Merge pull request #100 from trilitech/palmer@functori@reintroduce-th…

…e-custom-screensaver

Reintroduce the custom screensaver

README.md

@@ -457,6 +457,14 @@ $ octez-client list connected ledgers
 
 ## How the app works
 
+### Screen saver
+
+The screen saver is the one provided by Ledger ([Configure screen saver timeout](https://support.ledger.com/hc/en-us/articles/360017152034-Configure-PIN-lock-and-screen-saver?docs=true)).
+
+On Nanos devices, the Ledger screensaver can slow down the baking app. This is why it is deactivated during signings.
+After a signature, a low-cost screensaver will take over. It will switch the screen off after 20 seconds of inactivity.
+Press any button to exit sleep mode. When the sleep mode is exited, the Ledger screen saver will take over again if there are no more signatures.
+
 ### High water mark (HWM)
 
 To avoid double baking, double attestation and double pre-attestation, the application maintains a high water mark (HWM) corresponding to the last level/round encountered during signature requests. The HWMs are displayed on the home screen and are updated after each signature.

src/apdu_sign.c

@@ -208,6 +208,10 @@ static int baking_sign_complete(bool const send_hash) {
         case MAGIC_BYTE_PREATTESTATION:
         case MAGIC_BYTE_ATTESTATION:
             TZ_CHECK(guard_baking_authorized(&G.parsed_baking_data, &global.path_with_curve));
+#ifdef TARGET_NANOS
+            // To be efficient, the signing needs a low-cost display
+            ux_set_low_cost_display_mode(true);
+#endif
             result = perform_signature(send_hash);
 #ifdef HAVE_BAGL
             // Ignore calculation errors

src/globals.h

@@ -28,6 +28,7 @@
 
 #include "operations.h"
 #include "ui.h"
+#include "ui_screensaver.h"
 
 /**
  * @brief Zeros out all globals that can keep track of APDU instruction state
@@ -118,8 +119,12 @@ typedef struct {
         ui_callback_t ok_callback;
         /// Callback function if user rejected prompt.
         ui_callback_t cxl_callback;
-        /// Screensaver is on/off.
-        bool is_blank_screen;
+#ifdef HAVE_BAGL
+        /// If the low-cost display mode is enabled
+        bool low_cost_display_mode;
+        /// Screensaver context
+        ux_screensaver_state_t screensaver_state;
+#endif  // TARGET_NANOS
     } dynamic_display;
 
     bip32_path_with_curve_t path_with_curve;  ///< holds the bip32 path and curve of the current key

src/ui.h

@@ -42,6 +42,17 @@ void __attribute__((noreturn)) app_exit(void);
 
 #ifdef HAVE_BAGL
 
+#ifdef TARGET_NANOS
+/**
+ * @brief Sets low-cost display mode
+ *
+ *       Low-cost display stop handling `TICKER_EVENT`
+ *
+ * @param enable: if enable the mode or not
+ */
+void ux_set_low_cost_display_mode(bool enable);
+#endif  // HAVE_BAGL
+
 /**
  * @brief Calculates the chain id for the idle screens
  *

src/ui_bagl.c

@@ -32,12 +32,88 @@
 #include "memory.h"
 #include "os_cx.h"  // ui-menu
 #include "to_string.h"
+#include "ui_screensaver.h"
 
