From 880e867ae823dbbd140731f2eaa2ea656b4b9153 Mon Sep 17 00:00:00 2001 From: Michael Karcher Date: Fri, 15 Apr 2011 00:03:37 +0000 Subject: 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 Acked-by: Carl-Daniel Hailfinger --- jedec.c | 45 +++++++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 18 deletions(-) diff --git a/jedec.c b/jedec.c index 199c64d3..f23cf535 100644 --- a/jedec.c +++ b/jedec.c @@ -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); -- cgit v1.2.3