Add USE_LEDSTRIP_CACHE_MGMT option to use explicit cache management for LED strip.

Ensure DMA_RAM section is at start of RAM and the the region defining the shareable region is covered.
Enable USE_LEDSTRIP_CACHE_MGMT on NUCLEOH743 target

src/link/stm32_flash_h750_128k.ld

@@ -50,8 +50,6 @@ REGION_ALIAS("STACKRAM", DTCM_RAM)
 REGION_ALIAS("FASTRAM", DTCM_RAM)
 REGION_ALIAS("MAIN", FLASH)
 
-INCLUDE "stm32_h750_common.ld"
-
 SECTIONS
 {
   .DMA_RAM (NOLOAD) :
@@ -91,4 +89,5 @@ SECTIONS
   } >RAM
   }
 
+INCLUDE "stm32_h750_common.ld"
 INCLUDE "stm32_h750_common_post.ld"

src/link/stm32_flash_h750_1m.ld

@@ -50,8 +50,6 @@ REGION_ALIAS("STACKRAM", DTCM_RAM)
 REGION_ALIAS("FASTRAM", DTCM_RAM)
 REGION_ALIAS("MAIN", FLASH)
 
-INCLUDE "stm32_h750_common.ld"
-
 SECTIONS
 {
   .DMA_RAM (NOLOAD) :
@@ -91,4 +89,5 @@ SECTIONS
   } >RAM
 }
 
+INCLUDE "stm32_h750_common.ld"
 INCLUDE "stm32_h750_common_post.ld"

src/link/stm32_ram_h750_exst.ld

@@ -73,8 +73,6 @@ REGION_ALIAS("STACKRAM", DTCM_RAM)
 REGION_ALIAS("FASTRAM", DTCM_RAM)
 REGION_ALIAS("MAIN", CODE_RAM)
 
-INCLUDE "stm32_h750_common.ld"
-
 SECTIONS
 {
   .DMA_RAM (NOLOAD) :
@@ -114,6 +112,7 @@ SECTIONS
   } >RAM
 }
 
+INCLUDE "stm32_h750_common.ld"
 INCLUDE "stm32_h750_common_post.ld"
 INCLUDE "stm32_ram_h750_exst_post.ld"
 

src/main/drivers/light_ws2811strip.c

@@ -44,6 +44,16 @@
 
 #include "light_ws2811strip.h"
 
+#ifdef USE_LEDSTRIP_CACHE_MGMT
+// WS2811_DMA_BUFFER_SIZE is multiples of uint32_t
+// Number of bytes required for buffer
+#define WS2811_DMA_BUF_BYTES              (WS2811_DMA_BUFFER_SIZE * sizeof (uint32_t))
+// Number of bytes required to cache align buffer
+#define WS2811_DMA_BUF_CACHE_ALIGN_BYTES  ((WS2811_DMA_BUF_BYTES + 0x20) & ~0x1f)
+// Size of array to create a cache aligned buffer
+#define WS2811_DMA_BUF_CACHE_ALIGN_LENGTH (WS2811_DMA_BUF_CACHE_ALIGN_BYTES / sizeof (uint32_t))
+__attribute__((aligned(32))) uint32_t ledStripDMABuffer[WS2811_DMA_BUF_CACHE_ALIGN_LENGTH];
+#else
 #if defined(STM32F1) || defined(STM32F3)
 uint8_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
 #elif defined(STM32F7)
@@ -53,6 +63,7 @@ DMA_RAM uint32_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
 #else
 uint32_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
 #endif
+#endif
 
 static ioTag_t ledStripIoTag;
 static bool ws2811Initialised = false;
@@ -184,6 +195,10 @@ void ws2811UpdateStrip(ledStripFormatRGB_e ledFormat)
     }
     needsFullRefresh = false;
 
