[PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Tokunori Ikegami]

The regression issue has been caused on S29GL064N and reported it.
Also the change mentioned is to use chip_good() for buffered write.
So disable the change on S29GL064N and use chip_ready() as before.

Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
---
 drivers/mtd/chips/cfi_cmdset_0002.c | 89 +++++++++++++++--------------
 1 file changed, 47 insertions(+), 42 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index a761134fd3be..5e14b60e8638 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -48,6 +48,7 @@
 #define SST49LF040B		0x0050
 #define SST49LF008A		0x005a
 #define AT49BV6416		0x00d6
+#define S29GL064N_MN12		0x0c01
 
 /*
  * Status Register bit description. Used by flash devices that don't
@@ -462,7 +463,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
 	{ CFI_MFR_AMD, 0x0056, fixup_use_secsi },
 	{ CFI_MFR_AMD, 0x005C, fixup_use_secsi },
 	{ CFI_MFR_AMD, 0x005F, fixup_use_secsi },
-	{ CFI_MFR_AMD, 0x0c01, fixup_s29gl064n_sectors },
+	{ CFI_MFR_AMD, S29GL064N_MN12, fixup_s29gl064n_sectors },
 	{ CFI_MFR_AMD, 0x1301, fixup_s29gl064n_sectors },
 	{ CFI_MFR_AMD, 0x1a00, fixup_s29gl032n_sectors },
 	{ CFI_MFR_AMD, 0x1a01, fixup_s29gl032n_sectors },
@@ -801,22 +802,12 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd)
 	return NULL;
 }
 
-/*
- * Return true if the chip is ready.
- *
- * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
- * non-suspended sector) and is indicated by no toggle bits toggling.
- *
- * Note that anything more complicated than checking if no bits are toggling
- * (including checking DQ5 for an error status) is tricky to get working
- * correctly and is therefore not done	(particularly with interleaved chips
- * as each chip must be checked independently of the others).
- */
-static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
-			       unsigned long addr)
+static int __xipram chip_check(struct map_info *map, struct flchip *chip,
+			       unsigned long addr, map_word *expected)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
-	map_word d, t;
+	map_word oldd, curd;
+	int ret;
 
 	if (cfi_use_status_reg(cfi)) {
 		map_word ready = CMD(CFI_SR_DRB);
@@ -826,17 +817,35 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
 		 */
 		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 				 cfi->device_type, NULL);
-		d = map_read(map, addr);
+		curd = map_read(map, addr);
 
-		return map_word_andequal(map, d, ready, ready);
+		return map_word_andequal(map, curd, ready, ready);
 	}
 
-	d = map_read(map, addr);
-	t = map_read(map, addr);
+	oldd = map_read(map, addr);
+	curd = map_read(map, addr);
+
+	ret = map_word_equal(map, oldd, curd);
 
-	return map_word_equal(map, d, t);
+	if (!ret || !expected)
+		return ret;
+
+	return map_word_equal(map, curd, *expected);
 }
 
+/*
+ * Return true if the chip is ready.
+ *
+ * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
+ * non-suspended sector) and is indicated by no toggle bits toggling.
+ *
+ * Note that anything more complicated than checking if no bits are toggling
+ * (including checking DQ5 for an error status) is tricky to get working
+ * correctly and is therefore not done	(particularly with interleaved chips
+ * as each chip must be checked independently of the others).
+ */
+#define chip_ready(map, chip, addr) chip_check(map, chip, addr, NULL)
+
 /*
  * Return true if the chip is ready and has the correct value.
  *
@@ -855,28 +864,24 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
 static int __xipram chip_good(struct map_info *map, struct flchip *chip,
 			      unsigned long addr, map_word expected)
 {
-	struct cfi_private *cfi = map->fldrv_priv;
-	map_word oldd, curd;
-
-	if (cfi_use_status_reg(cfi)) {
-		map_word ready = CMD(CFI_SR_DRB);
+	return chip_check(map, chip, addr, &expected);
+}
 
