Fernly runs on MT6261

Makefile

@@ -1,13 +1,19 @@
 include mkenv.mk
 include magic.mk
 
+# isogashii:
+BUILD = build
+CROSS_COMPILE=arm-none-eabi-
+
 CFLAGS = -march=armv5te -mfloat-abi=soft -Wall \
-	 -Os -ggdb -Iinclude -marm -fno-stack-protector
+	 -Os -Iinclude -marm -fno-stack-protector
 AFLAGS = 
 
 LDFLAGS = --nostdlib -T fernvale.ld
 LIBS = lib/libgcc-armv5.a
 
+STAGE1_LDFLAGS = --nostdlib -T stage1.ld
+
 SRC_C = \
 	bionic.c \
 	cmd-hex.c \
@@ -42,7 +48,19 @@ SRC_S = \
 
 OBJ = $(addprefix $(BUILD)/, $(SRC_S:.S=.o) $(SRC_C:.c=.o))
 
+STAGE1_SRC_C = \
+	stage1.c \
+	serial.c \
+	vectors.c
+
+STAGE1_SRC_S = \
+	start.S
+
+STAGE1_OBJ = $(addprefix $(BUILD)/, $(STAGE1_SRC_S:.S=.o) $(STAGE1_SRC_C:.c=.o))
+
 all: $(BUILD)/firmware.bin \
+	$(BUILD)/stage1.bin \
+	$(BUILD)/dump-rom-usb.bin \
 	$(BUILD)/usb-loader.bin \
 	$(BUILD)/mt6261-test.bin \
 	$(BUILD)/fernly-usb-loader
@@ -62,6 +80,12 @@ $(BUILD)/firmware.bin: $(BUILD)/firmware.elf
 $(BUILD)/firmware.elf: $(OBJ)
 	$(LD) $(LDFLAGS) --entry=reset_handler -o $@ $(OBJ) $(LIBS)
 
+$(BUILD)/stage1.bin: $(BUILD)/stage1.elf
+	$(OBJCOPY) -S -O binary $(BUILD)/stage1.elf $@
+
+$(BUILD)/stage1.elf: $(STAGE1_OBJ)
+	$(LD) $(STAGE1_LDFLAGS) --entry=reset_handler -o $@ $(STAGE1_OBJ) $(LIBS)
+
 $(OBJ): $(HEADER_BUILD)/generated.h | $(OBJ_DIRS)
 $(HEADER_BUILD)/generated.h: | $(HEADER_BUILD)
 	  touch $@

README.md

@@ -26,6 +26,43 @@ For example:
     make CROSS_COMPILE=arm-none-linux-gnueabi-
 
 
+Running on MT6261 devices
+-------------------------
+
+To run the Fernly shell on an MT6261 device, follow the instructions below
+except that the command would be:
+
+    build/fernly-usb-loader -s /dev/fernvale build/stage1.bin build/firmware.bin
+
+Stage1.bin uses Fernly's own USR serial I/O code instead of calling ROM
+routines, allowing Fernly to load at address 0x70000000 at the bottom of
+RAM. This is helpful-bordering-on-necessary because of the size of Fernly
+and the smaller RAM capacity of the MT6261 compared to the 6260. The ROM
+routines can't load this low because that area is used for their buffer
+memory and program variables.
+
+To capture the contents of ROM, run the command:
+
+    build/fernly-usb-loader /dev/fernvale build/dump-rom-usb.bin
+
+Capture the output to a text file, edit out the diagnostic lines from
+fernly-usb-loader, prepend the one line:
+
+data = [
+
+and append the six lines:
+
+]
+
+f = open('rom.bin','wb')
+for s in data:
+  f.write(chr(int(s,16)))
+f.close()
+
+Save it as a file with a ".py" suffix and run it as a Python script.
+It will save the binary rom image as the file "rom.bin".
+
+
 Running Fernly
 --------------
 

