ui: introduce double buffering

Create a new module called "canvas" which is responsible for double
buffering. Double buffering is required to enable asynchronous transfer
of the frame buffer. While the "active" frame buffer is being
transferred to the oled in the background, the ui will render to a
"working" frame buffer. When the rendering is complete the buffers are
flipped with "canvas_commit".

Author: NickeZ

src/CMakeLists.txt

@@ -53,6 +53,7 @@ set(DBB-FIRMWARE-USB-SOURCES ${DBB-FIRMWARE-USB-SOURCES} PARENT_SCOPE)
 set(DBB-FIRMWARE-UI-SOURCES
     ${CMAKE_SOURCE_DIR}/src/screen.c
     ${CMAKE_SOURCE_DIR}/src/ui/graphics/graphics.c
+    ${CMAKE_SOURCE_DIR}/src/ui/canvas.c
     ${CMAKE_SOURCE_DIR}/src/ui/graphics/lock_animation.c
     ${CMAKE_SOURCE_DIR}/src/ui/ugui/ugui.c
     ${CMAKE_SOURCE_DIR}/src/ui/fonts/font_a_9X9.c
@@ -112,6 +113,7 @@ set(DBB-BOOTLOADER-SOURCES
   ${CMAKE_SOURCE_DIR}/src/memory/memory_spi.c
   ${CMAKE_SOURCE_DIR}/src/queue.c
   ${CMAKE_SOURCE_DIR}/src/usb/usb_processing.c
+  ${CMAKE_SOURCE_DIR}/src/ui/canvas.c
   ${CMAKE_SOURCE_DIR}/src/ui/ugui/ugui.c
   ${CMAKE_SOURCE_DIR}/src/ui/fonts/font_a_9X9.c
   ${CMAKE_SOURCE_DIR}/src/ui/fonts/font_a_11X10.c

src/bootloader/bootloader.c

@@ -26,6 +26,7 @@
 #include <screen.h>
 #include <stdint.h>
 #include <string.h>
+#include <ui/canvas.h>
 #include <ui/components/ui_images.h>
 #include <ui/fonts/arial_fonts.h>
 #include <ui/graphics/graphics.h>
@@ -328,15 +329,14 @@ static void _render_message(const char* message, int duration)
 {
     char print[100];
     snprintf(print, sizeof(print), "%s", message);
-    UG_ClearBuffer();
     UG_PutString(0, 0, print, false);
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
     delay_ms(duration);
 }
 
 void bootloader_render_default_screen(void)
 {
-    UG_ClearBuffer();
     _load_logo();
 #if PLATFORM_BITBOX02PLUS == 1
     UG_PutString(0, SCREEN_HEIGHT - 9 * 2 - 5, "See the BitBoxApp", false);
@@ -354,7 +354,8 @@ void bootloader_render_default_screen(void)
     }
     UG_PutString(0, SCREEN_HEIGHT - 9, "See the BitBoxApp", false);
 #endif
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
 }
 
 #if PLATFORM_BITBOX02PLUS
@@ -368,7 +369,6 @@ void bootloader_render_ble_confirm_screen(bool confirmed)
     uint32_t pairing_code_int = (*(uint32_t*)&bootloader_pairing_code_bytes[0]) % 1000000;
     char code_str[10] = {0};
     snprintf(code_str, sizeof(code_str), "%06u", (unsigned)pairing_code_int);
-    UG_ClearBuffer();
     uint16_t check_width = IMAGE_DEFAULT_CHECKMARK_HEIGHT + IMAGE_DEFAULT_CHECKMARK_HEIGHT / 2 - 1;
     if (confirmed) {
         UG_PutString(15, 0, "Confirm on app", false);
@@ -380,13 +380,13 @@ void bootloader_render_ble_confirm_screen(bool confirmed)
     UG_FontSelect(&font_monogram_5X9);
     UG_PutString(45, SCREEN_HEIGHT / 2 - 9, code_str, false);
     UG_FontSelect(&font_font_a_9X9);
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
 }
 #endif
 
