[flashrom] [commit] r1288 - trunk
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Fri Apr 15 02:03:37 CEST 2011
Author: mkarcher
Date: Fri Apr 15 02:03:37 2011
New Revision: 1288
URL: http://flashrom.org/trac/flashrom/changeset/1288
Log:
Remove delays in JEDEC erase sequence
It is extremely unlikely that a chip not requiring delays in probe does
require them in erase. We observed unreliable erasing with a SST49LF004A
with these delays, so remove them if the are not required.
In review, I got the hint that "probe_jedec goes further by making that
call conditional on nonzero delay". I decided to ignore that. For
internal_delay, the small amount of clock cycles wasted for calling
programmer_delay(0) is negligible compared to LPC cycle times. It might
be an issue for 5 wasted bytes on the serial line in serprog. OTOH,
flash erase is still slow compared to 6*5 bytes on a serial port at
reasonable speed.
Signed-off-by: Michael Karcher <flashrom at mkarcher.dialup.fu-berlin.de>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Modified:
trunk/jedec.c
Modified: trunk/jedec.c
==============================================================================
--- trunk/jedec.c Fri Apr 15 01:43:19 2011 (r1287)
+++ trunk/jedec.c Fri Apr 15 02:03:37 2011 (r1288)
@@ -242,21 +242,24 @@
unsigned int pagesize, unsigned int mask)
{
chipaddr bios = flash->virtual_memory;
+ int delay_us = 0;
+ if(flash->probe_timing != TIMING_ZERO)
+ delay_us = 10;
/* Issue the Sector Erase command */
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x80, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x30, bios + page);
- programmer_delay(10);
+ programmer_delay(delay_us);
/* wait for Toggle bit ready */
toggle_ready_jedec_slow(bios);
@@ -272,21 +275,24 @@
unsigned int blocksize, unsigned int mask)
{
chipaddr bios = flash->virtual_memory;
+ int delay_us = 0;
+ if(flash->probe_timing != TIMING_ZERO)
+ delay_us = 10;
/* Issue the Sector Erase command */
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x80, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x50, bios + block);
- programmer_delay(10);
+ programmer_delay(delay_us);
/* wait for Toggle bit ready */
toggle_ready_jedec_slow(bios);
@@ -302,21 +308,24 @@
{
int total_size = flash->total_size * 1024;
chipaddr bios = flash->virtual_memory;
+ int delay_us = 0;
+ if(flash->probe_timing != TIMING_ZERO)
+ delay_us = 10;
/* Issue the JEDEC Chip Erase command */
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x80, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0xAA, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x55, bios + (0x2AAA & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
chip_writeb(0x10, bios + (0x5555 & mask));
- programmer_delay(10);
+ programmer_delay(delay_us);
toggle_ready_jedec_slow(bios);
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