FL-549 Reading iButton "Cyfral" by HW comparator (#273)

* new comparator-based reader
* working comparator reader
* add keys "integrity" check
* reset events queue

applications/ibutton/ibutton_mode_cyfral_read.h

@@ -1,12 +1,12 @@
 #pragma once
 #include "ibutton.h"
-#include "cyfral_reader.h"
+#include "cyfral_reader_comp.h"
 
 class AppiButtonModeCyfralRead : public AppTemplateMode<AppiButtonState, AppiButtonEvent> {
 public:
     const char* name = "cyfral read";
     AppiButton* app;
-    CyfralReader* reader;
+    CyfralReaderComp* reader;
 
     void event(AppiButtonEvent* event, AppiButtonState* state);
     void render(Canvas* canvas, AppiButtonState* state);
@@ -15,16 +15,48 @@ public:
 
     AppiButtonModeCyfralRead(AppiButton* parent_app) {
         app = parent_app;
-        reader = new CyfralReader(ADC1, ADC_CHANNEL_14);
+
+        // TODO open record
+        const GpioPin* one_wire_pin_record = &ibutton_gpio;
+        reader = new CyfralReaderComp(one_wire_pin_record);
     };
+
+    static const uint8_t key_length = 4;
+    static const uint8_t num_keys_to_check = 4;
+    uint8_t key_index = 0;
+    uint8_t keys[num_keys_to_check][4];
 };
 
 void AppiButtonModeCyfralRead::event(AppiButtonEvent* event, AppiButtonState* state) {
     if(event->type == AppiButtonEvent::EventTypeTick) {
-        uint8_t data[8];
-        if(reader->read(data, 4)) {
-            memcpy(app->state.cyfral_address[app->state.cyfral_address_index], data, 4);
-            app->blink_green();
+        // if we read a key
+        if(reader->read(keys[key_index], key_length)) {
+            // read next key
+            key_index++;
+
+            // if we read sufficient amount of keys
+            if(key_index >= num_keys_to_check) {
+                bool result = true;
+                key_index = 0;
+
+                // compare all keys
+                for(uint8_t i = 1; i < num_keys_to_check; i++) {
+                    if(memcmp(keys[i], keys[i - 1], key_length) != 0) {
+                        result = false;
+                        break;
+                    }
+                }
+
+                // if all keys is same
+                if(result) {
+                    // copy key to mem and blink
+                    memcpy(
+                        app->state.cyfral_address[app->state.cyfral_address_index],
+                        keys[key_index],
+                        key_length);
+                    app->blink_green();
+                }
+            }
         }
     } else if(event->type == AppiButtonEvent::EventTypeKey) {
         if(event->value.input.state && event->value.input.input == InputUp) {