 static void _render_progress(float progress)
 {
-    UG_ClearBuffer();
     _load_logo();
     if (progress > 0) {
         char label[5] = {0};
@@ -401,7 +401,8 @@ static void _render_progress(float progress)
         msg = "INSTALLING";
     }
     UG_PutString(SCREEN_WIDTH / 2 - 3, SCREEN_HEIGHT - 9 * 2, msg, false);
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
 }
 
 static void _render_hash(const char* title, const uint8_t* hash)
@@ -433,7 +434,6 @@ static void _render_hash(const char* title, const uint8_t* hash)
         &hash_hex[48]);
 
     for (uint8_t i = 1; i <= seconds; i++) {
-        UG_ClearBuffer();
         UG_PutString(0, 0, title, false);
 
         snprintf(timer_buf, sizeof(timer_buf), "%ds", seconds - i);
@@ -449,7 +449,8 @@ static void _render_hash(const char* title, const uint8_t* hash)
 
         UG_FontSelect(f_regular);
 
-        UG_SendBuffer();
+        canvas_commit();
+        oled_blit();
         delay_ms(1000);
     }
     bootloader_render_default_screen();
@@ -1013,7 +1014,6 @@ static void _check_init(boot_data_t* data)
 #ifdef BOOTLOADER_DEVDEVICE
 static bool _devdevice_enter(secbool_u32 firmware_verified)
 {
-    UG_ClearBuffer();
     UG_PutString(0, 0, "    <Enter bootloader>", false);
     UG_PutString(0, SCREEN_HEIGHT / 2 - 11, "DEV DEVICE", false);
     UG_PutString(0, SCREEN_HEIGHT / 2 + 2, "NOT FOR VALUE", false);
@@ -1043,7 +1043,8 @@ static bool _devdevice_enter(secbool_u32 firmware_verified)
         UG_DrawLine(xpos + 5, ypos, xpos, ypos + 5, C_WHITE);
         UG_DrawLine(xpos - 2, ypos + 3, xpos, ypos + 5, C_WHITE);
     }
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
     while (true) {
         do {
             qtouch_process();

src/bootloader/startup.c

@@ -22,6 +22,7 @@
 #include <rust/rust.h>
 #include <screen.h>
 #include <string.h>
+#include <ui/canvas.h>
 #include <ui/oled/oled.h>
 #include <usb/class/hid/hww/hid_hww.h>
 #include <usb/usb_processing.h>
@@ -83,7 +84,7 @@ int main(void)
     bootloader_init();
     platform_init();
     __stack_chk_guard = rand_sync_read32(&RAND_0);
-    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
+    screen_init(oled_set_pixel, oled_mirror);
 #if defined(BOOTLOADER_DEVDEVICE) || PLATFORM_BITBOX02PLUS == 1
     qtouch_init();
 #endif
@@ -189,7 +190,6 @@ int main(void)
 
             if (qtouch_is_scroller_active(top_slider)) {
                 bool ok;
-                UG_ClearBuffer();
                 if (qtouch_get_scroller_position(top_slider) < 127) {
                     bootloader_render_default_screen();
                     ok = false;
@@ -218,7 +218,8 @@ int main(void)
                     ringbuffer_put(&uart_write_queue, tmp[i]);
                 }
                 bootloader_pairing_request = false;
-                UG_SendBuffer();
+                canvas_commit();
+                oled_blit();
             }
         }
 #endif

src/factorysetup.c

@@ -577,7 +577,7 @@ int main(void)
     system_init();
     platform_init();
     __stack_chk_guard = common_stack_chk_guard();
-    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
+    screen_init(oled_set_pixel, oled_mirror);
     screen_splash();
     common_main();
 

src/firmware.c

@@ -41,7 +41,7 @@ int main(void)
     system_init();
     platform_init();
     __stack_chk_guard = common_stack_chk_guard();
-    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
+    screen_init(oled_set_pixel, oled_mirror);
     screen_splash();
     qtouch_init();
     common_main();

src/reset.c

@@ -23,12 +23,14 @@
 #include "system.h"
 #include "uart.h"
 #include <screen.h>
+#include <ui/canvas.h>
 
 #ifndef TESTING
 #include "securechip/securechip.h"
 #include <driver_init.h>
 #include <hal_delay.h>
 #include <ui/components/status.h>
+#include <ui/oled/oled.h>
 #include <ui/ugui/ugui.h>
 #endif
 