+#ifdef USE_LEDSTRIP_CACHE_MGMT
+    SCB_CleanDCache_by_Addr(ledStripDMABuffer, WS2811_DMA_BUF_CACHE_ALIGN_BYTES);
+#endif
+
     ws2811LedDataTransferInProgress = true;
     ws2811LedStripDMAEnable();
 }

src/main/drivers/light_ws2811strip.h

@@ -31,7 +31,7 @@
 #if defined(USE_WS2811_SINGLE_COLOUR)
 #define WS2811_DATA_BUFFER_SIZE    1
 #define WS2811_DMA_BUFFER_SIZE     (WS2811_DATA_BUFFER_SIZE * WS2811_BITS_PER_LED)
-// Do 2 extra iterations of the DMA transfer with the ouptut set to low to generate the > 50us delay.
+// Do 2 extra iterations of the DMA transfer with the output set to low to generate the > 50us delay.
 #define WS2811_DELAY_ITERATIONS    2
 #else
 #define WS2811_DATA_BUFFER_SIZE    WS2811_LED_STRIP_LENGTH
@@ -41,6 +41,23 @@
 #define WS2811_DMA_BUFFER_SIZE     (WS2811_DATA_BUFFER_SIZE * WS2811_BITS_PER_LED + WS2811_DELAY_BUFFER_LENGTH)
 #endif
 
+#ifdef USE_LEDSTRIP_CACHE_MGMT
+// WS2811_DMA_BUFFER_SIZE is multiples of uint32_t
+// Number of bytes required for buffer
+#define WS2811_DMA_BUF_BYTES              (WS2811_DMA_BUFFER_SIZE * sizeof (uint32_t))
+// Number of bytes required to cache align buffer
+#define WS2811_DMA_BUF_CACHE_ALIGN_BYTES  ((WS2811_DMA_BUF_BYTES + 0x20) & ~0x1f)
+// Size of array to create a cache aligned buffer
+#define WS2811_DMA_BUF_CACHE_ALIGN_LENGTH (WS2811_DMA_BUF_CACHE_ALIGN_BYTES / sizeof (uint32_t))
+extern uint32_t ledStripDMABuffer[WS2811_DMA_BUF_CACHE_ALIGN_LENGTH];
+#else
+#if defined(STM32F1) || defined(STM32F3)
+extern uint8_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
+#else
+extern uint32_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
+#endif
+#endif
+
 #define WS2811_TIMER_MHZ           48
 #define WS2811_CARRIER_HZ          800000
 
@@ -71,11 +88,6 @@ void setUsedLedCount(unsigned ledCount);
 
 bool isWS2811LedStripReady(void);
 
-#if defined(STM32F1) || defined(STM32F3)
-extern uint8_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
-#else
-extern uint32_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
-#endif
 extern volatile bool ws2811LedDataTransferInProgress;
 
 extern uint16_t BIT_COMPARE_1;

src/main/drivers/memprot_hal.c

@@ -68,7 +68,7 @@ void memProtConfigure(mpuRegion_t *regions, unsigned regionCount)
 
             int msbpos = flsl(length) - 1;
 
-            if (length == (1U << msbpos)) {
+            if (length != (1U << msbpos)) {
                 msbpos += 1;
             }
 

src/main/target/NUCLEOH743/target.h

@@ -29,12 +29,15 @@
 #define LED1_PIN                PB7 // PE1 on NUCLEO-H743ZI2 (may collide with UART8_TX)
 //#define LED2_PIN                PB14 // SDMMC2_D0
 
+// Use explicit cache management as per https://github.com/betaflight/betaflight/pull/10378
+#define USE_LEDSTRIP_CACHE_MGMT
+
 // Nucleo-H743 has one button (The blue USER button).
 // Force two buttons to look at the single button so config reset on button works
 #define USE_BUTTONS
-#define	BUTTON_A_PIN            PC13
+#define BUTTON_A_PIN            PC13
 #define BUTTON_A_PIN_INVERTED // Active high
-#define	BUTTON_B_PIN            PC13
+#define BUTTON_B_PIN            PC13
 #define BUTTON_B_PIN_INVERTED // Active high
 
 #define USE_BEEPER