-		/*
-		 * For chips that support status register, check device
-		 * ready bit
-		 */
-		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
-				 cfi->device_type, NULL);
-		curd = map_read(map, addr);
+static bool cfi_use_chip_ready_for_write(struct map_info *map)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
 
-		return map_word_andequal(map, curd, ready, ready);
-	}
+	return cfi->mfr == CFI_MFR_AMD && cfi->id == S29GL064N_MN12;
+}
 
-	oldd = map_read(map, addr);
-	curd = map_read(map, addr);
+static int __xipram chip_good_for_write(struct map_info *map,
+					struct flchip *chip, unsigned long addr,
+					map_word expected)
+{
+	if (cfi_use_chip_ready_for_write(map))
+		return chip_ready(map, chip, addr);
 
-	return	map_word_equal(map, oldd, curd) &&
-		map_word_equal(map, curd, expected);
+	return chip_good(map, chip, addr, expected);
 }
 
 static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr, int mode)
@@ -1699,7 +1704,7 @@ static int __xipram do_write_oneword_once(struct map_info *map,
 		 * "chip_good" to avoid the failure due to scheduling.
 		 */
 		if (time_after(jiffies, timeo) &&
-		    !chip_good(map, chip, adr, datum)) {
+		    !chip_good_for_write(map, chip, adr, datum)) {
 			xip_enable(map, chip, adr);
 			printk(KERN_WARNING "MTD %s(): software timeout\n", __func__);
 			xip_disable(map, chip, adr);
@@ -1707,7 +1712,7 @@ static int __xipram do_write_oneword_once(struct map_info *map,
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum)) {
+		if (chip_good_for_write(map, chip, adr, datum)) {
 			if (cfi_check_err_status(map, chip, adr))
 				ret = -EIO;
 			break;
@@ -1979,14 +1984,14 @@ static int __xipram do_write_buffer_wait(struct map_info *map,
 		 * "chip_good" to avoid the failure due to scheduling.
 		 */
 		if (time_after(jiffies, timeo) &&
-		    !chip_good(map, chip, adr, datum)) {
+		    !chip_good_for_write(map, chip, adr, datum)) {
 			pr_err("MTD %s(): software timeout, address:0x%.8lx.\n",
 			       __func__, adr);
 			ret = -EIO;
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum)) {
+		if (chip_good_for_write(map, chip, adr, datum)) {
 			if (cfi_check_err_status(map, chip, adr))
 				ret = -EIO;
 			break;
-- 
2.32.0

[PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Tokunori Ikegami]

The regression issue has been caused on S29GL064N and reported it.
Also the change mentioned is to use chip_good() for buffered write.
So disable the change on S29GL064N and use chip_ready() as before.

Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
---
 drivers/mtd/chips/cfi_cmdset_0002.c | 89 +++++++++++++++--------------
 1 file changed, 47 insertions(+), 42 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index a761134fd3be..5e14b60e8638 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -48,6 +48,7 @@
 #define SST49LF040B		0x0050
 #define SST49LF008A		0x005a
 #define AT49BV6416		0x00d6
+#define S29GL064N_MN12		0x0c01
 
 /*
  * Status Register bit description. Used by flash devices that don't
@@ -462,7 +463,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
 	{ CFI_MFR_AMD, 0x0056, fixup_use_secsi },
 	{ CFI_MFR_AMD, 0x005C, fixup_use_secsi },
 	{ CFI_MFR_AMD, 0x005F, fixup_use_secsi },
-	{ CFI_MFR_AMD, 0x0c01, fixup_s29gl064n_sectors },
+	{ CFI_MFR_AMD, S29GL064N_MN12, fixup_s29gl064n_sectors },
 	{ CFI_MFR_AMD, 0x1301, fixup_s29gl064n_sectors },
 	{ CFI_MFR_AMD, 0x1a00, fixup_s29gl032n_sectors },
 	{ CFI_MFR_AMD, 0x1a01, fixup_s29gl032n_sectors },
@@ -801,22 +802,12 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd)
 	return NULL;
 }
 
