#!/usr/bin/env python3
"""RK3588 DDR Blob Patcher - converts infinite poll loops to single checks."""
import struct, os

def patch_blob(inpath, outpath):
    with open(inpath, 'rb') as f:
        blob = bytearray(f.read())
    
    patched = 0
    patches = []
    NOP = 0xD503201F
    
    for i in range(0, len(blob) - 12, 4):
        inst = struct.unpack_from('<I', blob, i)[0]
        if (inst & 0xFF000010) == 0x54000000:
            imm19 = (inst >> 5) & 0x7FFFF
            if imm19 & 0x40000:
                offset = -((~imm19 & 0x7FFFF) + 1) * 4
                if -16 <= offset <= -4:
                    loop_start = i + offset
                    has_load = False
                    for j in range(loop_start, i, 4):
                        w = struct.unpack_from('<I', blob, j)[0]
                        if (w & 0xFFC00000) in (0xB9400000, 0xF9400000, 0xB9800000):
                            has_load = True
                            break
                    if has_load:
                        cond = inst & 0xF
                        cond_names = ['EQ','NE','CS','CC','MI','PL','VS','VC','HI','LS','GE','LT','GT','LE','AL','NV']
                        old = struct.unpack_from('<I', blob, i)[0]
                        struct.pack_into('<I', blob, i, NOP)
                        patches.append((i, old, cond_names[cond], offset))
                        patched += 1
    
    with open(outpath, 'wb') as f:
        f.write(blob)
    
    print(f'Patched {patched} tight poll loops:')
    for addr, old, cond, offset in patches:
        print(f'  0x{addr:05x}: B.{cond} {offset} -> NOP')
    
    return patched, len(blob)

infile = '/opt/rkbin/bin/rk35/rk3588_ddr_lp4_2112MHz_lp5_2400MHz_v1.19.bin'
outfile = '/opt/work/rk3588_ddr_v1.19_patched.bin'
n, size = patch_blob(infile, outfile)
orig_size = os.path.getsize(infile)
print(f'\nOriginal: {orig_size}, Patched: {size} ({"MATCH" if orig_size == size else "MISMATCH!"})')