Re: [PATCH linux-next 1/5] mtd: spi-nor: properly detect the memory when it boots in Quad or Dual mode

[Cyrille Pitchen <cyrille.pitchen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>]

Hi Brian,

I will be on vacation till 2016 January, 4th.
I will try to answer your questions as soon as possible.

Best regards,

Cyrille

Le 18/12/2015 02:55, Brian Norris a écrit :
> Hi Cyrille,
> 
> On Mon, Dec 07, 2015 at 03:09:10PM +0100, Cyrille Pitchen wrote:
>> The quad (or dual) mode of a spi-nor memory may be enabled at boot time by
>> non-volatile bits in some setting register. Also such a mode may have
>> already been enabled at early stage by some boot loader.
>>
>> Hence, we should not guess the spi-nor memory is always configured for the
>> regular SPI 1-1-1 protocol.
>>
>> Micron and Macronix memories, once their Quad (or dual for Micron) mode
>> enabled, no longer process the regular JEDEC Read ID (0x9f) command but
>> instead reply to a new command: JEDEC Read ID Multiple I/O (0xaf).
>> Besides, in Quad mode both memory manufacturers expect ALL commands to
>> use the SPI 4-4-4 protocol. For Micron memories, enabling their Dual mode
>> implies to use the SPI 2-2-2 protocol for ALL commands.
>>
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
>> ---
>>  drivers/mtd/spi-nor/spi-nor.c | 52 +++++++++++++++++++++++++++++++++++++++----
>>  include/linux/mtd/spi-nor.h   | 23 +++++++++++++++++--
>>  2 files changed, 69 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index 3b2460efc019..bf17736750c1 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -73,6 +73,11 @@ struct flash_info {
>>  
>>  #define JEDEC_MFR(info)	((info)->id[0])
>>  
>> +struct read_id_config {
>> +	enum read_mode		mode;
>> +	enum spi_protocol	proto;
>> +};
>> +
>>  static const struct flash_info *spi_nor_match_id(const char *name);
>>  
>>  /*
>> @@ -867,11 +872,16 @@ static const struct flash_info spi_nor_ids[] = {
>>  	{ },
>>  };
>>  
>> -static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>> +static const struct flash_info *spi_nor_read_id(struct spi_nor *nor,
>> +						enum read_mode mode)
> 
> It's unclear what you're trying to do with the 'read_mode' enum now.
> (Admittedly it may not be clear in the current code either, given the
> confusion we already have over Micron support.)
> 
> Would you care to document it better?
> 
>>  {
>> -	int			tmp;
>> +	int			i, tmp;
>>  	u8			id[SPI_NOR_MAX_ID_LEN];
>>  	const struct flash_info	*info;
>> +	static const struct read_id_config configs[] = {
>> +		{SPI_NOR_QUAD, SPI_PROTO_4_4_4},
>> +		{SPI_NOR_DUAL, SPI_PROTO_2_2_2}
>> +	};
>>  
>>  	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
>>  	if (tmp < 0) {
>> @@ -879,6 +889,34 @@ static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>>  		return ERR_PTR(tmp);
>>  	}
>>  
>> +	/* Special case for Micron/Macronix qspi nor. */
>> +	if ((id[0] == 0xff && id[1] == 0xff && id[2] == 0xff) ||
>> +	    (id[0] == 0x00 && id[1] == 0x00 && id[2] == 0x00))
>> +		for (i = 0; i < ARRAY_SIZE(configs); ++i) {
>> +			if (configs[i].mode != mode)
>> +				continue;
>> +
>> +			/* Set this protocol for all commands. */
>> +			nor->reg_proto = configs[i].proto;
>> +			nor->read_proto = configs[i].proto;
>> +			nor->write_proto = configs[i].proto;
>> +			nor->erase_proto = configs[i].proto;
> 
> Are these all fully independent? Do we really need 4 fields for this?
> 
>> +
>> +			/*
>> +			 * Multiple I/O Read ID only returns the Manufacturer ID
>> +			 * (1 byte) and the Device ID (2 bytes). So we reset the
>> +			 * remaining bytes.
>> +			 */
>> +			memset(id, 0, sizeof(id));
>> +			tmp = nor->read_reg(nor, SPINOR_OP_MIO_RDID, id, 3);
>> +			if (tmp < 0) {
>> +				dev_dbg(nor->dev,
>> +					"error %d reading JEDEC ID Multi I/O\n",
>> +					tmp);
>> +				return ERR_PTR(tmp);
>> +			}
>> +		}
>> +
>>  	for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
>>  		info = &spi_nor_ids[tmp];
>>  		if (info->id_len) {
