[PATCH v3 0/2] Added support for spi-nor device pm in m25p80

[PATCH v3 0/2] Added support for spi-nor device pm in m25p80

[Kamal Dasu]

The V3 changes below implements power management support in m25p80 driver.
m25p80 pm resume() calls newly a implemented spi_nor_init() function
that sets up the spi-nor flash to its probed state. This is needed on
platfroms that turn off power to the spi-nor flash on pm suspend.
The code has been rebased to git://github.com/spi-nor/linux.git next
branch.

Kamal Dasu (2):
  mtd: spi-nor: Added spi-nor reset function
  mtd: m25p80: Added pm ops support

 drivers/mtd/devices/m25p80.c  | 16 ++++++++++
 drivers/mtd/spi-nor/spi-nor.c | 72 +++++++++++++++++++++++++++----------------
 include/linux/mtd/spi-nor.h   | 21 ++++++++++++-
 3 files changed, 81 insertions(+), 28 deletions(-)

-- 
1.9.1

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[PATCH v3 1/2] mtd: spi-nor: Added spi-nor reset function

[Kamal Dasu]

Refactored spi_nor_scan() code to add spi_nor_init() function that
programs the spi-nor flash to:
1) remove flash protection if applicable
2) set read mode to quad mode if configured such
3) set the address width based on the flash size and vendor

On pm resume spi-nor flash may need to be reconfigured after power
reset, there is no need to go through a full spi_nor_scan(), flash
device driver needs to call spi_nor_reset() to reprogram the flash
to its probed state.

Signed-off-by: Kamal Dasu <kdasu.kdev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Conflicts:
	drivers/mtd/spi-nor/spi-nor.c
---
 drivers/mtd/spi-nor/spi-nor.c | 72 +++++++++++++++++++++++++++----------------
 include/linux/mtd/spi-nor.h   | 21 ++++++++++++-
 2 files changed, 65 insertions(+), 28 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 70e52ff..2bf7f4f 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1526,6 +1526,44 @@ static int s3an_nor_scan(const struct flash_info *info, struct spi_nor *nor)
 	return 0;
 }
 
+int spi_nor_init(struct spi_nor *nor)
+{
+	int ret = 0;
+	const struct flash_info *info = nor->info;
+	struct device *dev = nor->dev;
+
+	/*
+	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
+	 * with the software protection bits set
+	 */
+
+	if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
+	    JEDEC_MFR(info) == SNOR_MFR_INTEL ||
+	    JEDEC_MFR(info) == SNOR_MFR_SST ||
+	    info->flags & SPI_NOR_HAS_LOCK) {
+		write_enable(nor);
+		write_sr(nor, 0);
+		spi_nor_wait_till_ready(nor);
+	}
+
+	if (nor->flash_read == SPI_NOR_QUAD) {
+		ret = set_quad_mode(nor, info);
+		if (ret) {
+			dev_err(dev, "quad mode not supported\n");
+			return ret;
+		}
+	}
+
+	if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
+	    info->flags & SPI_NOR_4B_OPCODES)
+		spi_nor_set_4byte_opcodes(nor, info);
+	else
+		set_4byte(nor, info, 1);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(spi_nor_init);
+
 int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 {
 	const struct flash_info *info = NULL;
@@ -1571,6 +1609,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 		}
 	}
 
+	nor->info = info;
 	mutex_init(&nor->lock);
 
 	/*
@@ -1581,20 +1620,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 	if (info->flags & SPI_S3AN)
 		nor->flags |=  SNOR_F_READY_XSR_RDY;
 