@@ -41,9 +43,10 @@ static void _show_reset_label(bool status)
 {
     const char* msg = "Device reset";
     component_t* comp = status_create(msg, status, NULL, NULL);
-    screen_clear();
+    canvas_clear();
     comp->f->render(comp);
-    UG_SendBuffer();
+    canvas_commit();
+    oled_blit();
     comp->f->cleanup(comp);
     delay_ms(3000);
 }

src/rust/bitbox02-rust/src/general/screen.rs

@@ -14,13 +14,14 @@
 
 use core::time::Duration;
 
-use bitbox02::{delay, ug_clear_buffer, ug_font_select_9x9, ug_put_string, ug_send_buffer};
+use bitbox02::{canvas_clear, canvas_commit, delay, oled_blit, ug_font_select_9x9, ug_put_string};
 
 pub fn print_debug_internal(duration: Duration, msg: &str) {
-    ug_clear_buffer();
+    canvas_clear();
     ug_font_select_9x9();
     ug_put_string(0, 0, msg, false);
-    ug_send_buffer();
+    canvas_commit();
+    oled_blit();
     delay(duration);
 }
 

src/rust/bitbox02-sys/build.rs

@@ -53,14 +53,14 @@ const ALLOWLIST_TYPES: &[&str] = &[
 ];
 
 const ALLOWLIST_FNS: &[&str] = &[
-    "UG_ClearBuffer",
     "UG_FontSelect",
     "UG_PutString",
-    "UG_SendBuffer",
     "bip32_derive_xpub",
     "bitbox02_smarteeprom_init",
     "bitbox_secp256k1_dleq_prove",
     "bitbox_secp256k1_dleq_verify",
+    "canvas_clear",
+    "canvas_commit",
     "confirm_create",
     "confirm_transaction_address_create",
     "confirm_transaction_fee_create",
@@ -114,6 +114,7 @@ const ALLOWLIST_FNS: &[&str] = &[
     "memory_get_platform",
     "memory_get_securechip_type",
     "memory_spi_get_active_ble_firmware_version",
+    "oled_blit",
     "spi_mem_protected_area_write",
     "menu_create",
     "fake_memory_factoryreset",
@@ -199,6 +200,7 @@ const BITBOX02_SOURCES: &[&str] = &[
     "src/u2f.c",
     "src/u2f/u2f_app.c",
     "src/u2f/u2f_packet.c",
+    "src/ui/canvas.c",
     "src/ui/components/button.c",
     "src/ui/components/confirm_gesture.c",
     "src/ui/components/confirm_transaction.c",
@@ -402,6 +404,7 @@ pub fn main() -> Result<(), &'static str> {
         "test/hardware-fakes/src/fake_component.c",
         "test/hardware-fakes/src/fake_diskio.c",
         "test/hardware-fakes/src/fake_memory.c",
+        "test/hardware-fakes/src/fake_oled.c",
         "test/hardware-fakes/src/fake_qtouch.c",
         "test/hardware-fakes/src/fake_screen.c",
         "test/hardware-fakes/src/fake_securechip.c",

src/rust/bitbox02-sys/wrapper.h

@@ -29,6 +29,7 @@
 #include <securechip/securechip.h>
 #include <system.h>
 #include <time.h>
+#include <ui/canvas.h>
 #include <ui/components/confirm.h>
 #include <ui/components/confirm_transaction.h>
 #include <ui/components/empty.h>

src/rust/bitbox02/src/lib.rs

@@ -62,12 +62,16 @@ pub fn ug_put_string(x: i16, y: i16, input: &str, inverted: bool) {
     }
 }
 
-pub fn ug_clear_buffer() {
-    unsafe { bitbox02_sys::UG_ClearBuffer() }
+pub fn canvas_clear() {
+    unsafe { bitbox02_sys::canvas_clear() }
 }
 
-pub fn ug_send_buffer() {
-    unsafe { bitbox02_sys::UG_SendBuffer() }
+pub fn canvas_commit() {
+    unsafe { bitbox02_sys::canvas_commit() }
+}
+
+pub fn oled_blit() {
+    unsafe { bitbox02_sys::oled_blit() }
 }
 
 pub fn ug_font_select_9x9() {