esp32: add simple boot support

The Simple Boot feature for Espressif chips is a method of booting
that doesn't depend on a 2nd stage bootloader. Its not the
intention to replace a 2nd stage bootloader such as MCUboot and
ESP-IDF bootloader, but to have a minimal and straight-forward way
of booting, and also simplify the building.

This commit also removes deprecated code and makes this bootloader
configuration as default for esp32 targets and removes the need
for running 'make bootloader' command for it.

Signed-off-by: Almir Okato <almir.okato@espressif.com>

Documentation/platforms/xtensa/esp32/index.rst

@@ -99,14 +99,48 @@ These steps are given in the setup guide in
 Building and flashing NuttX
 ===========================
 
-Firmware for ESP32 is flashed via the USB/UART interface using the ``esptool.py`` tool.
-It's a two step process where the first converts the ELF file into a ESP32-compatible binary
-and the second flashes it to the board.  These steps are included into the build system and you can
-flash your NuttX firmware simply by running::
+Bootloader and partitions
+-------------------------
+
+NuttX can boot the ESP32 directly using the so-called "Simple Boot". An externally-built
+2nd stage bootloader is not required in this case as all functions required to boot the device
+are built within NuttX. Simple boot does not require any specific configuration (it is selectable
+by default if no other 2nd stage bootloader is used).
+
+If other features are required, an externally-built 2nd stage bootloader is needed. The bootloader
+is built using the ``make bootloader`` command. This command generates the firmware in the
+``nuttx`` folder. The ``ESPTOOL_BINDIR`` is used in the ``make flash`` command to specify the path
+to the bootloader. For compatibility among other SoCs and future options of 2nd stage bootloaders,
+the commands ``make bootloader`` and the ``ESPTOOL_BINDIR`` option (for the ``make flash``) can be
+used even if no externally-built 2nd stage bootloader is being built (they will be ignored if
+Simple Boot is used, for instance)::
+
+  $ make bootloader
+
+.. note:: It is recommended that if this is the first time you are using the board with NuttX to
+   perform a complete SPI FLASH erase.
+
+    .. code-block:: console
+
+      $ esptool.py erase_flash
+
+Building and Flashing
+---------------------
+
+First, make sure that ``esptool.py`` is installed.  This tool is used to convert the ELF to a
+compatible ESP32 image and to flash the image into the board.
+It can be installed with: ``pip install esptool==4.8.dev4``.
+
+It's a two-step process where the first converts the ELF file into an ESP32 compatible binary
+and the second flashes it to the board. These steps are included in the build system and it is
+possible to build and flash the NuttX firmware simply by running::
 
-    $ make flash ESPTOOL_PORT=<port>
+    $ make flash ESPTOOL_PORT=<port> ESPTOOL_BINDIR=./
 
-where ``<port>`` is typically ``/dev/ttyUSB0`` or similar. You can change the baudrate by passing ``ESPTOOL_BAUD``.
+where ``<port>`` is typically ``/dev/ttyUSB0`` or similar. ``ESPTOOL_BINDIR=./`` is the path of the
+externally-built 2nd stage bootloader and the partition table (if applicable): when built using the
+``make bootloader``, these files are placed into ``nuttx`` folder. ``ESPTOOL_BAUD`` is able to
+change the flash baud rate if desired.
 
 Debugging with OpenOCD
 ======================
@@ -135,24 +169,6 @@ OpenOCD can then be used::
 
   openocd -c 'set ESP_RTOS hwthread; set ESP_FLASH_SIZE 0' -f board/esp32-wrover-kit-1.8v.cfg
 
-Bootloader and partitions
--------------------------
-
-ESP32 requires a bootloader to be flashed as well as a set of FLASH partitions. This is only needed the first time
-(or any time you which to modify either of these). An easy way is to use prebuilt binaries for NuttX `from here <https://github.com/espressif/esp-nuttx-bootloader>`__. In there you will find instructions to rebuild these if necessary.
-Once you downloaded both binaries, you can flash them by adding an ``ESPTOOL_BINDIR`` parameter, pointing to the directory where these binaries were downloaded:
-
-.. code-block:: console
-
-   $ make flash ESPTOOL_PORT=<port> ESPTOOL_BINDIR=<dir>
-
-.. note:: It is recommended that if this is the first time you are using the board with NuttX that you perform a complete
-   SPI FLASH erase.
-
-   .. code-block:: console
-
-      $ esptool.py erase_flash
-
 Peripheral Support
 ==================
 

arch/xtensa/src/common/espressif/Make.defs

@@ -30,6 +30,7 @@ CHIP_CSRCS += esp_mcpwm.c
 endif
 
 ifeq ($(filter $(CONFIG_ESPRESSIF_SIMPLE_BOOT) \
+      $(CONFIG_ESP32_APP_FORMAT_MCUBOOT) \
       $(CONFIG_ESP32S2_APP_FORMAT_MCUBOOT) \
       $(CONFIG_ESP32S3_APP_FORMAT_MCUBOOT),y),y)
 CHIP_CSRCS += esp_loader.c

arch/xtensa/src/common/espressif/esp_loader.c

@@ -35,10 +35,13 @@
 #include "hal/cache_types.h"
 #include "hal/cache_ll.h"
 #include "hal/cache_hal.h"
-#include "soc/extmem_reg.h"
 #include "rom/cache.h"
 #include "spi_flash_mmap.h"
 
