arm: drop intermediate cpu_model -> cpu type parsing and use cpu type directly

there are 2 use cases to deal with:
  1: fixed CPU models per board/soc
  2: boards with user configurable cpu_model and fallback to
     default cpu_model if user hasn't specified one explicitly

For the 1st
  drop intermediate cpu_model parsing and use const cpu type
  directly, which replaces:
     typename = object_class_get_name(
           cpu_class_by_name(TYPE_ARM_CPU, cpu_model))
     object_new(typename)
  with
     object_new(FOO_CPU_TYPE_NAME)
  or
     cpu_generic_init(BASE_CPU_TYPE, "my cpu model")
  with
     cpu_create(FOO_CPU_TYPE_NAME)

as result 1st use case doesn't have to invoke not necessary
translation and not needed code is removed.

For the 2nd
 1: set default cpu type with MachineClass::default_cpu_type and
 2: use generic cpu_model parsing that done before machine_init()
    is run and:
    2.1: drop custom cpu_model parsing where pattern is:
       typename = object_class_get_name(
           cpu_class_by_name(TYPE_ARM_CPU, cpu_model))
       [parse_features(typename, cpu_model, &err) ]

    2.2: or replace cpu_generic_init() which does what
         2.1 does + create_cpu(typename) with just
         create_cpu(machine->cpu_type)
as result cpu_name -> cpu_type translation is done using
generic machine code one including parsing optional features
if supported/present (removes a bunch of duplicated cpu_model
parsing code) and default cpu type is defined in an uniform way
within machine_class_init callbacks instead of adhoc places
in boadr's machine_init code.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <1505318697-77161-6-git-send-email-imammedo@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
diff --git a/hw/arm/gumstix.c b/hw/arm/gumstix.c
index 092ce36..bba9e9f 100644
--- a/hw/arm/gumstix.c
+++ b/hw/arm/gumstix.c
@@ -44,6 +44,7 @@
 #include "sysemu/block-backend.h"
 #include "exec/address-spaces.h"
 #include "sysemu/qtest.h"
+#include "cpu.h"
 
 static const int sector_len = 128 * 1024;
 
@@ -86,7 +87,6 @@
 
 static void verdex_init(MachineState *machine)
 {
-    const char *cpu_model = machine->cpu_model;
     PXA2xxState *cpu;
     DriveInfo *dinfo;
     int be;
@@ -95,7 +95,7 @@
     uint32_t verdex_rom = 0x02000000;
     uint32_t verdex_ram = 0x10000000;
 
-    cpu = pxa270_init(address_space_mem, verdex_ram, cpu_model ?: "pxa270-c0");
+    cpu = pxa270_init(address_space_mem, verdex_ram, machine->cpu_type);
 
     dinfo = drive_get(IF_PFLASH, 0, 0);
     if (!dinfo && !qtest_enabled()) {
@@ -144,6 +144,7 @@
     mc->desc = "Gumstix Verdex (PXA270)";
     mc->init = verdex_init;
     mc->ignore_memory_transaction_failures = true;
+    mc->default_cpu_type = ARM_CPU_TYPE_NAME("pxa270-c0");
 }
 
 static const TypeInfo verdex_type = {