feat(trng): Add TRNG read to Epicardium API

epicardium/ble/ble.c

@@ -8,7 +8,6 @@
 #include "ble_api.h"
 #include "hci_vs.h"
 #include "att_api.h"
-#include "trng.h"
 
 #include "FreeRTOS.h"
 #include "timers.h"
@@ -101,7 +100,7 @@ static void setAddress(void)
 		bdAddr[0] = 0xCA;
 		bdAddr[1] = 0x4D;
 		bdAddr[2] = 0x10;
-		TRNG_Read(MXC_TRNG, bdAddr + 3, 3);
+		epic_trng_read(bdAddr + 3, 3);
 		sprintf(buf,
 			"%02x:%02x:%02x:%02x:%02x:%02x\n",
 			bdAddr[0],

epicardium/epicardium.h

@@ -98,6 +98,9 @@ typedef _Bool bool;
 #define API_GPIO_GET_PIN_MODE      0xA1
 #define API_GPIO_WRITE_PIN         0xA2
 #define API_GPIO_READ_PIN          0xA3
+
+#define API_TRNG_READ              0xB0
+
 /* clang-format on */
 
 typedef uint32_t api_int_id_t;
@@ -1209,4 +1212,21 @@ API(API_RTC_SCHEDULE_ALARM, int epic_rtc_schedule_alarm(uint32_t timestamp));
  */
 API_ISR(EPIC_INT_RTC_ALARM, epic_isr_rtc_alarm);
 
+/**
+ * TRNG
+ * ====
+ */
+
+/**
+ * Read random bytes from the TRNG.
+ *
+ * :param uint8_t * dest: Destination buffer
+ * :param size: Number of bytes to read.
+ * :return: `0` on success or a negative value if an error occured. Possible
+ *    errors:
+ *
+ *    - ``-EFAULT``: Invalid destination address.
+ */
+API(API_TRNG_READ, int epic_trng_read(uint8_t *dest, size_t size));
+
 #endif /* _EPICARDIUM_H */

epicardium/modules/hardware.c

@@ -18,6 +18,7 @@
 #include "gpio.h"
 #include "i2c.h"
 #include "spi.h"
+#include "trng.h"
 
 /*
  * Early init is called at the very beginning and is meant for modules which

epicardium/modules/meson.build

@@ -13,5 +13,6 @@ module_sources = files(
   'rtc.c',
   'serial.c',
   'stream.c',
+  'trng.c',
   'vibra.c',
 )

epicardium/modules/trng.c

+#include "epicardium.h"
+#include "trng.h"
+
+int epic_trng_read(uint8_t *dest, size_t size)
+{
+	if (dest == NULL)
+		return -EFAULT;
+
+	TRNG_Read(MXC_TRNG, dest, size);
+
+	return 0;
+}