+#ifndef CONFIG_ARCH_CHIP_ESP32
+#  include "soc/extmem_reg.h"
+#endif
+
 #  include "bootloader_flash_priv.h"
 #ifdef CONFIG_ESPRESSIF_SIMPLE_BOOT
 #  include "bootloader_init.h"
@@ -107,6 +110,16 @@ extern uint8_t _image_drom_size[];
 
 extern int ets_printf(const char *fmt, ...) printf_like(1, 2);
 
+#ifdef CONFIG_ARCH_CHIP_ESP32
+extern void cache_read_enable(int cpu);
+extern void cache_read_disable(int cpu);
+extern void cache_flush(int cpu);
+extern unsigned int cache_flash_mmu_set(int cpu_no, int pid,
+                                        unsigned int vaddr,
+                                        unsigned int paddr,
+                                        int psize, int num);
+#endif
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -140,6 +153,11 @@ int map_rom_segments(uint32_t app_drom_start, uint32_t app_drom_vaddr,
   uint32_t app_drom_start_aligned = app_drom_start & MMU_FLASH_MASK;
   uint32_t app_drom_vaddr_aligned = app_drom_vaddr & MMU_FLASH_MASK;
 
+#ifdef CONFIG_ARCH_CHIP_ESP32
+  uint32_t drom_page_count = 0;
+  uint32_t irom_page_count = 0;
+#endif
+
 #ifdef CONFIG_ESPRESSIF_SIMPLE_BOOT
   esp_image_header_t image_header; /* Header for entire image */
   esp_image_segment_header_t WORD_ALIGNED_ATTR segment_hdr;
@@ -244,7 +262,8 @@ int map_rom_segments(uint32_t app_drom_start, uint32_t app_drom_vaddr,
 #endif
 
 #if defined (CONFIG_ESP32S2_APP_FORMAT_MCUBOOT) || \
-    defined (CONFIG_ESP32S3_APP_FORMAT_MCUBOOT)
+    defined (CONFIG_ESP32S3_APP_FORMAT_MCUBOOT) || \
+    defined (CONFIG_ESP32_APP_FORMAT_MCUBOOT)
   ets_printf("IROM segment aligned lma 0x%08x vma 0x%08x len 0x%06x (%u)\n",
       app_irom_start_aligned, app_irom_vaddr_aligned,
       app_irom_size, app_irom_size);
@@ -253,21 +272,46 @@ int map_rom_segments(uint32_t app_drom_start, uint32_t app_drom_vaddr,
       app_drom_size, app_drom_size);
 #endif
 
+#ifdef CONFIG_ARCH_CHIP_ESP32
+  cache_read_disable(0);
+  cache_flush(0);
+#else
   cache_hal_disable(CACHE_TYPE_ALL);
+#endif
 
   /* Clear the MMU entries that are already set up,
    * so the new app only has the mappings it creates.
    */
 
   mmu_hal_unmap_all();
 
+#ifdef CONFIG_ARCH_CHIP_ESP32
+  drom_page_count = (app_drom_size + SPI_FLASH_MMU_PAGE_SIZE - 1) /
+                              SPI_FLASH_MMU_PAGE_SIZE;
+  rc  = cache_flash_mmu_set(0, 0, app_drom_vaddr_aligned,
+                            app_drom_start_aligned, 64,
+                            (int)drom_page_count);
+  rc |= cache_flash_mmu_set(1, 0, app_drom_vaddr_aligned,
+                            app_drom_start_aligned, 64,
+                            (int)drom_page_count);
+
+  irom_page_count = (app_irom_size + SPI_FLASH_MMU_PAGE_SIZE - 1) /
+                              SPI_FLASH_MMU_PAGE_SIZE;
+  rc |= cache_flash_mmu_set(0, 0, app_irom_vaddr_aligned,
+                            app_irom_start_aligned, 64,
+                            (int)irom_page_count);
+  rc |= cache_flash_mmu_set(1, 0, app_irom_vaddr_aligned,
+                            app_irom_start_aligned, 64,
+                            (int)irom_page_count);
+#else
   mmu_hal_map_region(0, MMU_TARGET_FLASH0,
                      app_drom_vaddr_aligned, app_drom_start_aligned,
                      app_drom_size, &actual_mapped_len);
 
   mmu_hal_map_region(0, MMU_TARGET_FLASH0,
                      app_irom_vaddr_aligned, app_irom_start_aligned,
                      app_irom_size, &actual_mapped_len);
+#endif
 