-	/*
-	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
-	 * with the software protection bits set
-	 */
-
-	if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
-	    JEDEC_MFR(info) == SNOR_MFR_INTEL ||
-	    JEDEC_MFR(info) == SNOR_MFR_SST ||
-	    info->flags & SPI_NOR_HAS_LOCK) {
-		write_enable(nor);
-		write_sr(nor, 0);
-		spi_nor_wait_till_ready(nor);
-	}
-
 	if (!mtd->name)
 		mtd->name = dev_name(dev);
 	mtd->priv = nor;
@@ -1669,11 +1694,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 
 	/* Quad/Dual-read mode takes precedence over fast/normal */
 	if (mode == SPI_NOR_QUAD && info->flags & SPI_NOR_QUAD_READ) {
-		ret = set_quad_mode(nor, info);
-		if (ret) {
-			dev_err(dev, "quad mode not supported\n");
-			return ret;
-		}
 		nor->flash_read = SPI_NOR_QUAD;
 	} else if (mode == SPI_NOR_DUAL && info->flags & SPI_NOR_DUAL_READ) {
 		nor->flash_read = SPI_NOR_DUAL;
@@ -1702,17 +1722,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 
 	if (info->addr_width)
 		nor->addr_width = info->addr_width;
-	else if (mtd->size > 0x1000000) {
+	else if (mtd->size > 0x1000000)
 		/* enable 4-byte addressing if the device exceeds 16MiB */
 		nor->addr_width = 4;
-		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
-		    info->flags & SPI_NOR_4B_OPCODES)
-			spi_nor_set_4byte_opcodes(nor, info);
-		else
-			set_4byte(nor, info, 1);
-	} else {
+	else
 		nor->addr_width = 3;
-	}
 
 	if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
 		dev_err(dev, "address width is too large: %u\n",
@@ -1728,6 +1742,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 			return ret;
 	}
 
+	ret = spi_nor_init(nor);
+	if (ret)
+		return ret;
+
 	dev_info(dev, "%s (%lld Kbytes)\n", info->name,
 			(long long)mtd->size >> 10);
 
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index f2a7180..945b4d4 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -143,6 +143,8 @@ enum spi_nor_option_flags {
 	SNOR_F_READY_XSR_RDY	= BIT(4),
 };
 
+struct flash_info;
+
 /**
  * struct spi_nor - Structure for defining a the SPI NOR layer
  * @mtd:		point to a mtd_info structure
@@ -176,6 +178,7 @@ enum spi_nor_option_flags {
  * @priv:		the private data
  */
 struct spi_nor {
+	const struct flash_info *info;
 	struct mtd_info		mtd;
 	struct mutex		lock;
 	struct device		*dev;
@@ -220,12 +223,28 @@ static inline struct device_node *spi_nor_get_flash_node(struct spi_nor *nor)
 }
 
 /**
+ * spi_nor_init() - reset scan the SPI NOR
+ * @nor:	the spi_nor structure
+ *
+ * The drivers uses this function to initialize the SPI NOR flash device to
+ * its scanned state, it shall use all nor information set on poweron
+ * for the read mode, address width and remove protection for certain spi-nor
+ * manufacturers. This would be needed to be called for flash devices that are
+ * reset during power management.
+ *
+ * The chip type name can be provided through the @name parameter.
+ *
+ * Return: 0 for success, others for failure.
+ */
+int spi_nor_init(struct spi_nor *nor);
+
+/**
  * spi_nor_scan() - scan the SPI NOR
  * @nor:	the spi_nor structure
  * @name:	the chip type name
  * @mode:	the read mode supported by the driver
  *
- * The drivers can use this fuction to scan the SPI NOR.
+ * The drivers can use this function to scan the SPI NOR.
  * In the scanning, it will try to get all the necessary information to
  * fill the mtd_info{} and the spi_nor{}.
  *
-- 
1.9.1

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Re: [PATCH v3 1/2] mtd: spi-nor: Added spi-nor reset function

[Marek Vasut]

On 02/10/2017 10:49 PM, Kamal Dasu wrote:
> Refactored spi_nor_scan() code to add spi_nor_init() function that
> programs the spi-nor flash to:
> 1) remove flash protection if applicable
> 2) set read mode to quad mode if configured such
> 3) set the address width based on the flash size and vendor
> 
> On pm resume spi-nor flash may need to be reconfigured after power
> reset, there is no need to go through a full spi_nor_scan(), flash
> device driver needs to call spi_nor_reset() to reprogram the flash
                                      ^^^^^
                                           _init() ? or _setup() ?

