[PATCH 2/2] mtd: cfi_cmdset_0002: fix delayed error detection on HyperFlash

[Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>]

The commit 4844ef80305d ("mtd: cfi_cmdset_0002: Add support for polling
status register") added checking for the status register error bits into
chip_good() to only return 1 if these bits are zero. Unfortunately, this
means that polling using chip_good() always reaches a time-out condition
when erase or program failure bits are set. I think the status register
error checking should be fully delegated to cfi_check_err_status() that
should return whether any error bits were set or not...

Fixes: 4844ef80305d ("mtd: cfi_cmdset_0002: Add support for polling status register")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/chips/cfi_cmdset_0002.c |   55 +++++++++++++++++++-----------------
 1 file changed, 30 insertions(+), 25 deletions(-)

Index: linux/drivers/mtd/chips/cfi_cmdset_0002.c
===================================================================
--- linux.orig/drivers/mtd/chips/cfi_cmdset_0002.c
+++ linux/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -123,14 +123,14 @@ static int cfi_use_status_reg(struct cfi
 		(extp->SoftwareFeatures & poll_mask) == CFI_POLL_STATUS_REG;
 }
 
-static void cfi_check_err_status(struct map_info *map, struct flchip *chip,
-				 unsigned long adr)
+static int cfi_check_err_status(struct map_info *map, struct flchip *chip,
+				unsigned long adr)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status;
 
 	if (!cfi_use_status_reg(cfi))
-		return;
+		return 0;
 
 	cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 			 cfi->device_type, NULL);
@@ -138,7 +138,7 @@ static void cfi_check_err_status(struct
 
 	/* The error bits are invalid while the chip's busy */
 	if (!map_word_bitsset(map, status, CMD(CFI_SR_DRB)))
-		return;
+		return 0;
 
 	if (map_word_bitsset(map, status, CMD(0x3a))) {
 		unsigned long chipstatus = MERGESTATUS(status);
@@ -155,7 +155,9 @@ static void cfi_check_err_status(struct
 		if (chipstatus & CFI_SR_SLSB)
 			pr_err("%s sector write protected, status %lx\n",
 			       map->name, chipstatus);
+		return 1;
 	}
+	return 0;
 }
 
 /* #define DEBUG_CFI_FEATURES */
@@ -852,20 +854,16 @@ static int __xipram chip_good(struct map
 
 	if (cfi_use_status_reg(cfi)) {
 		map_word ready = CMD(CFI_SR_DRB);
-		map_word err = CMD(CFI_SR_PSB | CFI_SR_ESB);
+
 		/*
 		 * For chips that support status register, check device
-		 * ready bit and Erase/Program status bit to know if
-		 * operation succeeded.
+		 * ready bit
 		 */
 		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 				 cfi->device_type, NULL);
 		curd = map_read(map, addr);
 
-		if (map_word_andequal(map, curd, ready, ready))
-			return !map_word_bitsset(map, curd, err);
-
-		return 0;
+		return map_word_andequal(map, curd, ready, ready);
 	}
 
 	oldd = map_read(map, addr);
@@ -1703,8 +1701,11 @@ static int __xipram do_write_oneword_onc
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum))
+		if (chip_good(map, chip, adr, datum)) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		/* Latency issues. Drop the lock, wait a while and retry */
 		UDELAY(map, chip, adr, 1);
@@ -1777,7 +1778,6 @@ static int __xipram do_write_oneword_ret
 	ret = do_write_oneword_once(map, chip, adr, datum, mode, cfi);
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -1974,12 +1974,17 @@ static int __xipram do_write_buffer_wait
 		 */
 		if (time_after(jiffies, timeo) &&
 		    !chip_good(map, chip, adr, datum)) {
+			pr_warn("MTD %s(): software timeout, address:0x%.8lx.\n",
+				__func__, adr);
 			ret = -EIO;
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum))
+		if (chip_good(map, chip, adr, datum)) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		/* Latency issues. Drop the lock, wait a while and retry */
 		UDELAY(map, chip, adr, 1);
@@ -2075,12 +2080,8 @@ static int __xipram do_write_buffer(stru
 				chip->word_write_time);
 
 	ret = do_write_buffer_wait(map, chip, adr, datum);
-	if (ret) {
-		cfi_check_err_status(map, chip, adr);
+	if (ret)
 		do_write_buffer_reset(map, chip, cfi);
-		pr_err("MTD %s(): software timeout, address:0x%.8lx.\n",
-		       __func__, adr);
-	}
 
 	xip_enable(map, chip, adr);
 
@@ -2275,9 +2276,9 @@ retry:
 		udelay(1);
 	}
 
-	if (!chip_good(map, chip, adr, datum)) {
+	if (!chip_good(map, chip, adr, datum) ||
+	    cfi_check_err_status(map, chip, adr)) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -2471,8 +2472,11 @@ static int __xipram do_erase_chip(struct
 			chip->erase_suspended = 0;
 		}
 
-		if (chip_good(map, chip, adr, map_word_ff(map)))
+		if (chip_good(map, chip, adr, map_word_ff(map))) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		if (time_after(jiffies, timeo)) {
 			printk(KERN_WARNING "MTD %s(): software timeout\n",
@@ -2487,7 +2491,6 @@ static int __xipram do_erase_chip(struct
 	/* Did we succeed? */
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -2568,8 +2571,11 @@ static int __xipram do_erase_oneblock(st
 			chip->erase_suspended = 0;
 		}
 
-		if (chip_good(map, chip, adr, map_word_ff(map)))
+		if (chip_good(map, chip, adr, map_word_ff(map))) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		if (time_after(jiffies, timeo)) {
 			printk(KERN_WARNING "MTD %s(): software timeout\n",
@@ -2584,7 +2590,6 @@ static int __xipram do_erase_oneblock(st
 	/* Did we succeed? */
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 

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