[v2,1/2] mtd: spi-nor: add Global Block Unlock support
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Message ID 20190824122700.23558-2-tudor.ambarus@microchip.com
State New
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  • mtd: spi-nor: add Global Block Unlock support
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Commit Message

Tudor Ambarus Aug. 24, 2019, 12:27 p.m. UTC
From: Tudor Ambarus <tudor.ambarus@microchip.com>

To avoid inadvertent writes during power-up, some flashes are
write-protected by default after a power-on reset cycle.
A Global Block-Protection Unlock command offers a single
command cycle that unlocks the entire memory array. This is
identical with what other nor flashes are doing by clearing
the block protection bits from the status register: disable
the write protection after a power-on reset cycle.

We can't determine this purely by manufacturer type and it's not
autodetectable by anything like SFDP, so make a new flag for it:
UNLOCK_GLOBAL_BLOCK.

Note that the Global Block Unlock command has different names
depending on the manufacturer, but always the same command value:
0x98. Macronix's MX25U12835F names it Gang Block Unlock,
Winbound's W25Q128FV names it Global Block Unlock and
Microchip's SST26VF064B names it Global Block Protection Unlock.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
v2: the check for UNLOCK_GLOBAL_BLOCK should be done the first
thing in spi_nor_disable_block_protection(). We use it for a faster
throughput, a single command cycle that unlocks the entire memory
array. Fix it.

 drivers/mtd/spi-nor/spi-nor.c | 46 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/mtd/spi-nor.h   |  1 +
 2 files changed, 46 insertions(+), 1 deletion(-)

Comments

Boris Brezillon Aug. 25, 2019, 12:49 p.m. UTC | #1
On Sat, 24 Aug 2019 12:27:12 +0000
<Tudor.Ambarus@microchip.com> wrote:

> From: Tudor Ambarus <tudor.ambarus@microchip.com>
> 
> To avoid inadvertent writes during power-up, some flashes are
> write-protected by default after a power-on reset cycle.
> A Global Block-Protection Unlock command offers a single
> command cycle that unlocks the entire memory array. This is
> identical with what other nor flashes are doing by clearing
> the block protection bits from the status register: disable
> the write protection after a power-on reset cycle.
> 
> We can't determine this purely by manufacturer type and it's not
> autodetectable by anything like SFDP, so make a new flag for it:
> UNLOCK_GLOBAL_BLOCK.
> 
> Note that the Global Block Unlock command has different names
> depending on the manufacturer, but always the same command value:
> 0x98. Macronix's MX25U12835F names it Gang Block Unlock,
> Winbound's W25Q128FV names it Global Block Unlock and
> Microchip's SST26VF064B names it Global Block Protection Unlock.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> v2: the check for UNLOCK_GLOBAL_BLOCK should be done the first
> thing in spi_nor_disable_block_protection(). We use it for a faster
> throughput, a single command cycle that unlocks the entire memory
> array. Fix it.
> 
>  drivers/mtd/spi-nor/spi-nor.c | 46 ++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/mtd/spi-nor.h   |  1 +
>  2 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 1896d36a7d11..c0ba6fe62461 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -196,7 +196,7 @@ struct flash_info {
>  	u16		page_size;
>  	u16		addr_width;
>  
> -	u16		flags;
> +	u32		flags;
>  #define SECT_4K			BIT(0)	/* SPINOR_OP_BE_4K works uniformly */
>  #define SPI_NOR_NO_ERASE	BIT(1)	/* No erase command needed */
>  #define SST_WRITE		BIT(2)	/* use SST byte programming */
> @@ -233,6 +233,7 @@ struct flash_info {
>  #define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
>  #define USE_CLSR		BIT(14)	/* use CLSR command */
>  #define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
> +#define UNLOCK_GLOBAL_BLOCK	BIT(16)	/* Unlock global block protection */

Let's add the corresponding SNOR_F_ flag so that manufacturer/sfdp init
can set the flag directly.

