[PATCH v2 0/2] Add support to Disable the flash quad mode

[PATCH v2 0/2] Add support to Disable the flash quad mode

[Yicong Yang]

Previously we didn't disable the flash's quad mode when it's removed
Then comes the problem that if we next time load the flash
in Standard/Dual SPI mode, the quad enable bits is not cleared,
and the function of flash's WP# and RESET#/HOLD# pin will not
be restored.

This series adds the capability to disable the flash's quad mode. And
restore the flash when it's removed in spi_nor_restore().

Change since v1:
- Address the comments by Tudor
- Reword the commit message in Patch 2/2. 

Yicong Yang (2):
  mtd: spi-nor: Add capability to disable flash quad mode
  mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()

 drivers/mtd/spi-nor/core.c | 57 ++++++++++++++++++++++++++++++----------------
 drivers/mtd/spi-nor/core.h | 10 ++++----
 2 files changed, 43 insertions(+), 24 deletions(-)

-- 
2.8.1


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[PATCH v2 1/2] mtd: spi-nor: Add capability to disable flash quad mode

[Yicong Yang]

Previous we didn't provide a way to disable the flash's quad mode.
Which means we cannot do some cleanup works when to remove or
poweroff the flash, like what set 4-byte address mode does in
spi_nor_restore().

Add the capability to disable the flash quad mode, by introducing
an enable flag in the flash parameters quad_enable() hooks and
related functions.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
---
 drivers/mtd/spi-nor/core.c | 55 ++++++++++++++++++++++++++++++----------------
 drivers/mtd/spi-nor/core.h | 10 ++++-----
 2 files changed, 41 insertions(+), 24 deletions(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 0369d98..f3d4b96 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1907,15 +1907,16 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 }
 
 /**
- * spi_nor_sr1_bit6_quad_enable() - Set the Quad Enable BIT(6) in the Status
- * Register 1.
+ * spi_nor_sr1_bit6_quad_enable() - Set/Unset the Quad Enable BIT(6) in the
+ *                                  Status Register 1.
  * @nor:	pointer to a 'struct spi_nor'
+ * @enable:	true to enable Quad mode. false to disable Quad mode.
  *
  * Bit 6 of the Status Register 1 is the QE bit for Macronix like QSPI memories.
  *
  * Return: 0 on success, -errno otherwise.
  */
-int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor)
+int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor, bool enable)
 {
 	int ret;
 
@@ -1923,45 +1924,56 @@ int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor)
 	if (ret)
 		return ret;
 
-	if (nor->bouncebuf[0] & SR1_QUAD_EN_BIT6)
+	if ((enable && (nor->bouncebuf[0] & SR1_QUAD_EN_BIT6)) ||
+	    (!enable && !(nor->bouncebuf[0] & SR1_QUAD_EN_BIT6)))
 		return 0;
 
-	nor->bouncebuf[0] |= SR1_QUAD_EN_BIT6;
+	if (enable)
+		nor->bouncebuf[0] |= SR1_QUAD_EN_BIT6;
+	else
+		nor->bouncebuf[0] &= ~SR1_QUAD_EN_BIT6;
 
 	return spi_nor_write_sr1_and_check(nor, nor->bouncebuf[0]);
 }
 
 /**
- * spi_nor_sr2_bit1_quad_enable() - set the Quad Enable BIT(1) in the Status
- * Register 2.
+ * spi_nor_sr2_bit1_quad_enable() - set/unset the Quad Enable BIT(1) in the
+ *                                  Status Register 2.
  * @nor:       pointer to a 'struct spi_nor'.
+ * @enable:	true to enable Quad mode. false to disable Quad mode.
  *
  * Bit 1 of the Status Register 2 is the QE bit for Spansion like QSPI memories.
  *
  * Return: 0 on success, -errno otherwise.
  */
-int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor)
+int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor, bool enable)
 {
 	int ret;
 
 	if (nor->flags & SNOR_F_NO_READ_CR)
-		return spi_nor_write_16bit_cr_and_check(nor, SR2_QUAD_EN_BIT1);
+		return spi_nor_write_16bit_cr_and_check(nor,
+						enable ? SR2_QUAD_EN_BIT1 : 0);
 
 	ret = spi_nor_read_cr(nor, nor->bouncebuf);
 	if (ret)
 		return ret;
 
-	if (nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)
+	if ((enable && (nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)) ||
+	    (!enable && !(nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)))
 		return 0;
 
-	nor->bouncebuf[0] |= SR2_QUAD_EN_BIT1;
+	if (enable)
+		nor->bouncebuf[0] |= SR2_QUAD_EN_BIT1;
+	else
+		nor->bouncebuf[0] &= ~SR2_QUAD_EN_BIT1;
 
 	return spi_nor_write_16bit_cr_and_check(nor, nor->bouncebuf[0]);
 }
 
 /**
- * spi_nor_sr2_bit7_quad_enable() - set QE bit in Status Register 2.
+ * spi_nor_sr2_bit7_quad_enable() - set/unset QE bit in Status Register 2.
  * @nor:	pointer to a 'struct spi_nor'
+ * @enable:	true to enable Quad mode. false to disable Quad mode.
  *
  * Set the Quad Enable (QE) bit in the Status Register 2.
  *
@@ -1971,7 +1983,7 @@ int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor)
  *
  * Return: 0 on success, -errno otherwise.
  */
-int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor)
+int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor, bool enable)
 {
 	u8 *sr2 = nor->bouncebuf;
 	int ret;
@@ -1981,11 +1993,15 @@ int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor)
 	ret = spi_nor_read_sr2(nor, sr2);
 	if (ret)
 		return ret;
-	if (*sr2 & SR2_QUAD_EN_BIT7)
+	if ((enable && (*sr2 & SR2_QUAD_EN_BIT7)) ||
+	    (!enable && !(*sr2 & SR2_QUAD_EN_BIT7)))
 		return 0;
 
