MSC on-board flash: Persist RTC across reboot and use as file timestamp

Adds support to persist the RTC (if set) across the reboot if entering mass storage mode for on-board flash. The value is then used as the timestamp for the files exposed in the virtual FAT32 filesystem. The files will then have reasonable creation dates when copied to the host computer.

If the RTC is not set (or supported), then the default timestamp of 2018-01-01 will be used (unchanged from previous).

Included some improvements to the RTC functions and exposed the `tz_offsetMinutes` in the `timeConfig` PG. Support already existed for timezone offsets but the parameter wasn't exposed to the user and couldn't be set.

Move timezone offset up a layer as a parameter to systemResetToMsc()
Adds support for specifying a custom timezone offset from both the CLI and MSP calls to enter mass storage mode.

Added an option timezone offset minutes to the CLI `msc` command. If no parameter is specified then the default as specified by `timezone_offset_minutes` will be used. So to reboot into mass storage mode and force the file timestamps to be in UTC, use `msc 0`.

Added reboot message `MSP_REBOOT_MSC_UTC` to support rebooting into mass storage mode and forcing the timestamps to use UTC time (0 offset). The Configurator will need to be modified to use this message for operating systems that expect UTC times for FAT file systems (like Linux).

src/main/common/time.c

@@ -30,6 +30,8 @@
 #include "common/printf.h"
 #include "common/time.h"
 
+#include "drivers/persistent.h"
+
 #include "pg/pg_ids.h"
 
 #include "drivers/time.h"
@@ -262,4 +264,31 @@ bool rtcSetDateTime(dateTime_t *dt)
     return rtcSet(&t);
 }
 
+void rtcPersistWrite(int16_t offsetMinutes)
+{
+    rtcTime_t workTime;
+    uint32_t highLongWord = 0;
+    uint32_t lowLongWord = 0;
+    if (rtcGet(&workTime)) {
+        workTime += (offsetMinutes * 60 * MILLIS_PER_SECOND);
+        highLongWord = (uint32_t)(workTime >> 32);
+        lowLongWord = (uint32_t)(workTime & 0xffffffff);
+    }
+    persistentObjectWrite(PERSISTENT_OBJECT_RTC_HIGH, highLongWord);
+    persistentObjectWrite(PERSISTENT_OBJECT_RTC_LOW, lowLongWord);
+}
+
+bool rtcPersistRead(rtcTime_t *t)
+{
+    const uint32_t highLongWord = persistentObjectRead(PERSISTENT_OBJECT_RTC_HIGH);
+    const uint32_t lowLongWord = persistentObjectRead(PERSISTENT_OBJECT_RTC_LOW);
+
+    if ((highLongWord != 0) || (lowLongWord != 0)) {
+        *t = ((uint64_t)highLongWord << 32) + lowLongWord;
+        return true;
+    } else {
+        return false;
+    }
+}
+
 #endif

src/main/common/time.h

@@ -40,6 +40,9 @@ typedef uint32_t timeUs_t;
 #define TIMEUS_MAX UINT32_MAX
 #endif
 
+#define TIMEZONE_OFFSET_MINUTES_MIN -780  // -13 hours
+#define TIMEZONE_OFFSET_MINUTES_MAX 780   // +13 hours
+
 static inline timeDelta_t cmpTimeUs(timeUs_t a, timeUs_t b) { return (timeDelta_t)(a - b); }
 
 #define FORMATTED_DATE_TIME_BUFSIZE 30
@@ -95,4 +98,6 @@ bool rtcSet(rtcTime_t *t);
 bool rtcGetDateTime(dateTime_t *dt);
 bool rtcSetDateTime(dateTime_t *dt);
 
+void rtcPersistWrite(int16_t offsetMinutes);
+bool rtcPersistRead(rtcTime_t *t);
 #endif

src/main/drivers/persistent.h

@@ -30,6 +30,8 @@ typedef enum {
     PERSISTENT_OBJECT_HSE_VALUE,
     PERSISTENT_OBJECT_OVERCLOCK_LEVEL,
     PERSISTENT_OBJECT_BOOTLOADER_REQUEST,
+    PERSISTENT_OBJECT_RTC_HIGH,           // high 32 bits of rtcTime_t
+    PERSISTENT_OBJECT_RTC_LOW,            // low 32 bits of rtcTime_t
     PERSISTENT_OBJECT_COUNT,
 } persistentObjectId_e;
 

