xtensa/esp32: Implement board_boot_image for mcuboot/nxboot support

This commit adds the board_boot_image() implementation for ESP32, enabling support for MCUboot and nxboot bootloaders. It includes parsing the image header and setting up the necessary MMU mappings.

Signed-off-by: Aviral Garg <aviral.garg.2023@gmail.com>

arch/xtensa/include/esp32/partition.h

@@ -33,8 +33,7 @@
 
 /* OTA image operation code */
 
-enum ota_img_ctrl
-{
+enum ota_img_ctrl {
   OTA_IMG_GET_BOOT = 0xe1,
   OTA_IMG_SET_BOOT = 0xe2,
   OTA_IMG_SET_ENCRYPTED = 0xe3,
@@ -43,15 +42,15 @@ enum ota_img_ctrl
   OTA_IMG_GET_SUBTYPE = 0xe6,
   OTA_IMG_INVALIDATE_BOOT = 0xe7,
   OTA_IMG_IS_MAPPED_AS_TEXT = 0xe8,
+  OTA_IMG_GET_OFFSET = 0xe9,
 };
 
 /* OTA image boot sequency */
 
-enum ota_img_bootseq
-{
-  OTA_IMG_BOOT_FACTORY    = 0,
-  OTA_IMG_BOOT_OTA_0      = 1,
-  OTA_IMG_BOOT_OTA_1      = 2,
+enum ota_img_bootseq {
+  OTA_IMG_BOOT_FACTORY = 0,
+  OTA_IMG_BOOT_OTA_0 = 1,
+  OTA_IMG_BOOT_OTA_1 = 2,
   OTA_IMG_BOOT_SEQ_MAX
 };
 
@@ -72,7 +71,7 @@ enum ota_img_bootseq
  *
  ****************************************************************************/
 
-int esp32_partition_read_decrypt(const char *label, size_t offset,
-                                 void *buf, size_t size);
+int esp32_partition_read_decrypt(const char *label, size_t offset, void *buf,
+                                 size_t size);
 
 #endif /* __ARCH_XTENSA_INCLUDE_ESP32_PARTITION_H */

boards/xtensa/esp32/common/src/Make.defs

@@ -178,6 +178,8 @@ ifeq ($(CONFIG_ETC_ROMFS),y)
   RCSRCS  = etc/init.d/rc.sysinit etc/init.d/rcS
 endif
 
+CSRCS += esp32_boot_image.c
+
 DEPPATH += --dep-path src
 VPATH += :src
 CFLAGS += ${INCDIR_PREFIX}$(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)src