dump-rom-usb.S

@@ -0,0 +1,92 @@
+.text
+
+.global _start
+_start:
+disable_interrupts:
+	mrs	r0, cpsr
+	mov	r1, #0xc0
+	orr	r0, r0, r1
+	msr	cpsr_cxsf, r0
+
+relocate_stack:
+        ldr     r0, =0x70009ffc // stack_start
+	mov     sp, r0
+
+dump_memory:
+	bl	output_newline
+
+	ldr     r7, =0xfff00000 // start address
+	add	r8, r7, #0x8800  // count
+	mov	r5, #0
+
+encode_hex_loop:
+# hex encoding borrowed from gcc output:
+	ldrb	r2, [r7], #1
+	mov	r1, r2, lsr #4
+	add	r1, r1, #48
+	and	r2, r2, #15
+	add	r2, r2, #48
+	cmp	r1, #57
+	addhi	r1, r1, #39
+	cmp	r2, #57
+	addhi	r2, r2, #39
+
+        adr     r0, hex_msg
+        strb    r1, [r0, #1]
+        strb    r2, [r0, #2]
+        bl      output_hex
+
+	add	r5, r5, #1
+	tst	r5, #15
+	bleq	output_newline
+
+	cmp	r7, r8
+	bne	encode_hex_loop
+
+	bl	output_banner
+
+        bl      reboot
+error:
+        b       error
+
+output_hex:
+	adr	r0, hex_msg
+	mov	r1, #6
+
+	b	usb_out
+
+output_banner:
+	adr	r0, fake_banner
+	mov	r1, #11
+
+	b	usb_out
+
+output_newline:
+	adr	r0, newline_msg
+	mov	r1, #1
+
+usb_out:
+        push    {lr}
+
+# void usb_uart_write(char *data, int bytes, int timeout)
+	ldr	r3, =0xfff00b7f
+	blx	r3
+
+# void usb_uart_flush(void)
+	ldr	r3, =0xfff01cb1
+	blx	r3
+
+	pop	{lr}
+	bx	lr
+
+        // trigger WDT reboot
+reboot:
+        ldr     r0, =0xa003001c
+        ldr     r1, =0x1209
+        str     r1, [r0]
+        bx      lr              // shouldn't get here
+
+hex_msg: 	.asciz	"\"xx\", "
+newline_msg: 	.asciz "\n"
+fake_banner:	.asciz	"# >"
+

fernly-usb-loader.c

@@ -19,7 +19,7 @@
 #define STAGE_2_WRITE_SIZE 1
 #define STAGE_3_WRITE_ALL_AT_ONCE 1 /* Write stage 3 in one write() */
 #define STAGE_3_WRITE_SIZE 1
-#define FERNLY_USB_LOADER_ADDR 0x7000a000
+#define FERNLY_USB_LOADER_ADDR 0x70009000
 
 #define ASSERT(x) do { if ((x)) exit(1); } while(0)
 
@@ -937,6 +937,8 @@ int fernvale_set_serial(int serfd) {
 	cfsetispeed(&t, BAUDRATE);
 	cfsetospeed(&t, BAUDRATE);
 	cfmakeraw(&t);
+	t.c_cc[VMIN] = 0;
+	t.c_cc[VTIME] = 100;	// timeout in deciseconds.. that's 10 sec
 	ret = tcsetattr(serfd, TCSANOW, &t);
 	if (-1 == ret) {
 		perror("Failed to set attributes");
@@ -956,7 +958,9 @@ static int fernvale_wait_banner(int fd, const char *banner, int banner_size) {
 	int i;
 
 	while (1 == read(fd, &buf[offset], 1)) {
-
+
+		printf("%c", buf[offset]);
+
 		tst = (offset + 1) % sizeof(buf);
 
 		i = 0;
@@ -1459,12 +1463,14 @@ static void cmd_end_fmt(const char *fmt, ...) {
 
 static void print_help(const char *name)
 {
-	printf("Usage: %s [-l logfile] [-s] [serial port] "
+	printf("Usage: %s [-a address] [-l logfile] [-s] [serial port] "
 			"[stage 1 bootloader] "
 			"[[stage 2 bootloader]] "
 			"[payload]\n", name);
 	printf("\n");
 	printf("Arguments:\n");
+	printf("    -a [address]      Set load address for stage 1 bootloader (default: 0x%x)\n",
+		FERNLY_USB_LOADER_ADDR);
 	printf("    -l [logfile]      Log boot output to the specified file\n");
 	printf("    -w                Wait for serial port to appear\n");
 	printf("    -s                Enter boot shell\n");
@@ -1482,17 +1488,23 @@ static void print_help(const char *name)
 }
 
 int main(int argc, char **argv) {
-	int serfd, binfd, s1blfd, payloadfd = -1, logfd = -1;
+	int serfd, binfd = -1, s1blfd, payloadfd = -1, logfd = -1;
 	char *logname = NULL;
 	uint32_t ret;
 	int opt;
 	int shell = 0;
 	int wait_serial = 0;
 	int factory_test = 0;
 