   /* ------------------Enable corresponding buses--------------------- */
 
@@ -285,7 +329,10 @@ int map_rom_segments(uint32_t app_drom_start, uint32_t app_drom_vaddr,
 
   /* ------------------Enable Cache----------------------------------- */
 
+#ifdef CONFIG_ARCH_CHIP_ESP32
+  cache_read_enable(0);
+#else
   cache_hal_enable(CACHE_TYPE_ALL);
-
+#endif
   return (int)rc;
 }

arch/xtensa/src/esp32/Bootloader.mk

@@ -20,7 +20,7 @@
 
 .PHONY: bootloader clean_bootloader
 
-ifeq ($(CONFIG_ESP32_BOOTLOADER_BUILD_FROM_SOURCE),y)
+ifeq ($(CONFIG_ESPRESSIF_SIMPLE_BOOT),)
 
 TOOLSDIR           = $(TOPDIR)/tools/espressif
 CHIPDIR            = $(TOPDIR)/arch/xtensa/src/chip
@@ -112,8 +112,13 @@ else ifeq ($(CONFIG_ESP32_APP_FORMAT_LEGACY),y)
 		$(call cfg_val,CONFIG_PARTITION_TABLE_OFFSET,$(CONFIG_ESP32_PARTITION_TABLE_OFFSET)) \
 	} >> $(BOOTLOADER_CONFIG)
 endif
+endif
 
-ifeq ($(CONFIG_ESP32_APP_FORMAT_MCUBOOT),y)
+ifeq ($(CONFIG_ESPRESSIF_SIMPLE_BOOT),y)
+bootloader:
+	$(Q) echo "Using direct bootloader to boot NuttX."
+
+else ifeq ($(CONFIG_ESP32_APP_FORMAT_MCUBOOT),y)
 
 BOOTLOADER_BIN        = $(TOPDIR)/mcuboot-esp32.bin
 BOOTLOADER_SIGNED_BIN = $(TOPDIR)/mcuboot-esp32.signed.bin
@@ -186,22 +191,3 @@ clean_bootloader:
 	$(call DELFILE,$(TOPDIR)/partition-table-esp32.bin)
 
 endif
-
-else ifeq ($(CONFIG_ESP32_BOOTLOADER_DOWNLOAD_PREBUILT),y)
-
-BOOTLOADER_VERSION = latest
-BOOTLOADER_URL     = https://github.com/espressif/esp-nuttx-bootloader/releases/download/$(BOOTLOADER_VERSION)
-
-ifeq ($(CONFIG_ESP32_APP_FORMAT_LEGACY),y)
-
-bootloader:
-	$(call DOWNLOAD,$(BOOTLOADER_URL),bootloader-esp32.bin,$(TOPDIR)/bootloader-esp32.bin)
-	$(call DOWNLOAD,$(BOOTLOADER_URL),partition-table-esp32.bin,$(TOPDIR)/partition-table-esp32.bin)
-
-clean_bootloader:
-	$(call DELFILE,$(TOPDIR)/bootloader-esp32.bin)
-	$(call DELFILE,$(TOPDIR)/partition-table-esp32.bin)
-
-endif
-
-endif

arch/xtensa/src/esp32/Kconfig

@@ -103,6 +103,11 @@ config ESPRESSIF_CHIP_SERIES
 	string
 	default "esp32"
 
+config ESPRESSIF_NUM_CPUS
+	int
+	default 1 if ESP32_SINGLE_CPU
+	default 2 if ESP32_DUAL_CPU
+
 config ESP32_SINGLE_CPU
 	bool
 	default n
@@ -1890,7 +1895,6 @@ comment "Partition Table Configuration"
 config ESP32_PARTITION_TABLE
 	bool "Create MTD partitions from Partition Table"
 	default n
-	select ESP32_BOOTLOADER_BUILD_FROM_SOURCE
 	---help---
 		Decode partition table and initialize partitions as MTD.
 
@@ -2560,39 +2564,26 @@ config ESP32_HAVE_OTA_PARTITION
 
 menu "Bootloader and Image Configuration"
 
+config ESPRESSIF_SIMPLE_BOOT
+	bool
+	depends on !ESP32_APP_FORMAT_MCUBOOT && !ESP32_APP_FORMAT_LEGACY
+	default y
+
 config ESP32_APP_FORMAT_LEGACY
 	bool "Enable legacy IDF bootloader format"
-	default y if !ESP32_APP_FORMAT_MCUBOOT
-	depends on !ESP32_APP_FORMAT_MCUBOOT
+	default y if BUILD_PROTECTED
 	---help---
 		This is the legacy application image format, as supported by the ESP-IDF
 		2nd stage bootloader.
 
 config ESP32_APP_FORMAT_MCUBOOT
 	bool "Enable MCUboot-bootable format"
 	depends on !MCUBOOT_BOOTLOADER
+	default n
 	select ESP32_HAVE_OTA_PARTITION
-	select ESP32_BOOTLOADER_BUILD_FROM_SOURCE
 	---help---
 		Enables the Espressif port of MCUboot to be used as 2nd stage bootloader.
 