 #include <stdbool.h>
 #include <string.h>
 
 #define G_display global.dynamic_display
 
+#ifdef TARGET_NANOS
+#include "io.h"
+
+void ux_set_low_cost_display_mode(bool enable) {
+    if (G_display.low_cost_display_mode != enable) {
+        G_display.low_cost_display_mode = enable;
+        if (G_display.low_cost_display_mode) {
+            ux_screensaver_start_clock();
+        } else {
+            ux_screensaver_stop_clock();
+        }
+    }
+}
+
+uint8_t io_event(uint8_t channel);
+
+/**
+ * Function similar to the one in `lib_standard_app/` except that the
+ * `TICKER_EVENT` handling is not enabled on low-cost display mode.
+ *
+ * Low-cost display mode is deactivated when the button is pressed and
+ * activated during signing because `TICKER_EVENT` handling slows down
+ * the application.
+ *
+ */
+uint8_t io_event(uint8_t channel) {
+    (void) channel;
+
+    switch (G_io_seproxyhal_spi_buffer[0]) {
+        case SEPROXYHAL_TAG_BUTTON_PUSH_EVENT:
+            ux_set_low_cost_display_mode(false);
+            UX_BUTTON_PUSH_EVENT(G_io_seproxyhal_spi_buffer);
+            break;
+        case SEPROXYHAL_TAG_STATUS_EVENT:
+            if ((G_io_apdu_media == IO_APDU_MEDIA_USB_HID) &&
+                !(U4BE(G_io_seproxyhal_spi_buffer, 3) &
+                  SEPROXYHAL_TAG_STATUS_EVENT_FLAG_USB_POWERED)) {
+                THROW(EXCEPTION_IO_RESET);
+            }
+            __attribute__((fallthrough));
+        case SEPROXYHAL_TAG_DISPLAY_PROCESSED_EVENT:
+#ifdef HAVE_BAGL
+            UX_DISPLAYED_EVENT({});
+#endif  // HAVE_BAGL
+#ifdef HAVE_NBGL
+            UX_DEFAULT_EVENT();
+#endif  // HAVE_NBGL
+            break;
+#ifdef HAVE_NBGL
+        case SEPROXYHAL_TAG_FINGER_EVENT:
+            UX_FINGER_EVENT(G_io_seproxyhal_spi_buffer);
+            break;
+#endif  // HAVE_NBGL
+        case SEPROXYHAL_TAG_TICKER_EVENT:
+            if (!G_display.low_cost_display_mode) {
+                app_ticker_event_callback();
+                UX_TICKER_EVENT(G_io_seproxyhal_spi_buffer, {});
+            } else {
+                ux_screensaver_apply_tick();
+            }
+            break;
+        default:
+            UX_DEFAULT_EVENT();
+            break;
+    }
+
+    if (!io_seproxyhal_spi_is_status_sent()) {
+        io_seproxyhal_general_status();
+    }
+
+    return 1;
+}
+
+#endif  // TARGET_NANOS
+
 static void ui_refresh_idle_hwm_screen(void);
 
 /**
@@ -68,7 +144,11 @@ void ui_menu_init(void);   ///> Load main menu page
  *        - Exit screen
  *
  */
+#ifdef TARGET_NANOS
+UX_STEP_CB(ux_app_is_ready_step, nn, ui_start_screensaver(), {"Application", "is ready"});
+#else   // TARGET_NANOS
 UX_STEP_NOCB(ux_app_is_ready_step, nn, {"Application", "is ready"});
+#endif  // TARGET_NANOS
 UX_STEP_NOCB(ux_version_step, bnnn_paging, {"Tezos Baking", APPVERSION});
 UX_STEP_NOCB(ux_chain_id_step, bnnn_paging, {"Chain", home_context.chain_id});
 UX_STEP_NOCB(ux_authorized_key_step, bnnn_paging, {"Public Key Hash", home_context.authorized_key});