> to its probed state.
> 
> Signed-off-by: Kamal Dasu <kdasu.kdev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> Conflicts:
> 	drivers/mtd/spi-nor/spi-nor.c
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 72 +++++++++++++++++++++++++++----------------
>  include/linux/mtd/spi-nor.h   | 21 ++++++++++++-
>  2 files changed, 65 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 70e52ff..2bf7f4f 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1526,6 +1526,44 @@ static int s3an_nor_scan(const struct flash_info *info, struct spi_nor *nor)
>  	return 0;
>  }
>  
> +int spi_nor_init(struct spi_nor *nor)
> +{
> +	int ret = 0;
> +	const struct flash_info *info = nor->info;
> +	struct device *dev = nor->dev;
> +
> +	/*
> +	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
> +	 * with the software protection bits set
> +	 */
> +
> +	if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
> +	    JEDEC_MFR(info) == SNOR_MFR_INTEL ||
> +	    JEDEC_MFR(info) == SNOR_MFR_SST ||
> +	    info->flags & SPI_NOR_HAS_LOCK) {
> +		write_enable(nor);
> +		write_sr(nor, 0);
> +		spi_nor_wait_till_ready(nor);
> +	}
> +
> +	if (nor->flash_read == SPI_NOR_QUAD) {
> +		ret = set_quad_mode(nor, info);
> +		if (ret) {
> +			dev_err(dev, "quad mode not supported\n");
> +			return ret;
> +		}
> +	}
> +
> +	if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> +	    info->flags & SPI_NOR_4B_OPCODES)
> +		spi_nor_set_4byte_opcodes(nor, info);
> +	else
> +		set_4byte(nor, info, 1);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(spi_nor_init);
> +
>  int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  {
>  	const struct flash_info *info = NULL;
> @@ -1571,6 +1609,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  		}
>  	}
>  
> +	nor->info = info;
>  	mutex_init(&nor->lock);
>  
>  	/*
> @@ -1581,20 +1620,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  	if (info->flags & SPI_S3AN)
>  		nor->flags |=  SNOR_F_READY_XSR_RDY;
>  
> -	/*
> -	 * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
> -	 * with the software protection bits set
> -	 */
> -
> -	if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
> -	    JEDEC_MFR(info) == SNOR_MFR_INTEL ||
> -	    JEDEC_MFR(info) == SNOR_MFR_SST ||
> -	    info->flags & SPI_NOR_HAS_LOCK) {
> -		write_enable(nor);
> -		write_sr(nor, 0);
> -		spi_nor_wait_till_ready(nor);
> -	}
> -
>  	if (!mtd->name)
>  		mtd->name = dev_name(dev);
>  	mtd->priv = nor;
> @@ -1669,11 +1694,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  
>  	/* Quad/Dual-read mode takes precedence over fast/normal */
>  	if (mode == SPI_NOR_QUAD && info->flags & SPI_NOR_QUAD_READ) {
> -		ret = set_quad_mode(nor, info);
> -		if (ret) {
> -			dev_err(dev, "quad mode not supported\n");
> -			return ret;
> -		}
>  		nor->flash_read = SPI_NOR_QUAD;
>  	} else if (mode == SPI_NOR_DUAL && info->flags & SPI_NOR_DUAL_READ) {
>  		nor->flash_read = SPI_NOR_DUAL;
> @@ -1702,17 +1722,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  
>  	if (info->addr_width)
>  		nor->addr_width = info->addr_width;
> -	else if (mtd->size > 0x1000000) {
> +	else if (mtd->size > 0x1000000)
>  		/* enable 4-byte addressing if the device exceeds 16MiB */
>  		nor->addr_width = 4;
> -		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> -		    info->flags & SPI_NOR_4B_OPCODES)
> -			spi_nor_set_4byte_opcodes(nor, info);
> -		else
> -			set_4byte(nor, info, 1);
> -	} else {
> +	else
>  		nor->addr_width = 3;
> -	}
>  
>  	if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
>  		dev_err(dev, "address width is too large: %u\n",
> @@ -1728,6 +1742,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>  			return ret;
>  	}
>  
> +	ret = spi_nor_init(nor);
> +	if (ret)
> +		return ret;
> +
>  	dev_info(dev, "%s (%lld Kbytes)\n", info->name,
>  			(long long)mtd->size >> 10);
>  
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index f2a7180..945b4d4 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -143,6 +143,8 @@ enum spi_nor_option_flags {
>  	SNOR_F_READY_XSR_RDY	= BIT(4),
>  };
>  
> +struct flash_info;
> +
>  /**
>   * struct spi_nor - Structure for defining a the SPI NOR layer
>   * @mtd:		point to a mtd_info structure
> @@ -176,6 +178,7 @@ enum spi_nor_option_flags {
>   * @priv:		the private data
>   */
>  struct spi_nor {
> +	const struct flash_info *info;

New entry is not documented (see the comment above the struct), also it
shouldn't be at the top IMO , just put it at the bottom or at some more
sensible location.

