Diff: hal/mbed_itm_api.c

Revision:

184:08ed48f1de7f

Child:

187:0387e8f68319

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hal/mbed_itm_api.c	Thu Apr 19 17:12:19 2018 +0100
@@ -0,0 +1,87 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if defined(DEVICE_ITM)
+
+#include "hal/itm_api.h"
+#include "cmsis.h"
+
+#include <stdbool.h>
+
+#define ITM_ENABLE_WRITE 0xC5ACCE55 
+
+#define SWO_NRZ 0x02
+#define SWO_STIMULUS_PORT 0x01
+
+void mbed_itm_init(void)
+{
+    static bool do_init = true;
+
+    if (do_init) {
+        do_init = false;
+
+        itm_init();
+
+        /* Enable write access to ITM registers. */
+        ITM->LAR  = ITM_ENABLE_WRITE;
+
+        /* Trace Port Interface Selected Pin Protocol Register. */
+        TPI->SPPR = (SWO_NRZ << TPI_SPPR_TXMODE_Pos);
+
+        /* Trace Port Interface Formatter and Flush Control Register */
+        TPI->FFCR = (1 << TPI_FFCR_TrigIn_Pos);
+
+        /* Data Watchpoint and Trace Control Register */
+        DWT->CTRL = (1 << DWT_CTRL_CYCTAP_Pos)       |
+                    (0xF << DWT_CTRL_POSTINIT_Pos)   |
+                    (0xF << DWT_CTRL_POSTPRESET_Pos) |
+                    (1 << DWT_CTRL_CYCCNTENA_Pos);
+
+        /* Trace Privilege Register.
+         * Disable access to trace channel configuration from non-privileged mode.
+         */
+        ITM->TPR  = 0x0;
+
+        /* Trace Control Register */
+        ITM->TCR  = (1 << ITM_TCR_TraceBusID_Pos) | 
+                    (1 << ITM_TCR_DWTENA_Pos)     | 
+                    (1 << ITM_TCR_SYNCENA_Pos)    |
+                    (1 << ITM_TCR_ITMENA_Pos);
+
+        /* Trace Enable Register */
+        ITM->TER = SWO_STIMULUS_PORT;    
+    }
+}
+
+uint32_t mbed_itm_send(uint32_t port, uint32_t data)
+{
+    /* Check if ITM and port is enabled */
+    if (((ITM->TCR & ITM_TCR_ITMENA_Msk) != 0UL) &&      /* ITM enabled */
+        ((ITM->TER & (1UL << port)     ) != 0UL)   )     /* ITM Port enabled */
+    {
+        /* write data to port */
+        ITM->PORT[port].u32 = data;
+
+        /* Wait until data has been clocked out */
+        while (ITM->PORT[port].u32 == 0UL) {
+            __NOP();
+        }
+    }
+
+    return data;
+}
+
+#endif // defined(DEVICE_ITM)