 	/* Update the Quad Enable bit. */
-	*sr2 |= SR2_QUAD_EN_BIT7;
+	if (enable)
+		*sr2 |= SR2_QUAD_EN_BIT7;
+	else
+		*sr2 &= ~SR2_QUAD_EN_BIT7;
 
 	ret = spi_nor_write_sr2(nor, sr2);
 	if (ret)
@@ -2898,12 +2914,13 @@ static int spi_nor_init_params(struct spi_nor *nor)
 }
 
 /**
- * spi_nor_quad_enable() - enable Quad I/O if needed.
+ * spi_nor_quad_enable() - enable/disable Quad I/O if needed.
  * @nor:                pointer to a 'struct spi_nor'
+ * @enable:             true to enable Quad mode. false to disable Quad mode.
  *
  * Return: 0 on success, -errno otherwise.
  */
-static int spi_nor_quad_enable(struct spi_nor *nor)
+static int spi_nor_quad_enable(struct spi_nor *nor, bool enable)
 {
 	if (!nor->params->quad_enable)
 		return 0;
@@ -2912,7 +2929,7 @@ static int spi_nor_quad_enable(struct spi_nor *nor)
 	      spi_nor_get_protocol_width(nor->write_proto) == 4))
 		return 0;
 
-	return nor->params->quad_enable(nor);
+	return nor->params->quad_enable(nor, enable);
 }
 
 /**
@@ -2936,7 +2953,7 @@ static int spi_nor_init(struct spi_nor *nor)
 {
 	int err;
 
-	err = spi_nor_quad_enable(nor);
+	err = spi_nor_quad_enable(nor, true);
 	if (err) {
 		dev_dbg(nor->dev, "quad mode not supported\n");
 		return err;
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 6f2f6b2..222e0d3 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -198,7 +198,7 @@ struct spi_nor_locking_ops {
  *                      higher index in the array, the higher priority.
  * @erase_map:		the erase map parsed from the SFDP Sector Map Parameter
  *                      Table.
- * @quad_enable:	enables SPI NOR quad mode.
+ * @quad_enable:	enables/disables SPI NOR quad mode.
  * @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
  * @convert_addr:	converts an absolute address into something the flash
  *                      will understand. Particularly useful when pagesize is
@@ -219,7 +219,7 @@ struct spi_nor_flash_parameter {
 
 	struct spi_nor_erase_map        erase_map;
 
-	int (*quad_enable)(struct spi_nor *nor);
+	int (*quad_enable)(struct spi_nor *nor, bool enable);
 	int (*set_4byte_addr_mode)(struct spi_nor *nor, bool enable);
 	u32 (*convert_addr)(struct spi_nor *nor, u32 addr);
 	int (*setup)(struct spi_nor *nor, const struct spi_nor_hwcaps *hwcaps);
@@ -406,9 +406,9 @@ int spi_nor_write_ear(struct spi_nor *nor, u8 ear);
 int spi_nor_wait_till_ready(struct spi_nor *nor);
 int spi_nor_lock_and_prep(struct spi_nor *nor);
 void spi_nor_unlock_and_unprep(struct spi_nor *nor);
-int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor);
-int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor);
-int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor);
+int spi_nor_sr1_bit6_quad_enable(struct spi_nor *nor, bool enable);
+int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor, bool enable);
+int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor, bool enable);
 
 int spi_nor_xread_sr(struct spi_nor *nor, u8 *sr);
 ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
-- 
2.8.1


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[PATCH v2 2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()

[Yicong Yang]

If the flash's quad mode is enabled, it'll remain in the quad mode when
it's removed. If we drive the flash next time in Standard/Dual SPI mode,
the QE bit is not cleared and the function of flash's WP# and RESET#/HOLD#
have been switched to IO2 and IO3 and are not restored.

Disable the Quad mode in spi_nor_restore(), then the flash's QE bit will
be cleared when removed. This will make sure the flash always enter the
Standard/Dual SPI mode when loaded.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
---
 drivers/mtd/spi-nor/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index f3d4b96..2099403 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3000,6 +3000,8 @@ void spi_nor_restore(struct spi_nor *nor)
 	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
 	    nor->flags & SNOR_F_BROKEN_RESET)
 		nor->params->set_4byte_addr_mode(nor, false);
+
+	spi_nor_quad_enable(nor, false);
 }
 EXPORT_SYMBOL_GPL(spi_nor_restore);
 
-- 
2.8.1


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Re: [PATCH v2 0/2] Add support to Disable the flash quad mode

[Tudor Ambarus]

On Mon, 6 Jul 2020 17:22:34 +0800, Yicong Yang wrote:
> Previously we didn't disable the flash's quad mode when it's removed
> Then comes the problem that if we next time load the flash
> in Standard/Dual SPI mode, the quad enable bits is not cleared,
> and the function of flash's WP# and RESET#/HOLD# pin will not
> be restored.
> 
> This series adds the capability to disable the flash's quad mode. And
> restore the flash when it's removed in spi_nor_restore().
> 
> [...]

Applied to spi-nor/next, thanks!

[1/2] mtd: spi-nor: Add capability to disable flash quad mode
      https://git.kernel.org/mtd/c/be192209d5a3
[2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()
      https://git.kernel.org/mtd/c/cc59e6bb6cd6

Best regards,
-- 
Tudor Ambarus <tudor.ambarus@microchip.com>

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