[nrf][clock] use nrfx lib clock driver

Using Nordic's nrfx driver for the clock control peripheral since
it address a handful of errata and abstracts some differences
in the nrf52 family of parts.

external/platform/nrfx/rules.mk

@@ -3,11 +3,12 @@ LOCAL_DIR := $(GET_LOCAL_DIR)
 MODULE := $(LOCAL_DIR)
 
 MODULE_SRCS := \
+	$(LOCAL_DIR)/drivers/src/nrfx_clock.c \
 	$(LOCAL_DIR)/drivers/src/nrfx_twi.c \
 	$(LOCAL_DIR)/drivers/src/nrfx_twi_twim.c \
 	$(LOCAL_DIR)/drivers/src/nrfx_twim.c \
 	$(LOCAL_DIR)/drivers/src/nrfx_usbd.c \
-	$(LOCAL_DIR)/mdk/system_nrf52.c \
+	$(LOCAL_DIR)/mdk/system_nrf52840.c \
 	$(LOCAL_DIR)/soc/nrfx_atomic.c \
 
 # The nrfx library doesn't follow the typical lk include directory layout

platform/nrf52xxx/clock.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2020 Eric Holland
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+
+#include <sys/types.h>
+#include <lk/err.h>
+#include <kernel/event.h>
+#include <nrfx.h>
+#include <nrfx_clock.h>
+#include <hal/nrf_clock.h>
+#include <platform/clock.h>
+
+
+event_t hf_clk_evt = EVENT_INITIAL_VALUE(hf_clk_evt, false, 0);
+event_t lf_clk_evt = EVENT_INITIAL_VALUE(lf_clk_evt, false, 0);
+
+void nrf52_POWER_CLOCK_IRQ(void) {
+    arm_cm_irq_entry();
+    nrfx_clock_irq_handler();
+    arm_cm_irq_exit(true);
+}
+
+// Handler runs in interrupt context
+void nrf52_clock_handler(nrfx_clock_evt_type_t event) {
+    switch (event) {
+        case NRFX_CLOCK_EVT_HFCLK_STARTED :
+            event_signal(&hf_clk_evt, false);
+            break;
+        case NRFX_CLOCK_EVT_LFCLK_STARTED :
+            event_signal(&lf_clk_evt, false);
+            break;
+        default:
+            break;
+    }
+}
+
+status_t nrf52_clock_init(void) {
+    status_t status = nrfx_clock_init(nrf52_clock_handler);
+    if (status == NO_ERROR) {
+        nrfx_clock_enable();
+    }
+    return status;
+}
+
+status_t nrf52_clock_hf_use_xtal_source(void) {
+    // Check if already running on hfclk xtal
+    if (nrfx_clock_hfclk_is_running()) {
+        return NO_ERROR;
+    }
+    event_unsignal(&hf_clk_evt);
+    nrfx_clock_hfclk_start();
+    if (event_wait_timeout(&hf_clk_evt, 100) != NO_ERROR) {
+        dprintf(CRITICAL, "Timeout waiting for hf source\n");
+        return ERR_TIMED_OUT;
+    }
+    return NO_ERROR;
+}
+
+// Switch to using the internal 64MHz oscillator for HF clock
+void nrf52_clock_hf_use_internal_source(void) {
+    //The clock controller will automatically switch to the internal
+    // oscillator as the source when the external xtal is stopped.
+    // this nrfx function is poorly named as it does not stop the hf clock
+    // but only stops the external xtal oscillator.
+    nrfx_clock_hfclk_stop();
+}
+
+status_t nrf52_clock_lfclk_enable(nrf_clock_lfclk_t src) {
+    if (nrfx_clock_lfclk_is_running()) {
+        nrf_clock_lfclk_t current_src = nrf_clock_lf_actv_src_get(NRF_CLOCK);
+        if (current_src == src) {
+            //Already running on the requested source, do nothing.
+            return NO_ERROR;
+        }
+        // If we make it here, it is running, but not right source, so shut it down to change
+        nrfx_clock_lfclk_stop();
+    }
+    nrf_clock_lf_src_set(NRF_CLOCK, src);
+    event_unsignal(&lf_clk_evt);
+    nrfx_clock_lfclk_start();
+    if (event_wait_timeout(&lf_clk_evt, 100) != NO_ERROR) {
+        dprintf(CRITICAL, "Timeout waiting for lf clock start\n");
+        return ERR_TIMED_OUT;
+    }
+    return NO_ERROR;
+}
+

platform/nrf52xxx/include/platform/clock.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2020 Eric Holland
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+#pragma once
+
+#include <nrfx.h>
+#include <nrfx_clock.h>
+#include <hal/nrf_clock.h>
+
+
+// Must be called before other functions can be used.
+status_t nrf52_clock_init(void);
+
+status_t nrf52_clock_hf_use_xtal_source(void);
+void nrf52_clock_hf_use_internal_source(void);
+
+status_t nrf52_clock_lfclk_enable(nrf_clock_lfclk_t src);

platform/nrf52xxx/init.c

@@ -11,17 +11,29 @@
 #include <dev/i2c.h>
 #include <dev/uart.h>
 #include <platform.h>
+#include <platform/init.h>
+#include <platform/clock.h>
 #include <nrfx.h>
 #include <mdk/system_nrf52.h>
+#include <nrfx_clock.h>
 
 void platform_early_init(void) {
-    // Crank up the clock before initing timers.
+
     SystemInit();
+    // Initialize the clock control peripheral
+    nrf52_clock_init();
+
     arm_cm_systick_init(32768);
 }
 
