[PATCH v2 0/3] add support for is25wp256 spi-nor device.

[PATCH v2 0/3] add support for is25wp256 spi-nor device.

[Sagar Shrikant Kadam]

The patch set is tested on HiFive Unleashed board and is based on mainline
kernel v 5.1-rc5. Its intended to add support for 32 MB spi-nor flash
mounted on the board. Memory Device supports 4/32/and 64 KB sectors size.
The device id table is updated accordingly.

Flash parameter table for ISSI device is set to use macronix_quad_enable
procedure to set the QE (quad-enable) bit of Status register.

With issi_lock and unlock schemes support for block protection is added 
in patch 2 and 3.
These patches are extended from base work done in a patch at following commit:
https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b

Erase/Read/Write operations are verified on HiFive Unleashed board using  mtd and flash utils (v1.5.2):
1. mtd_debug  	:Options available are : erase/read/write.
2. flashcp	:Single utility that erases flash, writes a file to flash and verifies the data back.
3. flash_lock	:Lock flash memory blocks.
4. flash_unlock: Unlock flash memory blocks.

Unlock scheme clears the bit protection bits of all blocks in the Status register.
Lock schemes in patch  3 is based on stm_lock mechanism. With current implementation entire flash memory
gets protected.

Block protection schemes are tested with flash_lock and unlock utils.

Revision history:
V1<-> V2:
-Incorporated changes suggested by reviewers regarding patch/cover letter versioning, references of patch.
-Updated cover letter with description for flash operations verified with these changes.
-Add support for unlocking is25xxxxxx device
-Add support for locking is25xxxxxx device.

v1:
-Add support for is25wp256 device.

Sagar Shrikant Kadam (3):
  mtd: spi-nor: add support for is25wp256
  mtd: spi-nor: add support to unlock flash device.
  mtd: spi-nor: add locking support for is25xxxxx device

 drivers/mtd/spi-nor/spi-nor.c | 116 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/mtd/spi-nor.h   |   2 +
 2 files changed, 117 insertions(+), 1 deletion(-)

-- 
1.9.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 1/3] mtd: spi-nor: add support for is25wp256

[Sagar Shrikant Kadam]

Update spi_nor_id tablet for is25wp256 (32MB)device from ISSI,
present on HiFive Unleashed dev board (Rev: A00).

Set method to enable quad mode for ISSI device in flash parameters
table.

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 10 +++++++++-
 include/linux/mtd/spi-nor.h   |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index fae1474..c5408ed 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1834,6 +1834,10 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
 			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
 	{ "is25wp128",  INFO(0x9d7018, 0, 64 * 1024, 256,
 			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+	{ "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
+			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+			SPI_NOR_4B_OPCODES)
+	},
 
 	/* Macronix */
 	{ "mx25l512e",   INFO(0xc22010, 0, 64 * 1024,   1, SECT_4K) },
@@ -3650,6 +3654,10 @@ static int spi_nor_init_params(struct spi_nor *nor,
 		case SNOR_MFR_MACRONIX:
 			params->quad_enable = macronix_quad_enable;
 			break;
+		case SNOR_MFR_ISSI:
+			params->quad_enable = macronix_quad_enable;
+			break;
+
 
 		case SNOR_MFR_ST:
 		case SNOR_MFR_MICRON:
@@ -4127,7 +4135,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	if (ret)
 		return ret;
 
-	if (nor->addr_width) {
+	if (nor->addr_width && JEDEC_MFR(info) != SNOR_MFR_ISSI) {
 		/* already configured from SFDP */
 	} else if (info->addr_width) {
 		nor->addr_width = info->addr_width;
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index b3d360b..ff13297 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -19,6 +19,7 @@
 #define SNOR_MFR_ATMEL		CFI_MFR_ATMEL
 #define SNOR_MFR_GIGADEVICE	0xc8
 #define SNOR_MFR_INTEL		CFI_MFR_INTEL
+#define SNOR_MFR_ISSI		0x9d		/* ISSI */
 #define SNOR_MFR_ST		CFI_MFR_ST	/* ST Micro */
 #define SNOR_MFR_MICRON		CFI_MFR_MICRON	/* Micron */
 #define SNOR_MFR_MACRONIX	CFI_MFR_MACRONIX
-- 
1.9.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 1/3] mtd: spi-nor: add support for is25wp256

