Implement Goldfish RTC

.ci/boot-linux.sh

@@ -22,6 +22,9 @@ function ASSERT
 
 cleanup
 
+# To test RTC clock
+HOST_UTC_YEAR=$(LC_ALL=C date -u +%Y)
+
 ENABLE_VBLK=1
 VBLK_IMG=build/disk.img
 [ -f "${VBLK_IMG}" ] || ENABLE_VBLK=0
@@ -33,10 +36,93 @@ OPTS_BASE+=" -i build/linux-image/rootfs.cpio"
 TEST_OPTIONS=("base (${OPTS_BASE})")
 EXPECT_CMDS=('
     expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
     expect "# " { send "uname -a\n" } timeout { exit 2 }
     expect "riscv32 GNU/Linux" { send "\x01"; send "x" } timeout { exit 3 }
 ')
 
+# RTC alarm and settime tests
+TEST_OPTIONS+=("${OPTS_BASE}")
+EXPECT_CMDS+=('
+    expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
+    expect "# " { send "uname -a\n" } timeout { exit 2 }
+    expect "riscv32 GNU/Linux" { } timeout { exit 3 }
+    expect "# " { send "rtc_alarm\n" } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "alarm_IRQ	: yes" { } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "# " { send "\x01"; send "x" } timeout { exit 3 }
+')
+year1=1980
+year2=2030
+TEST_OPTIONS+=("${OPTS_BASE}")
+EXPECT_CMDS+=('
+    expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
+    expect "# " { send "uname -a\n" } timeout { exit 2 }
+    expect "riscv32 GNU/Linux" { } timeout { exit 3 }
+    expect "# " { send "rtc_settime ${year1}\n" } timeout { exit 3 }
+    expect "rtc_date	: ${year1}-01-01" { } timeout { exit 3 }
+    expect "# " { send "\x01"; send "x" } timeout { exit 3 }
+')
+TEST_OPTIONS+=("${OPTS_BASE}")
+EXPECT_CMDS+=('
+    expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
+    expect "# " { send "uname -a\n" } timeout { exit 2 }
+    expect "riscv32 GNU/Linux" { } timeout { exit 3 }
+    expect "# " { send "rtc_settime ${year2}\n" } timeout { exit 3 }
+    expect "rtc_date	: ${year2}-01-01" { } timeout { exit 3 }
+    expect "# " { send "\x01"; send "x" } timeout { exit 3 }
+')
+TEST_OPTIONS+=("${OPTS_BASE}")
+EXPECT_CMDS+=('
+    expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
+    expect "# " { send "uname -a\n" } timeout { exit 2 }
+    expect "riscv32 GNU/Linux" { } timeout { exit 3 }
+    expect "# " { send "rtc_settime ${year1}\n" } timeout { exit 3 }
+    expect "rtc_date	: ${year1}-01-01" { } timeout { exit 3 }
+    expect "# " { send "rtc_alarm\n" } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "alarm_IRQ	: yes" { } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "# " { send "\x01"; send "x" } timeout { exit 3 }
+')
+TEST_OPTIONS+=("${OPTS_BASE}")
+EXPECT_CMDS+=('
+    expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+    expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+    expect "rtc0" { } timeout { exit 3 }
+    expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+    expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
+    expect "# " { send "uname -a\n" } timeout { exit 2 }
+    expect "riscv32 GNU/Linux" { } timeout { exit 3 }
+    expect "# " { send "rtc_settime ${year2}\n" } timeout { exit 3 }
+    expect "rtc_date	: ${year2}-01-01" { } timeout { exit 3 }
+    expect "# " { send "rtc_alarm\n" } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "alarm_IRQ	: yes" { } timeout { exit 3 }
+    expect "alarm_IRQ	: no" { } timeout { exit 3 }