-/*
- * Return true if the chip is ready.
- *
- * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
- * non-suspended sector) and is indicated by no toggle bits toggling.
- *
- * Note that anything more complicated than checking if no bits are toggling
- * (including checking DQ5 for an error status) is tricky to get working
- * correctly and is therefore not done	(particularly with interleaved chips
- * as each chip must be checked independently of the others).
- */
-static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
-			       unsigned long addr)
+static int __xipram chip_check(struct map_info *map, struct flchip *chip,
+			       unsigned long addr, map_word *expected)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
-	map_word d, t;
+	map_word oldd, curd;
+	int ret;
 
 	if (cfi_use_status_reg(cfi)) {
 		map_word ready = CMD(CFI_SR_DRB);
@@ -826,17 +817,35 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
 		 */
 		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 				 cfi->device_type, NULL);
-		d = map_read(map, addr);
+		curd = map_read(map, addr);
 
-		return map_word_andequal(map, d, ready, ready);
+		return map_word_andequal(map, curd, ready, ready);
 	}
 
-	d = map_read(map, addr);
-	t = map_read(map, addr);
+	oldd = map_read(map, addr);
+	curd = map_read(map, addr);
+
+	ret = map_word_equal(map, oldd, curd);
 
-	return map_word_equal(map, d, t);
+	if (!ret || !expected)
+		return ret;
+
+	return map_word_equal(map, curd, *expected);
 }
 
+/*
+ * Return true if the chip is ready.
+ *
+ * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
+ * non-suspended sector) and is indicated by no toggle bits toggling.
+ *
+ * Note that anything more complicated than checking if no bits are toggling
+ * (including checking DQ5 for an error status) is tricky to get working
+ * correctly and is therefore not done	(particularly with interleaved chips
+ * as each chip must be checked independently of the others).
+ */
+#define chip_ready(map, chip, addr) chip_check(map, chip, addr, NULL)
+
 /*
  * Return true if the chip is ready and has the correct value.
  *
@@ -855,28 +864,24 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
 static int __xipram chip_good(struct map_info *map, struct flchip *chip,
 			      unsigned long addr, map_word expected)
 {
-	struct cfi_private *cfi = map->fldrv_priv;
-	map_word oldd, curd;
-
-	if (cfi_use_status_reg(cfi)) {
-		map_word ready = CMD(CFI_SR_DRB);
+	return chip_check(map, chip, addr, &expected);
+}
 
-		/*
-		 * For chips that support status register, check device
-		 * ready bit
-		 */
-		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
-				 cfi->device_type, NULL);
-		curd = map_read(map, addr);
+static bool cfi_use_chip_ready_for_write(struct map_info *map)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
 
-		return map_word_andequal(map, curd, ready, ready);
-	}
+	return cfi->mfr == CFI_MFR_AMD && cfi->id == S29GL064N_MN12;
+}
 
-	oldd = map_read(map, addr);
-	curd = map_read(map, addr);
+static int __xipram chip_good_for_write(struct map_info *map,
+					struct flchip *chip, unsigned long addr,
+					map_word expected)
+{
+	if (cfi_use_chip_ready_for_write(map))
+		return chip_ready(map, chip, addr);
 
-	return	map_word_equal(map, oldd, curd) &&
-		map_word_equal(map, curd, expected);
+	return chip_good(map, chip, addr, expected);
 }
 
 static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr, int mode)
@@ -1699,7 +1704,7 @@ static int __xipram do_write_oneword_once(struct map_info *map,
 		 * "chip_good" to avoid the failure due to scheduling.
 		 */
 		if (time_after(jiffies, timeo) &&
-		    !chip_good(map, chip, adr, datum)) {
+		    !chip_good_for_write(map, chip, adr, datum)) {
 			xip_enable(map, chip, adr);
 			printk(KERN_WARNING "MTD %s(): software timeout\n", __func__);
 			xip_disable(map, chip, adr);
@@ -1707,7 +1712,7 @@ static int __xipram do_write_oneword_once(struct map_info *map,
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum)) {
+		if (chip_good_for_write(map, chip, adr, datum)) {
 			if (cfi_check_err_status(map, chip, adr))
 				ret = -EIO;
 			break;
@@ -1979,14 +1984,14 @@ static int __xipram do_write_buffer_wait(struct map_info *map,
 		 * "chip_good" to avoid the failure due to scheduling.
 		 */
 		if (time_after(jiffies, timeo) &&
-		    !chip_good(map, chip, adr, datum)) {
+		    !chip_good_for_write(map, chip, adr, datum)) {
 			pr_err("MTD %s(): software timeout, address:0x%.8lx.\n",
 			       __func__, adr);
 			ret = -EIO;
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum)) {
+		if (chip_good_for_write(map, chip, adr, datum)) {
 			if (cfi_check_err_status(map, chip, adr))
 				ret = -EIO;
 			break;
-- 
2.32.0


