K22F: Enable TRNG (#3599)

Signed-off-by: Mahadevan Mahesh <[email protected]>

Author: mmahadevan108

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K22F/trng_api.c

@@ -0,0 +1,82 @@
+/*
+ *  Hardware entropy collector for the K22F, using Freescale's RNGA
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  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_TRNG)
+
+#include <stdlib.h>
+#include "cmsis.h"
+#include "fsl_common.h"
+#include "fsl_clock.h"
+#include "trng_api.h"
+
+void trng_init(trng_t *obj)
+{
+    (void)obj;
+    CLOCK_EnableClock(kCLOCK_Rnga0);
+    CLOCK_DisableClock(kCLOCK_Rnga0);
+    CLOCK_EnableClock(kCLOCK_Rnga0);
+}
+
+void trng_free(trng_t *obj)
+{
+    (void)obj;
+    CLOCK_DisableClock(kCLOCK_Rnga0);
+}
+
+/*
+ * Get one byte of entropy from the RNG, assuming it is up and running.
+ * As recommended, get only one bit of each output.
+ */
+static void trng_get_byte(unsigned char *byte)
+{
+    size_t bit;
+
+    /* 34.5 Steps 3-4-5: poll SR and read from OR when ready */
+    for( bit = 0; bit < 8; bit++ )
+    {
+        while((RNG->SR & RNG_SR_OREG_LVL_MASK) == 0 );
+        *byte |= (RNG->OR & 1) << bit;
+    }
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    (void)obj;
+    size_t i;
+
+    /* Set "Interrupt Mask", "High Assurance" and "Go",
+     * unset "Clear interrupt" and "Sleep" */
+    RNG->CR = RNG_CR_INTM_MASK | RNG_CR_HA_MASK | RNG_CR_GO_MASK;
+
+    for (i = 0; i < length; i++) {
+        trng_get_byte(output + i);
+    }
+
+    /* Just be extra sure that we didn't do it wrong */
+    if ((RNG->SR & RNG_SR_SECV_MASK) != 0) {
+        return -1;
+    }
+
+    *output_length = length;
+
+    return 0;
+}
+
+#endif

targets/targets.json

@@ -493,7 +493,7 @@
         "macros": ["CPU_MK22FN512VLH12", "FSL_RTOS_MBED"],
         "inherits": ["Target"],
         "detect_code": ["0231"],
-        "device_has": ["ANALOGIN", "ANALOGOUT", "ERROR_RED", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
+        "device_has": ["ANALOGIN", "ANALOGOUT", "ERROR_RED", "I2C", "I2CSLAVE", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES", "TRNG"],
         "device_name": "MK22DN512xxx5"
     },
     "K22F": {
@@ -2498,7 +2498,7 @@
         "macros_add": ["BOARD_PCA10040", "NRF52_PAN_12", "NRF52_PAN_15", "NRF52_PAN_58", "NRF52_PAN_55", "NRF52_PAN_54", "NRF52_PAN_31", "NRF52_PAN_30", "NRF52_PAN_51", "NRF52_PAN_36", "NRF52_PAN_53", "S132", "CONFIG_GPIO_AS_PINRESET", "BLE_STACK_SUPPORT_REQD", "SWI_DISABLE0", "NRF52_PAN_20", "NRF52_PAN_64", "NRF52_PAN_62", "NRF52_PAN_63"],
         "device_has": ["ANALOGIN", "ERROR_PATTERN", "I2C", "I2C_ASYNCH", "INTERRUPTIN", "LOWPOWERTIMER", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SLEEP", "SPI", "SPI_ASYNCH", "SPISLAVE"],
         "release_versions": ["2", "5"],
-        "overrides": {"uart_hwfc": 0},	
+        "overrides": {"uart_hwfc": 0},
         "device_name": "nRF52832_xxAA"
     },
     "UBLOX_EVK_NINA_B1": {