+    expect "# " { send "\x01"; send "x" } timeout { exit 3 }
+')
+
 COLOR_G='\e[32;01m' # Green
 COLOR_R='\e[31;01m' # Red
 COLOR_Y='\e[33;01m' # Yellow
@@ -54,6 +140,10 @@ if [ "${ENABLE_VBLK}" -eq "1" ]; then
     TEST_OPTIONS+=("${OPTS_BASE} -x vblk:${VBLK_IMG},readonly")
     EXPECT_CMDS+=('
         expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+        expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+        expect "rtc0" { } timeout { exit 3 }
+        expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+        expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
         expect "# " { send "uname -a\n" } timeout { exit 2 }
         expect "riscv32 GNU/Linux" { send "mkdir mnt && mount /dev/vda mnt\n" } timeout { exit 3 }
         expect "# " { send "echo rv32emu > mnt/emu.txt\n" } timeout { exit 3 }
@@ -65,6 +155,10 @@ if [ "${ENABLE_VBLK}" -eq "1" ]; then
     TEST_OPTIONS+=("${OPTS_BASE} -x vblk:${VBLK_IMG},readonly -x vblk:${BLK_DEV},readonly")
     EXPECT_CMDS+=('
         expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+        expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+        expect "rtc0" { } timeout { exit 3 }
+        expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+        expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
         expect "# " { send "uname -a\n" } timeout { exit 2 }
         expect "riscv32 GNU/Linux" { send "mkdir mnt && mount /dev/vda mnt\n" } timeout { exit 3 }
         expect "# " { send "echo rv32emu > mnt/emu.txt\n" } timeout { exit 3 }
@@ -79,6 +173,10 @@ if [ "${ENABLE_VBLK}" -eq "1" ]; then
     TEST_OPTIONS+=("${OPTS_BASE} -x vblk:${VBLK_IMG}")
     VBLK_EXPECT_CMDS='
         expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+        expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+        expect "rtc0" { } timeout { exit 3 }
+        expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+        expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
         expect "# " { send "uname -a\n" } timeout { exit 2 }
         expect "riscv32 GNU/Linux" { send "mkdir mnt && mount /dev/vda mnt\n" } timeout { exit 3 }
         expect "# " { send "echo rv32emu > mnt/emu.txt\n" } timeout { exit 3 }
@@ -96,6 +194,10 @@ if [ "${ENABLE_VBLK}" -eq "1" ]; then
     TEST_OPTIONS+=("${OPTS_BASE} -x vblk:${VBLK_IMG} -x vblk:${BLK_DEV}")
     VBLK_EXPECT_CMDS='
         expect "buildroot login:" { send "root\n" } timeout { exit 1 }
+        expect "# " { send "dmesg | grep rtc\n" } timeout { exit 2 }
+        expect "rtc0" { } timeout { exit 3 }
+        expect "# " { send "date -u +%Y\n" } timeout { exit 2 }
+        expect "${HOST_UTC_YEAR}" { } timeout { exit 3 }
         expect "# " { send "uname -a\n" } timeout { exit 2 }
         expect "riscv32 GNU/Linux" { send "mkdir mnt && mount /dev/vda mnt\n" } timeout { exit 3 }
         expect "# " { send "echo rv32emu > mnt/emu.txt\n" } timeout { exit 3 }
@@ -121,6 +223,9 @@ for i in "${!TEST_OPTIONS[@]}"; do
     RUN_LINUX="build/rv32emu ${OPTS}"
 
     ASSERT expect <<- DONE
+	set HOST_UTC_YEAR ${HOST_UTC_YEAR}
+	set year1 ${year1}
+	set year2 ${year2}
 	set timeout ${TIMEOUT}
 	spawn ${RUN_LINUX}
 	${EXPECT_CMDS[$i]}

