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author | Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de> | 2011-04-15 00:03:37 +0000 |
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committer | Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de> | 2011-04-15 00:03:37 +0000 |
commit | 880e867ae823dbbd140731f2eaa2ea656b4b9153 (patch) | |
tree | 6f6ccde262a1878c3e3fe788e4923811a26628ef | |
parent | 4b177369854b0f1b0f5769b809f2cf1b0ea4f347 (diff) | |
download | ast2050-flashrom-880e867ae823dbbd140731f2eaa2ea656b4b9153.zip ast2050-flashrom-880e867ae823dbbd140731f2eaa2ea656b4b9153.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.
Corresponding to flashrom svn r1288.
Signed-off-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
-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); |