Try to fix bank test

Author: multiplemonomials

connectivity/drivers/emac/TARGET_STM/STM32EthMACv1.cpp

@@ -62,17 +62,15 @@ bool STM32EthMACv1::TxDMA::descOwnedByDMA(size_t descIdx) {
 
 bool STM32EthMACv1::TxDMA::isDMAReadableBuffer(uint8_t const *start, size_t size) const {
 #ifdef TARGET_STM32F7
-    if(reinterpret_cast<ptrdiff_t>(start) < 1024*16) {
+    if(bufferTouchesMemoryBank(start, size, 0, 1024*16)) {
         // In ITCM memory, not accessible by DMA. Note that ITCM is not included in the CMSIS memory map (yet).
         return false;
     }
 #endif
 
 #if TARGET_STM32F2 || TARGET_STM32F4
     // On STM32F2 and F2, ethernet DMA cannot access the flash memory.
-    if(reinterpret_cast<ptrdiff_t>(start) >= MBED_ROM_START ||
-        reinterpret_cast<ptrdiff_t>(start + size) <= MBED_ROM_START + MBED_ROM_SIZE)
-    {
+    if(bufferTouchesMemoryBank(start, size, MBED_ROM_START, MBED_ROM_SIZE)) {
         return false;
     }
 #endif

connectivity/drivers/emac/TARGET_STM/STM32EthMACv2.cpp

@@ -66,18 +66,14 @@ namespace mbed {
         // On STM32H7, the Ethernet DMA cannot access data in DTCM.  So, if someone sends
         // a packet with a data pointer in DTCM (e.g. a stack allocated payload), everything
         // will break if we don't copy it first.
-        if(reinterpret_cast<ptrdiff_t>(start) >= MBED_RAM_BANK_SRAM_DTC_START ||
-            reinterpret_cast<ptrdiff_t>(start + size) <= MBED_RAM_BANK_SRAM_DTC_START + MBED_RAM_BANK_SRAM_DTC_SIZE)
-        {
+        if(bufferTouchesMemoryBank(start, size, MBED_RAM_BANK_SRAM_DTC_START, MBED_RAM_BANK_SRAM_DTC_SIZE)) {
             return false;
         }
 #endif
 
 #ifdef TARGET_STM32H5
-        // On STM32H7, the Ethernet DMA cannot access data in backup SRAM.
-        if(reinterpret_cast<ptrdiff_t>(start) >= MBED_RAM_BANK_SRAM_BKUP_START ||
-            reinterpret_cast<ptrdiff_t>(start + size) <= MBED_RAM_BANK_SRAM_BKUP_START + MBED_RAM_BANK_SRAM_BKUP_SIZE)
-        {
+        // On STM32H5, the Ethernet DMA cannot access data in backup SRAM.
+        if(bufferTouchesMemoryBank(start, size, MBED_RAM_BANK_SRAM_BKUP_START, MBED_RAM_BANK_SRAM_BKUP_SIZE)) {
             return false;
         }
 #endif

connectivity/drivers/emac/TARGET_STM/TARGET_STM32F7/CMakeLists.txt

@@ -12,13 +12,3 @@ elseif("NUCLEO_F756ZG" IN_LIST MBED_TARGET_LABELS)
 elseif("NUCLEO_F767ZI" IN_LIST MBED_TARGET_LABELS)
     add_subdirectory(TARGET_NUCLEO_F767ZI)
 endif()
-
-target_include_directories(mbed-emac
-    PUBLIC
-        .
-)
-
-target_sources(mbed-emac
-    PRIVATE
-        stm32f7_eth_conf.c
-)

connectivity/drivers/emac/include/GenericEthDMA.h

@@ -83,6 +83,25 @@ namespace mbed {
         /// to tell it to start running again.
         virtual void giveToDMA(size_t descIdx, uint8_t const * buffer, size_t len, bool firstDesc, bool lastDesc) = 0;
 
+        // Utility function for implementing isDMAReadableBuffer().
+        // 1D intersection test between a buffer and a memory bank.
+        static bool bufferTouchesMemoryBank(uint8_t const * start, size_t size, uint32_t bankStartAddr, uint32_t bankSize) {
+            const auto startAddrInt = reinterpret_cast<ptrdiff_t>(start);
+
+            if(startAddrInt < bankStartAddr) {
+                // Case 1: buffer begins before bank
+                return (startAddrInt + size) > bankStartAddr;
+            }
+            else if(startAddrInt >= bankStartAddr && startAddrInt < (bankStartAddr + bankSize)) {
+                // Case 2: buffer begins inside bank
+                return true;
+            }
+            else {
+                // Case 3: buffer begins after bank
+                return false;
+            }
+        }
+
     public:
         CompositeEMAC::ErrCode init() override {
             // At the start, we own all the descriptors