assets/system/configs/buildroot.config

@@ -45,3 +45,8 @@ BR2_TARGET_ROOTFS_CPIO_NONE=y
 BR2_PACKAGE_BUSYBOX_CONFIG="busybox.config"
 BR2_PACKAGE_COREMARK=y
 BR2_PACKAGE_DHRYSTONE=y
+BR2_PACKAGE_UTIL_LINUX=y
+BR2_PACKAGE_UTIL_LINUX_HWCLOCK=y
+
+BR2_PACKAGE_RTC_ALARM=y
+BR2_PACKAGE_RTC_SETTIME=y

assets/system/configs/linux.config

@@ -1026,7 +1026,66 @@ CONFIG_USB_OHCI_LITTLE_ENDIAN=y
 # CONFIG_ACCESSIBILITY is not set
 # CONFIG_INFINIBAND is not set
 CONFIG_EDAC_SUPPORT=y
-# CONFIG_RTC_CLASS is not set
+
+CONFIG_RTC_LIB=y
+CONFIG_RTC_CLASS=y
+CONFIG_RTC_HCTOSYS=y
+CONFIG_RTC_HCTOSYS_DEVICE="rtc0"
+# CONFIG_RTC_SYSTOHC is not set
+# CONFIG_RTC_DEBUG is not set
+# CONFIG_RTC_NVMEM is not set
+
+#
+# RTC interfaces
+#
+CONFIG_RTC_INTF_SYSFS=y
+CONFIG_RTC_INTF_PROC=y
+CONFIG_RTC_INTF_DEV=y
+# CONFIG_RTC_INTF_DEV_UIE_EMUL is not set
+# CONFIG_RTC_DRV_TEST is not set
+
+#
+# I2C RTC drivers
+#
+
+#
+# SPI RTC drivers
+#
+
+#
+# SPI and I2C RTC drivers
+#
+
+#
+# Platform RTC drivers
+#
+# CONFIG_RTC_DRV_DS1286 is not set
+# CONFIG_RTC_DRV_DS1511 is not set
+# CONFIG_RTC_DRV_DS1553 is not set
+# CONFIG_RTC_DRV_DS1685_FAMILY is not set
+# CONFIG_RTC_DRV_DS1742 is not set
+# CONFIG_RTC_DRV_DS2404 is not set
+# CONFIG_RTC_DRV_STK17TA8 is not set
+# CONFIG_RTC_DRV_M48T86 is not set
+# CONFIG_RTC_DRV_M48T35 is not set
+# CONFIG_RTC_DRV_M48T59 is not set
+# CONFIG_RTC_DRV_MSM6242 is not set
+# CONFIG_RTC_DRV_BQ4802 is not set
+# CONFIG_RTC_DRV_RP5C01 is not set
+# CONFIG_RTC_DRV_V3020 is not set
+# CONFIG_RTC_DRV_ZYNQMP is not set
+
+#
+# on-CPU RTC drivers
+#
+# CONFIG_RTC_DRV_CADENCE is not set
+# CONFIG_RTC_DRV_FTRTC010 is not set
+# CONFIG_RTC_DRV_R7301 is not set
+
+#
+# HID Sensor RTC drivers
+#
+CONFIG_RTC_DRV_GOLDFISH=y
 # CONFIG_DMADEVICES is not set
 
 #

src/common.h

@@ -29,7 +29,7 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
 
-#define MASK(n) (~((~0U << (n))))
+#define MASK(n) (~((~0UL << (n))))
 
 #if defined(_MSC_VER)
 #include <intrin.h>

src/devices/minimal.dts

@@ -66,14 +66,21 @@
             clock-frequency = <5000000>; /* the baudrate divisor is ignored */
         };
 
