adstraw commented on code in PR #12411:
URL: https://github.com/apache/tvm/pull/12411#discussion_r950496671
##########
src/runtime/hexagon/hexagon_user_dma.cc:
##########
@@ -90,32 +78,80 @@ int hexagon_user_dma_1d_sync_helper(void* dst, void* src,
uint32_t length) {
dma_desc_set_src(dma_desc, src32);
dma_desc_set_dst(dma_desc, dst32);
- dmstart(dma_desc);
- unsigned int status = dmwait() & DM0_STATUS_MASK;
- unsigned int done = dma_desc_get_done(dma_desc);
+ // only for first DMA
+ if (first_dma_) {
+ // reset DMA engine
+ auto status = Init();
+ if (status != DM0_STATUS_IDLE) {
+ return DMA_FAILURE;
+ }
+
+ // `dmstart` first descriptor
+ dmstart(dma_desc);
+ first_dma_ = false;
+ } else {
+ // `dmlink` descriptor to tail
+ dmlink(dma_descriptors_.back(), dma_desc);
+ }
- free(dma_desc);
+ // set descriptor as new tail
+ dma_descriptors_.push_back(dma_desc);
- if (status == DM0_STATUS_IDLE && done == DESC_DONE_COMPLETE) {
- return DMA_SUCCESS;
+ return DMA_SUCCESS;
+}
+
+void HexagonUserDMA::Wait(uint32_t max_dmas_in_flight) {
+ // wait (forever) until max DMAs in flight <= actual DMAs in flight
+ while (DMAsInFlight() > max_dmas_in_flight) {
+ }
+}
+
+uint32_t HexagonUserDMA::Poll() { return DMAsInFlight(); }
+
+uint32_t HexagonUserDMA::DMAsInFlight() {
+ // poll DMA engine to make sure DMA status is current
+ dmpoll();
+
+ // find the oldest DMA in flight
+ for (; oldest_dma_in_flight_ < dma_descriptors_.size();
++oldest_dma_in_flight_) {
+ // read the `done` bit from the DMA descriptor and stop if incomplete
+ unsigned int done =
dma_desc_get_done(dma_descriptors_[oldest_dma_in_flight_]);
+ if (done == DESC_DONE_INCOMPLETE) {
+ break;
+ }
+ }
+ // total DMAs in flight = total DMAs - oldest DMA in flight
+ return dma_descriptors_.size() - oldest_dma_in_flight_;
+}
+
+HexagonUserDMA::~HexagonUserDMA() {
+ Init(); // reset DMA engine
+ for (auto dma_desc : dma_descriptors_) {
+ free(dma_desc);
}
-#endif
- return DMA_FAILURE;
}
int hexagon_user_dma_1d_sync(void* dst, void* src, uint32_t length) {
Review Comment:
Marking this resolved as I am confident that deferring is the correct choice
here. Happy to be corrected if I'm wrong and this is needed now.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
