Restore EEPROM address to prior released location (#6537)

When the FS_END was adjusted to end on a full block (i.e. rounded down)
to avoid filesystem issues, but _FS_end was changed.  The EEPROM library
used _FS_end to implicitly calculate the start of the EEPROM data, so
this means after the _FS_end fix, EEPROM data written with prior
releases would "disappear."

Avoid the issue by explicitly calculating the EEPROM start location in
the linker, using the same formula as prior release.

Fixes #6531

Author: earlephilhower

libraries/EEPROM/EEPROM.cpp

@@ -30,7 +30,7 @@ extern "C" {
 #include "spi_flash.h"
 }
 
-extern "C" uint32_t _FS_end;
+extern "C" uint32_t _EEPROM_start;
 
 EEPROMClass::EEPROMClass(uint32_t sector)
 : _sector(sector)
@@ -41,7 +41,7 @@ EEPROMClass::EEPROMClass(uint32_t sector)
 }
 
 EEPROMClass::EEPROMClass(void)
-: _sector((((uint32_t)&_FS_end - 0x40200000) / SPI_FLASH_SEC_SIZE))
+: _sector((((uint32_t)&_EEPROM_start - 0x40200000) / SPI_FLASH_SEC_SIZE))
 , _data(0)
 , _size(0)
 , _dirty(false)

package/package_esp8266com_index.template.json

@@ -359,4 +359,4 @@
          ]
       }
    ]
-}
+}

tools/boards.txt.py

@@ -1181,6 +1181,11 @@ def flash_map (flashsize_kb, fs_kb = 0):
     rfcal_size_kb = 4
     sdkwifi_size_kb = 12
     fs_end = (flashsize_kb - sdkwifi_size_kb - rfcal_size_kb - eeprom_size_kb) * 1024
+
+    # For legacy reasons (#6531), the EEPROM sector needs to be at the old
+    # FS_end calculated without regards to block size
+    eeprom_start = fs_end
+
     rfcal_addr = (flashsize_kb - sdkwifi_size_kb - rfcal_size_kb) * 1024
     if flashsize_kb <= 1024:
         max_upload_size = (flashsize_kb - (fs_kb + eeprom_size_kb + rfcal_size_kb + sdkwifi_size_kb)) * 1024 - reserved
@@ -1264,6 +1269,7 @@ def flash_map (flashsize_kb, fs_kb = 0):
         print("PROVIDE ( _FS_end = 0x%08X );" % (0x40200000 + fs_end))
         print("PROVIDE ( _FS_page = 0x%X );" % page)
         print("PROVIDE ( _FS_block = 0x%X );" % fs_blocksize)
+        print("PROVIDE ( _EEPROM_start = 0x%08x );" % (0x40200000 + eeprom_start))
         print("")
         print('INCLUDE "local.eagle.app.v6.common.ld"')
 

tools/sdk/ld/eagle.flash.16m14m.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x40400000 );
 PROVIDE ( _FS_end = 0x411FA000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x2000 );
+PROVIDE ( _EEPROM_start = 0x411fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.16m15m.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x40300000 );
 PROVIDE ( _FS_end = 0x411FA000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x2000 );
+PROVIDE ( _EEPROM_start = 0x411fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.1m.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x402FB000 );
 PROVIDE ( _FS_end = 0x402FB000 );
 PROVIDE ( _FS_page = 0x0 );
 PROVIDE ( _FS_block = 0x0 );
+PROVIDE ( _EEPROM_start = 0x402fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.1m128.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x402DB000 );
 PROVIDE ( _FS_end = 0x402FB000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x1000 );
+PROVIDE ( _EEPROM_start = 0x402fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.1m144.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x402D7000 );
 PROVIDE ( _FS_end = 0x402FB000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x1000 );
+PROVIDE ( _EEPROM_start = 0x402fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.1m160.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x402D3000 );
 PROVIDE ( _FS_end = 0x402FB000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x1000 );
+PROVIDE ( _EEPROM_start = 0x402fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"

tools/sdk/ld/eagle.flash.1m192.ld

@@ -18,5 +18,6 @@ PROVIDE ( _FS_start = 0x402CB000 );
 PROVIDE ( _FS_end = 0x402FB000 );
 PROVIDE ( _FS_page = 0x100 );
 PROVIDE ( _FS_block = 0x1000 );
+PROVIDE ( _EEPROM_start = 0x402fb000 );
 
 INCLUDE "local.eagle.app.v6.common.ld"