[Paul Walmsley]

On Sun, 28 Apr 2019, Sagar Shrikant Kadam wrote:

> Update spi_nor_id tablet for is25wp256 (32MB)device from ISSI,
> present on HiFive Unleashed dev board (Rev: A00).
> 
> Set method to enable quad mode for ISSI device in flash parameters
> table.

This patch was based on one originally written by Wes and/or Palmer: 
https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b

The right thing to do is to note this in the commit message.

> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 10 +++++++++-
>  include/linux/mtd/spi-nor.h   |  1 +
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index fae1474..c5408ed 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1834,6 +1834,10 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
>  			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
>  	{ "is25wp128",  INFO(0x9d7018, 0, 64 * 1024, 256,
>  			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> +	{ "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
> +			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> +			SPI_NOR_4B_OPCODES)
> +	},
>  
>  	/* Macronix */
>  	{ "mx25l512e",   INFO(0xc22010, 0, 64 * 1024,   1, SECT_4K) },
> @@ -3650,6 +3654,10 @@ static int spi_nor_init_params(struct spi_nor *nor,
>  		case SNOR_MFR_MACRONIX:
>  			params->quad_enable = macronix_quad_enable;
>  			break;
> +		case SNOR_MFR_ISSI:
> +			params->quad_enable = macronix_quad_enable;
> +			break;
> +
>  
>  		case SNOR_MFR_ST:
>  		case SNOR_MFR_MICRON:
> @@ -4127,7 +4135,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	if (ret)
>  		return ret;
>  
> -	if (nor->addr_width) {
> +	if (nor->addr_width && JEDEC_MFR(info) != SNOR_MFR_ISSI) {
>  		/* already configured from SFDP */
>  	} else if (info->addr_width) {
>  		nor->addr_width = info->addr_width;
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index b3d360b..ff13297 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -19,6 +19,7 @@
>  #define SNOR_MFR_ATMEL		CFI_MFR_ATMEL
>  #define SNOR_MFR_GIGADEVICE	0xc8
>  #define SNOR_MFR_INTEL		CFI_MFR_INTEL
> +#define SNOR_MFR_ISSI		0x9d		/* ISSI */
>  #define SNOR_MFR_ST		CFI_MFR_ST	/* ST Micro */
>  #define SNOR_MFR_MICRON		CFI_MFR_MICRON	/* Micron */
>  #define SNOR_MFR_MACRONIX	CFI_MFR_MACRONIX
> -- 
> 1.9.1
> 
> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 1/3] mtd: spi-nor: add support for is25wp256

[Sagar Kadam]

Thank you Paul, for your review comments.

On Tue, Apr 30, 2019 at 10:33 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> On Sun, 28 Apr 2019, Sagar Shrikant Kadam wrote:
>
> > Update spi_nor_id tablet for is25wp256 (32MB)device from ISSI,
> > present on HiFive Unleashed dev board (Rev: A00).
> >
> > Set method to enable quad mode for ISSI device in flash parameters
> > table.
>
> This patch was based on one originally written by Wes and/or Palmer:
> https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b
>
> The right thing to do is to note this in the commit message.
>
Yes true, this is important as well.
I had mentioned this in the covering letter, but I missed to add the
details into the commit message,
I will submit V3 for this.


> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> > ---
> >  drivers/mtd/spi-nor/spi-nor.c | 10 +++++++++-
> >  include/linux/mtd/spi-nor.h   |  1 +
> >  2 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> > index fae1474..c5408ed 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -1834,6 +1834,10 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
> >                       SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> >       { "is25wp128",  INFO(0x9d7018, 0, 64 * 1024, 256,
> >                       SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> > +     { "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
> > +                     SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> > +                     SPI_NOR_4B_OPCODES)
> > +     },
> >
> >       /* Macronix */
> >       { "mx25l512e",   INFO(0xc22010, 0, 64 * 1024,   1, SECT_4K) },
> > @@ -3650,6 +3654,10 @@ static int spi_nor_init_params(struct spi_nor *nor,
> >               case SNOR_MFR_MACRONIX:
> >                       params->quad_enable = macronix_quad_enable;
> >                       break;
> > +             case SNOR_MFR_ISSI:
> > +                     params->quad_enable = macronix_quad_enable;
> > +                     break;
> > +
> >
> >               case SNOR_MFR_ST:
> >               case SNOR_MFR_MICRON:
> > @@ -4127,7 +4135,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> >       if (ret)
> >               return ret;
> >
> > -     if (nor->addr_width) {
> > +     if (nor->addr_width && JEDEC_MFR(info) != SNOR_MFR_ISSI) {
> >               /* already configured from SFDP */
> >       } else if (info->addr_width) {
> >               nor->addr_width = info->addr_width;
> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> > index b3d360b..ff13297 100644
> > --- a/include/linux/mtd/spi-nor.h
> > +++ b/include/linux/mtd/spi-nor.h
> > @@ -19,6 +19,7 @@
> >  #define SNOR_MFR_ATMEL               CFI_MFR_ATMEL
> >  #define SNOR_MFR_GIGADEVICE  0xc8
> >  #define SNOR_MFR_INTEL               CFI_MFR_INTEL
> > +#define SNOR_MFR_ISSI                0x9d            /* ISSI */
> >  #define SNOR_MFR_ST          CFI_MFR_ST      /* ST Micro */
> >  #define SNOR_MFR_MICRON              CFI_MFR_MICRON  /* Micron */
> >  #define SNOR_MFR_MACRONIX    CFI_MFR_MACRONIX
> > --
> > 1.9.1
> >
> >

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 2/3] mtd: spi-nor: add support to unlock flash device.

[Sagar Shrikant Kadam]

Nor device (is25wp256 mounted on HiFive unleashed Rev A00 board) from ISSI
have memory blocks guarded by block protection bits BP[0,1,2,3].

Clearing block protection bits,unlocks the flash memory regions
The unlock scheme is registered during nor scans.

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 48 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/mtd/spi-nor.h   |  1 +
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index c5408ed..81c7b3e 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1461,6 +1461,46 @@ static int macronix_quad_enable(struct spi_nor *nor)
 }
 
 /**
+ * issi_unlock() - clear BP[0123] write-protection.
+ * @nor: pointer to a 'struct spi_nor'
+ * @ofs: offset from which to unlock memory
+ * @len: number of bytes to unlock
+ * Bits [2345] of the Status Register are BP[0123].
+ * ISSI chips use a different block protection scheme than other chips.
+ * Just disable the write-protect unilaterally.
+ * Return: 0 on success, -errno otherwise.
+ */
+static int issi_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
+{
+	int ret, val;
+	u8 mask = SR_BP0 | SR_BP1 | SR_BP2 | SR_BP3;
+
+	val = read_sr(nor);
+	if (val < 0)
+		return val;
+	if (!(val & mask))
+		return 0;
+
+	write_enable(nor);
+
+	write_sr(nor, val & ~mask);
+
+	ret = spi_nor_wait_till_ready(nor);
+	if (ret)
+		return ret;
+
+	ret = read_sr(nor);
+	if (ret > 0 && !(ret & mask)) {
+		dev_info(nor->dev,
+			"ISSI Block Protection Bits cleared SR=0x%x", ret);
+		return 0;
+	} else {
+		dev_err(nor->dev, "ISSI Block Protection Bits not cleared\n");
+		return -EINVAL;
+	}
+}
+
+/**
  * spansion_quad_enable() - set QE bit in Configuraiton Register.
  * @nor:	pointer to a 'struct spi_nor'
  *
@@ -1836,7 +1876,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
 			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
 	{ "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
 			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
-			SPI_NOR_4B_OPCODES)
+			SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK)
 	},
 
