hardware_gen: add elfloader output

The elfloader is going to start using devices based on the device tree.
Add an output method for hardware_gen.py that generates header files
that the elfloader can use. Currently they contain an array of
"devices", where each device has a compatiblity string and a series of
regions (represented simply as the physical address of the region).

For now, the elfloader only uses the serial device specified by the
stdout-path property in the DTB.

tools/hardware/outputs/elfloader.py

@@ -0,0 +1,134 @@
+#
+# Copyright 2019, Data61
+# Commonwealth Scientific and Industrial Research Organisation (CSIRO)
+# ABN 41 687 119 230.
+#
+# This software may be distributed and modified according to the terms of
+# the GNU General Public License version 2. Note that NO WARRANTY is provided.
+# See "LICENSE_GPLv2.txt" for details.
+#
+# @TAG(DATA61_GPL)
+#
+
+''' generate a header file for the elfloader from a device tree '''
+
+import argparse
+import builtins
+import logging
+import pyfdt.pyfdt
+
+from jinja2 import Environment, BaseLoader
+
+from hardware import config, fdt
+from hardware.utils import memory, rule
+
+
+HEADER_TEMPLATE = '''/*
+ * Copyright 2019, Data61
+ * Commonwealth Scientific and Industrial Research Organisation (CSIRO)
+ * ABN 41 687 119 230.
+ *
+ * This software may be distributed and modified according to the terms of
+ * the GNU General Public License version 2. Note that NO WARRANTY is provided.
+ * See "LICENSE_GPLv2.txt" for details.
+ *
+ * @TAG(DATA61_GPL)
+ */
+/*
+ * This file is autogenerated by kernel/tools/hardware_gen.py
+ */
+
+#pragma once
+
+#define MAX_NUM_REGIONS {{ max_reg }}
+
+struct elfloader_driver;
+
+struct elfloader_device {
+    const char *compat;
+    volatile void *region_bases[MAX_NUM_REGIONS];
+    struct elfloader_driver *drv;
+};
+
+#ifdef DRIVER_COMMON
+struct elfloader_device elfloader_devices[] = {
+{% for d in devices %}
+    {
+        /* {{ d['path'] }} */
+        .compat = "{{ d['compat'] }}",
+        .region_bases = {
+            {% for r in d['regions'] %}
+            (void *){{ "0x{:x}".format(r.base) }},
+            {% endfor %}
+            {% for i in range(max_reg - len(d['regions'])) %}
+            (void *)0,
+            {% endfor %}
+        },
+    },
+{% endfor %}
+{% if devices | length == 0 %}
+    {
+        .compat = NULL,
+        .region_bases = {
+            {% for i in range(max_reg) %}
+            NULL,
+            {% endfor %}
+        },
+    },
+{% endif %}
+};
+#else
+struct elfloader_device *elfloader_devices;
+#endif
+'''
+
+
+def get_elfloader_devices(tree: fdt.FdtParser, rules: rule.HardwareYaml):
+    devices = []
+
+    # serial device
+    chosen = tree.get_path('/chosen')
+    if not chosen.has_prop('stdout-path') or type(chosen.get_prop('stdout-path')) != pyfdt.pyfdt.FdtPropertyStrings:
+        logging.info('DT has no stdout-path, elfloader may not produce output!')
+    else:
+        val = chosen.get_prop('stdout-path').strings[0]
+        if val[0] == '/':
+            path = val
+        else:
+            path = tree.lookup_alias(val)
+        devices.append(tree.get_path(path))
+    return devices
+
+
+def run(tree: fdt.FdtParser, hardware: rule.HardwareYaml, config: config.Config, args: argparse.Namespace):
+    devices = get_elfloader_devices(tree, hardware)
+    device_info = []
+    max_reg = 1
+    for dev in devices:
+        obj = {
+            'compat': hardware.get_matched_compatible(dev),
+            'path': dev.path,
+            'regions': dev.get_regions()
+        }
+        max_reg = max(len(obj['regions']), max_reg)
+
+        device_info.append(obj)
+
+    device_info.sort(key=lambda a: a['compat'])
+
+    template = Environment(loader=BaseLoader, trim_blocks=True,
+                           lstrip_blocks=True).from_string(HEADER_TEMPLATE)
+
+    template_args = dict(builtins.__dict__, **{
+        'devices': device_info,
+        'max_reg': max_reg
+    })
+
+    data = template.render(template_args)
+    args.elfloader_out.write(data)
+    args.elfloader_out.close()
+
+
+def add_args(parser):
+    parser.add_argument('--elfloader-out', help='output file for elfloader header',
+                        type=argparse.FileType('w'))

tools/hardware_gen.py

@@ -17,12 +17,13 @@ import logging
 import yaml
 
 from hardware import config, fdt
-from hardware.outputs import c_header, compat_strings, yaml as yaml_out
+from hardware.outputs import c_header, compat_strings, yaml as yaml_out, elfloader
 from hardware.utils.rule import HardwareYaml
 
 OUTPUTS = {
     'c_header': c_header,
     'compat_strings': compat_strings,
+    'elfloader': elfloader,
     'yaml': yaml_out,
 }