Issue #18: Check error memory entries at safety ram init

doc/source/firmware/backup-ram.rst

@@ -68,19 +68,22 @@ Weight override         ``0xA2``      ``Weight``       ``Flag Number``       res
 Persistance override    ``0x8E``      ``Persistance``  ``Flag Number``       reserved don't care (written as 0xBB) 
 ======================= ============ ================= ===================== =====================================
 
+All words, not matching the table above are ignored and do not cause an error. By default the firmware fills this memory area with zeroes.
 
 Error Memory
 ~~~~~~~~~~~~
 
 The error memory contains error entries in form of 32 bit words. The entries are coded as stated below.
 
-``Error Flag`` entries are used to restore error flags after boot. In theory, all flags can be set using this entry type,
+``Error Flag`` entries are used to restore error flags after boot. In theory, all flags can be set using this entry type.
-however, only persistent flags are stored in the error memory by the firmware.
+However, only persistent flags are stored in the error memory by the firmware.
 
 ``NOP`` entries have no meaning. They are used as a filler. When adding a new error memory entry, the error memory is scanned until the first ``NOP`` entry is found.
 It is replaced with a valid entry. If the error memory contains a word, that is not defined below, it is considered invalid and will trigger the RAM checker on boot.
-``NOP`` entries can be used to preallocate the error memory in advance.
+``NOP`` entries can be used to preallocate the error memory in advance. if the end of the error memory is reached, it is expanded by 1 word to first
+the new error entry, until the backup RAM is full. After this, no further errors are stored.
 
+If the same persistent error is triggered mutliple times, the ``COUNTER`` in the error entry is incremented.
 
 ======================= ============ ================= ===================== =====================================
 Entry                   Byte 1 (LSB) Byte 2            Byte 3                Byte 4 (MSB)

stm-firmware/include/reflow-controller/safety/safety-memory.h

@@ -28,6 +28,11 @@
  */
 #define SAFETY_MEMORY_MAGIC 0x12AA5CB7
 
+/**
+ * @brief Error memory NOP entry
+ */
+#define SAFETY_MEMORY_NOP_ENTRY 0xC1AA1222
+
 /**
  * @brief Offset address for the safety_memory_header.
  * @note Any other value than 0UL doesn't really make sense. Therfore, this should not be changed.

stm-firmware/main.c

@@ -154,14 +154,12 @@ static inline void setup_system(void)
 	setup_nvic_priorities();
 	systick_setup();
 
-
 	oven_driver_init();
 	digio_setup_default_all();
 	led_setup();
 	loudspeaker_setup();
 	reflow_menu_init();
 
-
 	uart_gpio_config();
 	setup_shell_uart(&shell_uart);
 

stm-firmware/safety/safety-memory.c

@@ -239,6 +239,35 @@ int safety_memory_set_boot_status(const struct safety_memory_boot_status *status
 	return 0;
 }
 
+static int safety_memory_check_error_entries()
+{
+	struct safety_memory_header header;
+	uint32_t addr;
+	uint32_t data;
+	int ret = 0;
+	int res;
+
+	if (safety_memory_get_header(&header) != SAFETY_MEMORY_INIT_VALID_MEMORY) {
+		return -2000;
+	}
+
+	for (addr = header.err_memory_offset; addr < header.err_memory_end; addr++) {
+		res = backup_ram_get_data(addr, &data, 1UL);
+		if (res)
+			return -100;
+
+		/* Valid flag entry */
+		if ((data & 0xFF) == 0x51)
+			continue;
+		if (data == SAFETY_MEMORY_NOP_ENTRY)
+			continue;
+
+		ret--;
+	}
+
+	return ret;
+}
+
 int safety_memory_get_error_entry_count(uint32_t *count);
 
 int safety_memory_check(void)
@@ -246,6 +275,10 @@ int safety_memory_check(void)
 	int res;
 
 	res = safety_memory_check_crc();
+	if (!res) {
+		res |= safety_memory_check_error_entries();
+	}
+
 	return -!!res;
 }