Initial RTC driver for google goldfish

kern/rtc.c

@@ -0,0 +1,51 @@
+#include <stdint.h>
+
+#define VIRT_RTC_BASE 0x0101000UL
+#define VIRT_RTC_SIZE 0x1000
+
+#define RTC_TIME_LOW   0x00
+#define RTC_TIME_HIGH  0x04
+#define RTC_ALARM_LOW  0x08
+#define RTC_ALARM_HIGH 0x0c
+
+#define RTC_IRQ_ENABLED     0x10
+#define RTC_CLEAR_ALARM     0x14
+#define RTC_ALARM_STATUS    0x18
+#define RTC_CLEAR_INTERRUPT 0x1c
+
+static inline uint32_t mmio_read32(uintptr_t addr) {
+    return *(volatile uint32_t *)addr;
+}
+
+static inline void mmio_write32(uintptr_t addr, uint32_t value) {
+    *(volatile uint32_t *)addr = value;
+}
+
+uint64_t rtc_read_time(void) {
+    uint32_t low = mmio_read32(VIRT_RTC_BASE + RTC_TIME_LOW);
+    uint32_t high = mmio_read32(VIRT_RTC_BASE + RTC_TIME_HIGH);
+    return ((uint64_t)high << 32) | low;
+}
+
+void rtc_alarm_set(uint64_t ns) {
+    mmio_write32(VIRT_RTC_BASE + RTC_ALARM_HIGH, ns >> 32);
+    mmio_write32(VIRT_RTC_BASE + RTC_ALARM_LOW, ns & 0xffffffff);
+}
+
+uint64_t rtc_alarm_read(void) {
+    uint32_t low = mmio_read32(VIRT_RTC_BASE + RTC_ALARM_LOW);
+    uint32_t high = mmio_read32(VIRT_RTC_BASE + RTC_ALARM_HIGH);
+    return ((uint64_t)high << 32) | low;
+}
+
+void rtc_alarm_enable(void) {
+    mmio_write32(VIRT_RTC_BASE + RTC_IRQ_ENABLED, 1);
+}
+
+void rtc_alarm_disable(void) {
+    mmio_write32(VIRT_RTC_BASE + RTC_IRQ_ENABLED, 0);
+}
+
+uint32_t rtc_alarm_status(void) {
+    return mmio_read32(VIRT_RTC_BASE + RTC_IRQ_ENABLED);
+}

kern/rtc.h

@@ -0,0 +1,14 @@
+#ifndef RTC_H
+#define RTC_H
+
+#include <stdint.h>
+
+uint64_t rtc_read_time(void);
+
+void     rtc_alarm_set(uint64_t ns);
+uint64_t rtc_alarm_read(void);
+void     rtc_alarm_enable(void);
+void     rtc_alarm_disable(void);
+uint32_t rtc_alarm_status(void);
+
+#endif // RTC_H