 	/* Macronix */
@@ -4078,6 +4118,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 		nor->flash_is_locked = stm_is_locked;
 	}
 
+	/* NOR protection support for ISSI chips */
+	if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
+	    info->flags & SPI_NOR_HAS_LOCK) {
+		nor->flash_unlock = issi_unlock;
+
+	}
 	if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) {
 		mtd->_lock = spi_nor_lock;
 		mtd->_unlock = spi_nor_unlock;
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index ff13297..9a7d719 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -127,6 +127,7 @@
 #define SR_BP0			BIT(2)	/* Block protect 0 */
 #define SR_BP1			BIT(3)	/* Block protect 1 */
 #define SR_BP2			BIT(4)	/* Block protect 2 */
+#define SR_BP3			BIT(5)	/* Block protect 3 for ISSI device*/
 #define SR_TB			BIT(5)	/* Top/Bottom protect */
 #define SR_SRWD			BIT(7)	/* SR write protect */
 /* Spansion/Cypress specific status bits */
-- 
1.9.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 2/3] mtd: spi-nor: add support to unlock flash device.

[Paul Walmsley]

On Sun, 28 Apr 2019, Sagar Shrikant Kadam wrote:

> Nor device (is25wp256 mounted on HiFive unleashed Rev A00 board) from ISSI
> have memory blocks guarded by block protection bits BP[0,1,2,3].
> 
> Clearing block protection bits,unlocks the flash memory regions
> The unlock scheme is registered during nor scans.

This also looks like it's partially based on Wes or Palmer's patch from 

https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b

Please note that in the patch message.

> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 48 ++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/mtd/spi-nor.h   |  1 +
>  2 files changed, 48 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index c5408ed..81c7b3e 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1461,6 +1461,46 @@ static int macronix_quad_enable(struct spi_nor *nor)
>  }
>  
>  /**
> + * issi_unlock() - clear BP[0123] write-protection.
> + * @nor: pointer to a 'struct spi_nor'
> + * @ofs: offset from which to unlock memory
> + * @len: number of bytes to unlock
> + * Bits [2345] of the Status Register are BP[0123].
> + * ISSI chips use a different block protection scheme than other chips.
> + * Just disable the write-protect unilaterally.
> + * Return: 0 on success, -errno otherwise.

This is closer to kernel-doc format, but not quite.  Please update this to 
align to

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst#n57


- Paul

> + */
> +static int issi_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> +	int ret, val;
> +	u8 mask = SR_BP0 | SR_BP1 | SR_BP2 | SR_BP3;
> +
> +	val = read_sr(nor);
> +	if (val < 0)
> +		return val;
> +	if (!(val & mask))
> +		return 0;
> +
> +	write_enable(nor);
> +
> +	write_sr(nor, val & ~mask);
> +
> +	ret = spi_nor_wait_till_ready(nor);
> +	if (ret)
> +		return ret;
> +
> +	ret = read_sr(nor);
> +	if (ret > 0 && !(ret & mask)) {
> +		dev_info(nor->dev,
> +			"ISSI Block Protection Bits cleared SR=0x%x", ret);
> +		return 0;
> +	} else {
> +		dev_err(nor->dev, "ISSI Block Protection Bits not cleared\n");
> +		return -EINVAL;
> +	}
> +}
> +
> +/**
>   * spansion_quad_enable() - set QE bit in Configuraiton Register.
>   * @nor:	pointer to a 'struct spi_nor'
>   *
> @@ -1836,7 +1876,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
>  			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
>  	{ "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
>  			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> -			SPI_NOR_4B_OPCODES)
> +			SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK)
>  	},
>  
>  	/* Macronix */
> @@ -4078,6 +4118,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  		nor->flash_is_locked = stm_is_locked;
>  	}
>  
> +	/* NOR protection support for ISSI chips */
> +	if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
> +	    info->flags & SPI_NOR_HAS_LOCK) {
> +		nor->flash_unlock = issi_unlock;
> +
> +	}
>  	if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) {
>  		mtd->_lock = spi_nor_lock;
>  		mtd->_unlock = spi_nor_unlock;
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index ff13297..9a7d719 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -127,6 +127,7 @@
>  #define SR_BP0			BIT(2)	/* Block protect 0 */
>  #define SR_BP1			BIT(3)	/* Block protect 1 */
>  #define SR_BP2			BIT(4)	/* Block protect 2 */
> +#define SR_BP3			BIT(5)	/* Block protect 3 for ISSI device*/
>  #define SR_TB			BIT(5)	/* Top/Bottom protect */
>  #define SR_SRWD			BIT(7)	/* SR write protect */
>  /* Spansion/Cypress specific status bits */
> -- 
> 1.9.1
> 
> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 2/3] mtd: spi-nor: add support to unlock flash device.

