From f59e2637d184eef8e3ef8914ac500161804fc526 Mon Sep 17 00:00:00 2001 From: Sean Nelson Date: Wed, 20 Oct 2010 21:13:19 +0000 Subject: Add a reset to probe_jedec before we read the chip's IDs Previous probes might have had too short delays for entering ID mode, so the chip may still be in the process of entering the ID mode. Due to that, an additional delay before the reset makes sense. Add FEATURE_RESET_MASK to deal cleanly with those feature bits. Maciej Pijanka tested the patch and it fixes probing for him with some old Atmel chips. Corresponding to flashrom svn r1216. Signed-off-by: Sean Nelson Signed-off-by: Carl-Daniel Hailfinger Acked-by: Anders Juel Jensen Tested-by: Maciej Pijanka Acked-by: Sean Nelson --- flash.h | 1 + jedec.c | 22 +++++++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/flash.h b/flash.h index 81fdbd7d..700b3f4f 100644 --- a/flash.h +++ b/flash.h @@ -83,6 +83,7 @@ enum chipbustype { #define FEATURE_LONG_RESET (0 << 4) #define FEATURE_SHORT_RESET (1 << 4) #define FEATURE_EITHER_RESET FEATURE_LONG_RESET +#define FEATURE_RESET_MASK (FEATURE_LONG_RESET | FEATURE_SHORT_RESET) #define FEATURE_ADDR_FULL (0 << 2) #define FEATURE_ADDR_MASK (3 << 2) #define FEATURE_ADDR_2AA (1 << 2) diff --git a/jedec.c b/jedec.c index 4f042f29..199c64d3 100644 --- a/jedec.c +++ b/jedec.c @@ -142,6 +142,26 @@ static int probe_jedec_common(struct flashchip *flash, unsigned int mask) return 0; } + /* Earlier probes might have been too fast for the chip to enter ID + * mode completely. Allow the chip to finish this before seeing a + * reset command. + */ + if (probe_timing_enter) + programmer_delay(probe_timing_enter); + /* Reset chip to a clean slate */ + if ((flash->feature_bits & FEATURE_RESET_MASK) == FEATURE_LONG_RESET) + { + chip_writeb(0xAA, bios + (0x5555 & mask)); + if (probe_timing_exit) + programmer_delay(10); + chip_writeb(0x55, bios + (0x2AAA & mask)); + if (probe_timing_exit) + programmer_delay(10); + } + chip_writeb(0xF0, bios + (0x5555 & mask)); + if (probe_timing_exit) + programmer_delay(probe_timing_exit); + /* Issue JEDEC Product ID Entry command */ chip_writeb(0xAA, bios + (0x5555 & mask)); if (probe_timing_enter) @@ -172,7 +192,7 @@ static int probe_jedec_common(struct flashchip *flash, unsigned int mask) } /* Issue JEDEC Product ID Exit command */ - if ((flash->feature_bits & FEATURE_SHORT_RESET) == FEATURE_LONG_RESET) + if ((flash->feature_bits & FEATURE_RESET_MASK) == FEATURE_LONG_RESET) { chip_writeb(0xAA, bios + (0x5555 & mask)); if (probe_timing_exit) -- cgit v1.2.3