>  
>  	/* Part specific fixup hooks. */
>  	const struct spi_nor_fixups *fixups;
> @@ -2031,6 +2032,41 @@ static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor)
>  	return spi_nor_clear_sr_bp(nor);
>  }
>  
> +/**
> + * spi_nor_unlock_global_block_protection() - Unlock the Global Block Protection
> + * @nor:        pointer to a 'struct spi_nor'
> + *
> + * The Global Block-Protection Unlock command offers a single command cycle
> + * that unlocks the entire memory array.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_unlock_global_block_protection(struct spi_nor *nor)
> +{
> +	int ret;
> +
> +	write_enable(nor);
> +
> +	if (nor->spimem) {
> +		struct spi_mem_op op =
> +			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_ULBPR, 1),
> +				   SPI_MEM_OP_NO_ADDR,
> +				   SPI_MEM_OP_NO_DUMMY,
> +				   SPI_MEM_OP_NO_DATA);
> +
> +		ret = spi_mem_exec_op(nor->spimem, &op);
> +	} else {
> +		ret = nor->write_reg(nor, SPINOR_OP_ULBPR, NULL, 0);
> +	}
> +
> +	if (ret < 0) {
> +		dev_err(nor->dev, "error %d on ULBPR\n", ret);
> +		return ret;
> +	}
> +
> +	return spi_nor_wait_till_ready(nor);
> +}
> +
>  /* Used when the "_ext_id" is two bytes at most */
>  #define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
>  		.id = {							\
> @@ -4697,6 +4733,14 @@ static int spi_nor_quad_enable(struct spi_nor *nor)
>   */
>  static int spi_nor_disable_block_protection(struct spi_nor *nor)
>  {
> +	/*
> +	 * If the flash supports the Global Block-Protection Unlock command,
> +	 * use it for faster throughput: a single command cycle that unlocks
> +	 * the entire memory array.
> +	 */
> +	if (nor->info->flags & UNLOCK_GLOBAL_BLOCK)
> +		return spi_nor_unlock_global_block_protection(nor);

Hm, I'd rather put that as a new hook in spi_nor_locking_ops, this way
we're ready to support any vendor-specific variant (and I like the idea
of having all locking-related functions placed in a separate _ops
struct).

> +
>  	if (!nor->params.disable_block_protection)
>  		return 0;
>  
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 4752d08e9a3e..31b99a7743fc 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -66,6 +66,7 @@
>  #define SPINOR_OP_CLFSR		0x50	/* Clear flag status register */
>  #define SPINOR_OP_RDEAR		0xc8	/* Read Extended Address Register */
>  #define SPINOR_OP_WREAR		0xc5	/* Write Extended Address Register */
> +#define SPINOR_OP_ULBPR		0x98	/* Global Block Unlock Protection */
>  
>  /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
>  #define SPINOR_OP_READ_4B	0x13	/* Read data bytes (low frequency) */
Tudor Ambarus Aug. 25, 2019, 2:27 p.m. UTC | #2
On 08/25/2019 03:49 PM, Boris Brezillon wrote:
> External E-Mail
> 
> 
> On Sat, 24 Aug 2019 12:27:12 +0000
> <Tudor.Ambarus@microchip.com> wrote:
> 
>> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>>
>> To avoid inadvertent writes during power-up, some flashes are
>> write-protected by default after a power-on reset cycle.
>> A Global Block-Protection Unlock command offers a single
>> command cycle that unlocks the entire memory array. This is
>> identical with what other nor flashes are doing by clearing
>> the block protection bits from the status register: disable
>> the write protection after a power-on reset cycle.
>>
>> We can't determine this purely by manufacturer type and it's not
>> autodetectable by anything like SFDP, so make a new flag for it:
>> UNLOCK_GLOBAL_BLOCK.
>>
>> Note that the Global Block Unlock command has different names
>> depending on the manufacturer, but always the same command value:
>> 0x98. Macronix's MX25U12835F names it Gang Block Unlock,
>> Winbound's W25Q128FV names it Global Block Unlock and
>> Microchip's SST26VF064B names it Global Block Protection Unlock.
>>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
>> ---
>> v2: the check for UNLOCK_GLOBAL_BLOCK should be done the first
>> thing in spi_nor_disable_block_protection(). We use it for a faster
>> throughput, a single command cycle that unlocks the entire memory
>> array. Fix it.
>>
>>  drivers/mtd/spi-nor/spi-nor.c | 46 ++++++++++++++++++++++++++++++++++++++++++-
>>  include/linux/mtd/spi-nor.h   |  1 +
>>  2 files changed, 46 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index 1896d36a7d11..c0ba6fe62461 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -196,7 +196,7 @@ struct flash_info {
>>  	u16		page_size;
>>  	u16		addr_width;
>>  
>> -	u16		flags;
>> +	u32		flags;
>>  #define SECT_4K			BIT(0)	/* SPINOR_OP_BE_4K works uniformly */
>>  #define SPI_NOR_NO_ERASE	BIT(1)	/* No erase command needed */
>>  #define SST_WRITE		BIT(2)	/* use SST byte programming */
>> @@ -233,6 +233,7 @@ struct flash_info {
>>  #define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
>>  #define USE_CLSR		BIT(14)	/* use CLSR command */
>>  #define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
>> +#define UNLOCK_GLOBAL_BLOCK	BIT(16)	/* Unlock global block protection */
> 
> Let's add the corresponding SNOR_F_ flag so that manufacturer/sfdp init
> can set the flag directly.

