From aac50698af231cb6350707485e64f6d36ebc785d Mon Sep 17 00:00:00 2001
From: Benjamin Vedder <benjamin@vedder.se>
Date: Sun, 24 Sep 2023 20:19:12 +0200
Subject: [PATCH] Added UART interrupt priority hack

---
 .../os/hal/ports/STM32/LLD/USARTv1/serial_lld.c    | 14 ++++++++------
 .../os/hal/ports/STM32/LLD/USARTv2/serial_lld.c    | 14 ++++++++------
 hwconf/mcuconf.h                                   |  2 ++
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv1/serial_lld.c b/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv1/serial_lld.c
index 69b725d1..efb9a068 100644
--- a/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv1/serial_lld.c
+++ b/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv1/serial_lld.c
@@ -427,41 +427,43 @@ void sd_lld_start(SerialDriver *sdp, const SerialConfig *config) {
   if (config == NULL)
     config = &default_config;
 
+  uint32_t prio = config->speed > 200000 ? 4 : 7;
+
   if (sdp->state == SD_STOP) {
 #if STM32_SERIAL_USE_USART1
     if (&SD1 == sdp) {
       rccEnableUSART1(FALSE);
-      nvicEnableVector(STM32_USART1_NUMBER, STM32_SERIAL_USART1_PRIORITY);
+      nvicEnableVector(STM32_USART1_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART2
     if (&SD2 == sdp) {
       rccEnableUSART2(FALSE);
-      nvicEnableVector(STM32_USART2_NUMBER, STM32_SERIAL_USART2_PRIORITY);
+      nvicEnableVector(STM32_USART2_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART3
     if (&SD3 == sdp) {
       rccEnableUSART3(FALSE);
-      nvicEnableVector(STM32_USART3_NUMBER, STM32_SERIAL_USART3_PRIORITY);
+      nvicEnableVector(STM32_USART3_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_UART4
     if (&SD4 == sdp) {
       rccEnableUART4(FALSE);
-      nvicEnableVector(STM32_UART4_NUMBER, STM32_SERIAL_UART4_PRIORITY);
+      nvicEnableVector(STM32_UART4_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_UART5
     if (&SD5 == sdp) {
       rccEnableUART5(FALSE);
-      nvicEnableVector(STM32_UART5_NUMBER, STM32_SERIAL_UART5_PRIORITY);
+      nvicEnableVector(STM32_UART5_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART6
     if (&SD6 == sdp) {
       rccEnableUSART6(FALSE);
-      nvicEnableVector(STM32_USART6_NUMBER, STM32_SERIAL_USART6_PRIORITY);
+      nvicEnableVector(STM32_USART6_NUMBER, prio);
     }
 #endif
   }
diff --git a/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv2/serial_lld.c b/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv2/serial_lld.c
index e78fe150..58bdd4fd 100644
--- a/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv2/serial_lld.c
+++ b/ChibiOS_3.0.5/os/hal/ports/STM32/LLD/USARTv2/serial_lld.c
@@ -423,41 +423,43 @@ void sd_lld_start(SerialDriver *sdp, const SerialConfig *config) {
   if (config == NULL)
     config = &default_config;
 
+  uint32_t prio = config->speed > 200000 ? 4 : 7;
+
   if (sdp->state == SD_STOP) {
 #if STM32_SERIAL_USE_USART1
     if (&SD1 == sdp) {
       rccEnableUSART1(FALSE);
-      nvicEnableVector(STM32_USART1_NUMBER, STM32_SERIAL_USART1_PRIORITY);
+      nvicEnableVector(STM32_USART1_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART2
     if (&SD2 == sdp) {
       rccEnableUSART2(FALSE);
-      nvicEnableVector(STM32_USART2_NUMBER, STM32_SERIAL_USART2_PRIORITY);
+      nvicEnableVector(STM32_USART2_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART3
     if (&SD3 == sdp) {
       rccEnableUSART3(FALSE);
-      nvicEnableVector(STM32_USART3_NUMBER, STM32_SERIAL_USART3_PRIORITY);
+      nvicEnableVector(STM32_USART3_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_UART4
     if (&SD4 == sdp) {
       rccEnableUART4(FALSE);
-      nvicEnableVector(STM32_UART4_NUMBER, STM32_SERIAL_UART4_PRIORITY);
+      nvicEnableVector(STM32_UART4_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_UART5
     if (&SD5 == sdp) {
       rccEnableUART5(FALSE);
-      nvicEnableVector(STM32_UART5_NUMBER, STM32_SERIAL_UART5_PRIORITY);
+      nvicEnableVector(STM32_UART5_NUMBER, prio);
     }
 #endif
 #if STM32_SERIAL_USE_USART6
     if (&SD6 == sdp) {
       rccEnableUSART6(FALSE);
-      nvicEnableVector(STM32_USART6_NUMBER, STM32_SERIAL_USART6_PRIORITY);
+      nvicEnableVector(STM32_USART6_NUMBER, prio);
     }
 #endif
   }
diff --git a/hwconf/mcuconf.h b/hwconf/mcuconf.h
index 74eb1c7b..d1b1782c 100644
--- a/hwconf/mcuconf.h
+++ b/hwconf/mcuconf.h
@@ -294,6 +294,8 @@
 #define STM32_SERIAL_USE_UART4              TRUE
 #define STM32_SERIAL_USE_UART5              TRUE
 #define STM32_SERIAL_USE_USART6             TRUE
+// NOTE: These are ignored as there is a hack in the chibios UART driver to increase these
+// based on the baud rate.
 #define STM32_SERIAL_USART1_PRIORITY        7
 #define STM32_SERIAL_USART2_PRIORITY        7
 #define STM32_SERIAL_USART3_PRIORITY        7