A new approach for erasing WiFi Settings

bootloaders/eboot/eboot.c

@@ -17,8 +17,39 @@
 
 #define SWRST do { (*((volatile uint32_t*) 0x60000700)) |= 0x80000000; } while(0);
 
-extern void ets_wdt_enable(void);
-extern void ets_wdt_disable(void);
+/*
+  After Power Enable Pin, EXT_RST, or HWDT event, at "main()" in eboot, WDT is
+  disabled. Key WDT hardware registers are zero.
+
+  After "ESP.restart()" and other soft restarts, at "main()" in eboot, WDT is enabled.
+
+  References for the under-documented ets_wdt_* API
+    https://mongoose-os.com/blog/esp8266-watchdog-timer/
+    http://cholla.mmto.org/esp8266/bootrom/boot.txt
+
+  After looking at esp8266-watchdog-timer some more, `ets_wdt_enable(4, 12, 12)`
+  is good for eboot's needs. From a ".map" the NON-OS SDK does not use the
+  ets_wdt_* APIs, so our choices are not too critical.
+  The SDK will set up the WDT as it wants it.
+
+  A rationale for keeping the "ets_wdt_enable()" line, if the system is not
+  stable during a "soft restart," the HWDT would provide a recovery reboot.
+*/
+extern void ets_wdt_enable(uint32_t mode, uint32_t arg1, uint32_t arg2);
+/*
+  "ets_wdt_disable"
+
+  Diables WDT, then feeds the dog.
+  For current modes other than 1 or 2, returns the current mode.
+  For current mode 1, calls ets_timer_disarm, then return the current mode.
+  For current mode 2, calls ets_isr_mask, then return the current mode.
+
+  I always see a return value of 0xFFFFFFFF.
+
+  The return value would normally be used with ets_wdt_restore; however, that is
+  not an option since a valid prior call to ets_wdt_enable() may not have been done.
+*/
+extern uint32_t ets_wdt_disable(void);
 
 int print_version(const uint32_t flash_addr)
 {
@@ -241,12 +272,12 @@ int main()
 
         ets_wdt_disable();
         res = copy_raw(cmd.args[0], cmd.args[1], cmd.args[2], false);
-        ets_wdt_enable();
+        ets_wdt_enable(4, 12, 12);  // WDT about 13 secs.
 
         ets_printf("%d\n", res);
 #if 0
-	//devyte: this verify step below (cmp:) only works when the end of copy operation above does not overwrite the 
-	//beginning of the image in the empty area, see #7458. Disabling for now. 
+	//devyte: this verify step below (cmp:) only works when the end of copy operation above does not overwrite the
+	//beginning of the image in the empty area, see #7458. Disabling for now.
         //TODO: replace the below verify with hash type, crc, or similar.
         // Verify the copy
         ets_printf("cmp:");
@@ -257,7 +288,7 @@ int main()
             }
 
         ets_printf("%d\n", res);
-#endif	    
+#endif
         if (res == 0) {
             cmd.action = ACTION_LOAD_APP;
             cmd.args[0] = cmd.args[1];

cores/esp8266/Esp.cpp

@@ -31,6 +31,7 @@
 #include "umm_malloc/umm_malloc.h"
 #include <pgmspace.h>
 #include "reboot_uart_dwnld.h"
+#include "hardware_reset.h"
 
 extern "C" {
 #include "user_interface.h"
@@ -519,7 +520,7 @@ struct rst_info * EspClass::getResetInfoPtr(void) {
 }
 
 bool EspClass::eraseConfig(void) {
-    const size_t cfgSize = 0x4000;
+    const size_t cfgSize = 0x4000;  // Sectors: RF_CAL + SYSTEMPARAM[3]
     size_t cfgAddr = ESP.getFlashChipSize() - cfgSize;
 
     for (size_t offset = 0; offset < cfgSize; offset += SPI_FLASH_SEC_SIZE) {
@@ -531,6 +532,17 @@ bool EspClass::eraseConfig(void) {
     return true;
 }
 
+bool EspClass::eraseConfigAndReset(void) {
+    // Before calling, ensure the WiFi state is equivalent to
+    // "WiFi.mode(WIFI_OFF)." This will reduce the likelihood of the SDK
+    // performing WiFi data writes to Flash between erasing and resetting.
+    bool reset = eraseConfig();
+    if (reset) {
+        hardware_reset();
+    }
+    return reset;
+}
+
 uint8_t *EspClass::random(uint8_t *resultArray, const size_t outputSizeBytes)
 {
   /**

cores/esp8266/Esp.h

@@ -212,6 +212,22 @@ class EspClass {
 
         static bool eraseConfig();
 
