reading eboot commands via RTC, flash erase/copy

Author: igrr

hardware/esp8266com/esp8266/bootloaders/eboot/Makefile

@@ -5,6 +5,7 @@ TARGET_DIR := ./
 
 TARGET_OBJ_FILES := \
 	eboot.o \
+	eboot_command.o \
 
 TARGET_OBJ_PATHS := $(addprefix $(TARGET_DIR)/,$(TARGET_OBJ_FILES))
 
@@ -17,7 +18,7 @@ OBJDUMP := $(XTENSA_TOOCHAIN)xtensa-lx106-elf-objdump
 
 CFLAGS += -std=gnu99
 
-CFLAGS += -O0 -g -Wpointer-arith -Wno-implicit-function-declaration -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mno-text-section-literals
+CFLAGS += -Os -g -Wpointer-arith -Wno-implicit-function-declaration -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mno-text-section-literals
 
 LDFLAGS	+= -nostdlib -Wl,--no-check-sections -umain
 

hardware/esp8266com/esp8266/bootloaders/eboot/eboot.c

@@ -10,6 +10,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include "eboot.h"
+#include "eboot_command.h"
 extern void* flashchip;
 
 #define SWRST do { (*((volatile uint32_t*) 0x60000700)) |= 0x80000000; } while(0);
@@ -71,9 +72,100 @@ int load_app_from_flash_raw(const uint32_t flash_addr)
 }
 
 
+
+int erase(const uint32_t start, const uint32_t size)
+{
+    if (start & (FLASH_SECTOR_SIZE - 1) != 0) {
+        return 1;
+    }
+
+    const uint32_t sectors_per_block = FLASH_BLOCK_SIZE / FLASH_SECTOR_SIZE;
+    uint32_t current_sector = start / FLASH_SECTOR_SIZE;
+    uint32_t sector_count = (size + FLASH_SECTOR_SIZE - 1) / FLASH_SECTOR_SIZE;
+    const uint32_t end = current_sector + sector_count;
+
+    for (; current_sector < end && (current_sector & (sectors_per_block-1)); 
+        ++current_sector, --sector_count) {
+        if (SPIEraseSector(current_sector)) {
+            return 2;
+        }
+    }
+
+    for (;current_sector + sectors_per_block <= end; 
+        current_sector += sectors_per_block, 
+        sector_count -= sectors_per_block) {
+        if (SPIEraseBlock(current_sector / sectors_per_block)) {
+            return 3;
+        }
+    }
+
+    for (; current_sector < end; 
+        ++current_sector, --sector_count) {
+        if (SPIEraseSector(current_sector)) {
+            return 4;
+        }
+    }
+
+    return 0;
+}
+
+int copy_raw(const uint32_t src_addr, 
+             const uint32_t dst_addr, 
+             const uint32_t size)
+{
+    // require regions to be aligned
+    if (src_addr & 0xfff != 0 ||
+        dst_addr & 0xfff != 0) {
+        return 1;
+    }
+
+    if (erase(dst_addr, size)) {
+        return 2;
+    }
+
+    const uint32_t buffer_size = 4096;
+    uint8_t buffer[buffer_size];
+
+    const uint32_t end = src_addr + size;
+    uint32_t saddr = src_addr;
+    uint32_t daddr = dst_addr;
+    uint32_t left = size;
+    while (saddr < end) {
+        uint32_t will_copy = (left < buffer_size) ? left : buffer_size;
+        if (SPIRead(saddr, buffer, will_copy)) {
+            return 3;
+        }
+        if (SPIWrite(daddr, buffer, will_copy)) {
+            return 4;
+        }
+        saddr += will_copy;
+        daddr += will_copy;
+        left  -= will_copy;
+    }
+
+    return 0;
+}
+
+
+
 void main()
 {
-    int res = load_app_from_flash_raw(0);
+    int res;
+    struct eboot_command cmd;
+
+    eboot_command_read(&cmd);
+
+    if (cmd.action == ACTION_COPY_RAW) {
+        res = copy_raw(cmd.args[0], cmd.args[1], cmd.args[2]);
+        if (res == 0) {
+            cmd.action = ACTION_LOAD_APP;
+        }
+    }
+
+    if (cmd.action == ACTION_LOAD_APP) {
+        res = load_app_from_flash_raw(0);
+    }
+
     if (res) {
         ets_putc('\n');
         ets_putc('#');

hardware/esp8266com/esp8266/bootloaders/eboot/eboot.elf

@@ -14,6 +14,9 @@ int SPIEraseSector(uint32_t sector);
 int SPIRead(uint32_t addr, void *dest, size_t size);
 int SPIWrite(uint32_t addr, void *src, size_t size);
 
+
+#define FLASH_SECTOR_SIZE 0x1000
+#define FLASH_BLOCK_SIZE 0x10000
 #define APP_START_OFFSET 0x1000
 
 typedef struct {

hardware/esp8266com/esp8266/bootloaders/eboot/eboot.h

@@ -0,0 +1,47 @@
+#include "eboot_command.h"
+
+uint32_t crc_update(uint32_t crc, const uint8_t *data, size_t length)
+{
+    uint32_t i;
+    bool bit;
+    uint8_t c;
+    
+    while (length--) {
+        c = *data++;
+        for (i = 0x80; i > 0; i >>= 1) {
+            bit = crc & 0x80000000;
+            if (c & i) {
+                bit = !bit;
+            }
+            crc <<= 1;
+            if (bit) {
+                crc ^= 0x04c11db7;
+            }
+        }
+    }
+    return crc;
+}
+
+uint32_t eboot_command_calculate_crc32(const struct eboot_command* cmd)
+{
+    return crc_update(0xffffffff, (const uint8_t*) cmd, 
+                      offsetof(struct eboot_command, crc32));
+}
+
+void eboot_command_read(struct eboot_command* cmd)
+{
+    const uint32_t dw_count = sizeof(struct eboot_command) / sizeof(uint32_t);
+    uint32_t* dst = (uint32_t *) cmd;
+    for (uint32_t i = 0; i < dw_count; ++i) {
+        dst[i] = RTC_MEM[i];
+    }
+
+    uint32_t crc32 = eboot_command_calculate_crc32(cmd);
+    if (cmd->magic & EBOOT_MAGIC_MASK != EBOOT_MAGIC || 
+        cmd->crc32 != crc32) {
+        
+        cmd->action = ACTION_LOAD_APP;
+        cmd->args[0] = 0;
+    }
+}
+

hardware/esp8266com/esp8266/bootloaders/eboot/eboot_command.c

@@ -0,0 +1,29 @@
+#ifndef EBOOT_COMMAND_H
+#define EBOOT_COMMAND_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#define RTC_MEM ((volatile uint32_t*)0x60001200)
+
+enum action_t {
+    ACTION_COPY_RAW = 0x00000001,
+    ACTION_LOAD_APP = 0xffffffff
+};
+
+#define EBOOT_MAGIC 	 0xeb001000
+#define EBOOT_MAGIC_MASK 0xfffff000
+
+struct eboot_command {
+    uint32_t magic;
+    enum action_t action;
+    uint32_t args[29];
+    uint32_t crc32;
+};
+
+
+void eboot_command_read(struct eboot_command* cmd);
+
+
+#endif //EBOOT_COMMAND_H