>  	struct mtd_info		mtd;
>  	struct mutex		lock;
>  	struct device		*dev;
> @@ -220,12 +223,28 @@ static inline struct device_node *spi_nor_get_flash_node(struct spi_nor *nor)
>  }
>  
>  /**
> + * spi_nor_init() - reset scan the SPI NOR

The description really doesn't match what the function does, no ?

> + * @nor:	the spi_nor structure
> + *
> + * The drivers uses this function to initialize the SPI NOR flash device to
> + * its scanned state, it shall use all nor information set on poweron
> + * for the read mode, address width and remove protection for certain spi-nor
> + * manufacturers. This would be needed to be called for flash devices that are
> + * reset during power management.

Doesn't this function just init the SPI NOR to state selected by Linux ?

> + * The chip type name can be provided through the @name parameter.
> + *
> + * Return: 0 for success, others for failure.
> + */
> +int spi_nor_init(struct spi_nor *nor);
> +
> +/**
>   * spi_nor_scan() - scan the SPI NOR
>   * @nor:	the spi_nor structure
>   * @name:	the chip type name
>   * @mode:	the read mode supported by the driver
>   *
> - * The drivers can use this fuction to scan the SPI NOR.
> + * The drivers can use this function to scan the SPI NOR.
>   * In the scanning, it will try to get all the necessary information to
>   * fill the mtd_info{} and the spi_nor{}.
>   *
> 


-- 
Best regards,
Marek Vasut
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[PATCH v3 2/2] mtd: m25p80: Added pm ops support

[Kamal Dasu]

Added power management ops for resume to be able to resan spi-nor
device and set it to right transfer modes in its probed state after
poweron. Some SoC implementations might  power down the spi-nor flash
and loose its initial settings on suspend. A resume should retore the
part to its probed state.

Signed-off-by: Kamal Dasu <kdasu.kdev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/mtd/devices/m25p80.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index c4df3b1..be94fba 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -324,10 +324,26 @@ static int m25p_remove(struct spi_device *spi)
 };
 MODULE_DEVICE_TABLE(of, m25p_of_table);
 
+#ifdef CONFIG_PM_SLEEP
+static int m25p_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int m25p_resume(struct device *dev)
+{
+	struct m25p *flash = dev_get_drvdata(dev);
+
+	return spi_nor_init(&flash->spi_nor);
+}
+#endif
+static SIMPLE_DEV_PM_OPS(m25p_pm_ops, m25p_suspend, m25p_resume);
+
 static struct spi_driver m25p80_driver = {
 	.driver = {
 		.name	= "m25p80",
 		.of_match_table = m25p_of_table,
+		.pm     = &m25p_pm_ops,
 	},
 	.id_table	= m25p_ids,
 	.probe	= m25p_probe,
-- 
1.9.1

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Re: [PATCH v3 2/2] mtd: m25p80: Added pm ops support

[Marek Vasut]

On 02/10/2017 10:49 PM, Kamal Dasu wrote:
> Added power management ops for resume to be able to resan spi-nor
> device and set it to right transfer modes in its probed state after
> poweron. Some SoC implementations might  power down the spi-nor flash
> and loose its initial settings on suspend. A resume should retore the
> part to its probed state.
> 
> Signed-off-by: Kamal Dasu <kdasu.kdev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/mtd/devices/m25p80.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index c4df3b1..be94fba 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -324,10 +324,26 @@ static int m25p_remove(struct spi_device *spi)
>  };
>  MODULE_DEVICE_TABLE(of, m25p_of_table);
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int m25p_suspend(struct device *dev)
> +{
> +	return 0;

Can't you omit this function ?

> +}
> +
> +static int m25p_resume(struct device *dev)
> +{
> +	struct m25p *flash = dev_get_drvdata(dev);
> +
> +	return spi_nor_init(&flash->spi_nor);
> +}
> +#endif
> +static SIMPLE_DEV_PM_OPS(m25p_pm_ops, m25p_suspend, m25p_resume);
> +
>  static struct spi_driver m25p80_driver = {
>  	.driver = {
>  		.name	= "m25p80",
>  		.of_match_table = m25p_of_table,
> +		.pm     = &m25p_pm_ops,
>  	},
>  	.id_table	= m25p_ids,
>  	.probe	= m25p_probe,
> 


-- 
Best regards,
Marek Vasut
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