Check ESP8285 at runtime (#8604)

* esp_is_8285() at runtime
* less code with less statics, just read again

cores/esp8266/core_esp8266_features.cpp

@@ -20,18 +20,19 @@
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
+#include <eagle_soc.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* precache()
  *  pre-loads flash data into the flash cache
  *  if f==0, preloads instructions starting at the address we were called from.
  *  otherwise preloads flash at the given address.
  *  All preloads are word aligned.
  */
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 void precache(void *f, uint32_t bytes) {
   // Size of a cache page in bytes. We only need to read one word per
   // page (ie 1 word in 8) for this to work.
@@ -46,6 +47,20 @@ void precache(void *f, uint32_t bytes) {
   (void)x;
 }
 
+/** based on efuse data, we could determine what type of chip this is
+ * - https://github.com/espressif/esptool/blob/f04d34bcab29ace798d2d3800ba87020cccbbfdd/esptool.py#L1060-L1070
+ * - https://github.com/espressif/ESP8266_RTOS_SDK/blob/3c055779e9793e5f082afff63a011d6615e73639/components/esp8266/include/esp8266/efuse_register.h#L20-L21
+ */
+bool esp_is_8285() {
+    const uint32_t data[] {
+        READ_PERI_REG(0x3ff00050), // aka MAC0
+        READ_PERI_REG(0x3ff00058), // aka CHIPID
+    };
+
+    return ((data[0] & (1 << 4)) > 0)
+        || ((data[1] & (1 << 16)) > 0);
+}
+
 #ifdef __cplusplus
 }
 #endif

cores/esp8266/core_esp8266_features.h

@@ -122,10 +122,21 @@ inline int esp_get_cpu_freq_mhz()
 }
 #endif
 
+
 // Call this function in your setup() to cause the phase locked version of the generator to
 // be linked in automatically.  Otherwise, the default PWM locked version will be used.
 void enablePhaseLockedWaveform(void);
 
+// Determine when the sketch runs on ESP8285
+#if !defined(CORE_MOCK)
+bool __attribute__((const, nothrow)) esp_is_8285();
+#else
+inline bool esp_is_8285()
+{
+    return false;
+}
+#endif
+
 #ifdef __cplusplus
 }
 #endif

variants/generic/common.h

@@ -30,7 +30,10 @@
 #define NUM_DIGITAL_PINS        17
 #define NUM_ANALOG_INPUTS       1
 
-#define isFlashInterfacePin(p)      ((p) >= 6 && (p) <= 11)
+#define isFlashInterfacePin(p)\
+    (esp_is_8285()\
+     ? ((p) == 6 || (p) == 7 || (p) == 8 || (p) == 11)\
+     : ((p) >= 6 && (p) <= 11))
 
 #define analogInputToDigitalPin(p)  ((p > 0) ? NOT_A_PIN : 0)
 #define digitalPinToInterrupt(p)    (((p) < EXTERNAL_NUM_INTERRUPTS)? (p) : NOT_AN_INTERRUPT)