boards/xtensa/esp32/common/src/esp32_boot_image.c

@@ -0,0 +1,230 @@
+/****************************************************************************
+ * boards/xtensa/esp32/common/src/esp32_boot_image.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <debug.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include <arch/esp32/partition.h>
+#include <nuttx/board.h>
+#include <nuttx/cache.h>
+#include <nuttx/irq.h>
+
+#include "esp_app_format.h"
+#include "esp_loader.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define ESP32_APP_IMAGE_MAGIC 0xE9
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct esp32_boot_loader_args_s {
+  uint32_t entry_addr;
+  uint32_t drom_addr;
+  uint32_t drom_vaddr;
+  uint32_t drom_size;
+  uint32_t irom_addr;
+  uint32_t irom_vaddr;
+  uint32_t irom_size;
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static void IRAM_ATTR esp32_boot_loader_stub(void *arg);
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp32_boot_loader_stub
+ *
+ * Description:
+ *   This function resides in IRAM and is responsible for switching MMU
+ *   mappings and jumping to the new application.
+ *
+ ****************************************************************************/
+
+static void IRAM_ATTR esp32_boot_loader_stub(void *arg) {
+  struct esp32_boot_loader_args_s *args =
+      (struct esp32_boot_loader_args_s *)arg;
+  void (*entry_point)(void) = (void (*)(void))args->entry_addr;
+
+  /* Disable interrupts */
+
+  up_irq_disable();
+
+  /* Disable cache */
+
+#ifdef CONFIG_ARCH_CHIP_ESP32
+  cache_read_disable(0);
+  cache_flush(0);
+#else
+  cache_hal_disable(CACHE_LL_LEVEL_EXT_MEM, CACHE_TYPE_ALL);
+#endif
+
+  /* Map new segments */
+
+  map_rom_segments(args->drom_addr, args->drom_vaddr, args->drom_size,
+                   args->irom_addr, args->irom_vaddr, args->irom_size);
+
+  /* Jump to entry point */
+
+  entry_point();
+
+  /* Should never reach here */
+
+  while (1) {
+  }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_boot_image
+ *
+ * Description:
+ *   Boot a new application image.
+ *
+ * Input Parameters:
+ *   path     - Path to the image file/partition
+ *   hdr_size - Size of the image header (unused for ESP32)
+ *
+ * Returned Value:
+ *   Does not return on success; returns error code on failure.
+ *
+ ****************************************************************************/
+
+int board_boot_image(FAR const char *path, uint32_t hdr_size) {
+  int fd;
+  int ret;
+  uint32_t offset;
+  esp_image_header_t image_header;
+  esp_image_segment_header_t segment_hdr;
+  struct esp32_boot_loader_args_s args = {0};
+  uint32_t current_offset;
+  int i;
+
+  /* Check for legacy format (not supported) */
+
+#ifdef CONFIG_ESP32_APP_FORMAT_LEGACY
+  ferr("ERROR: Legacy format not supported for board_boot_image\n");
+  return -ENOTSUP;
+#endif
+
+  /* Open the image file */
+
+  fd = open(path, O_RDONLY);
+  if (fd < 0) {
+    ferr("ERROR: Failed to open %s: %d\n", path, errno);
+    return -errno;
+  }
+
+  /* Get partition offset */
+
+  ret = ioctl(fd, OTA_IMG_GET_OFFSET, (unsigned long)&offset);
+  if (ret < 0) {
+    ferr("ERROR: Failed to get partition offset: %d\n", errno);
+    close(fd);
+    return -errno;
+  }
+
+  /* Read image header */
+
+  ret = read(fd, &image_header, sizeof(esp_image_header_t));
+  if (ret != sizeof(esp_image_header_t)) {
+    ferr("ERROR: Failed to read image header: %d\n", errno);
+    close(fd);
+    return -errno;
+  }
+
+  if (image_header.magic != ESP32_APP_IMAGE_MAGIC) {
+    ferr("ERROR: Invalid image magic: 0x%02x\n", image_header.magic);
+    close(fd);
+    return -EINVAL;
+  }
+
+  args.entry_addr = image_header.entry_addr;
+  current_offset = sizeof(esp_image_header_t);
+
+  /* Parse segments */
+
+  for (i = 0; i < image_header.segment_count; i++) {
+    ret = read(fd, &segment_hdr, sizeof(esp_image_segment_header_t));
+    if (ret != sizeof(esp_image_segment_header_t)) {
+      ferr("ERROR: Failed to read segment header: %d\n", errno);
+      close(fd);
+      return -errno;
+    }
+
+    /* Check for IROM/DROM segments */
+
+    if (segment_hdr.load_addr >= 0x3f400000 &&
+        segment_hdr.load_addr < 0x3f800000) /* DROM */
+    {
+      args.drom_addr =
+          offset + current_offset + sizeof(esp_image_segment_header_t);
+      args.drom_vaddr = segment_hdr.load_addr;
+      args.drom_size = segment_hdr.data_len;
+    } else if (segment_hdr.load_addr >= 0x400d0000 &&
+               segment_hdr.load_addr < 0x40400000) /* IROM */
+    {
+      args.irom_addr =
+          offset + current_offset + sizeof(esp_image_segment_header_t);
+      args.irom_vaddr = segment_hdr.load_addr;
+      args.irom_size = segment_hdr.data_len;
+    }
+
+    current_offset += sizeof(esp_image_segment_header_t) + segment_hdr.data_len;
+
+    /* Advance file pointer to next segment */
+
+    lseek(fd, segment_hdr.data_len, SEEK_CUR);
+  }
+
+  close(fd);
+
+  finfo("Booting image: entry=0x%08" PRIx32 ", drom=0x%08" PRIx32
+        " (0x%08" PRIx32 "), irom=0x%08" PRIx32 " (0x%08" PRIx32 ")\n",
+        args.entry_addr, args.drom_vaddr, args.drom_size, args.irom_vaddr,
+        args.irom_size);
+
+  /* Invoke IRAM loader stub */
+
+  esp32_boot_loader_stub(&args);
+
+  return 0;
+}