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 <audiohacked@gmail.com>
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Anders Juel Jensen <andersjjensen@gmail.com>
Tested-by: Maciej Pijanka <maciej.pijanka@gmail.com>
Acked-by: Sean Nelson <audiohacked@gmail.com>
diff --git a/flash.h b/flash.h
index 81fdbd7..700b3f4 100644
--- a/flash.h
+++ b/flash.h
@@ -83,6 +83,7 @@
#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 4f042f2..199c64d 100644
--- a/jedec.c
+++ b/jedec.c
@@ -142,6 +142,26 @@
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 @@
}
/* 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)