|  | 
|  | 1 | +""" | 
|  | 2 | +This module implements the communication protocol to load an image to SRAM, | 
|  | 3 | +that typically initializes DRAM, followed by optionally loading a secondary | 
|  | 4 | +image to start of DRAM, when a Rockchip device is in MASKROM mode. | 
|  | 5 | +""" | 
|  | 6 | +from time import sleep | 
|  | 7 | + | 
|  | 8 | +import usb.core | 
|  | 9 | +import usb.util | 
|  | 10 | + | 
|  | 11 | + | 
|  | 12 | +RK_RC4_KEY = [ | 
|  | 13 | +    0x7c, 0x4e, 0x03, 0x04, 0x55, 0x05, 0x09, 0x07, | 
|  | 14 | +    0x2d, 0x2c, 0x7b, 0x38, 0x17, 0x0d, 0x17, 0x11, | 
|  | 15 | +] | 
|  | 16 | + | 
|  | 17 | + | 
|  | 18 | +CRC16_TABLE = [ | 
|  | 19 | +    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, | 
|  | 20 | +    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, | 
|  | 21 | +    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, | 
|  | 22 | +    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, | 
|  | 23 | +    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, | 
|  | 24 | +    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, | 
|  | 25 | +    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, | 
|  | 26 | +    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, | 
|  | 27 | +    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, | 
|  | 28 | +    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, | 
|  | 29 | +    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, | 
|  | 30 | +    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, | 
|  | 31 | +    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, | 
|  | 32 | +    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, | 
|  | 33 | +    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, | 
|  | 34 | +    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, | 
|  | 35 | +    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, | 
|  | 36 | +    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, | 
|  | 37 | +    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, | 
|  | 38 | +    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, | 
|  | 39 | +    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, | 
|  | 40 | +    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, | 
|  | 41 | +    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, | 
|  | 42 | +    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, | 
|  | 43 | +    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, | 
|  | 44 | +    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, | 
|  | 45 | +    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, | 
|  | 46 | +    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, | 
|  | 47 | +    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, | 
|  | 48 | +    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, | 
|  | 49 | +    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, | 
|  | 50 | +    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, | 
|  | 51 | +] | 
|  | 52 | + | 
|  | 53 | + | 
|  | 54 | +def crc16(data, crc=0xffff): | 
|  | 55 | +    for byte in data: | 
|  | 56 | +        crc = ((crc << 8) & 0xff00) ^ CRC16_TABLE[((crc >> 8) & 0xff) ^ byte] | 
|  | 57 | +    return crc & 0xffff | 
|  | 58 | + | 
|  | 59 | + | 
|  | 60 | +def rc4_ksa(key): | 
|  | 61 | +    keylength = len(key) | 
|  | 62 | +    S = list(range(256)) | 
|  | 63 | +    j = 0 | 
|  | 64 | +    for i in range(256): | 
|  | 65 | +        j = (j + S[i] + key[i % keylength]) % 256 | 
|  | 66 | +        S[i], S[j] = S[j], S[i] | 
|  | 67 | +    return S | 
|  | 68 | + | 
|  | 69 | + | 
|  | 70 | +def rc4_prga(S): | 
|  | 71 | +    i = 0 | 
|  | 72 | +    j = 0 | 
|  | 73 | +    while True: | 
|  | 74 | +        i = (i + 1) % 256 | 
|  | 75 | +        j = (j + S[i]) % 256 | 
|  | 76 | +        S[i], S[j] = S[j], S[i] | 
|  | 77 | +        K = S[(S[i] + S[j]) % 256] | 
|  | 78 | +        yield K | 
|  | 79 | + | 
|  | 80 | + | 
|  | 81 | +class RKUSBMaskrom: | 
|  | 82 | +    def __init__(self, **args): | 
|  | 83 | +        self._dev = usb.core.find(**args) | 
|  | 84 | +        if self._dev is None: | 
|  | 85 | +            raise ValueError("Device not found") | 
|  | 86 | +        if self._dev.idVendor != 0x2207: | 
|  | 87 | +            raise ValueError(f"Unsupported device VID {self._dev.idVendor:x}") | 
|  | 88 | +        if self._dev.bcdUSB & 0x0001: | 
|  | 89 | +            raise ValueError("Device in LOADER mode") | 
|  | 90 | + | 
|  | 91 | +        if self._dev.is_kernel_driver_active(0): | 
|  | 92 | +            self._dev.detach_kernel_driver(0) | 
|  | 93 | + | 
|  | 94 | +        usb.util.claim_interface(self._dev, 0) | 
|  | 95 | + | 
|  | 96 | +    def __del__(self): | 
|  | 97 | +        usb.util.release_interface(self._dev, 0) | 
|  | 98 | +        usb.util.dispose_resources(self._dev) | 
|  | 99 | + | 
|  | 100 | +    def load(self, code, path): | 
|  | 101 | +        with open(path, 'rb') as fh: | 
|  | 102 | +            data = bytearray(fh.read()) | 
|  | 103 | + | 
|  | 104 | +        # encrypt data using the known rockchip key for older devices | 
|  | 105 | +        if self._dev.idProduct < 0x3500: | 
|  | 106 | +            keystream = rc4_prga(rc4_ksa(RK_RC4_KEY)) | 
|  | 107 | +            data = bytearray([byte ^ next(keystream) for byte in data]) | 
|  | 108 | + | 
|  | 109 | +        # ensure crc16 fit in the last chunk | 
|  | 110 | +        if len(data) % 4096 == 4095: | 
|  | 111 | +            data.append(0) | 
|  | 112 | + | 
|  | 113 | +        # append crc16 of data | 
|  | 114 | +        crc = crc16(data) | 
|  | 115 | +        data.append(crc >> 8) | 
|  | 116 | +        data.append(crc & 0xff) | 
|  | 117 | + | 
|  | 118 | +        # extra chunk to signal end of transfer | 
|  | 119 | +        if len(data) % 4096 == 0: | 
|  | 120 | +            data.append(0) | 
|  | 121 | + | 
|  | 122 | +        # transfer all chunks | 
|  | 123 | +        for i in range(0, len(data), 4096): | 
|  | 124 | +            chunk = data[i:i + 4096] | 
|  | 125 | +            self._dev.ctrl_transfer(64, 12, 0, code, chunk, 5000) | 
|  | 126 | + | 
|  | 127 | + | 
|  | 128 | +def handle_load(busnum, devnum, initial, secondary=None, delay=None): | 
|  | 129 | +    maskrom = RKUSBMaskrom(bus=busnum, address=devnum) | 
|  | 130 | +    maskrom.load(0x471, initial) | 
|  | 131 | +    if secondary is not None: | 
|  | 132 | +        if delay is not None: | 
|  | 133 | +            sleep(delay) | 
|  | 134 | +        maskrom.load(0x472, secondary) | 
|  | 135 | +    del maskrom | 
|  | 136 | + | 
|  | 137 | + | 
|  | 138 | +methods = { | 
|  | 139 | +    "load": handle_load, | 
|  | 140 | +} | 
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