfree86/common/xf86platformBus.h
+++ b/hw/xfree86/common/xf86platformBus.h
@@ -71,6 +71,77 @@ xf86_platform_odev_attributes(int index)
     return device->attribs;
 }
 
+#ifndef _XORG_CONFIG_H_
+/*
+ * Define the legacy API only for external builds
+ */
+
+/* path to kernel device node - Linux e.g. /dev/dri/card0 */
+#define ODEV_ATTRIB_PATH        1
+/* system device path - Linux e.g. /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card1 */
+#define ODEV_ATTRIB_SYSPATH     2
+/* DRI-style bus id */
+#define ODEV_ATTRIB_BUSID       3
+/* Server managed FD */
+#define ODEV_ATTRIB_FD          4
+/* Major number of the device node pointed to by ODEV_ATTRIB_PATH */
+#define ODEV_ATTRIB_MAJOR       5
+/* Minor number of the device node pointed to by ODEV_ATTRIB_PATH */
+#define ODEV_ATTRIB_MINOR       6
+/* kernel driver name */
+#define ODEV_ATTRIB_DRIVER      7
+
+/* Protect against a mismatch attribute type by generating a compiler
+ * error using a negative array size when an incorrect attribute is
+ * passed
+ */
+
+#define _ODEV_ATTRIB_IS_STRING(x)       ((x) == ODEV_ATTRIB_PATH ||     \
+                                         (x) == ODEV_ATTRIB_SYSPATH ||  \
+                                         (x) == ODEV_ATTRIB_BUSID ||    \
+                                         (x) == ODEV_ATTRIB_DRIVER)
+
+#define _ODEV_ATTRIB_STRING_CHECK(x)    ((int (*)[_ODEV_ATTRIB_IS_STRING(x)-1]) 0)
+
+static inline char *
+_xf86_get_platform_device_attrib(struct xf86_platform_device *device, int attrib, int (*fake)[0])
+{
+    switch (attrib) {
+    case ODEV_ATTRIB_PATH:
+        return xf86_platform_device_odev_attributes(device)->path;
+    case ODEV_ATTRIB_SYSPATH:
+        return xf86_platform_device_odev_attributes(device)->syspath;
+    case ODEV_ATTRIB_BUSID:
+        return xf86_platform_device_odev_attributes(device)->busid;
+    case ODEV_ATTRIB_DRIVER:
+        return xf86_platform_device_odev_attributes(device)->driver;
+    }
+}
+
+#define xf86_get_platform_device_attrib(device, attrib) _xf86_get_platform_device_attrib(device,attrib,_ODEV_ATTRIB_STRING_CHECK(attrib))
+
+#define _ODEV_ATTRIB_IS_INT(x)                  ((x) == ODEV_ATTRIB_FD || (x) == ODEV_ATTRIB_MAJOR || (x) == ODEV_ATTRIB_MINOR)
+#define _ODEV_ATTRIB_INT_DEFAULT(x)             ((x) == ODEV_ATTRIB_FD ? -1 : 0)
+#define _ODEV_ATTRIB_DEFAULT_CHECK(x,def)       (_ODEV_ATTRIB_INT_DEFAULT(x) == (def))
+#define _ODEV_ATTRIB_INT_CHECK(x,def)           ((int (*)[_ODEV_ATTRIB_IS_INT(x)*_ODEV_ATTRIB_DEFAULT_CHECK(x,def)-1]) 0)
+
+static inline int
+_xf86_get_platform_device_int_attrib(struct xf86_platform_device *device, int attrib, int (*fake)[0])
+{
+    switch (attrib) {
+    case ODEV_ATTRIB_FD:
+        return xf86_platform_device_odev_attributes(device)->fd;
+    case ODEV_ATTRIB_MAJOR:
+        return xf86_platform_device_odev_attributes(device)->major;
+    case ODEV_ATTRIB_MINOR:
+        return xf86_platform_device_odev_attributes(device)->minor;
+    }
+}
+
+#define xf86_get_platform_device_int_attrib(device, attrib, def) _xf86_get_platform_device_int_attrib(device,attrib,_ODEV_ATTRIB_INT_CHECK(attrib,def))
+
+#endif
+
 extern _X_EXPORT Bool
 xf86PlatformDeviceCheckBusID(struct xf86_platform_device *device, const char *busid);
 
-- 
2.0.1