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Re: [PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Vignesh Raghavendra]

+ Ahmad (who reported the bug)

Hi Ahmad,

On 06/03/22 9:02 pm, Tokunori Ikegami wrote:
> The regression issue has been caused on S29GL064N and reported it.
> Also the change mentioned is to use chip_good() for buffered write.
> So disable the change on S29GL064N and use chip_ready() as before.
> 
> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: stable@vger.kernel.org
> Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/

Could you please test this exact patch and provide Tested-by so that it
gets registered by patch tracking systems?

[...]

Regards
Vignesh

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Re: [PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Ahmad Fatoum]

Hello Vignesh,

On 09.03.22 09:17, Vignesh Raghavendra wrote:
> + Ahmad (who reported the bug)

Thanks for Cc'ing.

> Hi Ahmad,
> 
> On 06/03/22 9:02 pm, Tokunori Ikegami wrote:
>> The regression issue has been caused on S29GL064N and reported it.
>> Also the change mentioned is to use chip_good() for buffered write.
>> So disable the change on S29GL064N and use chip_ready() as before.
>>
>> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
>> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
>> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
>> Cc: Richard Weinberger <richard@nod.at>
>> Cc: Vignesh Raghavendra <vigneshr@ti.com>
>> Cc: linux-mtd@lists.infradead.org
>> Cc: stable@vger.kernel.org
>> Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
> 
> Could you please test this exact patch and provide Tested-by so that it
> gets registered by patch tracking systems?

Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Thanks,
Ahmad

> 
> [...]
> 
> Regards
> Vignesh
> 


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Re: [PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Vignesh Raghavendra]

Hi Miquel,

On 06/03/22 9:02 pm, Tokunori Ikegami wrote:
> The regression issue has been caused on S29GL064N and reported it.
> Also the change mentioned is to use chip_good() for buffered write.
> So disable the change on S29GL064N and use chip_ready() as before.
> 
> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: stable@vger.kernel.org
> Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/

Could you please pull this in for v5.18-rc1 as this is a regression
being tracked for a while?

Acked-by: Vignesh Raghavendra <vigneshr@ti.com>

[...]

Regards
Vignesh


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Re: [PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Miquel Raynal]

Hello,

vigneshr@ti.com wrote on Tue, 15 Mar 2022 11:41:52 +0530:

> Hi Miquel,
> 
> On 06/03/22 9:02 pm, Tokunori Ikegami wrote:
> > The regression issue has been caused on S29GL064N and reported it.
> > Also the change mentioned is to use chip_good() for buffered write.
> > So disable the change on S29GL064N and use chip_ready() as before.
> > 
> > Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
> > Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
> > Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> > Cc: Richard Weinberger <richard@nod.at>
> > Cc: Vignesh Raghavendra <vigneshr@ti.com>
> > Cc: linux-mtd@lists.infradead.org
> > Cc: stable@vger.kernel.org
> > Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/  
> 
> Could you please pull this in for v5.18-rc1 as this is a regression
> being tracked for a while?

I was about to apply the patch but reviewing it quickly shown a number
of issues. I can still pull the patch for -rc1 if all this is
corrected rather quickly but otherwise it will go through Fixes later
on.