src/ui_screensaver.c

@@ -0,0 +1,121 @@
+/* Tezos Ledger application - Screen-saver UI functions
+
+   Copyright 2024 TriliTech <[email protected]>
+   Copyright 2024 Functori <[email protected]>
+   Copyright 2023 Ledger
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+*/
+
+#ifdef HAVE_BAGL
+#include "ui_screensaver.h"
+
+#include "bolos_target.h"
+#include "globals.h"
+
+#define G_screensaver_state global.dynamic_display.screensaver_state
+
+/**
+ * @brief Blank screen element
+ *
+ */
+static const bagl_element_t blank_screen_elements[] = {{{BAGL_RECTANGLE,
+                                                         BAGL_NONE,
+                                                         0,
+                                                         0,
+                                                         BAGL_WIDTH,
+                                                         BAGL_HEIGHT,
+                                                         0,
+                                                         0,
+                                                         BAGL_FILL,
+                                                         0x000000,
+                                                         0xFFFFFF,
+                                                         0,
+                                                         0},
+                                                        .text = NULL},
+                                                       {}};
+
+/**
+ * @brief This structure represents the parameters needed for the blank layout
+ *
+ *        No parameters required
+ *
+ */
+typedef struct ux_layout_blank_params_s {
+} ux_layout_blank_params_t;
+
+/**
+ * @brief Initializes the blank layout
+ *
+ * @param stack_slot: index stack_slot
+ */
+static void ux_layout_blank_init(unsigned int stack_slot) {
+    ux_stack_init(stack_slot);
+    G_ux.stack[stack_slot].element_arrays[0].element_array = blank_screen_elements;
+    G_ux.stack[stack_slot].element_arrays[0].element_array_count = ARRAYLEN(blank_screen_elements);
+    G_ux.stack[stack_slot].element_arrays_count = 1;
+    G_ux.stack[stack_slot].button_push_callback = ux_flow_button_callback;
+    ux_stack_display(stack_slot);
+}
+
+/**
+ * @brief Exits the blank screen to home screen
+ *
+ */
+static void return_to_idle(void) {
+    G_screensaver_state.on = false;
+    ui_initial_screen();
+}
+
+/**
+ * @brief Blank screen flow
+ *
+ *        On any click: return_to_idle
+ *
+ */
+UX_STEP_CB(blank_screen_step, blank, return_to_idle(), {});
+UX_STEP_INIT(blank_screen_border, NULL, NULL, { return_to_idle(); });
+UX_FLOW(ux_blank_flow, &blank_screen_step, &blank_screen_border, FLOW_LOOP);
+
+void ui_start_screensaver(void) {
+    if (!G_screensaver_state.on) {
+        G_screensaver_state.on = true;
+        ux_flow_init(0, ux_blank_flow, NULL);
+    }
+}
+
+#define MS                  100u
+#define SCREENSAVER_TIMEOUT 20000u  // 20u * 10u * MS
+
+void ux_screensaver_start_clock(void) {
+    G_screensaver_state.clock.on = true;
+    G_screensaver_state.clock.timeout = SCREENSAVER_TIMEOUT;
+}
+
+void ux_screensaver_stop_clock(void) {
+    G_screensaver_state.clock.on = false;
+}
+
+void ux_screensaver_apply_tick(void) {
+    if (G_screensaver_state.clock.on) {
+        if (G_screensaver_state.clock.timeout < MS) {
+            ui_start_screensaver();
+            ux_screensaver_stop_clock();
+        } else {
+            G_screensaver_state.clock.timeout -= MS;
+        }
+    }
+}
+
+#endif

src/ui_screensaver.h

@@ -0,0 +1,70 @@
+/* Tezos Ledger application - Screen-saver UI functions
+
+   Copyright 2024 TriliTech <[email protected]>
+   Copyright 2024 Functori <[email protected]>
+   Copyright 2023 Ledger
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+*/
+#pragma once
+
+#include <stdbool.h>
+
+#ifdef HAVE_BAGL
+
+typedef struct {
+    /// Clock has started
+    bool on;
+    /// Timeout out before saving screen
+    unsigned int timeout;
+} ux_screensaver_clock_t;
+
+typedef struct {
+    /// Screensaver is on/off.
+    bool on;
+    /// Timeout out before saving screen
+    ux_screensaver_clock_t clock;
+} ux_screensaver_state_t;
+
+/**
+ * @brief Empties the screen
+ *
+ *        Waits a click to return to home screen
+ *
+ *        Applies only for Nanos devices
+ *
+ */
+void ui_start_screensaver(void);
+
+/**
+ * @brief Start a timeout before saving screen
+ *
+ */
+void ux_screensaver_start_clock(void);
+
+/**
+ * @brief Stop the clock
+ *
+ */
+void ux_screensaver_stop_clock(void);
+
+/**
+ * @brief Apply one tick to the clock
+ *
+ *        The tick is assumed to be 100 ms
+ *
+ */
+void ux_screensaver_apply_tick(void);
+
+#endif