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firmware_size.s
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firmware_size.s
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; SPDX-FileCopyrightText: 2023 Andreas Sig Rosvall
;
; SPDX-License-Identifier: GPL-3.0-or-later
.module firmware_size
.include "bsp/mem.inc"
.include "bsp/flash.inc"
.include "bsp/watchdog.inc"
.include "macros.inc"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.area DSEG (DATA)
; number of available 2k pages installed in chip
flash_page_count:: .ds 1
; last written page
fw_last_page:: .ds 1
; last written byte in last written page
fw_last_byte_l:: .ds 1
fw_last_byte_h:: .ds 1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.area CSEG (CODE)
; Figure out size of installed firmware by scanning through flash backwards to
; find the first byte that isn't 0xFF.
get_firmware_size::
; First find size of flash by finding the number of 32k-sized flash banks
; If we set MEMCTR to a non-existent bank, it won't stick
mov a, #MAX_BANK_COUNT
try_lower_bank:
mov r2, a
dec a
mov MEMCTR, a
cjne a, MEMCTR, try_lower_bank
; r2 = number 32k flash banks available
; Calculate and store number of pages = a * 16 = a << 4
mov a, r2
swap a
mov flash_page_count, a
mov r1, a
.print ^"flash page count: "
mov r0, #1
acall print_hex
; Now loop through flash backwards to find the first non-0xff byte
; We're only looking in the high 32k, where we can map all flash in
; MEMCTR is set to highest bank
memctr_loop:
mov r1, #0x80
mov MPAGE, #0
mpage_loop:
dec MPAGE
mov r0, #0
inner_loop:
dec r0
movx a, @r0
inc a
jnz found_a_written_byte
cjne r0, #0, inner_loop
djnz r1, mpage_loop
; Feed watchdog
mov WDCTL, #WDCTL_FEED1
mov WDCTL, #WDCTL_FEED2
dec MEMCTR
djnz r2, memctr_loop
; Unreachable: We didn't find a single written byte in flash
found_a_written_byte:
; MEMCTR 00000PPP
; MPAGE 1ppppHHH
; R0 LLLLLLLL
; last_page 0PPPpppp
; last_byte_h 00000HHH
; last_byte_l LLLLLLLL
.print ^"fw last byte: "
mov fw_last_byte_l, r0
mov a, MPAGE
anl a, #0b111
mov fw_last_byte_h, a
mov r2, a
mov r1, fw_last_byte_l
mov r0, #2
acall print_hex
.print ^"fw last page: "
mov a, MPAGE
rl a
anl a, #0xf0
orl a, MEMCTR
swap a
mov fw_last_page, a
mov r1, a
mov r0, #1
acall print_hex
; reset MEMCTR and MPAGE
mov MPAGE, #0
mov MEMCTR, #0
ret