-config ESP32_BOOTLOADER_DOWNLOAD_PREBUILT
-	bool
-	default y if !ESP32_BOOTLOADER_BUILD_FROM_SOURCE
-	depends on !ESP32_BOOTLOADER_BUILD_FROM_SOURCE
-	---help---
-		The build system will download the prebuilt binaries from
-		https://github.com/espressif/esp-nuttx-bootloader according to the chosen
-		Application Image Format (ESP32_APP_FORMAT_LEGACY or ESP32_APP_FORMAT_MCUBOOT)
-
-config ESP32_BOOTLOADER_BUILD_FROM_SOURCE
-	bool "Build binaries from source"
-	---help---
-		The build system will build all the required binaries from source. It will clone
-		the https://github.com/espressif/esp-nuttx-bootloader repository and build a
-		custom bootloader according to the chosen Application Image Format
-		(ESP32_APP_FORMAT_LEGACY or ESP32_APP_FORMAT_MCUBOOT) and partition information.
-
 choice
 	prompt "Target slot for image flashing"
 	default ESP32_ESPTOOL_TARGET_PRIMARY
@@ -2637,7 +2628,6 @@ config ESP32_CUSTOM_PARTITION_TABLE_OFFSET
 	bool "Customize partition table offset"
 	default n
 	depends on ESP32_APP_FORMAT_LEGACY
-	select ESP32_BOOTLOADER_BUILD_FROM_SOURCE
 	---help---
 		Enable to select the offset of the partition table in the flash.
 

arch/xtensa/src/esp32/Kconfig.security

@@ -20,9 +20,6 @@ config ESP32_SECURE_BOOT
 
 if ESP32_SECURE_BOOT
 
-comment "Secure Boot support requires building the bootloader from source (ESP32_BOOTLOADER_BUILD_FROM_SOURCE)"
-	depends on !ESP32_BOOTLOADER_BUILD_FROM_SOURCE
-
 config ESP32_SECURE_BOOT_BUILD_SIGNED_BINARIES
 	bool "Sign binaries during build"
 	default y
@@ -117,9 +114,6 @@ config ESP32_SECURE_FLASH_ENC_ENABLED
 
 if ESP32_SECURE_FLASH_ENC_ENABLED
 
-comment "Flash Encryption support requires building the bootloader from source (ESP32_BOOTLOADER_BUILD_FROM_SOURCE)"
-	depends on !ESP32_BOOTLOADER_BUILD_FROM_SOURCE
-
 choice ESP32_SECURE_FLASH_ENCRYPTION_MODE
 	bool "Enable usage mode"
 	default ESP32_SECURE_FLASH_ENCRYPTION_MODE_DEVELOPMENT

arch/xtensa/src/esp32/Make.defs

@@ -208,7 +208,7 @@ endif
 
 ESP_HAL_3RDPARTY_REPO   = esp-hal-3rdparty
 ifndef ESP_HAL_3RDPARTY_VERSION
-	ESP_HAL_3RDPARTY_VERSION = 966f1bbf7d80d3fac9a43f414e864985cbcfd680
+	ESP_HAL_3RDPARTY_VERSION = 0e6895d4ce431ce95b156027e6e3af50f9b4df37
 endif
 
 ifndef ESP_HAL_3RDPARTY_URL
@@ -232,6 +232,10 @@ chip/$(ESP_HAL_3RDPARTY_REPO):
 
 CFLAGS += -Wno-undef -Wno-unused-variable
 
+# Enable strict volatile bitfield access
+
+CFLAGS += -fstrict-volatile-bitfields
+
 # Files that require the HAL recipe
 
 CHIP_SERIES = $(patsubst "%",%,$(CONFIG_ESPRESSIF_CHIP_SERIES))
@@ -251,9 +255,6 @@ ifeq ($(CONFIG_ESP32_WIRELESS),y)
 	$(Q) cd chip/$(ESP_HAL_3RDPARTY_REPO)/components/mbedtls/mbedtls && git apply ../../../nuttx/patches/components/mbedtls/mbedtls/*.patch
 endif
 
-distclean::
-	$(call DELDIR, chip/$(ESP_HAL_3RDPARTY_REPO))
-
 ifeq ($(CONFIG_ESP32_WIRELESS),y)
 include chip/Wireless.mk
 endif