cypress: Add support for watchdog timer update in boot image

Add watchdog timer to MCUBootApp plus BlinkyApp to implement  additional way of boot/upgrade image operation confirmation.

Signed-off-by: Roman Okhrimenko <roman.okhrimenko@cypress.com>
diff --git a/boot/cypress/libs/watchdog/watchdog.c b/boot/cypress/libs/watchdog/watchdog.c
new file mode 100644
index 0000000..286e9c3
--- /dev/null
+++ b/boot/cypress/libs/watchdog/watchdog.c
@@ -0,0 +1,183 @@
+/***************************************************************************//**
+* \file cy_wdg.c
+*
+* \brief
+* Provides a high level interface for interacting with the Cypress Watchdog Timer.
+* This interface abstracts out the chip specific details. If any chip specific
+* functionality is necessary, or performance is critical the low level functions
+* can be used directly.
+*
+*
+********************************************************************************
+* \copyright
+* Copyright 2019-2020 Cypress Semiconductor Corporation
+* SPDX-License-Identifier: Apache-2.0
+*
+* 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.
+*******************************************************************************/
+
+#include <stdbool.h>
+#include "watchdog.h"
+#include "cy_wdt.h"
+#include "cy_utils.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+#if defined(COMPONENT_PSOC6)
+#define _cy_wdg_lock()   Cy_WDT_Lock()
+#define _cy_wdg_unlock() Cy_WDT_Unlock()
+#else
+#define _cy_wdg_lock()
+#define _cy_wdg_unlock()
+#endif
+
+// ((2^16 * 2) + (2^16 - 1)) * .030518 ms
+/** Maximum WDT timeout in milliseconds */
+#define _cy_wdg_MAX_TIMEOUT_MS 6000
+
+/** Maximum number of ignore bits */
+#define _cy_wdg_MAX_IGNORE_BITS 12
+
+typedef struct {
+    uint16_t min_period_ms; // Minimum period in milliseconds that can be represented with this many ignored bits
+    uint16_t round_threshold_ms; // Timeout threshold in milliseconds from which to round up to the minimum period
+} _cy_wdg_ignore_bits_data_t;
+
+// ILO Frequency = 32768 Hz
+// ILO Period = 1 / 32768 Hz = .030518 ms
+// WDT Reset Period (timeout_ms) = .030518 ms * (2 * 2^(16 - ignore_bits) + match)
+// ignore_bits range: 0 - 12
+// match range: 0 - (2^(16 - ignore_bits) - 1)
+static const _cy_wdg_ignore_bits_data_t _cy_wdg_ignore_data[] = {
+    {4001, 3001}, // 0 bits:  min period: 4001ms, max period: 6000ms, round up from 3001+ms
+    {2001, 1500}, // 1 bit:   min period: 2001ms, max period: 3000ms, round up from 1500+ms
+    {1001, 750},  // 2 bits:  min period: 1001ms, max period: 1499ms, round up from 750+ms
+    {501,  375},  // 3 bits:  min period: 501ms,  max period: 749ms,  round up from 375+ms
+    {251,  188},  // 4 bits:  min period: 251ms,  max period: 374ms,  round up from 188+ms
+    {126,  94},   // 5 bits:  min period: 126ms,  max period: 187ms,  round up from 94+ms
+    {63,   47},   // 6 bits:  min period: 63ms,   max period: 93ms,   round up from 47+ms
+    {32,   24},   // 7 bits:  min period: 32ms,   max period: 46ms,   round up from 24+ms
+    {16,   12},   // 8 bits:  min period: 16ms,   max period: 23ms,   round up from 12+ms
+    {8,    6},    // 9 bits:  min period: 8ms,    max period: 11ms,   round up from 6+ms
+    {4,    3},    // 10 bits: min period: 4ms,    max period: 5ms,    round up from 3+ms
+    {2,    2},    // 11 bits: min period: 2ms,    max period: 2ms
+    {1,    1}     // 12 bits: min period: 1ms,    max period: 1ms
+};
+
+static bool _cy_wdg_initialized = false;
+static bool _cy_wdg_pdl_initialized = false;
+static uint16_t _cy_wdg_initial_timeout_ms = 0;
+static uint8_t _cy_wdg_initial_ignore_bits = 0;
+
+static __INLINE uint32_t _cy_wdg_timeout_to_ignore_bits(uint32_t *timeout_ms) {
+    for (uint32_t i = 0; i <= _cy_wdg_MAX_IGNORE_BITS; i++)
+    {
+        if (*timeout_ms >= _cy_wdg_ignore_data[i].round_threshold_ms)
+        {
+            if (*timeout_ms < _cy_wdg_ignore_data[i].min_period_ms)
+                *timeout_ms = _cy_wdg_ignore_data[i].min_period_ms;
+            return i;
+        }
+    }
+    return _cy_wdg_MAX_IGNORE_BITS; // Should never reach this
+}
+
+static __INLINE uint16_t _cy_wdg_timeout_to_match(uint16_t timeout_ms, uint16_t ignore_bits)
+{
+    // match = (timeout_ms / .030518 ms) - (2 * 2^(16 - ignore_bits))
+    return (uint16_t)(timeout_ms / .030518) - (1UL << (17 - ignore_bits)) + Cy_WDT_GetCount();
+}
+
+/* Start API implementing */
+
+cy_rslt_t cy_wdg_init(uint32_t timeout_ms)
+{
+    if (timeout_ms == 0 || timeout_ms > _cy_wdg_MAX_TIMEOUT_MS)
+    {
+        return -1;
+    }
+
+    if (_cy_wdg_initialized)
+    {
+        return -1;
+    }
+
+    _cy_wdg_initialized = true;
+
+    if (!_cy_wdg_pdl_initialized)
+    {
+        Cy_WDT_Enable();
+        Cy_WDT_MaskInterrupt();
+        _cy_wdg_pdl_initialized = true;
+    }
+
+    cy_wdg_stop();
+
+    _cy_wdg_initial_timeout_ms = timeout_ms;
+    uint8_t ignore_bits = _cy_wdg_timeout_to_ignore_bits(&timeout_ms);
+    _cy_wdg_initial_ignore_bits = ignore_bits;
+
+    Cy_WDT_SetIgnoreBits(ignore_bits);
+
+    Cy_WDT_SetMatch(_cy_wdg_timeout_to_match(timeout_ms, ignore_bits));
+
+    cy_wdg_start();
+
+    return CY_RSLT_SUCCESS;
+}
+
+void cy_wdg_free()
+{
+    cy_wdg_stop();
+
+    _cy_wdg_initialized = false;
+}
+
+void cy_wdg_kick()
+{
+    /* Clear to prevent reset from WDT */
+    Cy_WDT_ClearWatchdog();
+
+    _cy_wdg_unlock();
+    Cy_WDT_SetMatch(_cy_wdg_timeout_to_match(_cy_wdg_initial_timeout_ms, _cy_wdg_initial_ignore_bits));
+    _cy_wdg_lock();
+}
+
+void cy_wdg_start()
+{
+    _cy_wdg_unlock();
+    Cy_WDT_Enable();
+    _cy_wdg_lock();
+}
+
+void cy_wdg_stop()
+{
+    _cy_wdg_unlock();
+    Cy_WDT_Disable();
+}
+
+uint32_t cy_wdg_get_timeout_ms()
+{
+    return _cy_wdg_initial_timeout_ms;
+}
+
+uint32_t cy_wdg_get_max_timeout_ms(void)
+{
+    return _cy_wdg_MAX_TIMEOUT_MS;
+}
+
+#if defined(__cplusplus)
+}
+#endif