>> @@ -1178,11 +1216,17 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>>  	if (ret)
>>  		return ret;
>>  
>> +	/* Reset SPI protocol for all commands */
>> +	nor->erase_proto = SPI_PROTO_1_1_1;
>> +	nor->read_proto = SPI_PROTO_1_1_1;
>> +	nor->write_proto = SPI_PROTO_1_1_1;
>> +	nor->reg_proto = SPI_PROTO_1_1_1;
>> +
>>  	if (name)
>>  		info = spi_nor_match_id(name);
>>  	/* Try to auto-detect if chip name wasn't specified or not found */
>>  	if (!info)
>> -		info = spi_nor_read_id(nor);
>> +		info = spi_nor_read_id(nor, mode);
>>  	if (IS_ERR_OR_NULL(info))
>>  		return -ENOENT;
>>  
>> @@ -1193,7 +1237,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>>  	if (name && info->id_len) {
>>  		const struct flash_info *jinfo;
>>  
>> -		jinfo = spi_nor_read_id(nor);
>> +		jinfo = spi_nor_read_id(nor, mode);
>>  		if (IS_ERR(jinfo)) {
>>  			return PTR_ERR(jinfo);
>>  		} else if (jinfo != info) {
>> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
>> index fac3f6f53981..c91986a99caf 100644
>> --- a/include/linux/mtd/spi-nor.h
>> +++ b/include/linux/mtd/spi-nor.h
>> @@ -75,8 +75,9 @@
>>  #define SPINOR_OP_BRWR		0x17	/* Bank register write */
>>  
>>  /* Used for Micron flashes only. */
>> -#define SPINOR_OP_RD_EVCR      0x65    /* Read EVCR register */
>> -#define SPINOR_OP_WD_EVCR      0x61    /* Write EVCR register */
>> +#define SPINOR_OP_MIO_RDID	0xaf	/* Multiple I/O Read JEDEC ID */
>> +#define SPINOR_OP_RD_EVCR	0x65    /* Read EVCR register */
>> +#define SPINOR_OP_WD_EVCR	0x61    /* Write EVCR register */
>>  
>>  /* Status Register bits. */
>>  #define SR_WIP			BIT(0)	/* Write in progress */
>> @@ -105,6 +106,16 @@ enum read_mode {
>>  	SPI_NOR_QUAD,
>>  };
>>  
>> +enum spi_protocol {
>> +	SPI_PROTO_1_1_1,	/* SPI */
>> +	SPI_PROTO_1_1_2,	/* Dual Output */
>> +	SPI_PROTO_1_1_4,	/* Quad Output */
>> +	SPI_PROTO_1_2_2,	/* Dual IO */
>> +	SPI_PROTO_1_4_4,	/* Quad IO */
>> +	SPI_PROTO_2_2_2,	/* Dual Command */
>> +	SPI_PROTO_4_4_4,	/* Quad Command */
> 
> Would it help at all to make this enum into something more like a
> bitfield? So in some cases, rather than a bit switch block, we can just
> extract the "number of lines" from the integer value? e.g.:
> 
> #define SNOR_PROTO(command, addr, data) \
> 	(((command) << 0) | \
> 	 ((addr) << 4) | \
> 	 ((data) << 8)) // or some other kind of macro magic
> 
> enum spi_nor_protocol {
> 	SNOR_PROTO_1_1_1		= SNOR_PROTO(1, 1, 1),
> 	SNOR_PROTO_1_1_2		= SNOR_PROTO(1, 1, 2),
> 	...
> };
> 
> static inline int spi_nor_io_lines_command(enum spi_nor_protocol proto)
> {
> 	return proto & 0xf;
> }
> 
> (Similar for addr and data phases. Also, my naming might suck. Feel free
> to improve!)
> 
> I don't think we should stomp on the SPI namespace with the
> "SPI_PROTO_*" definitions. That's why I chose SNOR_PROTO_ and spi_nor_
> prefixes.
> 
> Brian
> 
>> +};
>> +
>>  #define SPI_NOR_MAX_CMD_SIZE	8
>>  enum spi_nor_ops {
>>  	SPI_NOR_OPS_READ = 0,
>> @@ -132,6 +143,10 @@ enum spi_nor_option_flags {
>>   * @flash_read:		the mode of the read
>>   * @sst_write_second:	used by the SST write operation
>>   * @flags:		flag options for the current SPI-NOR (SNOR_F_*)
>> + * @erase_proto:	the SPI protocol used by erase operations
>> + * @read_proto:		the SPI protocol used by read operations
>> + * @write_proto:	the SPI protocol used by write operations
>> + * @reg_proto		the SPI protocol used by read_reg/write_reg operations
>>   * @cmd_buf:		used by the write_reg
>>   * @prepare:		[OPTIONAL] do some preparations for the
>>   *			read/write/erase/lock/unlock operations
>> @@ -160,6 +175,10 @@ struct spi_nor {
>>  	u8			read_opcode;
>>  	u8			read_dummy;
>>  	u8			program_opcode;
>> +	enum spi_protocol	erase_proto;
>> +	enum spi_protocol	read_proto;
>> +	enum spi_protocol	write_proto;
>> +	enum spi_protocol	reg_proto;
>>  	enum read_mode		flash_read;
>>  	bool			sst_write_second;
>>  	u32			flags;
>> -- 
>> 1.8.2.2
>>

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