[flashrom] [PATCH] Debug excessive toggle bit delay

[Carl-Daniel Hailfinger]

On 16.12.2009 01:08, Carl-Daniel Hailfinger wrote:
> Today's systems are quite capable of running 2^32 reads in short time.
> Some chips may be slow enough to fall off the loop here. This patch is
> an attempt at debugging a problem we're seeing on the Winbond W39V040C
> where the standard toggle bit algorithm seems to fail for block erases.
>
> Note: This probably needs a few tweaks before it can be committed.
>   

Next try. Use slow toggle for all erase stuff.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>

Index: flashrom-detect_excessive_toggle/jedec.c
===================================================================
--- flashrom-detect_excessive_toggle/jedec.c	(Revision 803)
+++ flashrom-detect_excessive_toggle/jedec.c	(Arbeitskopie)
@@ -33,7 +33,7 @@
 	return (val ^ (val >> 1)) & 0x1;
 }
 
-void toggle_ready_jedec(chipaddr dst)
+void toggle_ready_jedec_common(chipaddr dst, int delay)
 {
 	unsigned int i = 0;
 	uint8_t tmp1, tmp2;
@@ -41,14 +41,31 @@
 	tmp1 = chip_readb(dst) & 0x40;
 
 	while (i++ < 0xFFFFFFF) {
+		if (delay)
+			programmer_delay(delay);
 		tmp2 = chip_readb(dst) & 0x40;
 		if (tmp1 == tmp2) {
 			break;
 		}
 		tmp1 = tmp2;
 	}
+	if (i > 0x10000)
+		printf_debug("%s: excessive toggle, i=0x%x\n", __func__, i);
 }
 
+void toggle_ready_jedec(chipaddr dst)
+{
+	toggle_ready_jedec_common(dst, 0);
+}
+
+/* Some chips require a minimum delay between toggle bit reads.
+ * The Winbond W39V040C wants 50 ms between reads on sector erase toggle.
+ */
+void toggle_ready_jedec_slow(chipaddr dst)
+{
+	toggle_ready_jedec_common(dst, 50 * 1000);
+}
+
 void data_polling_jedec(chipaddr dst, uint8_t data)
 {
 	unsigned int i = 0;
@@ -62,6 +79,8 @@
 			break;
 		}
 	}
+	if (i > 0x10000)
+		printf_debug("%s: excessive data poll, i=0x%x\n", __func__, i);
 }
 
 void start_program_jedec(chipaddr bios)
@@ -178,7 +197,7 @@
 	programmer_delay(10);
 
 	/* wait for Toggle bit ready         */
-	toggle_ready_jedec(bios);
+	toggle_ready_jedec_slow(bios);
 
 	if (check_erased_range(flash, page, pagesize)) {
 		fprintf(stderr,"ERASE FAILED!\n");
@@ -207,7 +226,7 @@
 	programmer_delay(10);
 
 	/* wait for Toggle bit ready         */
-	toggle_ready_jedec(bios);
+	toggle_ready_jedec_slow(bios);
 
 	if (check_erased_range(flash, block, blocksize)) {
 		fprintf(stderr,"ERASE FAILED!\n");
@@ -236,7 +255,7 @@
 	chip_writeb(0x10, bios + 0x5555);
 	programmer_delay(10);
 
-	toggle_ready_jedec(bios);
+	toggle_ready_jedec_slow(bios);
 
 	if (check_erased_range(flash, 0, total_size)) {
 		fprintf(stderr,"ERASE FAILED!\n");


-- 
Developer quote of the month: 
"We are juggling too many chainsaws and flaming arrows and tigers."