57 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			57 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Copyright 2021 QMK
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 *
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 * This program is free software: you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation, either version 3 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
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 */
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#include "bootloader.h"
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#include <avr/wdt.h>
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#define FLASH_SIZE (FLASHEND + 1L)
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#if !defined(MCUCSR)
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#    if defined(MCUSR)
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#        define MCUCSR MCUSR
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#    endif
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#endif
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__attribute__((weak)) void bootloader_jump(void) {
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    // Taken with permission of Stephan Baerwolf from https://github.com/tinyusbboard/API/blob/master/apipage.c
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    wdt_enable(WDTO_15MS);
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    wdt_reset();
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    asm volatile("cli                    \n\t"
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                 "ldi    r29 ,       %[ramendhi] \n\t"
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                 "ldi    r28 ,       %[ramendlo] \n\t"
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#if (FLASHEND > 131071)
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                 "ldi    r18 ,       %[bootaddrhi]   \n\t"
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                 "st     Y+,         r18     \n\t"
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#endif
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                 "ldi    r18 ,       %[bootaddrme]   \n\t"
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                 "st     Y+,     r18     \n\t"
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                 "ldi    r18 ,       %[bootaddrlo]   \n\t"
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                 "st     Y+,     r18     \n\t"
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                 "out    %[mcucsrio],    __zero_reg__    \n\t"
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                 "bootloader_startup_loop%=:         \n\t"
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                 "rjmp bootloader_startup_loop%=     \n\t"
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                 :
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                 : [mcucsrio] "I"(_SFR_IO_ADDR(MCUCSR)),
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#if (FLASHEND > 131071)
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                   [ramendhi] "M"(((RAMEND - 2) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 2) >> 0) & 0xff), [bootaddrhi] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
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#else
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                   [ramendhi] "M"(((RAMEND - 1) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 1) >> 0) & 0xff),
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#endif
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                   [bootaddrme] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [bootaddrlo] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
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}
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