- I just don't understand the commit log, please rephrase it entirely.
  You can include the link to the bug report as well inside the commit
  text, not as part of a Link tag, because the Link tag is here to
  refer to the mailing list discussion and is added automatically.
  Something like:

	As pointed out by this bug report [1], <what> is now broken on
	S29GL064N. The reason is that <explain the problem>. One way to
	solve the issue is to <explain why I should choose this
	solution>.

	[1] <the link here>

- The patch itself should be split into at least three parts:
  * The ID definition (should not be part of the fix).
  * The chip_check/chip_ready/chip_good_for_write code moves/renaming
    independently of any functinal change as a preparation patch.
  * The actual fix within one of the above functions.

Aside from these, I don't quite get what the __xipram keyword is
supposed to carry. We return a boolean expression stored in an int
provided by the map_word_equal() macro which does return a simple int
declared on the stack. It's not stored anywhere else than regular RAM,
or am I missing something?

> Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
> 
> [...]
> 
> Regards
> Vignesh
> 

Thanks,
Miquèl

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Re: [PATCH v2] mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

[Tokunori Ikegami]

Hi,

On 2022/03/15 18:50, Miquel Raynal wrote:
> Hello,
>
> vigneshr@ti.com wrote on Tue, 15 Mar 2022 11:41:52 +0530:
>
>> Hi Miquel,
>>
>> On 06/03/22 9:02 pm, Tokunori Ikegami wrote:
>>> The regression issue has been caused on S29GL064N and reported it.
>>> Also the change mentioned is to use chip_good() for buffered write.
>>> So disable the change on S29GL064N and use chip_ready() as before.
>>>
>>> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
>>> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
>>> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
>>> Cc: Richard Weinberger <richard@nod.at>
>>> Cc: Vignesh Raghavendra <vigneshr@ti.com>
>>> Cc: linux-mtd@lists.infradead.org
>>> Cc: stable@vger.kernel.org
>>> Link: https://lore.kernel.org/r/b687c259-6413-26c9-d4c9-b3afa69ea124@pengutronix.de/
>> Could you please pull this in for v5.18-rc1 as this is a regression
>> being tracked for a while?
> I was about to apply the patch but reviewing it quickly shown a number
> of issues. I can still pull the patch for -rc1 if all this is
> corrected rather quickly but otherwise it will go through Fixes later
> on.
>
> - I just don't understand the commit log, please rephrase it entirely.
>    You can include the link to the bug report as well inside the commit
>    text, not as part of a Link tag, because the Link tag is here to
>    refer to the mailing list discussion and is added automatically.
>    Something like:
>
> 	As pointed out by this bug report [1], <what> is now broken on
> 	S29GL064N. The reason is that <explain the problem>. One way to
> 	solve the issue is to <explain why I should choose this
> 	solution>.
>
> 	[1] <the link here>
Thanks. Just fixed by the version 3 patches and sent them.
> - The patch itself should be split into at least three parts:
>    * The ID definition (should not be part of the fix).
>    * The chip_check/chip_ready/chip_good_for_write code moves/renaming
>      independently of any functinal change as a preparation patch.
>    * The actual fix within one of the above functions.
This is also fixed by the version patches.
>
> Aside from these, I don't quite get what the __xipram keyword is
> supposed to carry. We return a boolean expression stored in an int
> provided by the map_word_equal() macro which does return a simple int
> declared on the stack. It's not stored anywhere else than regular RAM,
> or am I missing something?

The __xipram keyword was implemented by the commit 02b15e343aee for the 
chip_ready and chip_good, etc.
Also the definision is implemneted in include/linux/mtd/xip.h as below.

/*
  * Function that are modifying the flash state away from array mode must
  * obviously not be running from flash.  The __xipram is therefore marking
  * those functions so they get relocated to ram.
  */
#ifdef CONFIG_XIP_KERNEL
#define __xipram noinline __section(".xiptext")
#endif

The changes for the fix just follows the implementation as same I think.
By the way it was added to use the __xipram keyword for 
cfi_use_chip_ready_for_write() also.

Regards,
Ikegami

>
>> Acked-by: Vignesh Raghavendra <vigneshr@ti.com>
>>
>> [...]
>>
>> Regards
>> Vignesh
>>
> Thanks,
> Miquèl

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