[Sagar Kadam]

On Tue, Apr 30, 2019 at 10:49 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> On Sun, 28 Apr 2019, Sagar Shrikant Kadam wrote:
>
> > Nor device (is25wp256 mounted on HiFive unleashed Rev A00 board) from ISSI
> > have memory blocks guarded by block protection bits BP[0,1,2,3].
> >
> > Clearing block protection bits,unlocks the flash memory regions
> > The unlock scheme is registered during nor scans.
>
> This also looks like it's partially based on Wes or Palmer's patch from
>
> https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b
>
> Please note that in the patch message.
Thank you Paul for pointing this out.
Yes,  I missed to add it to commit message and will submit a V3
version of the patch.

> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> > ---
> >  drivers/mtd/spi-nor/spi-nor.c | 48 ++++++++++++++++++++++++++++++++++++++++++-
> >  include/linux/mtd/spi-nor.h   |  1 +
> >  2 files changed, 48 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> > index c5408ed..81c7b3e 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -1461,6 +1461,46 @@ static int macronix_quad_enable(struct spi_nor *nor)
> >  }
> >
> >  /**
> > + * issi_unlock() - clear BP[0123] write-protection.
> > + * @nor: pointer to a 'struct spi_nor'
> > + * @ofs: offset from which to unlock memory
> > + * @len: number of bytes to unlock
> > + * Bits [2345] of the Status Register are BP[0123].
> > + * ISSI chips use a different block protection scheme than other chips.
> > + * Just disable the write-protect unilaterally.
> > + * Return: 0 on success, -errno otherwise.
>
> This is closer to kernel-doc format, but not quite.  Please update this to
> align to
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst#n57
>
This is a good pointer. I will align the function description
according to kernel-doc format.

