diff options
| author | mkarcher <mkarcher@2b7e53f0-3cfb-0310-b3e9-8179ed1497e1> | 2011-04-15 00:03:37 +0000 |
|---|---|---|
| committer | mkarcher <mkarcher@2b7e53f0-3cfb-0310-b3e9-8179ed1497e1> | 2011-04-15 00:03:37 +0000 |
| commit | 66ec6adea9cd57f6acd031f0c7808b06f14b01be (patch) | |
| tree | 6f6ccde262a1878c3e3fe788e4923811a26628ef /jedec.c | |
| parent | 64ecd20bd2874c5b69b2f29225749a7342b71460 (diff) | |
| download | flashrom-66ec6adea9cd57f6acd031f0c7808b06f14b01be.tar.gz | |
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@mkarcher.dialup.fu-berlin.de>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
git-svn-id: https://code.coreboot.org/svn/flashrom/trunk@1288 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'jedec.c')
| -rw-r--r-- | jedec.c | 45 |
1 files changed, 27 insertions, 18 deletions
@@ -242,21 +242,24 @@ static int erase_sector_jedec_common(struct flashchip *flash, unsigned int page, 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 @@ static int erase_block_jedec_common(struct flashchip *flash, unsigned int block, 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 @@ static int erase_chip_jedec_common(struct flashchip *flash, unsigned int mask) { 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); |