ppc: Mark the 'taihu' machine as deprecated

The PPC 405 CPU is a system-on-a-chip, so all 405 machines are very similar,
except for some external periphery. However, the periphery of the 'taihu'
machine is hardly emulated at all (e.g. neither the LCD nor the USB part had
been implemented), so there is not much value added by this board. The users
can use the 'ref405ep' machine to test their PPC405 code instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20211203164904.290954-2-thuth@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-3-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

docs/about/deprecated.rst

@@ -315,6 +315,15 @@ This machine is deprecated because we have enough AST2500 based OpenPOWER
 machines. It can be easily replaced by the ``witherspoon-bmc`` or the
 ``romulus-bmc`` machines.
 
+PPC 405 ``taihu`` machine (since 7.0)
+'''''''''''''''''''''''''''''''''''''
+
+The PPC 405 CPU is a system-on-a-chip, so all 405 machines are very similar,
+except for some external periphery. However, the periphery of the ``taihu``
+machine is hardly emulated at all (e.g. neither the LCD nor the USB part had
+been implemented), so there is not much value added by this board. Use the
+``ref405ep`` machine instead.
+
 Backend options
 ---------------
 

hw/ppc/ppc405_boards.c

@@ -547,6 +547,7 @@ static void taihu_class_init(ObjectClass *oc, void *data)
     mc->init = taihu_405ep_init;
     mc->default_ram_size = 0x08000000;
     mc->default_ram_id = "taihu_405ep.ram";
+    mc->deprecation_reason = "incomplete, use 'ref405ep' instead";
 }
 
 static const TypeInfo taihu_type = {