-	while ((opt = getopt(argc, argv, "hl:swt")) != -1) {
+	uint32_t usb_loader_addr = FERNLY_USB_LOADER_ADDR;
+
+	while ((opt = getopt(argc, argv, "a:hl:swt")) != -1) {
 		switch(opt) {
 
+		case 'a':
+			usb_loader_addr = strtoul(optarg, NULL, 0);
+			break;
+
 		case 'l':
 			logname = strdup(optarg);
 			break;
@@ -1521,7 +1533,8 @@ int main(int argc, char **argv) {
 	argc -= (optind - 1);
 	argv += (optind - 1);
 
-	if ((argc != 4) && (argc != 5)) {
+	if ((argc != 3) && (argc != 4) && (argc != 5)) {
+                printf("%d is wrong # of args\n", argc);
 		exit(1);
 	}
 
@@ -1554,10 +1567,12 @@ int main(int argc, char **argv) {
 		exit(1);
 	}
 
-	binfd = open(argv[3], O_RDONLY);
-	if (-1 == binfd) {
-		perror("Unable to open firmware file");
-		exit(1);
+	if (argc == 4 || argc == 5) {
+		binfd = open(argv[3], O_RDONLY);
+		if (-1 == binfd) {
+			perror("Unable to open firmware file");
+			exit(1);
+		}
 	}
 
 	if (argc == 5) {
@@ -1681,20 +1696,30 @@ int main(int argc, char **argv) {
 	cmd_end_fmt("0x%04x", ret);
 
 	cmd_begin("Loading Fernly USB loader");
-	ASSERT(fernvale_cmd_send_fd(serfd, FERNLY_USB_LOADER_ADDR, s1blfd));
+	ASSERT(fernvale_cmd_send_fd(serfd, usb_loader_addr, s1blfd));
 	cmd_end();
 
 	cmd_begin("Executing Ferly USB loader");
-	ASSERT(fernvale_cmd_jump(serfd, FERNLY_USB_LOADER_ADDR));
+	ASSERT(fernvale_cmd_jump(serfd, usb_loader_addr));
 	cmd_end();
 
 	cmd_begin("Waiting for Fernly USB loader banner");
 	ASSERT(fernvale_wait_banner(serfd, ">", 1));
 	cmd_end();
 
-	cmd_begin("Writing stage 2");
-	ASSERT(fernvale_write_stage2(serfd, binfd));
-	cmd_end();
+	if (binfd == -1) {
+		close(serfd);
+		return 0;
+	}
+
+// you can change this to "#if 0" during testing, at times when
+// you don't expect or need Fernly USB loader to actually work
+#if 1
+	if (binfd != -1) {
+		cmd_begin("Writing stage 2");
+		ASSERT(fernvale_write_stage2(serfd, binfd));
+		cmd_end();
+	}
 
 	if (factory_test) {
 		cmd_begin("Starting factory test");
@@ -1714,6 +1739,7 @@ int main(int argc, char **argv) {
 	}
 
 	if (shell) {
+		cmd_begin("Start Fernly shell");
 		uint8_t bfr;
 		int ret;
 		struct termios t;
@@ -1762,6 +1788,8 @@ int main(int argc, char **argv) {
 			if (FD_ISSET(STDIN_FILENO, &rfds)) {
 				if (1 != read(STDIN_FILENO, &bfr, sizeof(bfr)))
 					break;
+				if (bfr == 0x3)
+					break;
 				write(serfd, &bfr, sizeof(bfr));
 			}
 		}
@@ -1771,6 +1799,8 @@ int main(int argc, char **argv) {
 		fernvale_wait_banner(serfd, prompt, strlen(prompt));
 		cmd_end();
 	}
+#endif
+
 	close(serfd);
 	return 0;
 }

fernvale.ld

@@ -39,7 +39,7 @@ SECTIONS
 {
 	/* The OS entry point is here */
 
-	. = 0x70006000; /* bootloader will copy data to this address */
+	. = 0x70000000; /* bootloader will copy data to this address */
 	.text : {
 		_stext = ABSOLUTE(.);
 		KEEP(*(vectors))