From ff8f519a34ed4e167be442ca4abeac6f11cccdca Mon Sep 17 00:00:00 2001
From: Stefan Rueger <stefan.rueger@urclocks.com>
Date: Sun, 10 Jul 2022 23:25:31 +0100
Subject: [PATCH] Fix PICKit2 ATmega2560 flash paged flash read
The paged read in pickit2.c has two errors:
- It drops load extended address commands unless a paged read happens at a
64k byte boundary; this is invalid when reading files with holes
- It wrongly assumed that flash memory is byte addressed
The fix is to carry out a load extended address command, if needed, at the
beginning of each paged flash read with the correct word address. Although the
pickit2_paged_load() has independent parameters page_size, addr and n_bytes,
AVRDUDE only ever calls paged read/write functions with page_size and n_bytes
both set to mem->page_size and addr aligned with a page boundary. Therefore, it
is sufficient to set the load extended address at the beginning of each page
read.
---
src/pickit2.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/src/pickit2.c b/src/pickit2.c
index 9e4be94c..ac3781f5 100644
--- a/src/pickit2.c
+++ b/src/pickit2.c
@@ -491,18 +491,15 @@ static int pickit2_paged_load(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
pgm->pgm_led(pgm, ON);
+ if (lext) {
+ memset(cmd, 0, sizeof(cmd));
+ avr_set_bits(lext, cmd);
+ avr_set_addr(lext, cmd, addr/2);
+ pgm->cmd(pgm, cmd, res);
+ }
+
for (addr_base = addr; addr_base < max_addr; )
{
- if ((addr_base == 0 || (addr_base % /*ext_address_boundary*/ 65536) == 0)
- && lext != NULL)
- {
- memset(cmd, 0, sizeof(cmd));
-
- avr_set_bits(lext, cmd);
- avr_set_addr(lext, cmd, addr_base);
- pgm->cmd(pgm, cmd, res);
- }
-
// bytes to send in the next packet -- not necessary as pickit2_spi() handles breaking up
// the data into packets -- but we need to keep transfers frequent so that we can update the
// status indicator bar