Merge commit 'e067fcbe30' as 'stm32f103c8t6-bootloader'

stm32f103c8t6-bootloader/src/usb_util.c

@@ -0,0 +1,55 @@
+#include "usb_util.h"
+
+void USB_PMAToMemory(void *mem, uint16_t offset, size_t length)
+{
+    // Only words can be copied. Thus, if the length is not even, it has to be
+    // incremented to ensure that the last byte is copied. This of course means
+    // that the target memory area must be of even length!
+    if(length & 1)
+    {
+        length++;
+    }
+
+    uint8_t *dst = (uint8_t*)mem;
+
+    uint8_t *pma = (uint8_t*)(USB_PMA_ADDR + 2 * offset);
+    for(unsigned int i = 0; i < length / 2; i++)
+    {
+        dst[2 * i] = *pma++;
+        dst[2 * i + 1] = *pma++;
+        pma += 2;
+    }
+}
+
+void USB_MemoryToPMA(uint16_t offset, const void *mem, size_t length)
+{
+    // Only words can be copied. Thus, if the length is not even, it has to be
+    // incremented to ensure that the last byte is copied. Since the PMA buffer
+    // always has even size, this is not a problem.
+    if(length & 1)
+    {
+        length++;
+    }
+
+    const uint8_t *src = (const uint8_t*)mem;
+
+    uint16_t *pma = (uint16_t*)(USB_PMA_ADDR + 2 * offset);
+    for(unsigned int i = 0; i < length / 2; i++)
+    {
+        uint16_t tmp = src[2 * i] | (src[2 * i + 1] << 8);
+        *pma++ = tmp;
+        pma++;
+    }
+}
+
+void USB_SetEPR(volatile uint16_t *EPR, uint16_t status)
+{
+    // Caution: This function does a read-modify-write and is prone to
+    // unexpected behaviour when there are transactions going one, because the
+    // register contents might change during the function's execution. Thus,
+    // only use this function in initialisation code!
+    volatile uint16_t v = *EPR;
+    status ^= v & (USB_EP0R_DTOG_RX | USB_EP0R_STAT_RX |\
+        USB_EP0R_DTOG_TX | USB_EP0R_STAT_TX);
+    *EPR = status;
+}