Not really needed, because we can't determine this by parsing SFDP, there is no
field in SFDP to indicate this support. You can't set this at manufacturer
level, because it is not a per-manufacturer thing. Some flashes can support it,
some not even if all from the same manufacturer. So this global unlock command
it's at the per-chip level, and for the moment we should keep this flag just in
the flash_info's flags.

Patch
diff mbox series

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 1896d36a7d11..c0ba6fe62461 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -196,7 +196,7 @@  struct flash_info {
 	u16		page_size;
 	u16		addr_width;
 
-	u16		flags;
+	u32		flags;
 #define SECT_4K			BIT(0)	/* SPINOR_OP_BE_4K works uniformly */
 #define SPI_NOR_NO_ERASE	BIT(1)	/* No erase command needed */
 #define SST_WRITE		BIT(2)	/* use SST byte programming */
@@ -233,6 +233,7 @@  struct flash_info {
 #define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
 #define USE_CLSR		BIT(14)	/* use CLSR command */
 #define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
+#define UNLOCK_GLOBAL_BLOCK	BIT(16)	/* Unlock global block protection */
 
 	/* Part specific fixup hooks. */
 	const struct spi_nor_fixups *fixups;
@@ -2031,6 +2032,41 @@  static int spi_nor_spansion_clear_sr_bp(struct spi_nor *nor)
 	return spi_nor_clear_sr_bp(nor);
 }
 
+/**
+ * spi_nor_unlock_global_block_protection() - Unlock the Global Block Protection
+ * @nor:        pointer to a 'struct spi_nor'
+ *
+ * The Global Block-Protection Unlock command offers a single command cycle
+ * that unlocks the entire memory array.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_unlock_global_block_protection(struct spi_nor *nor)
+{
+	int ret;
+
+	write_enable(nor);
+
+	if (nor->spimem) {
+		struct spi_mem_op op =
+			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_ULBPR, 1),
+				   SPI_MEM_OP_NO_ADDR,
+				   SPI_MEM_OP_NO_DUMMY,
+				   SPI_MEM_OP_NO_DATA);
+
+		ret = spi_mem_exec_op(nor->spimem, &op);
+	} else {
+		ret = nor->write_reg(nor, SPINOR_OP_ULBPR, NULL, 0);
+	}
+
+	if (ret < 0) {
+		dev_err(nor->dev, "error %d on ULBPR\n", ret);
+		return ret;
+	}
+
+	return spi_nor_wait_till_ready(nor);
+}
+
 /* Used when the "_ext_id" is two bytes at most */
 #define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
 		.id = {							\
@@ -4697,6 +4733,14 @@  static int spi_nor_quad_enable(struct spi_nor *nor)
  */
 static int spi_nor_disable_block_protection(struct spi_nor *nor)
 {
+	/*
+	 * If the flash supports the Global Block-Protection Unlock command,
+	 * use it for faster throughput: a single command cycle that unlocks
+	 * the entire memory array.
+	 */
+	if (nor->info->flags & UNLOCK_GLOBAL_BLOCK)
+		return spi_nor_unlock_global_block_protection(nor);
+
 	if (!nor->params.disable_block_protection)
 		return 0;
 
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 4752d08e9a3e..31b99a7743fc 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -66,6 +66,7 @@ 
 #define SPINOR_OP_CLFSR		0x50	/* Clear flag status register */
 #define SPINOR_OP_RDEAR		0xc8	/* Read Extended Address Register */
 #define SPINOR_OP_WREAR		0xc5	/* Write Extended Address Register */
+#define SPINOR_OP_ULBPR		0x98	/* Global Block Unlock Protection */
 
 /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
 #define SPINOR_OP_READ_4B	0x13	/* Read data bytes (low frequency) */