+        rtc0: rtc@4100000 {
+            compatible = "google,goldfish-rtc";
+            reg = <0x4100000 0x1000>;
+            interrupts = <2>;
+            interrupt-parent = <&plic0>;
+        };
+
         /*
          * Virtio block example subnode
          * The actual subnode are generated dynamically depends on the CLI -x vblk option
          */
-        /*blk0: virtio@4100000 {
+        /*blk0: virtio@4200000 {
             compatible = "virtio,mmio";
-            reg = <0x4100000 0x200>;
-            interrupts = <2>;
+            reg = <0x4200000 0x200>;
+            interrupts = <3>;
         };*/
     };
 };

src/devices/rtc.c

@@ -0,0 +1,120 @@
+/*
+ * rv32emu is freely redistributable under the MIT License. See the file
+ * "LICENSE" for information on usage and redistribution of this file.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "rtc.h"
+
+static uint64_t now_nsec;
+
+uint64_t get_now_nsec(rtc_t *rtc)
+{
+    /* TODO:
+     * - detects timezone and use the correct UTC offset
+     * - a new CLI option should be added to main.c to let user to select
+     *   [UTC] or [UTC + offset](localtime) time. E.g., -x rtc:utc or -x
+     *   rtc:localtime
+     */
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    return (uint64_t) (ts.tv_sec * 1e9) + ts.tv_nsec + rtc->clock_offset;
+}
+
+uint32_t rtc_read(rtc_t *rtc, uint32_t addr)
+{
+    uint32_t rtc_read_val = 0;
+
+    switch (addr) {
+    case RTC_TIME_LOW:
+        now_nsec = get_now_nsec(rtc);
+        rtc->time_low = (uint32_t) (now_nsec & MASK(32));
+        rtc_read_val = rtc->time_low;
+        break;
+    case RTC_TIME_HIGH:
+        /* reuse the now_nsec when reading RTC_TIME_LOW */
+        rtc->time_high = (uint32_t) (now_nsec >> 32);
+        rtc_read_val = rtc->time_high;
+        break;
+    case RTC_ALARM_LOW:
+        rtc_read_val = rtc->alarm_low;
+        break;
+    case RTC_ALARM_HIGH:
+        rtc_read_val = rtc->alarm_high;
+        break;
+    case RTC_ALARM_STATUS:
+        rtc_read_val = rtc->alarm_status;
+        break;
+    default:
+        rv_log_error("Unsupported RTC read operation, 0x%x", addr);
+        break;
+    }
+
+    return rtc_read_val;
+}
+
+void rtc_write(rtc_t *rtc, uint32_t addr, uint32_t value)
+{
+    switch (addr) {
+    case RTC_TIME_LOW:
+        now_nsec = get_now_nsec(rtc);
+        rtc->clock_offset += (uint64_t) (value) - (now_nsec & MASK(32));
+        break;
+    case RTC_TIME_HIGH:
+        /* reuse the now_nsec when writing RTC_TIME_LOW */
+        rtc->clock_offset += ((uint64_t) (value) << 32) -
+                             (now_nsec & ((uint64_t) (MASK(32)) << 32));
+        break;
+    case RTC_ALARM_LOW:
+        rtc->alarm_low = value;
+        break;
+    case RTC_ALARM_HIGH:
+        rtc->alarm_high = value;
+        break;
+    case RTC_IRQ_ENABLED:
+        rtc->irq_enabled = value;
+        break;
+    case RTC_CLEAR_ALARM:
+        rtc->clear_alarm = value;
+        break;
+    case RTC_CLEAR_INTERRUPT:
+        rtc->clear_interrupt = value;
+        rtc->interrupt_status = 0;
+        break;
+    default:
+        rv_log_error("Unsupported RTC write operation, 0x%x", addr);
+        break;
+    }
+    return;
+}
+
+rtc_t *rtc_new()
+{
+    rtc_t *rtc = calloc(1, sizeof(rtc_t));
+    assert(rtc);
+
+    /*
+     * The rtc->time_low/high values can be updated through the RTC_SET_TIME
+     * ioctl operation. Therefore, they should be initialized to match the
+     * host OS time during initialization.
+     */
+    now_nsec = get_now_nsec(rtc);
+    rtc->time_low = (uint32_t) (now_nsec & MASK(32));
+    rtc->time_high = (uint32_t) (now_nsec >> 32);
+
+    return rtc;
+}
+
+void rtc_delete(rtc_t *rtc)
+{
+    free(rtc);
+}