 void platform_init(void) {
+
     dprintf(SPEW, "Nordic nrf52xxx platform for lk...\n");
+
+    char *variant = (char *)&NRF_FICR->FICR_INFO.VARIANT;
+    dprintf(SPEW, "Part Number - %x-%c%c%c%c\n", NRF_FICR->FICR_INFO.PART,
+            variant[3], variant[2], variant[1], variant[0]);
+    dprintf(SPEW, "\tRam: %dk\n", NRF_FICR->FICR_INFO.RAM);
     dprintf(SPEW, "\tFlash: %d pages of %d bytes each (%dk bytes total)\n", \
             NRF_FICR->CODESIZE, NRF_FICR->CODEPAGESIZE, \
             (NRF_FICR->CODESIZE * NRF_FICR->CODEPAGESIZE)>>10);
@@ -32,6 +44,7 @@ void platform_init(void) {
             (NRF_FICR->DEVICEADDR[0] >> 16) & 0xFF, \
             (NRF_FICR->DEVICEADDR[0] >>  8) & 0xFF, \
             (NRF_FICR->DEVICEADDR[0] >>  0) & 0xFF);
+
     // Note: i2c_init will only instantiate an i2c device if proper defines
     //   are set.  See comments at top of i2c_master.c for more info.
     i2c_init();

platform/nrf52xxx/rules.mk

@@ -37,10 +37,13 @@ GLOBAL_DEFINES += \
 	MEMSIZE=$(MEMSIZE)
 
 # Other important defines
-#GLOBAL_DEFINES += \
+GLOBAL_DEFINES += \
+	NRFX_CLOCK_ENABLED=1 \
+
 #	NRFX_ENABLE_LOGGING=1 \
 
 MODULE_SRCS += \
+	$(LOCAL_DIR)/clock.c \
 	$(LOCAL_DIR)/i2c_master.c \
 	$(LOCAL_DIR)/init.c \
 	$(LOCAL_DIR)/debug.c \

platform/nrf52xxx/timer.c

@@ -10,8 +10,12 @@
 #include <platform.h>
 #include <nrfx.h>
 #include <platform/timer.h>
+#include <platform/clock.h>
+#include <nrfx_clock.h>
 #include <sys/types.h>
 
+// TODO - integrate nrfx rtc driver instead of direct register manipulation here.
+
 //base counter is total number of clock cycles elapsed
 static volatile uint64_t base_counter = 0;
 
@@ -27,15 +31,12 @@ typedef enum handler_return (*platform_timer_callback)(void *arg, lk_time_t now)
 
 status_t platform_set_periodic_timer(platform_timer_callback callback, void *arg, lk_time_t interval) {
     ASSERT(clock_rate > 0);
-
+    ASSERT(nrfx_clock_lfclk_is_running());
     cb = callback;
     cb_args = arg;
 
     cycles_per_tick = clock_rate * interval / 1000 ;
 
-    NRF_CLOCK->LFCLKSRC =  CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos;
-    NRF_CLOCK->TASKS_LFCLKSTART = 1;
-
     NRF_RTC1->CC[0] = 0x00ffffff & (base_counter + cycles_per_tick);
 
     NRF_RTC1->PRESCALER = 0;
@@ -95,6 +96,9 @@ void nrf52_RTC1_IRQ(void) {
 }
 
 void arm_cm_systick_init(uint32_t hz) {
+    ASSERT(hz == 32768);
     clock_rate = hz;
+    //Enable the LF xtal oscillator
+    nrf52_clock_lfclk_enable(NRF_CLOCK_LFCLK_Xtal);
 }
 

platform/nrf52xxx/vectab.c

@@ -8,9 +8,6 @@
 #include <lk/debug.h>
 #include <lk/compiler.h>
 #include <arch/arm/cm.h>
-#include <lib/cbuf.h>
-#include <platform/nrf52.h>
-#include <target/debugconfig.h>
 
 /* un-overridden irq handler */
 void nrf52_dummy_irq(void) {

target/nrf-pca10056/include/target/gpioconfig.h

@@ -9,9 +9,20 @@
 #define __TARGET_GPIOCONFIG_H
 
 #define GPIO_LED1   13
+#define LED1_ON gpio_set(GPIO_LED1,0)
+#define LED1_OFF gpio_set(GPIO_LED1,1)
+
 #define GPIO_LED2   14
+#define LED2_ON gpio_set(GPIO_LED2,0)
+#define LED2_OFF gpio_set(GPIO_LED2,1)
+
 #define GPIO_LED3   15
+#define LED3_ON gpio_set(GPIO_LED3,0)
+#define LED3_OFF gpio_set(GPIO_LED3,1)
+
 #define GPIO_LED4   16
+#define LED4_ON gpio_set(GPIO_LED4,0)
+#define LED4_OFF gpio_set(GPIO_LED4,1)
 
 #define UART0_TX_PIN    6
 #define UART0_RX_PIN    8

target/nrf-pca10056/init.c

@@ -11,7 +11,7 @@
 #include <lk/compiler.h>
 #include <nrfx_usbd.h>
 #include <dev/gpio.h>
-#include <platform/nrf52.h>
+#include <platform/init.h>
 #include <target/gpioconfig.h>
 
 void target_early_init(void) {
@@ -20,10 +20,10 @@ void target_early_init(void) {
     gpio_config(GPIO_LED3, GPIO_OUTPUT);
     gpio_config(GPIO_LED4, GPIO_OUTPUT);
 
-    gpio_set(GPIO_LED1,0);
-    gpio_set(GPIO_LED2,0);
-    gpio_set(GPIO_LED3,0);
-    gpio_set(GPIO_LED4,0);
+    LED1_OFF;
+    LED2_OFF;
+    LED3_OFF;
+    LED4_OFF;
 
     nrf52_debug_early_init();
 }