From 0c5f5e8c2dde9c644d4a5dc30f0d189f63d44470 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?King=20K=C3=A9vin?= Date: Sun, 1 Mar 2020 23:21:07 +0100 Subject: [PATCH] usb_fusb302: add checksum calculation --- lib/usb_fusb302.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++ lib/usb_fusb302.h | 12 ++++++ 2 files changed, 114 insertions(+) diff --git a/lib/usb_fusb302.c b/lib/usb_fusb302.c index 4244cac..3dc125e 100644 --- a/lib/usb_fusb302.c +++ b/lib/usb_fusb302.c @@ -27,6 +27,7 @@ #include // real-time control clock library #include // general purpose input output library #include // I²C library +#include // CRC utilities /* own libraries */ #include "global.h" // global utilities @@ -51,6 +52,8 @@ int16_t usb_fusb302_setup(void) { + rcc_periph_clock_enable(RCC_CRC); // enable cock for CRC domain to calculate in hardware the CRC + i2c_master_setup(USB_FUSB302_I2C, 100); // setup I²C peripheral, with 100 kHz clock for compatibility with other devices (can go up to 1 MHz, but other slaves on the bus might not be able to go this fast) // test if FUSB302 is on the I²C bus @@ -522,3 +525,102 @@ int16_t usb_fusb302_packet_read(uint8_t* packet) return 3 + PD_HEADER_CNT(header) * 4 + 4; } + +bool usb_fusb302_packet_checksum(const uint8_t* packet) +{ + if (NULL == packet) { + return -1; + } + uint16_t header = *(uint16_t*)(&packet[1]); + uint32_t crc = usb_fusb302_crc(&packet[1], PD_HEADER_CNT(header) * 4 + 2); + uint32_t sum = *(uint32_t*)(&packet[1 + PD_HEADER_CNT(header) * 4 + 2]); + return crc == sum; +} + +uint32_t usb_fusb302_crc(const uint8_t* data, uint32_t length) +{ + if (NULL == data || 0 == length) { + return 0; + } + uint32_t crc = 0xffffffff; + crc_reset(); + + // calculate for words + uint32_t cycles = length >> 2; // optimized / 4 + while (cycles--) { + crc = *(uint32_t *)data; + data += 4; + __asm("rbit %0, %1" : "=r" (crc) : "r" (crc)); // reflect input/invert bit order + crc = crc_calculate(crc); + } + __asm("rbit %0, %1" : "=r" (crc) : "r" (crc)); // reflect/invert bit order of output + + // calculate for remaining bytes + cycles = length & 3; // optimized % 4 + while (cycles--) { + crc ^= (uint32_t)*data++; + for (uint8_t b = 0; b < 8; b++) { + if (crc & 1) { + crc = (crc >> 1) ^ 0xEDB88320; + } else { + crc >>= 1; + } + } + } + + return crc ^ 0xffffffff; // final XOR +} + +/* the look-up table method is fast than the hardware assisted calculation for small non-32-bit-aligned data, but uses 1 KB for the LUT +uint32_t usb_fusb302_crc(const uint8_t* data, uint32_t length) +{ + if (NULL == data || 0 == length) { + return 0; + } + // CRC-32 Look-Up Table: input reflected, result reflected, polynomial 0x4C11DB7, initial value: 0xFFFFFFFF, final xor value: 0xFFFFFFFF, table is reflected, generated by [pycrc](https://pycrc.org/) + static const uint32_t crc_table[256] = { + 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, + 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, + 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, + 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, + 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, + 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, + 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, + 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, + 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, + 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, + 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, + 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, + 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, + 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, + 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, + 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, + 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, + 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, + 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, + 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, + 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, + 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, + 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, + 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, + 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, + 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, + 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, + 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, + 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, + 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, + 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, + 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d + }; + uint32_t crc = 0xffffffff; + const unsigned char *d = (const unsigned char *)data; + unsigned int tbl_idx; + + while (length--) { + tbl_idx = (crc ^ *d) & 0xff; + crc = (crc_table[tbl_idx] ^ (crc >> 8)) & 0xffffffff; + d++; + } + return (crc & 0xffffffff) ^ 0xffffffff; +} +*/ diff --git a/lib/usb_fusb302.h b/lib/usb_fusb302.h index f18108c..2edb40f 100644 --- a/lib/usb_fusb302.h +++ b/lib/usb_fusb302.h @@ -88,6 +88,18 @@ int16_t usb_fusb302_discover_identity_request(void); * @warning PD channel must be configured */ int16_t usb_fusb302_packet_read(uint8_t* packet); +/** calculate CRC for paylod + * @param[in] data payload data for which to calculate the checksum + * @param[in] length length of data + * @return CRC checksum + * @implements CRC-32-IEEE also used for PD 3.0 specification (most common CRC-32) + */ +uint32_t usb_fusb302_crc(const uint8_t* data, uint32_t length); +/** verify CRC checksum of packet + * @param[in] packet packet for which to verify the checksum (CRC is included) + * @return if the calculated checksum matches the one included in the packet + */ +bool usb_fusb302_packet_checksum(const uint8_t* packet); /** FUSB302 register addresses and bit offset */ #define FUSB302_REG_DEVICE_ID 0x01