Change in simtrace2[master]: sniffing: decrease USB IRQ prioprity to prevent USART overrun

[Kévin Redon]

Kévin Redon has uploaded this change for review. ( https://gerrit.osmocom.org/9881


Change subject: sniffing: decrease USB IRQ prioprity to prevent USART overrun
......................................................................

sniffing: decrease USB IRQ prioprity to prevent USART overrun

Handling the USB message queue is done in an ISR and take quite some time.
This can cause a USART/SIM sniffing buffer overrun, resulting in data loss.
By setting the USB IRQ lower than the USART IRQ, the USB ISR can be
interrupted (for short) and no data gets lost.

Change-Id: I870a0aa8e251bbb53249c54bfcaa45de5b5a9486
---
M firmware/libcommon/source/sniffer.c
1 file changed, 4 insertions(+), 0 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/simtrace2 refs/changes/81/9881/1

diff --git a/firmware/libcommon/source/sniffer.c b/firmware/libcommon/source/sniffer.c
index 3719796..70d3734 100644
--- a/firmware/libcommon/source/sniffer.c
+++ b/firmware/libcommon/source/sniffer.c
@@ -829,6 +829,10 @@
 	sniff_usart.base->US_RTOR = 9600-12; /* -12 because the timer starts at the end of the 12 ETU frame */
 	/* Enable interrupt to indicate when data has been received or timeout occurred */
 	USART_EnableIt(sniff_usart.base, US_IER_RXRDY | US_IER_TIMEOUT);
+	/* Set USB priority lower than USART to not miss sniffing data (both at 0 per default) */
+	if (NVIC_GetPriority(IRQ_USART_SIM)>=NVIC_GetPriority(UDP_IRQn)) {
+		NVIC_SetPriority(UDP_IRQn, NVIC_GetPriority(IRQ_USART_SIM)+2);
+	}
 	/* Enable interrupt requests for the USART peripheral */
 	NVIC_EnableIRQ(IRQ_USART_SIM);
 

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Gerrit-Project: simtrace2
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I870a0aa8e251bbb53249c54bfcaa45de5b5a9486
Gerrit-Change-Number: 9881
Gerrit-PatchSet: 1
Gerrit-Owner: Kévin Redon <kredon at sysmocom.de>
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