>
> - Paul
>
> > + */
> > +static int issi_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> > +{
> > +     int ret, val;
> > +     u8 mask = SR_BP0 | SR_BP1 | SR_BP2 | SR_BP3;
> > +
> > +     val = read_sr(nor);
> > +     if (val < 0)
> > +             return val;
> > +     if (!(val & mask))
> > +             return 0;
> > +
> > +     write_enable(nor);
> > +
> > +     write_sr(nor, val & ~mask);
> > +
> > +     ret = spi_nor_wait_till_ready(nor);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = read_sr(nor);
> > +     if (ret > 0 && !(ret & mask)) {
> > +             dev_info(nor->dev,
> > +                     "ISSI Block Protection Bits cleared SR=0x%x", ret);
> > +             return 0;
> > +     } else {
> > +             dev_err(nor->dev, "ISSI Block Protection Bits not cleared\n");
> > +             return -EINVAL;
> > +     }
> > +}
> > +
> > +/**
> >   * spansion_quad_enable() - set QE bit in Configuraiton Register.
> >   * @nor:     pointer to a 'struct spi_nor'
> >   *
> > @@ -1836,7 +1876,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
> >                       SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> >       { "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
> >                       SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> > -                     SPI_NOR_4B_OPCODES)
> > +                     SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK)
> >       },
> >
> >       /* Macronix */
> > @@ -4078,6 +4118,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> >               nor->flash_is_locked = stm_is_locked;
> >       }
> >
> > +     /* NOR protection support for ISSI chips */
> > +     if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
> > +         info->flags & SPI_NOR_HAS_LOCK) {
> > +             nor->flash_unlock = issi_unlock;
> > +
> > +     }
> >       if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) {
> >               mtd->_lock = spi_nor_lock;
> >               mtd->_unlock = spi_nor_unlock;
> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> > index ff13297..9a7d719 100644
> > --- a/include/linux/mtd/spi-nor.h
> > +++ b/include/linux/mtd/spi-nor.h
> > @@ -127,6 +127,7 @@
> >  #define SR_BP0                       BIT(2)  /* Block protect 0 */
> >  #define SR_BP1                       BIT(3)  /* Block protect 1 */
> >  #define SR_BP2                       BIT(4)  /* Block protect 2 */
> > +#define SR_BP3                       BIT(5)  /* Block protect 3 for ISSI device*/
> >  #define SR_TB                        BIT(5)  /* Top/Bottom protect */
> >  #define SR_SRWD                      BIT(7)  /* SR write protect */
> >  /* Spansion/Cypress specific status bits */
> > --
> > 1.9.1
> >
> >

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH v2 3/3] mtd: spi-nor: add locking support for is25xxxxx device

[Sagar Shrikant Kadam]

The locking scheme for ISSI devices is based on stm_lock mechanism.
The is25xxxxx  devices have 4 bits for selecting the range of blocks to
be locked for write.

The current implementation, blocks entire 512 blocks of flash memory.

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 60 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 81c7b3e..2dba7e9 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1459,6 +1459,65 @@ static int macronix_quad_enable(struct spi_nor *nor)
 
 	return 0;
 }
+/**
+ * Lock a region of the flash.Implementation is based on stm_lock
+ * Supports the block protection bits BP{0,1,2,3} in the status register
+ * Returns negative on errors, 0 on success.
+ */
+static int issi_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
+{
+	struct mtd_info *mtd = &nor->mtd;
+	int status_old, status_new;
+	u8 mask = SR_BP3 | SR_BP2 | SR_BP1 | SR_BP0;
+	u8 shift = ffs(mask) - 1, pow, val = 0;
+	loff_t lock_len;
+	bool use_top = true;
+
+	status_old = read_sr(nor);
+
+	if (status_old < 0)
+		return status_old;
+
+	/* lock_len: length of region that should end up locked */
+	if (use_top)
+		lock_len = mtd->size - ofs;
+	else
+		lock_len = ofs + len;
+
+	/*
+	 * Need smallest pow such that:
+	 *
+	 *   1 / (2^pow) <= (len / size)
+	 *
+	 * so (assuming power-of-2 size) we do:
+	 *
+	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
+	 */
+	pow = ilog2(mtd->size) - ilog2(lock_len);
+	val = mask - (pow << shift);
+
+	if (val & ~mask)
+		return -EINVAL;
+
+	/* Don't "lock" with no region! */
+	if (!(val & mask))
+		return -EINVAL;
+
+	status_new = (status_old & ~mask & ~SR_TB) | val;
+
+	/* Disallow further writes if WP pin is asserted */
+	status_new |= SR_SRWD;
+
+	/* Don't bother if they're the same */
+	if (status_new == status_old)
+		return 0;
+
+	/* Only modify protection if it will not unlock other areas */
+	if ((status_new & mask) < (status_old & mask))
+		return -EINVAL;
+
+	return write_sr_and_check(nor, status_new, mask);
+}
 
 /**
  * issi_unlock() - clear BP[0123] write-protection.
@@ -4121,6 +4180,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
 	/* NOR protection support for ISSI chips */
 	if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
 	    info->flags & SPI_NOR_HAS_LOCK) {
+		nor->flash_lock = issi_lock;
 		nor->flash_unlock = issi_unlock;
 
