at32f43x: Add detection of AT32F405/402 and basic support (no USD)

* All of SRAM is declared regardless of parity checking
* Two flash sizes are detected from idcode
* DEBUG sleep and watchdog bits handling is enabled

src/target/at32f43x.c

@@ -25,6 +25,8 @@
  * References:
  * AT32F435/437 Series Reference Manual
  *   https://www.arterychip.com/download/RM/RM_AT32F435_437_EN_V2.04.pdf
+ * AT32F402/405 Series Reference Manual
+ *   https://www.arterychip.com/download/RM/RM_AT32F402_405_EN_V2.01.pdf
  */
 
 #include "general.h"
@@ -89,6 +91,9 @@ static bool at32f43_mass_erase(target_s *target);
 #define AT32F43x_2K_OB_COUNT 256U
 #define AT32F43x_4K_OB_COUNT 2048U
 
+#define AT32F405_USD_BASE 0x1ffff800U
+#define AT32F405_OB_COUNT 256U
+
 /*
  * refman: DEBUG has 5 registers, of which CTRL, APB1_PAUSE, APB2_PAUSE are
  * "asynchronously reset by POR Reset (not reset by system reset). It can be written by the debugger under reset."
@@ -114,6 +119,8 @@ static bool at32f43_mass_erase(target_s *target);
 #define AT32F4x_IDCODE_PART_MASK   0x00000fffU
 #define AT32F43_SERIES_4K          0x70084000U
 #define AT32F43_SERIES_2K          0x70083000U
+#define AT32F405_SERIES_256KB      0x70053000U
+#define AT32F405_SERIES_128KB      0x70042000U
 #define AT32F4x_PROJECT_ID         0x1ffff7f3U
 #define AT32F4x_FLASHSIZE          0x1ffff7e0U
 
@@ -292,6 +299,37 @@ static bool at32f43_detect(target_s *target, const uint16_t part_id)
 	return true;
 }
 
+/* Identify AT32F405 Mainstream devices */
+static bool at32f405_detect(target_s *target, const uint32_t series)
+{
+	/*
+	 * AT32F405/F402 always contain 1 bank with 128 sectors
+	 * Flash (C): 256 KiB, 2 KiB per sector, 0x7005_3000
+	 * Flash (B): 128 KiB, 1 KiB per sector, 0x7004_2000
+	 */
+	const uint16_t flash_size = target_mem32_read16(target, AT32F4x_FLASHSIZE);
+	const uint16_t sector_size = (series == AT32F405_SERIES_128KB) ? 1024U : 2048U;
+	at32f43_add_flash(target, 0x08000000, flash_size, sector_size, 0, AT32F43x_FLASH_BANK1_REG_OFFSET);
+
+	/*
+	 * Either 96 or 102 KiB of SRAM, depending on USD bit 7 nRAM_PRT_CHK:
+	 * when first 48 KiB are protected by odd parity, last 6 KiB are reserved for this purpose
+	 */
+	target_add_ram32(target, 0x20000000, 102U * 1024U);
+	target->driver = "AT32F405";
+	target->mass_erase = at32f43_mass_erase;
+
+	/* 512 byte User System Data area at 0x1fff_f800 (different USD_BASE, no EOPB0) */
+	//target_add_commands(target, at32f43_cmd_list, target->driver);
+
+	/* Same registers and freeze bits in DBGMCU as F437 */
+	target->attach = at32f43_attach;
+	target->detach = at32f43_detach;
+	at32f43_configure_dbgmcu(target);
+
+	return true;
+}
+
 /* Identify any Arterytek devices with Cortex-M4 and FPEC at 0x4002_3c00 */
 bool at32f43x_probe(target_s *target)
 {
@@ -311,6 +349,10 @@ bool at32f43x_probe(target_s *target)
 	/* 0x0e: F437 (has EMAC), 0x0d: F435 (no EMAC). 4K/2K describe sector sizes, not total flash capacity. */
 	if ((series == AT32F43_SERIES_4K || series == AT32F43_SERIES_2K) && (project_id == 0x0dU || project_id == 0x0eU))
 		return at32f43_detect(target, part_id);
+	/* 0x13: F405 (has USB HS), 0x14: F402 (no USB HS) */
+	if ((series == AT32F405_SERIES_256KB || series == AT32F405_SERIES_128KB) &&
+		(project_id == 0x13U || project_id == 0x14U))
+		return at32f405_detect(target, series);
 
 	return false;
 }