Aha! #BL602 hits a #RISCV Exception ... When processing the received #LoRa Packet! Let's follow these steps to troubleshoot...
https://lupyuen.github.io/articles/i2c#appendix-how-to-troubleshoot-risc-v-exceptions
Our #BL602 Build, Flash and Run Firmware script generates the #RISCV Disassembly ... Let's track down the address of the RISC-V Exception
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/run.sh
Oops the Program Counter for our #RISCV Exception is null ... So there must be a missing Callback Function somewhere in our #LoRa #BL602 Firmware 🤔
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
#BL602 #LoRa Exception happened because we passed a pointer to a stack object ... Which gets used by the Interrupt Handler 😲 ... This works OK in the original Mynewt code, but not for BL602
https://gist.github.com/lupyuen/1539f9dd52e9a83d4fbe7724481112bf
For #BL602 we fix this exception by copying the object ... Instead of storing a pointer to the object
#BL602 now displays the #LoRa Packet received from #WisBlock yay!
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
Mystery #BL602 GPIO Function ... What does it do? Will it fix our problem with triggering multiple GPIO Interrupts? 🤔
#BL602 Reference Manual mentions "GPIO_INT_CLR" but the address is undefined in the doc ... Methinks a chunk of addresses are missing from the doc 🤔
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
Searching GitHub for "GPIO_INT_CLR" shows ultraembedded RISC-V SoC ... Coincidence? 🤔
https://github.com/search?l=Markdown&q=GPIO_INT_CLR&type=Code
Ah my folly ways ... Multiple #BL602 GPIO Interrupts can't be registered like this ... Lemme fix this 🪠
Let's handle #BL602 GPIO Interrupts the smarter way ... By iterating thru the Interrupt Events created with the NimBLE Porting Layer
Reconnected #PineCone #BL602 @PINE64 ... To #LoRa SX1276 pins DIO0 to DIO3 ... For testing our GPIO interrupt handler
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/sx1276.h
Enabled #BL602 GPIO Interrupt Handler for #LoRa SX1276 ... And BL602 hits a #RISCV Exception ... At an invalid Program Address 🤔
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
Let's disable #LoRa Channel Activity Detection for now ... #BL602 receives first LoRa Packet ... But not the second packet 🤔
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
Can #BL602 show the Stack Trace for this #RISCV Exception? ... Let's find out 🤔
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
#BL602 shows Stack Trace when CONFIG_ENABLE_FP=1 ... But the addresses don't make sense ... They belong to the code that's dumping the Stack Trace 🤔
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/proj_config.mk#L40-L42
Let's dump the #BL602 Stack with this function ... And figure out why our Exception Stack Trace doesn't look right
Here are the #BL602 Stacks for the Foreground RTOS Task, Background Task and Exception Handler ... Let's see what's wrong with the Exception Stack
Complete #BL602 Stack Data for the Exception is here
https://gist.github.com/lupyuen/5ddbcdd1054c775521291c3d114f6cee
Below the #BL602 Exception Handler Stack ... Is another Stack! ... Does this Stack contain the Stack Trace that we need? 🤔
https://gist.github.com/lupyuen/5ddbcdd1054c775521291c3d114f6cee
Quiz: What's wrong with this C code? 🤔 ... I'm soooo upset I missed this simple bug 🙄
https://github.com/apache/mynewt-core/blob/master/apps/loraping/src/main.c#L215-L233
Answer: "radio_events" contains Undefined Fields ... Because it was allocated on the Stack! Lesson Learnt: ALWAYS Init Stack Variables! 🙏
https://github.com/apache/mynewt-core/blob/master/apps/loraping/src/main.c#L215-L233
Back to our #BL602 Stack Trace ... Yep the Correct Stack Trace is indeed lurking behind our (unhelpful) Exception Stack Trace ... How shall we show the Correct Stack Trace beyond the Emptiness? 🤔
https://gist.github.com/lupyuen/5ddbcdd1054c775521291c3d114f6cee
Let's do #BL602 #LoRa Receive Timeout with these Callout Functions from the NimBLE Porting Layer
https://lupyuen.github.io/pinetime-rust-mynewt/articles/dfu#nimble-callout-functions
#BL602 receives 4 #LoRa Packets by executing 458 SPI requests ... Great load test for SPI 👍
https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c
@lupyuen
What hw part is being talked to over said dma? Does order of dma reads matter? Can you cache requests issue dma read burst and send result asynchronously etc or per queue keeping order? We had similar problem in nokia on radiomodules i think. Dont remember exact solution though.
@lupyuen
Can you let me peek at source before port and after port? Curious. Not strong in dma but curious of it.
@PawelK Original LoRa SX1276 Driver for Mynewt OS:
https://github.com/apache/mynewt-core/blob/master/hw/drivers/lora/sx1276/src/sx1276.c
Ported to BL602:
The original code calls "hal_spi_tx_val", which is a Mynewt SPI Function that transfers 1 byte over SPI. It's clearly not designed for DMA.
@lupyuen
Ahh dma is sync and regions are continuous. Looks easy peasy. Ill try to play with this code if youll allow. Wish i had a board to play with.
@lupyuen
Ill start with full buffers solution and will chunkize them afterwards if required.
@PawelK Erm I'm still making changes to the driver and I'm writing an article about this driver ... Maybe we hold off the changes till I'm done?
@lupyuen
Sure no problem.
@lupyuen
Three questions. Is there upper bound or enum of served lengths of buffers?
Can we alloc temp buffers on stack or should globals be used? Do You suggest using fixed chunks say 16 bytes plus trailer use or can we dynalloc full buffers?
@lupyuen
Fine with me.