 	}
-- 
1.9.1


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 3/3] mtd: spi-nor: add locking support for is25xxxxx device

[Paul Walmsley]

On Sun, 28 Apr 2019, Sagar Shrikant Kadam wrote:

> The locking scheme for ISSI devices is based on stm_lock mechanism.
> The is25xxxxx  devices have 4 bits for selecting the range of blocks to
> be locked for write.
> 
> The current implementation, blocks entire 512 blocks of flash memory.
> 
> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 60 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 81c7b3e..2dba7e9 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -1459,6 +1459,65 @@ static int macronix_quad_enable(struct spi_nor *nor)
>  
>  	return 0;
>  }
> +/**

The above sequence indicates a kerneldoc-style comment, but the format of 
the comment is not in kerneldoc format.  Please fix this comment to 
conform with

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/kernel-docs.rst


> + * Lock a region of the flash.Implementation is based on stm_lock
> + * Supports the block protection bits BP{0,1,2,3} in the status register
> + * Returns negative on errors, 0 on success.
> + */
> +static int issi_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{

Almost all of this function is copied and pasted from stm_lock().  Please 
don't do this: it adds bloat, makes the code hard to maintain, and 
increases the risk that fixes will only target one function rather than 
both.  Instead please pull the common code out into a separate static 
function.

> +	struct mtd_info *mtd = &nor->mtd;
> +	int status_old, status_new;
> +	u8 mask = SR_BP3 | SR_BP2 | SR_BP1 | SR_BP0;
> +	u8 shift = ffs(mask) - 1, pow, val = 0;
> +	loff_t lock_len;
> +	bool use_top = true;
> +
> +	status_old = read_sr(nor);
> +
> +	if (status_old < 0)
> +		return status_old;
> +
> +	/* lock_len: length of region that should end up locked */
> +	if (use_top)
> +		lock_len = mtd->size - ofs;
> +	else
> +		lock_len = ofs + len;
> +
> +	/*
> +	 * Need smallest pow such that:
> +	 *
> +	 *   1 / (2^pow) <= (len / size)
> +	 *
> +	 * so (assuming power-of-2 size) we do:
> +	 *
> +	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
> +	 */
> +	pow = ilog2(mtd->size) - ilog2(lock_len);
> +	val = mask - (pow << shift);
> +
> +	if (val & ~mask)
> +		return -EINVAL;
> +
> +	/* Don't "lock" with no region! */
> +	if (!(val & mask))
> +		return -EINVAL;
> +
> +	status_new = (status_old & ~mask & ~SR_TB) | val;
> +
> +	/* Disallow further writes if WP pin is asserted */
> +	status_new |= SR_SRWD;
> +
> +	/* Don't bother if they're the same */
> +	if (status_new == status_old)
> +		return 0;
> +
> +	/* Only modify protection if it will not unlock other areas */
> +	if ((status_new & mask) < (status_old & mask))
> +		return -EINVAL;
> +
> +	return write_sr_and_check(nor, status_new, mask);
> +}
>  
>  /**
>   * issi_unlock() - clear BP[0123] write-protection.
> @@ -4121,6 +4180,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	/* NOR protection support for ISSI chips */
>  	if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
>  	    info->flags & SPI_NOR_HAS_LOCK) {
> +		nor->flash_lock = issi_lock;
>  		nor->flash_unlock = issi_unlock;
>  
>  	}
> -- 
> 1.9.1
> 
> 

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2 3/3] mtd: spi-nor: add locking support for is25xxxxx device

[Paul Walmsley]

On Tue, 30 Apr 2019, Paul Walmsley wrote:

> The above sequence indicates a kerneldoc-style comment, but the format of 
> the comment is not in kerneldoc format.  Please fix this comment to 
> conform with
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/kernel-docs.rst

This, rather:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst#n57


- Paul

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/