+        /**
+         * @brief Erases 4 sectors at the end of flash, 1 - RF_CAL and 3 - SYSTEMPARM.
+         * These are the same additional sectors that are erase when you select
+         * Erase Flash: "Sketch + WiFi Settings" from the Arduino IDE Tools menu.
+         *
+         * This operation erases the running SDK's flash configuration space.
+         * As a precaution before calling, first call "WiFi.mode(WIFI_OFF)."
+         *
+         * If you need to erase "WiFi Settings" and reboot consider using
+         * "ArduinoOTA.eraseConfigAndReset()" it handles shutting down WiFi
+         * before the erase.
+         * @return bool result of operation. Always False on return.
+         * Function does not return on success.
+         */
+        static bool eraseConfigAndReset();
+
         static uint8_t *random(uint8_t *resultArray, const size_t outputSizeBytes);
         static uint32_t random();
 

cores/esp8266/hardware_reset.cpp

@@ -0,0 +1,119 @@
+/*
+  Make the reset look like an EXT_RST reset by:
+    * Set INTLEVEL to 15 blocking NMI Software WDT interference
+    * set "restart reason" to REASON_EXT_SYS_RST
+    * Config Hardware WDT for 1.6ms
+    * Disable Hardware WDT Level-1 interrupt option
+    * wait, ...
+
+  Inspired by RTOS SDK hardware_restart in panic.c
+*/
+
+#include "Arduino.h"
+#include <user_interface.h>
+#include <ets_sys.h>
+#include "hardware_reset.h"
+
+
+// Extracted from RTOS_SDK eagle_soc.h
+/*
+ * ESPRSSIF MIT License
+ *
+ * Copyright (c) 2015 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>
+ *
+ * Permission is hereby granted for use on ESPRESSIF SYSTEMS ESP8266 only, in which case,
+ * it is free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the Software is furnished
+ * to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+#define REG_WRITE(_r, _v)       (*(volatile uint32_t *)(_r)) = (_v)
+#define REG_READ(_r)            (*(volatile uint32_t *)(_r))
+
+//Watchdog reg {{
+#define PERIPHS_WDT_BASEADDR        0x60000900
+
+#define WDT_CTL_ADDRESS             0
+#define WDT_OP_ADDRESS              0x4
+#define WDT_OP_ND_ADDRESS           0x8
+#define WDT_RST_ADDRESS             0x14
+
+#define WDT_CTL_RSTLEN_MASK         0x38
+#define WDT_CTL_RSPMOD_MASK         0x6
+#define WDT_CTL_EN_MASK             0x1
+
+#define WDT_CTL_RSTLEN_LSB          0x3
+#define WDT_CTL_RSPMOD_LSB          0x1
+#define WDT_CTL_EN_LSB              0
+
+#define WDT_FEED_VALUE              0x73
+
+#define WDT_REG_READ(_reg)                  REG_READ(PERIPHS_WDT_BASEADDR + _reg)
+#define WDT_REG_WRITE(_reg, _val)           REG_WRITE(PERIPHS_WDT_BASEADDR + _reg, _val)
+#define CLEAR_WDT_REG_MASK(_reg, _mask)     WDT_REG_WRITE(_reg, WDT_REG_READ(_reg) & (~_mask))
+#define SET_WDT_REG_MASK(_reg, _mask, _val) SET_PERI_REG_BITS((PERIPHS_WDT_BASEADDR + _reg), _mask, _val, 0)
+#undef WDT_FEED
+#define WDT_FEED()                          WDT_REG_WRITE(WDT_RST_ADDRESS, WDT_FEED_VALUE)
+//}}
+
+// Inspired by RTOS SDK task_wdt.c and hardware_restart in panic.c
+
+// Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+extern "C" {
+  [[noreturn]] void hardware_reset(void) {
+    volatile uint32_t* const rtc_mem = (volatile uint32_t *)0x60001100u;
+
+    // Block NMI or Software WDT from disturbing out restart reason
+    xt_rsil(15);
+
+    // An HWDT reason would imply a fault or bug, but this reset was requested.
+    // Set hint reason to EXT_RST. From empirical evidence, an HWDT looks a lot
+    // like an EXT_RST. The WDT registers are reset to zero like an EXT_RST;
+    // however, the PLL initialization is still set. We can still read the Boot
+    // ROM serial output messages.
+    // SDK restart reason/hint location
+    rtc_mem[0] = REASON_EXT_SYS_RST;
+
+    // Disable WDT
+    CLEAR_WDT_REG_MASK(WDT_CTL_ADDRESS, WDT_CTL_EN_MASK);
+
+    // Set Reset pulse to maximum
+    // Select Reset only - no level-1 interrupt
+    SET_WDT_REG_MASK(WDT_CTL_ADDRESS,
+                     WDT_CTL_RSTLEN_MASK       | WDT_CTL_RSPMOD_MASK,
+                     (7 << WDT_CTL_RSTLEN_LSB) | (2 << WDT_CTL_RSPMOD_LSB));
+
+    // Set WDT Reset timer to 1.6 ms.
+    WDT_REG_WRITE(WDT_OP_ADDRESS, 1);  // 2^n * 0.8ms, mask 0xf, n = 1 -> (2^1 = 2) * 0.8 * 0.001 = 0.0016
+
+    // Enable WDT
+    SET_WDT_REG_MASK(WDT_CTL_ADDRESS, WDT_CTL_EN_MASK, 1 << WDT_CTL_EN_LSB);
+
+    while (true);
+  }
+};

cores/esp8266/hardware_reset.h

@@ -0,0 +1,12 @@
+#ifndef HARDWARE_RESET_H
+#define HARDWARE_RESET_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+[[noreturn]] extern void hardware_reset(void);
+
+#ifdef __cplusplus
+}
+#endif
+#endif