#!/usr/bin/env python3
#
# Copyright (c) 2017 Intel Corporation
# SPDX-License-Identifier: Apache-2.0
#

import argparse
import struct
import sys
import os

ISR_FLAG_DIRECT = (1 << 0)

def debug(text):
    if not args.debug:
        return
    sys.stdout.write(os.path.basename(sys.argv[0]) + ": " + text + "\n")

def error(text):
    sys.stderr.write(os.path.basename(sys.argv[0]) + ": " + text + "\n")
    raise Exception()

def endian_prefix():
    if args.big_endian:
        return ">"
    else:
        return "<"

def read_intlist(intlist_path):
    """read a binary file containing the contents of the kernel's .intList
    section. This is an instance of a header created by
    include/linker/intlist.ld:

     struct {
       void * spurious_irq_handler;
       void * sw_irq_handler;
       u32_t num_isrs;
       u32_t num_vectors; <- typically CONFIG_NUM_IRQS
       struct _isr_list isrs[];  <- of size num_isrs
    }

    Followed by instances of struct _isr_list created by IRQ_CONNECT()
    calls:

    struct _isr_list {
        /** IRQ line number */
        s32_t irq;
        /** Flags for this IRQ, see ISR_FLAG_* definitions */
        s32_t flags;
        /** ISR to call */
        void *func;
        /** Parameter for non-direct IRQs */
        void *param;
    };
    """

    intlist = {}

    prefix = endian_prefix()

    intlist_header_fmt = prefix + "IIIII"
    intlist_entry_fmt = prefix + "iiII"

    with open(intlist_path, "rb") as fp:
        intdata = fp.read()

    header_sz = struct.calcsize(intlist_header_fmt)
    header = struct.unpack_from(intlist_header_fmt, intdata, 0)
    intdata = intdata[header_sz:]

    debug(str(header))

    intlist["spurious_handler"] = header[0]
    intlist["sw_irq_handler"] = header[1]
    intlist["num_vectors"] = header[2]
    intlist["offset"] = header[3]
    intlist["num_isrs"] = header[4]

    debug("spurious handler: %s" % hex(header[0]))

    intlist["interrupts"] = [i for i in
            struct.iter_unpack(intlist_entry_fmt, intdata)]

    debug("Configured interrupt routing")
    debug("handler    irq flags param")
    debug("--------------------------")

    for irq in intlist["interrupts"]:
        debug("{0:<10} {1:<3} {2:<3}   {3}".format(
            hex(irq[2]), irq[0], irq[1], hex(irq[3])))

    return intlist


def parse_args():
    global args

    parser = argparse.ArgumentParser(description = __doc__,
            formatter_class = argparse.RawDescriptionHelpFormatter)

    parser.add_argument("-e", "--big-endian", action="store_true",
            help="Target encodes data in big-endian format (little endian is "
                 "the default)")
    parser.add_argument("-d", "--debug", action="store_true",
            help="Print additional debugging information")
    parser.add_argument("-o", "--output-source", required=True,
            help="Output source file")
    parser.add_argument("-s", "--sw-isr-table", action="store_true",
            help="Generate SW ISR table")
    parser.add_argument("-V", "--vector-table", action="store_true",
            help="Generate vector table")
    parser.add_argument("-i", "--intlist", required=True,
            help="Zephyr intlist binary for intList extraction")

    args = parser.parse_args()

source_header = """
/* AUTO-GENERATED by gen_isr_tables.py, do not edit! */

#include <toolchain.h>
#include <sections.h>
#include <sw_isr_table.h>

"""

def write_source_file(fp, vt, swt, intlist):
    fp.write(source_header)

    nv = intlist["num_vectors"]

    if vt:
        fp.write("u32_t __irq_vector_table _irq_vector_table[%d] = {\n" % nv)
        for i in range(nv):
            fp.write("\t0x%x,\n" % vt[i])
        fp.write("};\n")

    if not swt:
        return

    fp.write("struct _isr_table_entry __sw_isr_table _sw_isr_table[%d] = {\n"
            % nv)
    for i in range(nv):
        param, func = swt[i]
        fp.write("\t{(void *)0x%x, (void *)0x%x},\n" % (param, func))
    fp.write("};\n")

def main():
    parse_args()

    intlist = read_intlist(args.intlist)
    nvec = intlist["num_vectors"]
    offset = intlist["offset"]
    prefix = endian_prefix()

    # Set default entries in both tables
    if args.sw_isr_table:
        # All vectors just jump to the common sw_irq_handler. If some entries
        # are used for direct interrupts, they will be replaced later.
        if args.vector_table:
            vt = [intlist["sw_irq_handler"] for i in range(nvec)]
        else:
            vt = None
        # Default to spurious interrupt handler. Configured interrupts
        # will replace these entries.
        swt = [(0, intlist["spurious_handler"]) for i in range(nvec)]
    else:
        if args.vector_table:
            vt = [intlist["spurious_handler"] for i in range(nvec)]
        else:
            error("one or both of -s or -V needs to be specified on command line")
        swt = None

    for irq, flags, func, param in intlist["interrupts"]:
        if (flags & ISR_FLAG_DIRECT):
            if (param != 0):
                error("Direct irq %d declared, but has non-NULL parameter"
                        % irq)
            vt[irq - offset] = func
        else:
            # Regular interrupt
            if not swt:
                error("Regular Interrupt %d declared with parameter 0x%x "
                        "but no SW ISR_TABLE in use"
                        % (irq, param))
            swt[irq - offset] = (param, func)

    with open(args.output_source, "w") as fp:
        write_source_file(fp, vt, swt, intlist)

if __name__ == "__main__":
    main()