src/main/drivers/usb_msc.h

@@ -31,4 +31,4 @@ bool mscCheckBoot(void);
 uint8_t mscStart(void);
 bool mscCheckButton(void);
 void mscWaitForButton(void);
-void systemResetToMsc(void);
+void systemResetToMsc(int timezoneOffsetMinutes);

src/main/drivers/usb_msc_f4xx.c

@@ -159,11 +159,18 @@ void mscWaitForButton(void)
     }
 }
 
-void systemResetToMsc(void)
+void systemResetToMsc(int timezoneOffsetMinutes)
 {
     *((uint32_t *)0x2001FFF0) = MSC_MAGIC;
 
     __disable_irq();
+
+    // Persist the RTC across the reboot to use as the file timestamp
+#ifdef USE_PERSISTENT_MSC_RTC
+    rtcPersistWrite(timezoneOffsetMinutes);
+#else
+    UNUSED(timezoneOffsetMinutes);
+#endif
     NVIC_SystemReset();
 }
 #endif

src/main/drivers/usb_msc_f7xx.c

@@ -164,11 +164,18 @@ void mscWaitForButton(void)
     }
 }
 
-void systemResetToMsc(void)
+void systemResetToMsc(int timezoneOffsetMinutes)
 {
     *((__IO uint32_t*) BKPSRAM_BASE + 16) = MSC_MAGIC;
 
     __disable_irq();
+
+    // Persist the RTC across the reboot to use as the file timestamp
+#ifdef USE_PERSISTENT_MSC_RTC
+    rtcPersistWrite(timezoneOffsetMinutes);
+#else
+    UNUSED(timezoneOffsetMinutes);
+#endif
     NVIC_SystemReset();
 }
 #endif

src/main/fc/init.c

@@ -58,6 +58,7 @@
 #include "drivers/light_led.h"
 #include "drivers/mco.h"
 #include "drivers/nvic.h"
+#include "drivers/persistent.h"
 #include "drivers/pwm_esc_detect.h"
 #include "drivers/pwm_output.h"
 #include "drivers/rx/rx_pwm.h"
@@ -89,6 +90,10 @@
 #include "interface/cli.h"
 #include "interface/msp.h"
 
+#ifdef USE_PERSISTENT_MSC_RTC
+#include "msc/usbd_storage.h"
+#endif
+
 #include "msp/msp_serial.h"
 
 #include "pg/adc.h"
@@ -428,6 +433,12 @@ void init(void)
     }
 #endif
 
+#ifdef USE_PERSISTENT_MSC_RTC
+    // if we didn't enter MSC mode then clear the persistent RTC value
+    persistentObjectWrite(PERSISTENT_OBJECT_RTC_HIGH, 0);
+    persistentObjectWrite(PERSISTENT_OBJECT_RTC_LOW, 0);
+#endif
+
 #ifdef USE_I2C
     i2cHardwareConfigure(i2cConfig(0));
 

src/main/interface/cli.c

@@ -4483,16 +4483,27 @@ static void cliDiff(char *cmdline)
 #if defined(USE_USB_MSC)
 static void cliMsc(char *cmdline)
 {
-    UNUSED(cmdline);
-
     if (mscCheckFilesystemReady()) {
+#ifdef USE_RTC_TIME
+        int timezoneOffsetMinutes = timeConfig()->tz_offsetMinutes;
+        if (!isEmpty(cmdline)) {
+            timezoneOffsetMinutes = atoi(cmdline);
+            if ((timezoneOffsetMinutes < TIMEZONE_OFFSET_MINUTES_MIN) || (timezoneOffsetMinutes > TIMEZONE_OFFSET_MINUTES_MAX)) {
+                cliPrintErrorLinef("INVALID TIMEZONE OFFSET");
+                return;
+            }
+        }
+#else
+        int timezoneOffsetMinutes = 0;
+        UNUSED(cmdline);
+#endif
         cliPrintHashLine("Restarting in mass storage mode");
         cliPrint("\r\nRebooting");
         bufWriterFlush(cliWriter);
         waitForSerialPortToFinishTransmitting(cliPort);
         stopPwmAllMotors();
 
