From fcbebde3021b1caa61f3f32def245dd358833d6a Mon Sep 17 00:00:00 2001
From: Mateusz Holenko <mholenko@antmicro.com>
Date: Wed, 7 Jul 2021 10:21:56 +0200
Subject: [PATCH] Add Zephyr DTS overlay generator

---
 litex/tools/litex_zephyr_dts_generator.py | 182 ++++++++++++++++++++++
 1 file changed, 182 insertions(+)
 create mode 100755 litex/tools/litex_zephyr_dts_generator.py

diff --git a/litex/tools/litex_zephyr_dts_generator.py b/litex/tools/litex_zephyr_dts_generator.py
new file mode 100755
index 000000000..3fcb40639
--- /dev/null
+++ b/litex/tools/litex_zephyr_dts_generator.py
@@ -0,0 +1,182 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2019-2021 Antmicro <www.antmicro.com>
+# Copyright (c) 2021 Henk Vergonet <henk.vergonet@gmail.com>
+#
+# Zephyr DTS & config overlay generator for LiteX SoC.
+#
+# This script parses LiteX 'csr.json' file and generates DTS and config
+# files overlay for Zephyr.
+
+# Changelog:
+# - 2021-07-05 Henk Vergonet <henk.vergonet@gmail.com>
+#    removed dependency on intermediate interpretation layers
+#    switch to JSON csr
+#    fix uart size parameter
+# - 2021-07-15 Henk Vergonet <henk.vergonet@gmail.com>
+#    added identifier_mem handler as dna0
+#    added spiflash as spi0
+#
+
+import argparse
+import json
+
+
+# DTS formatting
+def dts_open(name, parm): return "&{} {{\n".format(parm.get('alias', name))
+def dts_close():          return "};\n"
+def dts_intr(name, csr):  return "    interrupts = <{} 0>;\n".format(
+                                    hex(csr['constants'][name + '_interrupt']))
+def dts_reg(regs):        return "    reg = <{}>;\n".format(regs)
+
+
+# DTS handlers
+def disabled_handler(name, parm, csr):
+    return "    status = \"disabled\";\n"
+
+
+def ram_handler(name, parm, csr):
+    return dts_reg(" ".join([
+                hex(csr['memories'][name]['base']),
+                hex(csr['memories'][name]['size'])]))
+
+
+def ethmac_handler(name, parm, csr):
+    dtsi  = dts_reg(" ".join([
+                hex(csr['csr_bases'][name]),
+                hex(parm['size']),
+                hex(csr['memories'][name]['base']),
+                hex(csr['memories'][name]['size'])]))
+    dtsi += dts_intr(name, csr)
+    return dtsi
+
+
+def i2c_handler(name, parm, csr):
+    dtsi  = dts_reg(" ".join([
+                hex(csr['csr_bases'][name]),
+                hex(parm['size']),
+                hex(csr['csr_bases'][name] + parm['size']),
+                hex(parm['size'])]))
+    dtsi += dts_intr(name, csr)
+    return dtsi
+
+
+def peripheral_handler(name, parm, csr):
+    dtsi  = dts_reg(" ".join([
+                hex(csr['csr_bases'][name]),
+                hex(parm['size'])]))
+    try:
+        dtsi += dts_intr(name, csr)
+    except KeyError as e:
+        print('  dtsi key', e, 'not found, no interrupt override')
+    return dtsi
+
+
+overlay_handlers = {
+    'uart': {
+        'handler': peripheral_handler,
+        'alias': 'uart0',
+        'size': 0x20,
+        'config_entry': 'UART_LITEUART'
+    },
+    'timer0': {
+        'handler': peripheral_handler,
+        'size': 0x40,
+        'config_entry': 'LITEX_TIMER'
+    },
+    'ethmac': {
+        'handler': ethmac_handler,
+        'alias': 'eth0',
+        'size': 0x80,
+        'config_entry': 'ETH_LITEETH'
+    },
+    'spiflash': {
+        'handler': peripheral_handler,
+        'alias': 'spi0',
+        'size': 12,
+        'config_entry': 'SPI_LITESPI'
+    },
+    'i2c0' : {
+        'handler': i2c_handler,
+        'size': 0x4,
+        'config_entry': 'I2C_LITEX'
+    },
+    'main_ram': {
+        'handler': ram_handler,
+        'alias': 'ram0',
+    },
+    'identifier_mem': {
+        'handler': peripheral_handler,
+        'alias': 'dna0',
+        'size': 0x100,
+    }
+}
+
+
+def generate_dts_config(csr):
+    dts = cnf = ''
+
+    for name, parm in overlay_handlers.items():
+        print('Generating overlay for:',name)
+        enable = 'y'
+        dtsi = dts_open(name, parm)
+
+        try:
+            dtsi += parm['handler'](name, parm, csr)
+        except KeyError as e:
+            print('  dtsi key', e, 'not found, disable', name)
+            enable = 'n'
+            dtsi += disabled_handler(name, parm, csr)
+
+        dtsi += dts_close()
+        dts += dtsi
+        if 'config_entry' in parm:
+            cnf += ' -DCONFIG_' + parm['config_entry'] + '=' + enable 
+
+    for name, value in csr['csr_bases'].items():
+        if name not in overlay_handlers.keys():
+            print('No overlay handler for:', name, 'at', hex(value))
+
+    return dts, cnf
+
+
+# helpers
+def print_or_save(filepath, lines):
+    """ Prints given string on standard output or to the file.
+
+    Args:
+        filepath (string): path to the file lines should be written to
+                           or '-' to write to a standard output
+        lines (string): content to be printed/written
+    """
+    if filepath == '-':
+        print(lines)
+    else:
+        with open(filepath, 'w') as f:
+            f.write(lines)
+
+
+def parse_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('conf_file',
+                        help='JSON configuration generated by LiteX')
+    parser.add_argument('--dts', action='store', required=True,
+                        help='Output DTS overlay file')
+    parser.add_argument('--config', action='store', required=True,
+                        help='Output config overlay file')
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+
+    with open(args.conf_file) as f:
+        csr = json.load(f)
+    dts, config = generate_dts_config(csr)
+
+    print_or_save(args.dts, dts)
+    print_or_save(args.config, config)
+
+
+if __name__ == '__main__':
+    main()