Add fuse and lock bits reading

[budvar10]

Implementation of STK500 Universal Command for BIGBOOT setup instead of dummy functionality; the bootlader can return real fuse and lock bits instead of zeroes (avrdude -v parameter).

[hecko]

Is this something to review and is considered to be interesting for the project @WestfW ?

@budvar10 can you maybe review this pull request and provide a little more information on how do you propose to test your patch against real hardware - for example with avrdude - like comparing avrdude with atmel-ice ISP programmer output and avrdude with adruino programmer maybe?

[mcuee]

The repo (https://github.com/budvar10/optiboot/tree/patch-1) does not seem to build correctly under git bash + Atmel toochain (tried both avr-gcc 5.4.0 version and 7.3.0 version).

MINGW64 /c/work/avr/avrdude_test/others/optiboot_pr210/optiboot/bootloaders/optiboot (patch-1)
$ make atmega328 BIGBOOT=1
avr-gcc (AVR_8_bit_GNU_Toolchain_3.6.2_1778) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BAUD RATE CHECK: Desired: 115200, Real: 117647, UBRRL = 16, Error=2.1%
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=3 -DBIGBOOT=1       -c -o optiboot.o optiboot.c
optiboot.c:305:6: warning: #warning BAUD_RATE error greater than 2% [-Wcpp]
     #warning BAUD_RATE error greater than 2%
      ^
In file included from optiboot.c:253:0:
optiboot.c: In function 'main':
boot.h:637:5: warning: asm operand 3 probably doesn't match constraints
     __asm__ __volatile__                                   \
     ^
optiboot.c:588:19: note: in expansion of macro 'boot_lock_fuse_bits_get'
           ucr   = boot_lock_fuse_bits_get((uint16_t)ucb1);
                   ^
boot.h:637:5: error: impossible constraint in 'asm'
     __asm__ __volatile__                                   \
     ^
optiboot.c:588:19: note: in expansion of macro 'boot_lock_fuse_bits_get'
           ucr   = boot_lock_fuse_bits_get((uint16_t)ucb1);
                   ^
make: *** [<builtin>: optiboot.o] Error 1

[mcuee]

I tried the patch with git HEAD and it can build correctly.

$ git diff
diff --git a/optiboot/bootloaders/optiboot/optiboot.c b/optiboot/bootloaders/optiboot/optiboot.c
index 6d9e0cc..6d19f17 100644
--- a/optiboot/bootloaders/optiboot/optiboot.c
+++ b/optiboot/bootloaders/optiboot/optiboot.c
@@ -979,9 +979,30 @@ int main(void) {
         putch(0x00);
       }
       else {
-        // everything else is ignored
-        getNch(3);
-        putch(0x00);
+    /* STK500 Universal Command */
+    } else if(ch == STK_UNIVERSAL) {
+      #if defined(BIGBOOT)           // real data
+      /* read fuse and lock bits; it takes additional 80 bytes */
+        uint8_t ucb1 = getch();      // universal command byte 1
+        uint8_t ucb2 = getch();      // universal command byte 2
+        getNch(2);                   // discard universal command byte 3-4
+        uint8_t ucr  = 0;            // response
+
+      /* mapping algorithm for function parameter, optimized to save a space:
+        ucb1(0x50), ucb2(0x00) -> GET_LOW_FUSE_BITS     (0x0000)
+        ucb1(0x58), ucb2(0x00) -> GET_LOCK_BITS         (0x0001)
+        ucb1(0x50), ucb2(0x08) -> GET_EXTENDED_FUSE_BITS(0x0002)
+        ucb1(0x58), ucb2(0x08) -> GET_HIGH_FUSE_BITS    (0x0003)
+       */
+        if((ucb1 & ~(0x08)) == 0x50 && (ucb2 & ~(0x08)) == 0x00) {
+          ucb1  = ((ucb1 & 0x08) ? 1 : 0) | (ucb2 >> 2);
+          ucr   = boot_lock_fuse_bits_get((uint16_t)ucb1);
+        }
+       putch(ucr);
+      #else                          // universal command is ignored
+        getNch(4);                   // 4 bytes of data/command
+       putch(0x00);                 // response
+      #endif
       }
 #else
       // UNIVERSAL command is ignored

$ make atmega328 BIGBOOT=1
avr-gcc (AVR_8_bit_GNU_Toolchain_3.6.2_1778) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BAUD RATE CHECK: Desired: 115200, Real: 117647, UBRRL = 16, Difference=2.1%
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=3 -DBIGBOOT=1                -c -o optiboot.o optiboot.c
optiboot.c:429:2: warning: #warning BAUD_RATE off by greater than 2% [-Wcpp]
 #warning BAUD_RATE off by greater than 2%
  ^
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=3 -DBIGBOOT=1              -Wl,-Tlink_optiboot.ld -Wl,--relax -nostartfiles -o optiboot_atmega328.elf optiboot.o
avr-size optiboot_atmega328.elf
   text    data     bss     dec     hex filename
    709       0       0     709     2c5 optiboot_atmega328.elf
avr-objcopy -j .text -j .data -j .version --set-section-flags .version=alloc,load -O ihex optiboot_atmega328.elf optiboot_atmega328.hex
avr-objdump -h -S optiboot_atmega328.elf > optiboot_atmega328.lst
rm optiboot.o

$ make virboot328 BIGBOOT=1
avr-gcc (AVR_8_bit_GNU_Toolchain_3.6.2_1778) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BAUD RATE CHECK: Desired: 115200, Real: 117647, UBRRL = 16, Difference=2.1%
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=3 -DBIGBOOT=1              '-DVIRTUAL_BOOT_PARTITION'   -c -o optiboot.o optiboot.c
optiboot.c:429:2: warning: #warning BAUD_RATE off by greater than 2% [-Wcpp]
 #warning BAUD_RATE off by greater than 2%
  ^
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=3 -DBIGBOOT=1              '-DVIRTUAL_BOOT_PARTITION' -Wl,-Tlink_optiboot.ld -Wl,--relax -nostartfiles -o optiboot_virboot328.elf optiboot.o
avr-size optiboot_virboot328.elf
   text    data     bss     dec     hex filename
    846       0       0     846     34e optiboot_virboot328.elf
avr-objcopy -j .text -j .data -j .version --set-section-flags .version=alloc,load -O ihex optiboot_virboot328.elf optiboot_virboot328.hex
avr-objdump -h -S optiboot_virboot328.elf > optiboot_virboot328.lst
rm optiboot.o

[mcuee]

But it does not seem to work.
Note: the board is using ATmega328PB but the booloader is built for ATmega328P.

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude -c arduino -P COM4 -p m328p -U lfuse:r:-:h -U hfuse:r:-:h -U efuse:r:-:h

avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e950f (probably m328p)
avrdude: reading lfuse memory ...
avrdude: writing output file <stdout>
0x0
avrdude: reading hfuse memory ...
avrdude: writing output file <stdout>
0x0
avrdude: reading efuse memory ...
avrdude: writing output file <stdout>
0x0

avrdude done.  Thank you.

PS C:\work\avr\avrdude_test\avrdude_bin> .\avrdude -c usbasp -p m328pb -U lfuse:r:-:h -U hfuse:r:-:h -U efuse:r:-:h

avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e9516 (probably m328pb)
avrdude: reading lfuse memory ...
avrdude: writing output file <stdout>
0xff
avrdude: reading hfuse memory ...
avrdude: writing output file <stdout>
0xd7
avrdude: reading efuse memory ...
avrdude: writing output file <stdout>
0xf5

avrdude done.  Thank you.