-        systemResetToMsc();
+        systemResetToMsc(timezoneOffsetMinutes);
     } else {
         cliPrintHashLine("Storage not present or failed to initialize!");
     }
@@ -4598,7 +4609,11 @@ const clicmd_t cmdTable[] = {
 #endif
     CLI_COMMAND_DEF("motor",  "get/set motor", "<index> [<value>]", cliMotor),
 #ifdef USE_USB_MSC
+#ifdef USE_RTC_TIME
+    CLI_COMMAND_DEF("msc", "switch into msc mode", "[<timezone offset minutes>]", cliMsc),
+#else
     CLI_COMMAND_DEF("msc", "switch into msc mode", NULL, cliMsc),
+#endif
 #endif
     CLI_COMMAND_DEF("name", "name of craft", NULL, cliName),
 #ifndef MINIMAL_CLI

src/main/interface/msp.c

@@ -138,6 +138,7 @@ enum {
     MSP_REBOOT_FIRMWARE = 0,
     MSP_REBOOT_BOOTLOADER,
     MSP_REBOOT_MSC,
+    MSP_REBOOT_MSC_UTC,
     MSP_REBOOT_COUNT,
 };
 
@@ -253,8 +254,14 @@ static void mspRebootFn(serialPort_t *serialPort)
         break;
 #if defined(USE_USB_MSC)
     case MSP_REBOOT_MSC:
-        systemResetToMsc();
-
+    case MSP_REBOOT_MSC_UTC: {
+#ifdef USE_RTC_TIME
+        const int16_t timezoneOffsetMinutes = (rebootMode == MSP_REBOOT_MSC) ? timeConfig()->tz_offsetMinutes : 0;
+        systemResetToMsc(timezoneOffsetMinutes);
+#else
+        systemResetToMsc(0);
+#endif
+        }
         break;
 #endif
     default:

src/main/interface/settings.c

@@ -30,6 +30,7 @@
 #include "cms/cms.h"
 
 #include "common/utils.h"
+#include "common/time.h"
 
 #include "drivers/adc.h"
 #include "drivers/bus_i2c.h"
@@ -1266,6 +1267,11 @@ const clivalue_t valueTable[] = {
     { "spektrum_spi_mfg_id",       VAR_UINT8 | MASTER_VALUE | MODE_ARRAY, .config.array.length = 4, PG_RX_SPEKTRUM_SPI_CONFIG, offsetof(spektrumConfig_t, mfgId) },
     { "spektrum_spi_num_channels", VAR_UINT8 | MASTER_VALUE, .config.minmax = { 0, DSM_MAX_CHANNEL_COUNT }, PG_RX_SPEKTRUM_SPI_CONFIG, offsetof(spektrumConfig_t, numChannels) },
 #endif
+
+// PG_TIMECONFIG
+#ifdef USE_RTC_TIME
+    { "timezone_offset_minutes",  VAR_INT16 | MASTER_VALUE, .config.minmax = { TIMEZONE_OFFSET_MINUTES_MIN, TIMEZONE_OFFSET_MINUTES_MAX }, PG_TIME_CONFIG, offsetof(timeConfig_t, tz_offsetMinutes) },
+#endif
 };
 
 const uint16_t valueTableEntryCount = ARRAYLEN(valueTable);

src/main/msc/emfat_file.c

@@ -22,14 +22,18 @@
  * Author: jflyper@github.com
  */
 
-#include "common/utils.h"
-#include "common/printf.h"
-
+#include "platform.h"
 #include "emfat.h"
 #include "emfat_file.h"
 
+#include "common/printf.h"
+#include "common/time.h"
+#include "common/utils.h"
+
 #include "io/flashfs.h"
 
+#include "msc/usbd_storage.h"
+
 #define FILESYSTEM_SIZE_MB 256
 
 #define USE_EMFAT_AUTORUN
@@ -269,6 +273,14 @@ static emfat_entry_t entries[EMFAT_MAX_ENTRY];
 static char logNames[EMFAT_MAX_LOG_ENTRY][8+3];
 
 emfat_t emfat;
+static uint32_t cmaTime = CMA_TIME;
+
+static void emfat_set_entry_cma(emfat_entry_t *entry)
+{
+    entry->cma_time[0] = cmaTime;
+    entry->cma_time[1] = cmaTime;
+    entry->cma_time[2] = cmaTime;
+}
 
 static void emfat_add_log(emfat_entry_t *entry, int number, uint32_t offset, uint32_t size)
 {
@@ -278,10 +290,8 @@ static void emfat_add_log(emfat_entry_t *entry, int number, uint32_t offset, uin
     entry->offset = offset;
     entry->curr_size = size;
     entry->max_size = entry->curr_size;
-    entry->cma_time[0] = CMA_TIME;
-    entry->cma_time[1] = CMA_TIME;
-    entry->cma_time[2] = CMA_TIME;
     entry->readcb = bblog_read_proc;
+    emfat_set_entry_cma(entry);
 }
 
 static int emfat_find_log(emfat_entry_t *entry, int maxCount)
@@ -327,8 +337,17 @@ void emfat_init_files(void)
     emfat_entry_t *entry;
     memset(entries, 0, sizeof(entries));
 
