PASS1-139: Implement code to allow OCD to capture a screenshot over JTAG

ports/stm32/Justfile

@@ -55,6 +55,9 @@ clean:
 run-ocd-command command:
     sudo /usr/local/bin/openocd -f stlink.cfg -c "adapter speed 1000; transport select hla_swd" -f stm32h7x.cfg -c "init; reset halt; {{command}}" -c "exit"
 
+run-ocd-command-no-halt command:
+    sudo /usr/local/bin/openocd -f stlink.cfg -c "adapter speed 1000; transport select hla_swd" -f stm32h7x.cfg -c "init; {{command}}" -c "exit"
+
 # Build all Python graphics
 graphics-py:
     just -f boards/Passport/graphics/py/Justfile build
@@ -127,3 +130,41 @@ fmt-c:
 
 # Format the project's source code under boards/Passport
 fmt: fmt-py fmt-c
+
+# Convert a raw pixel map to a PNG
+convert-screenshot from_file to_file:
+    #!/usr/bin/python3
+    from PIL import Image, ImageOps
+    raw_bits = open('{{from_file}}', 'rb').read()
+    WIDTH = 230
+    HEIGHT = 303
+    SCAN_WIDTH = 240
+
+    # Convert
+    img = Image.frombuffer('1', (SCAN_WIDTH, HEIGHT), raw_bits)
+
+    # Crop to actual width (framebuffer is 240 vs 230 for actual display)
+    img = img.crop((0, 0, WIDTH, HEIGHT))
+
+    # Invert since raw image is actually white on black - have to convert to grayscale first since invert() doesn't work
+    # for 1-bit per pixel black/white images.
+    img = ImageOps.grayscale(img)
+    img = ImageOps.invert(img)
+
+    # Apply a color shift to make it look nicer
+    img = ImageOps.colorize(img, (0,0,0,0), '#E0E0E0')
+
+    img.save('{{to_file}}')
+
+# Capture a screenshot from Passport via OCD
+screenshot filename:
+    #!/usr/bin/env bash
+    ADDR_FILE=screenshot-addr.tmp
+    TMP_FILE=screenshot.tmp
+    just run-ocd-command-no-halt "dump_image $ADDR_FILE 0x38006920 4"
+    N=`head -c 4 $ADDR_FILE | od -An --endian=little -t u4`
+    FRAMEBUFFER_ADDR=`printf '%x\n' $N`
+    echo FRAMEBUFFER_ADDR=$FRAMEBUFFER_ADDR
+    just run-ocd-command-no-halt "dump_image screenshot.tmp 0x$FRAMEBUFFER_ADDR 9090"
+    just convert-screenshot $TMP_FILE {{filename}}
+    rm -f $TMP_FILE $ADDR_FILE

ports/stm32/boards/Passport/modfoundation.c

@@ -205,6 +205,8 @@ const mp_obj_type_t keypad_type = {
 /*=============================================================================
  * Start of LCD class
  *=============================================================================*/
+#define FRAMEBUFFER_ADDR_SRAM4 0x38006920 // NOTE: If SRAM4 layout changes, this must change too!
+
 void
 lcd_obj_print(const mp_print_t* print, mp_obj_t self_in, mp_print_kind_t kind)
 {
@@ -224,6 +226,18 @@ lcd_obj_make_new(const mp_obj_type_t* type, size_t n_args, size_t n_kw, const mp
     lcd->base.type = &lcd_type;
     lcd->spi = &spi_obj[0];
     // lcd_init(false);
+
+    // If a framebuffer address was passed, save it to a known location
+    if (n_args == 1) {
+        // Get the buffer info from the passed in object
+        mp_buffer_info_t framebuffer_info;
+        mp_get_buffer_raise(args[0], &framebuffer_info, MP_BUFFER_READ);
+
+        // Save the actual address
+        uint32_t* framebuffer_addr = (uint32_t*)FRAMEBUFFER_ADDR_SRAM4;
+        *framebuffer_addr = (uint32_t)(framebuffer_info.buf);
+    }
+
     return MP_OBJ_FROM_PTR(lcd);
 }
 

ports/stm32/boards/Passport/modules/display.py

@@ -42,11 +42,11 @@ class Display:
 
     def __init__(self):
         # Setup frame buffer, in show we will call scrn.update(self.dis) to show the buffer
-        self.scrn = LCD()
-
         self.dis = framebuf.FrameBuffer(bytearray(
             self.LINE_SIZE_BYTES * self.HEIGHT), self.FB_WIDTH, self.HEIGHT, framebuf.MONO_HLSB)
 
+        self.scrn = LCD(self.dis)
+
         self.backlight = Backlight()
 
         self.clear()

ports/stm32/boards/Passport/modules/sram4.py

@@ -36,5 +36,7 @@ flash_cache_buf = _alloc(16 * 1024)
 tmp_buf = _alloc(1024)
 psbt_tmp256 = _alloc(256)
 viewfinder_buf = _alloc((VIEWFINDER_WIDTH*VIEWFINDER_HEIGHT) // 8)
+framebuffer_addr = _alloc(4) # Address of the frmebuffer memory so we can read it from OCD
+
 
 assert _start <= SRAM4_END