Make additional memory available as dram2_uninit (#2079)

* Make additional memory available as `dram2_uninit`

* CHANGELOG.md

esp-hal/CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Flex` now implements `Wait`. (#2075)
 - Added sleep and wakeup support for esp32c2 (#1922)
 - `Input`, `Output`, `OutputOpenDrain` and `Flex` now implement `Peripheral`. (#2094)
+- Previously unavailable memory is available via `.dram2_uninit` section (#2079)
 
 ### Changed
 

esp-hal/ld/esp32/esp32.x

@@ -26,15 +26,9 @@ INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "rtc_slow.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
-/* an uninitialized section for use as the wifi-heap in esp-wifi */
-SECTIONS {
-    .dram2_uninit (NOLOAD) : ALIGN(4) {
-        *(.dram2_uninit)
-    } > dram2_seg
-}
-
 EXTERN(DefaultHandler);
 
 EXTERN(WIFI_EVENT); /* Force inclusion of WiFi libraries */

esp-hal/ld/esp32c2/esp32c2.x

@@ -85,6 +85,7 @@ INCLUDE "rodata.x"
 INCLUDE "rwtext.x"
 INCLUDE "rwdata.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 INCLUDE "debug.x"

esp-hal/ld/esp32c2/memory.x

@@ -12,12 +12,14 @@ MEMORY
                       [0x4037C000, 0x403C0000, "IRAM"]]
     */
 
-    /* 272K of on soc RAM, 16K reserved for cache */
+    ICACHE : ORIGIN = 0x4037C000, LENGTH = 16K
-    ICACHE : ORIGIN = 0x4037C000,  LENGTH = 16K
     /* Instruction RAM */
-    IRAM : ORIGIN = 0x4037C000 + 16K, LENGTH = 272K - 16K
+    IRAM : ORIGIN = 0x4037C000 + LENGTH(ICACHE), LENGTH = 186k
     /* Data RAM */
-    DRAM : ORIGIN = 0x3FCA0000, LENGTH = 0x30000
+    DRAM : ORIGIN = 0x3FCA0000, LENGTH = 186k
+
+    /* memory available after the 2nd stage bootloader is finished */
+    dram2_seg ( RW )       : ORIGIN = ORIGIN(DRAM) + LENGTH(DRAM), len = 0x3fcdeb70 - (ORIGIN(DRAM) + LENGTH(DRAM))
 
     /* External flash */
     /* Instruction ROM */

esp-hal/ld/esp32c3/esp32c3.x

@@ -86,6 +86,7 @@ INCLUDE "rwtext.x"
 INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 INCLUDE "debug.x"

esp-hal/ld/esp32c3/memory.x

@@ -13,14 +13,15 @@ MEMORY
                   [0x50000000, 0x50002000, "RTC_IRAM"],
                   [0x50000000, 0x50002000, "RTC_DRAM"],
                   [0x600FE000, 0x60100000, "MEM_INTERNAL2"]]
-    */
+
-    /* 400K of on soc RAM, 16K reserved for cache */
     ICACHE : ORIGIN = 0x4037C000,  LENGTH = 0x4000
     /* Instruction RAM */
-    IRAM : ORIGIN = 0x4037C000 + 0x4000, LENGTH = 400K - 0x4000
+    IRAM : ORIGIN = 0x4037C000 + 0x4000, LENGTH = 313K - 0x4000
     /* Data RAM */
-    DRAM : ORIGIN = 0x3FC80000, LENGTH = 0x50000
+    DRAM : ORIGIN = 0x3FC80000, LENGTH = 313K
     
+    /* memory available after the 2nd stage bootloader is finished */
+    dram2_seg ( RW )       : ORIGIN = ORIGIN(DRAM) + LENGTH(DRAM), len = 0x3fcde710 - (ORIGIN(DRAM) + LENGTH(DRAM))
 
     /* External flash */
     /* Instruction ROM */

esp-hal/ld/esp32c6/esp32c6.x

@@ -78,6 +78,7 @@ INCLUDE "rodata.x"
 INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 INCLUDE "debug.x"

esp-hal/ld/esp32c6/memory.x

@@ -21,6 +21,9 @@ MEMORY
     */
     RAM : ORIGIN = 0x40800000 , LENGTH = 0x6E610
 
+    /* memory available after the 2nd stage bootloader is finished */
+    dram2_seg ( RW )       : ORIGIN = ORIGIN(RAM) + LENGTH(RAM), len = 0x4087e610 - (ORIGIN(RAM) + LENGTH(RAM))
+
     /* External flash */
     /* Instruction and Data ROM */
     ROM : ORIGIN =   0x42000000 + 0x20, LENGTH = 0x400000 - 0x20