+#ifdef USE_PERSISTENT_MSC_RTC
+    rtcTime_t mscRebootRtc;
+    if (rtcPersistRead(&mscRebootRtc)) {
+        const int32_t rtcSeconds = rtcTimeGetSeconds(&mscRebootRtc);
+        cmaTime = emfat_cma_time_from_unix((uint32_t)rtcSeconds);
+    }
+#endif
+
     for (size_t i = 0 ; i < PREDEFINED_ENTRY_COUNT ; i++) {
         entries[i] = entriesPredefined[i];
+        emfat_set_entry_cma(&entries[i]);
     }
 
     // Detect and create entries for each individual log
@@ -343,6 +362,7 @@ void emfat_init_files(void)
         entry = &entries[entryIndex];
         entry->curr_size = flashfsIdentifyStartOfFreeSpace();
         entry->max_size = entry->curr_size;
+        emfat_set_entry_cma(entry);
         ++entryIndex;
     }
 
@@ -352,6 +372,7 @@ void emfat_init_files(void)
     // used space is doubled because of the individual files plus the single complete file
     entry->curr_size = (FILESYSTEM_SIZE_MB * 1024 * 1024) - (flashfsIdentifyStartOfFreeSpace() * 2);
     entry->max_size = entry->curr_size;
+    emfat_set_entry_cma(entry);
 
     emfat_init(&emfat, "BETAFLT", entries);
 }

src/main/msc/usbd_storage.c

@@ -21,6 +21,9 @@
 /*
  * Author: jflyper (https://github.com/jflyper)
  */
+ 
+#include "platform.h"
+#include "common/time.h"
 
 #ifdef USE_HAL_DRIVER
 #include "usbd_msc.h"

src/main/msc/usbd_storage.h

@@ -27,6 +27,8 @@
 #include "usbd_msc_core.h"
 #endif
 
+#include "common/time.h"
+
 #ifdef USE_HAL_DRIVER
 extern USBD_StorageTypeDef *USBD_STORAGE_fops;
 #ifdef USE_SDCARD_SDIO

src/main/target/common_post.h

@@ -223,3 +223,7 @@
 #define SPI_PREINIT_COUNT 16 // 2 x 8 (GYROx2, BARO, MAG, MAX, FLASHx2, RX)
 #endif
 #endif
+
+#if (!defined(USE_FLASHFS) || !defined(USE_RTC_TIME) || !defined(USE_USB_MSC))
+#undef USE_PERSISTENT_MSC_RTC
+#endif

src/main/target/common_pre.h

@@ -59,6 +59,7 @@
 #define USE_ADC_INTERNAL
 #define USE_USB_CDC_HID
 #define USE_USB_MSC
+#define USE_PERSISTENT_MSC_RTC
 
 #if defined(STM32F40_41xxx) || defined(STM32F411xE)
 #define USE_OVERCLOCK
@@ -78,6 +79,7 @@
 #define USE_ADC_INTERNAL
 #define USE_USB_CDC_HID
 #define USE_USB_MSC
+#define USE_PERSISTENT_MSC_RTC
 #define USE_MCO
 #endif
 

src/test/unit/osd_unittest.cc

@@ -37,6 +37,7 @@ extern "C" {
     #include "common/time.h"
 
     #include "drivers/max7456_symbols.h"
+    #include "drivers/persistent.h"
     #include "drivers/serial.h"
 
     #include "fc/config.h"
@@ -1080,4 +1081,6 @@ extern "C" {
     bool failsafeIsActive(void) { return false; }
     bool gpsRescueIsConfigured(void) { return false; }
     int8_t calculateThrottlePercent(void) { return 0; }
+    uint32_t persistentObjectRead(persistentObjectId_e) { return 0; }
+    void persistentObjectWrite(persistentObjectId_e, uint32_t) {}
 }