Basic flash peripheral management api for board bringup

1 files changed, 33 insertions, 16 deletions

diff --git a/libmaple/flash.c b/libmaple/flash.c
index 9442c44..828f938 100644
--- a/libmaple/flash.c
+++ b/libmaple/flash.c
@@ -22,32 +22,49 @@
  * THE SOFTWARE.
  * ****************************************************************************/
 
+/**
+ *  @brief flash peripheral management functions
+ */
+
+
 #include "libmaple.h"
 #include "flash.h"
 
-#define ACR_PRFTBE                ((uint32)0xFFFFFFEF)
-#define ACR_PRFTBE_ENABLE ((uint32)0x00000010)  /* FLASH Prefetch Buffer Enable */
-#define ACR_PRFTBE_DISABLE ((uint32)0x00000000)  /* FLASH Prefetch Buffer Disable */
+/* flash registers  */
+#define FLASH_BASE                      0x40022000
+#define FLASH_ACR                       FLASH_BASE
+
+/* flash prefetcher  */
+#define ACR_PRFTBE                      BIT(4)
+#define ACR_PRFTBE_ENABLE               BIT(4)
 
-#define ACR_LATENCY               ((uint32)0x00000038)
-#define ACR_LATENCY_0                ((uint32)0x00000000)  /* FLASH Zero Latency cycle */
-#define ACR_LATENCY_1                ((uint32)0x00000001)  /* FLASH One Latency cycle */
-#define ACR_LATENCY_2                ((uint32)0x00000002)  /* FLASH Two Latency cycles */
+/* flash wait states  */
+#define ACR_LATENCY                     (0x7)
 
+#define FLASH_WRITE_ACR(val)            __write(FLASH_ACR, val)
+#define FLASH_READ_ACR()                __read(FLASH_ACR)
+
+/**
+ * @brief turn on the hardware prefetcher
+ */
 void flash_enable_prefetch(void) {
-   uint32 acr = __read(FLASH_ACR);
+   uint32 val = FLASH_READ_ACR();
 
-   acr &= ACR_PRFTBE;
-   acr |= ACR_PRFTBE_ENABLE;
+   val |= ACR_PRFTBE_ENABLE;
 
-   __write(FLASH_ACR, acr);
+   FLASH_WRITE_ACR(val);
 }
 
-void flash_set_latency(void) {
-   uint32 acr = __read(FLASH_ACR);
 
-   acr &= ACR_LATENCY;
-   acr |= ACR_LATENCY_2;
+/**
+ * @brief set flash wait states
+ * @param number of wait states
+ */
+void flash_set_latency(uint32 wait_states) {
+   uint32 val = FLASH_READ_ACR();
+
+   val &= ~ACR_LATENCY;
+   val |= wait_states;
 
-   __write(FLASH_ACR, acr);
+   FLASH_WRITE_ACR(val);
 }