Implement RTC(Real Time Clock) API on CM3DS target

- Modify CMSDK_CM3DS.h: add register interface
- Modify targets.json: add RTC as available device to CM3DS
- Create rtc_api.c: implement mandatory API functions

Change-Id: I14bc1074a9ac0d5e4cbada46d3c90ca82c1e28b0
Signed-off-by: Tamas Ban <Tamas.Ban@arm.com>

targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/device/CMSDK_CM3DS.h

@@ -779,6 +779,22 @@ typedef struct
 #define CMSDK_Watchdog_INTEGTESTOUTSET_Pos    1                                              /* CMSDK_Watchdog INTEGTESTOUTSET: Integration Test Output Set Position */
 #define CMSDK_Watchdog_INTEGTESTOUTSET_Msk   (0x1ul << CMSDK_Watchdog_INTEGTESTOUTSET_Pos)   /* CMSDK_Watchdog INTEGTESTOUTSET: Integration Test Output Set Mask */
 
+/*------------------------- Real Time Clock(RTC) ----------------------------------------------*/
+typedef struct
+{
+    __I  uint32_t RTCDR;                     /* 0x00 RO RTC Data Register */
+    __IO uint32_t RTCMR;                     /* 0x04 RW RTC Match Register */
+    __IO uint32_t RTCLR;                     /* 0x08 RW RTC Load Register */
+    __IO uint32_t RTCCR;                     /* 0x0C RW RTC Control Register */
+    __IO uint32_t RTCIMSC;                   /* 0x10 RW RTC Inerrupt Mask Set and Clear Register */
+    __I  uint32_t RTCRIS;                    /* 0x14 RO RTC Raw Inerrupt Status Register */
+    __I  uint32_t RTCMIS;                    /* 0x18 RO RTC Masked Inerrupt Status Register */
+    __O  uint32_t RTCICR;                    /* 0x1C WO RTC Interrupt Clear Register */
+} CMSDK_RTC_TypeDef;
+
+#define CMSDK_RTC_Enable_Pos                  0                                  /* CMSDK_RTC Enable: Real Time Clock Enable Position */
+#define CMSDK_RTC_Enable_Msk                  (0x1ul << CMSDK_RTC_Enable_Pos)    /* CMSDK_RTC Enable: Real Time Clock Enable Mask */
+
 /* --------------------  End of section using anonymous unions  ------------------- */
 #if defined ( __CC_ARM   )
   #pragma pop
@@ -821,6 +837,7 @@ typedef struct
 #define CMSDK_UART2_BASE        (0x4002C000UL)
 #define CMSDK_UART3_BASE        (0x4002D000UL)
 #define CMSDK_UART4_BASE        (0x4002E000UL)
+#define CMSDK_RTC_BASE          (CMSDK_APB_BASE + 0x6000UL)
 #define CMSDK_WATCHDOG_BASE     (CMSDK_APB_BASE + 0x8000UL)
 
 /* AHB peripherals */
@@ -848,6 +865,7 @@ typedef struct
 #define CMSDK_DUALTIMER         ((CMSDK_DUALTIMER_BOTH_TypeDef  *) CMSDK_DUALTIMER_BASE )
 #define CMSDK_DUALTIMER1        ((CMSDK_DUALTIMER_SINGLE_TypeDef  *) CMSDK_DUALTIMER_1_BASE )
 #define CMSDK_DUALTIMER2        ((CMSDK_DUALTIMER_SINGLE_TypeDef  *) CMSDK_DUALTIMER_2_BASE )
+#define CMSDK_RTC               ((CMSDK_RTC_TypeDef    *) CMSDK_RTC_BASE )
 #define CMSDK_WATCHDOG          ((CMSDK_WATCHDOG_TypeDef  *) CMSDK_WATCHDOG_BASE   )
 #define CMSDK_DMA               ((CMSDK_PL230_TypeDef  *) CMSDK_PL230_BASE   )
 #define CMSDK_GPIO0             ((CMSDK_GPIO_TypeDef   *) CMSDK_GPIO0_BASE   )

targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/rtc_api.c

@@ -0,0 +1,78 @@
+/*
+ * 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.
+ */
+
+#include "rtc_api.h"
+#include "device.h"
+#include "cmsis.h"
+
+/**
+ * \defgroup hal_rtc RTC hal functions
+ * @{
+ */
+
+/**
+ * \brief Initialize the RTC peripheral.
+ *        The RTC starts counting from 0x0 at reset and increments
+ *        with a frequency of 1hz (clock source: CLK1HZ).
+ *        The current value can be read through the DATA register
+ */
+void rtc_init(void)
+{
+    CMSDK_RTC->RTCCR |= (1 << CMSDK_RTC_Enable_Pos);
+}
+
+/**
+ * \brief Deinitialize the RTC peripheral
+ *        According to DDI0224B_RTC_PL031_TRM.pdf chapter 3.3.4 there is
+ *        no reason to implement.
+ */
+void rtc_free(void)
+{
+    /* Not supported */
+}
+
+/**
+ * \brief Get the RTC enable status
+ *
+ * \return 0 disabled, 1 enabled
+ */
+int rtc_isenabled(void)
+{
+    return (CMSDK_RTC->RTCCR & CMSDK_RTC_Enable_Msk);
+}
+
+/**
+ * \brief Get the current time from the RTC peripheral
+ *
+ * \return The current time in seconds
+ */
+time_t rtc_read(void)
+{
+    return (time_t)CMSDK_RTC->RTCDR;
+}
+
+/**
+ * \brief Set the current time to the RTC peripheral, write it to LOAD register
+ *
+ * \param[in] t The current time to be set in seconds
+ */
+
+void rtc_write(time_t t)
+{
+    CMSDK_RTC->RTCLR = (uint32_t)t;
+}
+/**@}*/
+

targets/targets.json

@@ -1938,7 +1938,7 @@
         "supported_toolchains": ["ARM"],
         "extra_labels": ["ARM_SSG", "CM3DS_MPS2"],
         "macros": ["CMSDK_CM3DS"],
-        "device_has": ["ETHERNET","INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "SERIAL", "SPI"],
+        "device_has": ["ETHERNET","INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "SERIAL", "SPI", "RTC"],
         "release_versions": ["2", "5"]
     },
     "ARM_BEETLE_SOC": {