lib/cyfral/cyfral_reader_comp.h

@@ -0,0 +1,283 @@
+#pragma once
+#include "flipper.h"
+#include "flipper_v2.h"
+#include "callback-connector.h"
+#include <atomic>
+
+enum class CyfralReaderCompError : uint8_t {
+    NO_ERROR = 0,
+    UNABLE_TO_DETECT = 1,
+    RAW_DATA_SIZE_ERROR = 2,
+    UNKNOWN_NIBBLE_VALUE = 3,
+    NO_START_NIBBLE = 4,
+    NOT_ENOUGH_DATA = 5,
+};
+
+extern COMP_HandleTypeDef hcomp1;
+
+typedef struct {
+    bool value;
+    uint32_t dwt_value;
+} CompEvent;
+
+class CyfralReaderComp {
+private:
+    bool capture_data(bool* data, uint16_t capture_size);
+    bool parse_data(bool* raw_data, uint16_t capture_size, uint8_t* data, uint8_t count);
+    uint32_t search_array_in_array(
+        const bool* haystack,
+        const uint32_t haystack_size,
+        const bool* needle,
+        const uint32_t needle_size);
+
+    // key is 9 nibbles
+    static const uint16_t bits_in_nibble = 4;
+    static const uint16_t key_length = 9;
+    static const uint32_t capture_size = key_length * bits_in_nibble * 2;
+    CyfralReaderCompError error;
+    const GpioPin* pin_record;
+
+    std::atomic<bool> ready_to_process;
+    void comparator_trigger_callback(void* hcomp, void* comp_ctx);
+    osMessageQueueId_t comp_event_queue;
+
+public:
+    CyfralReaderComp(const GpioPin* emulate_pin);
+    ~CyfralReaderComp();
+    void start(void);
+    void stop(void);
+    bool read(uint8_t* data, uint8_t count);
+};
+
+bool CyfralReaderComp::capture_data(bool* data, uint16_t capture_size) {
+    uint32_t prev_timing = 0;
+    uint16_t data_index = 0;
+    CompEvent event_0, event_1;
+    osStatus_t status;
+
+    // read first event to get initial timing
+    status = osMessageQueueGet(comp_event_queue, &event_0, NULL, 0);
+
+    if(status != osOK) {
+        return false;
+    }
+
+    prev_timing = event_0.dwt_value;
+
+    // read second event until we get 0
+    while(1) {
+        status = osMessageQueueGet(comp_event_queue, &event_0, NULL, 0);
+        if(status != osOK) {
+            return false;
+        }
+        prev_timing = event_0.dwt_value;
+        if(event_0.value == 0) break;
+    }
+
+    while(1) {
+        // if event "zero" correct
+        if(status == osOK && event_0.value == 0) {
+            // get timing
+            event_0.dwt_value -= prev_timing;
+            prev_timing += event_0.dwt_value;
+
+            // read next event
+            status = osMessageQueueGet(comp_event_queue, &event_1, NULL, 0);
+
+            // if event "one" correct
+            if(status == osOK && event_1.value == 1) {
+                // get timing
+                event_1.dwt_value -= prev_timing;
+                prev_timing += event_1.dwt_value;
+
+                // calculate percentage of event "one" to full timing
+                uint32_t full_timing = event_0.dwt_value + event_1.dwt_value;
+                uint32_t percentage_1 = 1000000 / full_timing * event_1.dwt_value;
+
+                // write captured data
+                data[data_index] = percentage_1 > 500000 ? 0 : 1;
+                data_index++;
+                if(data_index >= capture_size) return true;
+
+                status = osMessageQueueGet(comp_event_queue, &event_0, NULL, 0);
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+    osMessageQueueReset(comp_event_queue);
+}
+
+uint32_t CyfralReaderComp::search_array_in_array(
+    const bool* haystack,
+    const uint32_t haystack_size,
+    const bool* needle,
+    const uint32_t needle_size) {
+    uint32_t haystack_index = 0, needle_index = 0;
+
+    while(haystack_index < haystack_size && needle_index < needle_size) {
+        if(haystack[haystack_index] == needle[needle_index]) {
+            haystack_index++;
+            needle_index++;
+            if(needle_index == needle_size) {
+                return (haystack_index - needle_size);
+            };
+        } else {
+            haystack_index = haystack_index - needle_index + 1;
+            needle_index = 0;
+        }
+    }
+
+    return haystack_index;
+}
+
+void CyfralReaderComp::comparator_trigger_callback(void* hcomp, void* comp_ctx) {
+    CyfralReaderComp* _this = static_cast<CyfralReaderComp*>(comp_ctx);
+    COMP_HandleTypeDef* _hcomp = static_cast<COMP_HandleTypeDef*>(hcomp);
+
+    // check that hw is comparator 1
+    if(_hcomp != &hcomp1) return;
+
+    // if queue if not full
