dma-latency: pkt tx is not equal to descq-> tx_time

[jumpmanhou]

Hi, I'm using the 2022.1.5 QDMA Linux driver to validate the QDMA bandwidth and latency, but the dma-latency report some error while running the test. I add some debug log to the driver and seems the address "tx_time_pkt_offset" is not the same with "pkt_tx_time", which cause the *pkt_tx_time != descq->ping_pong_tx_time.

BTW, I'm running this test on an ARM platform and I modify the rdtsc_gettime function according to the ARM architecture. u64 rdtsc_gettime(void) { u64 val;

asm volatile("mrs %0, cntpct_el0" : "=r" (val));
return val;

}

Any idea on this issue?