unoq: replace flash_mode with wait_for_app

Flash mode (RAM) has always been a hack; get rid of it with a better syncronization with arduino-router and arduino-appl-cli.

If compiled in wait_for_app mode, the sketch will wait until a command like

/opt/openocd/bin/openocd -d2 -s /opt/openocd -s /opt/openocd/share/openocd/scripts -f openocd_gpiod.cfg -c "init; mwb 0x40036400 8; shutdown"

is issued by the Linux side. The storage in BKPSRAM is always assured to be at offset 0

If using remoteocd, no extra command is required

Author: facchinm

boards.txt

@@ -1,6 +1,5 @@
 menu.debug=Debug
 menu.link_mode=Link mode
-menu.flash_mode=Flash mode
 menu.wait_linux_boot=Startup mode
 
 ##########################################################################################
@@ -706,13 +705,11 @@ unoq.menu.link_mode.static=Static
 unoq.menu.link_mode.static.build.link_mode=static
 unoq.menu.link_mode.static.upload.extension=bin-zsk.bin
 
-unoq.menu.flash_mode.flash=Flash
-unoq.menu.flash_mode.flash.openocd_cfg=flash_sketch.cfg
-unoq.menu.flash_mode.ram=RAM
-unoq.menu.flash_mode.ram.openocd_cfg=flash_sketch_ram.cfg
 unoq.menu.wait_linux_boot.yes=Wait for Linux
 unoq.menu.wait_linux_boot.no=Immediate
 unoq.menu.wait_linux_boot.no.build.boot_mode=immediate
+unoq.menu.wait_linux_boot.app=Wait for App
+unoq.menu.wait_linux_boot.app.build.boot_mode=app
 
 unoq.build.zephyr_target=arduino_uno_q
 unoq.build.zephyr_args=
@@ -724,6 +721,8 @@ unoq.build.fpu=-mfpu=fpv5-sp-d16
 unoq.build.architecture=cortex-m33
 unoq.compiler.zephyr.arch.define=
 
+unoq.openocd_cfg=flash_sketch.cfg
+
 unoq.build.float-abi=-mfloat-abi=hard
 unoq.build.extra_flags=
 unoq.build.postbuild.cmd="{tools.imgtool.path}/{tools.imgtool.cmd}" exit

extra/artifacts/_common.json

@@ -30,7 +30,7 @@
     {
       "packager": "arduino",
       "name": "zephyr-sketch-tool",
-      "version": "0.2.1"
+      "version": "0.3.0"
     },
     {
       "packager": "arduino",

loader/main.c

@@ -34,9 +34,10 @@ struct sketch_header_v1 {
 	uint8_t flags;  // @ 0x0e
 } __attribute__((packed));
 
-#define SKETCH_FLAG_DEBUG     0x01
-#define SKETCH_FLAG_LINKED    0x02
-#define SKETCH_FLAG_IMMEDIATE 0x04
+#define SKETCH_FLAG_DEBUG        0x01
+#define SKETCH_FLAG_LINKED       0x02
+#define SKETCH_FLAG_IMMEDIATE    0x04
+#define SKETCH_FLAG_WAIT_FOR_APP 0x08
 
 #define SKETCH_RAM_BUFFER_LEN 131072
 
@@ -110,6 +111,11 @@ __attribute__((retain)) const uintptr_t sketch_max_size = DT_REG_SIZE(DT_NODELAB
 #endif
 __attribute__((retain)) const uintptr_t loader_max_size = LOADER_MAX_SIZE;
 
+struct backup_store {
+	uint32_t wait_for_app_magic;
+};
+volatile __stm32_backup_sram_section struct backup_store backup;
+
 static int loader(const struct shell *sh) {
 	const struct flash_area *fa;
 	int rc;
@@ -194,6 +200,8 @@ static int loader(const struct shell *sh) {
 		char buf_loop;
 	};
 
+	backup.wait_for_app_magic = 0;
+
 	uintptr_t bootanimation_addr = DT_REG_ADDR(DT_GPARENT(DT_NODELABEL(bootanimation))) +
 								   DT_REG_ADDR(DT_NODELABEL(bootanimation));
 
@@ -213,17 +221,6 @@ static int loader(const struct shell *sh) {
 
 		gpio_pin_configure_dt(&spec, GPIO_INPUT | GPIO_PULL_DOWN);
 		k_sleep(K_MSEC(200));
-		uint8_t *ram_firmware = NULL;
-		uint32_t *ram_start = (uint32_t *)0x20000000;
-		if (!sketch_valid) {
-			ram_firmware = (uint8_t *)malloc(SKETCH_RAM_BUFFER_LEN);
-			if (!ram_firmware) {
-				printk("Failed to allocate RAM for firmware\n");
-				return -ENOMEM;
-			}
-			memset(ram_firmware, 0, SKETCH_RAM_BUFFER_LEN);
-			*ram_start = (uint32_t)&ram_firmware[0];
-		}
 		if (gpio_pin_get_dt(&spec) == 0) {
 			matrixBegin();
 			matrixSetGrayscaleBits(8);
@@ -236,15 +233,10 @@ static int loader(const struct shell *sh) {
 			k_sleep(K_MSEC(10));
 			matrixEnd();
 		}
-		while (!sketch_valid) {
-			__asm__("bkpt");
-			// poll the first bytes, if filled try to use them for booting
-			sketch_hdr = (struct sketch_header_v1 *)(ram_firmware + 7);
-			if (sketch_hdr->ver == 0x1 && sketch_hdr->magic == 0x2341) {
-				// Found valid data, use it for booting
-				base_addr = (uintptr_t)ram_firmware;
-				*ram_start = 0;
-				sketch_valid = true;
+
+		if (sketch_hdr->flags & SKETCH_FLAG_WAIT_FOR_APP) {
+			while (backup.wait_for_app_magic == 0) {
+				k_sleep(K_MSEC(100));
 			}
 		}
 	}

platform.txt

@@ -77,6 +77,7 @@ build.zsk_args.debug=
 build.zsk_args.mode-dynamic=
 build.zsk_args.mode-static=-prelinked
 build.zsk_args.startup-mode-wait=
+build.zsk_args.startup-mode-app=-wait_for_app
 build.zsk_args.startup-mode-immediate=-immediate
 
 # These can be overridden in platform.local.txt

variants/arduino_uno_q_stm32u585xx/arduino_uno_q_stm32u585xx.conf

@@ -41,6 +41,8 @@ CONFIG_DYNAMIC_THREAD_ALLOC=y
 
 CONFIG_MAIN_THREAD_PRIORITY=5
 
+CONFIG_STM32_BACKUP_SRAM=y
+
 #CONFIG_VIDEO=y
 #CONFIG_VIDEO_LOG_LEVEL_DBG=y
 #CONFIG_VIDEO_STM32_DCMI=y

variants/arduino_uno_q_stm32u585xx/arduino_uno_q_stm32u585xx.overlay

@@ -44,6 +44,10 @@
 	pinctrl-names = "default";
 };
 
+&backup_sram {
+	status = "okay";
+};
+
 /*
 &dcmi {
 	status = "okay";

variants/arduino_uno_q_stm32u585xx/flash_sketch.cfg

@@ -8,4 +8,6 @@ halt
 flash info 0
 flash write_image erase ${filename} 0x8100000 bin
 reset
+sleep 100
+mww 0x40036400 0xCAFFEEEE
 shutdown