esp-hal/ld/esp32h2/esp32h2.x

@@ -71,6 +71,7 @@ INCLUDE "rodata.x"
 INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 INCLUDE "debug.x"

esp-hal/ld/esp32h2/memory.x

@@ -17,11 +17,14 @@ MEMORY
 
     /* 320K of on soc RAM, 16K reserved for cache */
     /* Instruction and Data RAM 
-    0x4086E610 = 2nd stage bootloader iram_loader_seg start address
+    0x4083EFD0 = 2nd stage bootloader iram_loader_seg start address
     see https://github.com/espressif/esp-idf/blob/03414a15508036c8fc0f51642aed7a264e9527df/components/esp_system/ld/esp32h2/memory.ld.in#L26
     */
     RAM : ORIGIN = 0x40800000, LENGTH = 0x3EFD0
 
+    /* memory available after the 2nd stage bootloader is finished */
+    dram2_seg ( RW )       : ORIGIN = ORIGIN(RAM) + LENGTH(RAM), len = 0x4084fee0 - (ORIGIN(RAM) + LENGTH(RAM))
+
     /* External flash */
     /* Instruction and Data ROM */
     ROM : ORIGIN =   0x42000000, LENGTH = 0x400000

esp-hal/ld/esp32s2/esp32s2.x

@@ -34,6 +34,7 @@ INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "rtc_slow.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 EXTERN(DefaultHandler);

esp-hal/ld/esp32s2/memory.x

@@ -15,11 +15,14 @@ VECTORS_SIZE = 0x400;
 /* Specify main memory areas */
 MEMORY
 {
-  vectors_seg ( RX )     : ORIGIN = 0x40020000 + RESERVE_CACHES, len = VECTORS_SIZE /* SRAM0 */
+  vectors_seg ( RX )     : ORIGIN = 0x40020000 + RESERVE_CACHES, len = VECTORS_SIZE
-  iram_seg ( RX )        : ORIGIN = 0x40020000 + RESERVE_CACHES + VECTORS_SIZE, len = 192k - RESERVE_CACHES - VECTORS_SIZE /* SRAM0 */
+  iram_seg ( RX )        : ORIGIN = 0x40020000 + RESERVE_CACHES + VECTORS_SIZE, len = 188k - RESERVE_CACHES - VECTORS_SIZE
 
   dram_seg ( RW )        : ORIGIN = 0x3FFB0000 + RESERVE_CACHES + VECTORS_SIZE, len = 188k - RESERVE_CACHES - VECTORS_SIZE
 
+  /* memory available after the 2nd stage bootloader is finished */
+  dram2_seg ( RW )       : ORIGIN = ORIGIN(dram_seg) + LENGTH(dram_seg), len = 0x3ffffa10 - (ORIGIN(dram_seg) + LENGTH(dram_seg))
+
   /* external flash 
      The 0x20 offset is a convenience for the app binary image generation.
      Flash cache has 64KB pages. The .bin file which is flashed to the chip

esp-hal/ld/esp32s3/esp32s3.x

@@ -48,6 +48,7 @@ INCLUDE "rwdata.x"
 INCLUDE "rtc_fast.x"
 INCLUDE "rtc_slow.x"
 INCLUDE "stack.x"
+INCLUDE "dram2.x"
 /* End of Shared sections */
 
 EXTERN(DefaultHandler);

esp-hal/ld/esp32s3/memory.x

@@ -24,6 +24,9 @@ MEMORY
   iram_seg ( RX )        : ORIGIN = 0x40370000 + RESERVE_ICACHE + VECTORS_SIZE, len = 328k - VECTORS_SIZE - RESERVE_ICACHE
   dram_seg ( RW )        : ORIGIN = 0x3FC88000 , len = 345856 
 
+  /* memory available after the 2nd stage bootloader is finished */
+  dram2_seg ( RW )       : ORIGIN = ORIGIN(dram_seg) + LENGTH(dram_seg), len = 0x3fced710 - (ORIGIN(dram_seg) + LENGTH(dram_seg))
+
   /* external flash 
      The 0x20 offset is a convenience for the app binary image generation.
      Flash cache has 64KB pages. The .bin file which is flashed to the chip

esp-hal/ld/sections/dram2.x

@@ -0,0 +1,6 @@
+/* an uninitialized section of RAM otherwise not useable */
+SECTIONS {
+    .dram2_uninit (NOLOAD) : ALIGN(4) {
+        *(.dram2_uninit)
+    } > dram2_seg
+}