+    if(_this->ready_to_process == false) {
+        // send event to queue
+        CompEvent event;
+        event.value = (HAL_COMP_GetOutputLevel(_hcomp) == COMP_OUTPUT_LEVEL_HIGH);
+        event.dwt_value = DWT->CYCCNT;
+        osStatus_t status = osMessageQueuePut(_this->comp_event_queue, &event, 0, 0);
+
+        // queue is full, so we need to process data
+        if(status != osOK) {
+            _this->ready_to_process = true;
+        };
+    }
+}
+
+bool CyfralReaderComp::parse_data(
+    bool* raw_data,
+    uint16_t capture_size,
+    uint8_t* data,
+    uint8_t count) {
+    const bool start_nibble[bits_in_nibble] = {1, 1, 1, 0};
+    uint32_t start_position =
+        search_array_in_array(raw_data, capture_size, start_nibble, bits_in_nibble);
+    uint32_t end_position = 0;
+
+    memset(data, 0, count);
+
+    if(start_position < capture_size) {
+        start_position = start_position + bits_in_nibble;
+        end_position = start_position + count * 2 * bits_in_nibble;
+
+        if(end_position >= capture_size) {
+            error = CyfralReaderCompError::RAW_DATA_SIZE_ERROR;
+            return false;
+        }
+
+        bool first_nibble = true;
+        uint8_t data_position = 0;
+        uint8_t nibble_value = 0;
+
+        while(data_position < count) {
+            nibble_value = !raw_data[start_position] << 3 | !raw_data[start_position + 1] << 2 |
+                           !raw_data[start_position + 2] << 1 | !raw_data[start_position + 3];
+
+            switch(nibble_value) {
+            case(0x7):
+            case(0xB):
+            case(0xD):
+            case(0xE):
+                break;
+            default:
+                error = CyfralReaderCompError::UNKNOWN_NIBBLE_VALUE;
+                return false;
+                break;
+            }
+
+            if(first_nibble) {
+                data[data_position] |= nibble_value << 4;
+            } else {
+                data[data_position] |= nibble_value;
+            }
+
+            first_nibble = !first_nibble;
+
+            if(first_nibble) {
+                data_position++;
+            }
+
+            start_position = start_position + bits_in_nibble;
+        }
+
+        error = CyfralReaderCompError::NO_ERROR;
+        return true;
+    }
+
+    error = CyfralReaderCompError::NO_START_NIBBLE;
+    return false;
+}
+
+CyfralReaderComp::CyfralReaderComp(const GpioPin* gpio_pin) {
+    pin_record = gpio_pin;
+}
+
+CyfralReaderComp::~CyfralReaderComp() {
+}
+
+void CyfralReaderComp::start(void) {
+    // pulldown lf-rfid pins to prevent interference
+    // TODO open record
+    GpioPin rfid_pull_pin = {.port = RFID_PULL_GPIO_Port, .pin = RFID_PULL_Pin};
+    gpio_init((GpioPin*)&rfid_pull_pin, GpioModeOutputOpenDrain);
+    gpio_write((GpioPin*)&rfid_pull_pin, false);
+
+    // TODO open record
+    GpioPin rfid_out_pin = {.port = RFID_OUT_GPIO_Port, .pin = RFID_OUT_Pin};
+    gpio_init((GpioPin*)&rfid_out_pin, GpioModeOutputOpenDrain);
+    gpio_write((GpioPin*)&rfid_out_pin, false);
+
+    // connect comparator callback
+    void* comp_ctx = this;
+    comp_event_queue = osMessageQueueNew(capture_size * 2 + 2, sizeof(CompEvent), NULL);
+    ready_to_process = false;
+
+    auto cmp_cb = cbc::obtain_connector(this, &CyfralReaderComp::comparator_trigger_callback);
+    api_interrupt_add(cmp_cb, InterruptTypeComparatorTrigger, comp_ctx);
+
+    // start comaparator
+    HAL_COMP_Start(&hcomp1);
+}
+
+void CyfralReaderComp::stop(void) {
+    // stop comaparator
+    HAL_COMP_Stop(&hcomp1);
+
+    // disconnect comparator callback
+    auto cmp_cb = cbc::obtain_connector(this, &CyfralReaderComp::comparator_trigger_callback);
+    api_interrupt_remove(cmp_cb);
+    osMessageQueueDelete(comp_event_queue);
+}
+
+bool CyfralReaderComp::read(uint8_t* data, uint8_t count) {
+    bool raw_data[capture_size];
+    bool result = false;
+    error = CyfralReaderCompError::NO_ERROR;
+
+    if(ready_to_process == false) {
+        error = CyfralReaderCompError::NOT_ENOUGH_DATA;
+    } else {
+        memset(raw_data, 0, sizeof(bool) * capture_size);
+        if(capture_data(raw_data, capture_size)) {
+            if(parse_data(raw_data, capture_size, data, count)) {
+                result = true;
+            }
+        }
+
+        ready_to_process = false;
+    }
+
+    return result;
+}