Add bootloader for copying code from flash to ram

CMakeLists.txt

@@ -123,7 +123,7 @@ if(PROJECT_IS_TOP_LEVEL)
 
   # Bitstream generation
 
-  set(CLOCK_FREQUENCY 60)
+  set(CLOCK_FREQUENCY 68)
   add_ecp5_pll_generation(
     INPUT_FREQ 24
     OUTPUT_FREQ ${CLOCK_FREQUENCY}

firmware/CMakeLists.txt

@@ -56,8 +56,7 @@ add_custom_command(
 
 add_custom_target(helloworld DEPENDS helloworld.dump helloworld.load)
 
-
-add_executable(bootloader.elf ${CMAKE_CURRENT_LIST_DIR}/bootloader/bootloader.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/uart.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/spi.S)
+add_executable(bootloader.elf ${CMAKE_CURRENT_LIST_DIR}/bootloader/bootloader.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/uart.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/spi.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/flash.S ${CMAKE_CURRENT_LIST_DIR}/bootloader/elf.S)
 set_target_properties(bootloader.elf PROPERTIES COMPILE_FLAGS "${CC_OPTS} -march=rv32g -mabi=ilp32"
   LINK_FLAGS    "${CC_OPTS} -march=rv32g -mabi=ilp32 -T${CMAKE_CURRENT_LIST_DIR}/link.ld")
 

firmware/bootloader/bootloader.S

@@ -19,61 +19,62 @@
 # You should have received a copy of the GNU General Public License
 # along with ECAP5-DSOC.  If not, see <http://www.gnu.org/licenses/>.
 
+.equ FLASH_MFID,     0xEF
+.equ FLASH_DEVTYPE,  0x40
+.equ FLASH_SIZE,     0x18
+
+.equ EXE_ADDR, 0x300000
+
 .section .text
 .global _start
 _start:
+  la   sp, __BOOT_STACK_TOP__
+
   call configure_uart
   call configure_spi
-  call enable_cs
-
-  la   a0, boot_str
-  call send_string
 
-  la   a0, readingflash_str
-  call send_string
+  # Checking the flash ID
+  li   a0, FLASH_MFID
+  li   a1, FLASH_DEVTYPE
+  li   a2, FLASH_SIZE
+  call check_flash_id
+  bne  a0, x0, _booterr
 
-  li   a0, 0x9F
-  call send_spi
+  # Checking ELF 
+  li   a0, EXE_ADDR
+  call check_elf_type
+  bne  a0, x0, _booterr
 
-  li   a0, 0x00
-  call send_spi
-  mv   s0, a0
+  # Loading ELF in RAM
+  li   a0, EXE_ADDR
+  call load_elf_in_ram
+  bne  a0, x0, _booterr
 
-  li   a0, 0x00
-  call send_spi
-  mv   s1, a0
+  # Get the ELF entry point
+  la   a0, EXE_ADDR
+  call get_elf_entry
 
-  li   a0, 0x00
-  call send_spi
-  mv   s2, a0
+  # Move the entry to ra
+  mv   ra, a0
 
-  la   a0, mfid_str
-  call send_string
-
-  mv   a0, s0
-  call send_hex
+  # Set the stack pointer
+  la   sp, __RAM_END__
 
-  la   a0, type_str
-  call send_string
+  # Clear registers (except x0, ra and sp)
+  .irp r, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
+    mv x\r, x0
+  .endr
 
-  mv   a0, s1
-  call send_hex
+  # Jump to ra
+  ret
 
-  la   a0, size_str
+_booterr:
+  la   a0, bootfail_str 
   call send_string
-
-  mv   a0, s2
-  call send_hex
-
-  call disable_cs
-
-_loop:
+_loop: 
   j  _loop
 
 .align 4
 
-boot_str:         .asciz "\n\nBooting..."
-readingflash_str: .asciz "\nReading flash..."
-mfid_str:         .asciz "\nManufacturer ID : "
-type_str:        .asciz "\nType : "
-size_str:        .asciz "\nSize : "
+bootfail_str: .asciz "\n[BOOT] FAIL\n"
+pon_str: .asciz "\n[BOOT] FAIL\n"