Re: [PATCH v4 5/6] mtd: dataflash: Make use of "extened device information"

[Marek Vasut]

On 04/20/2017 06:29 PM, Andrey Smirnov wrote:
> In anticipation of supporting chips that need it, extend the size of
> struct flash_info's 'jedec_id' field to make room 2 byte of extended
> device information as well as add code to fetch this data during
> jedec_probe().
> 
> Cc: cphealy@xxxxxxxxx
> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> Cc: Brian Norris <computersforpeace@xxxxxxxxx>
> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> Cc: Marek Vasut <marek.vasut@xxxxxxxxx>
> Cc: Richard Weinberger <richard@xxxxxx>
> Cc: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> ---
> 
> Changes since [v3]:
> 
> 	- Convert patch to use SUP_EXTID flag and avoid patching
>           dataflash_data table
> 
> Changes since [v2]:
> 
> 	- Make 'id' have same size as 'jedec'
> 
> 	- Get rid of eid_mask variable in favour of using GENMASK
>           in-place
> 
> Changes since [v1]:
> 
> 	- Formatting
> 
> [v1] http://lkml.kernel.org/r/20170411161722.11164-1-andrew.smirnov@xxxxxxxxx
> [v2] http://lkml.kernel.org/r/20170418142127.23301-3-andrew.smirnov@xxxxxxxxx
> [v3] http://lkml.kernel.org/r/20170419152305.17226-5-andrew.smirnov@xxxxxxxxx
> 
>  drivers/mtd/devices/mtd_dataflash.c | 88 ++++++++++++++++++++++++-------------
>  1 file changed, 57 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
> index 2d3e403..9342cc47 100644
> --- a/drivers/mtd/devices/mtd_dataflash.c
> +++ b/drivers/mtd/devices/mtd_dataflash.c
> @@ -84,6 +84,9 @@
>  
>  #define CFI_MFR_ATMEL		0x1F
>  
> +#define DATAFLASH_SHIFT_EXTID	24
> +#define DATAFLASH_SHIFT_ID	40
> +
>  struct dataflash {
>  	u8			command[4];
>  	char			name[24];
> @@ -687,7 +690,7 @@ struct flash_info {
>  	/* JEDEC id has a high byte of zero plus three data bytes:
>  	 * the manufacturer id, then a two byte device id.
>  	 */
> -	u32		jedec_id;
> +	u64		jedec_id;
>  
>  	/* The size listed here is what works with OP_ERASE_PAGE. */
>  	unsigned	nr_pages;
> @@ -695,6 +698,7 @@ struct flash_info {
>  	u16		pageoffset;
>  
>  	u16		flags;
> +#define SUP_EXTID	BIT(3)

Two nits, can we keep things consistent please ? In this case, 0x0004 .
Also, you wanted to use BIT(2)=0x4 here, not BIT(3)=0x8 .

Other than that,
Acked-by: Marek Vasut <marek.vasut@xxxxxxxxx>

>  #define SUP_POW2PS	0x0002		/* supports 2^N byte pages */
>  #define IS_POW2PS	0x0001		/* uses 2^N byte pages */
>  };
> @@ -734,42 +738,18 @@ static struct flash_info dataflash_data[] = {
>  	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
>  };
>  
> -static struct flash_info *jedec_probe(struct spi_device *spi)
> +static struct flash_info *jedec_lookup(struct spi_device *spi,
> +				       u64 jedec, bool use_extid)
>  {
> -	int ret;
> -	u8 code = OP_READ_ID;
> -	u8 id[3];
> -	u32 jedec;
>  	struct flash_info *info;
>  	int status;
>  
> -	/*
> -	 * JEDEC also defines an optional "extended device information"
> -	 * string for after vendor-specific data, after the three bytes
> -	 * we use here.  Supporting some chips might require using it.
> -	 *
> -	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
> -	 * That's not an error; only rev C and newer chips handle it, and
> -	 * only Atmel sells these chips.
> -	 */
> -	ret = spi_write_then_read(spi, &code, 1, id, 3);
> -	if (ret < 0) {
> -		dev_dbg(&spi->dev, "error %d reading JEDEC ID\n", ret);
> -		return ERR_PTR(ret);
> -	}
> -
> -	if (id[0] != CFI_MFR_ATMEL)
> -		return NULL;
> -
> -	jedec = id[0];
> -	jedec = jedec << 8;
> -	jedec |= id[1];
> -	jedec = jedec << 8;
> -	jedec |= id[2];
> -
>  	for (info = dataflash_data;
>  	     info < dataflash_data + ARRAY_SIZE(dataflash_data);
>  	     info++) {
> +		if (use_extid && !(info->flags & SUP_EXTID))
> +			continue;
> +
>  		if (info->jedec_id == jedec) {
>  			dev_dbg(&spi->dev, "OTP, sector protect%s\n",
>  				(info->flags & SUP_POW2PS) ?
> @@ -793,12 +773,58 @@ static struct flash_info *jedec_probe(struct spi_device *spi)
>  		}
>  	}
>  
> +	return ERR_PTR(-ENODEV);
> +}
> +
> +static struct flash_info *jedec_probe(struct spi_device *spi)
> +{
> +	int ret;
> +	u8 code = OP_READ_ID;
> +	u64 jedec;
> +	u8 id[sizeof(jedec)] = {0};
> +	const unsigned int id_size = 5;
> +	struct flash_info *info;
> +
> +	/*
> +	 * JEDEC also defines an optional "extended device information"
> +	 * string for after vendor-specific data, after the three bytes
> +	 * we use here.  Supporting some chips might require using it.
> +	 *
> +	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
> +	 * That's not an error; only rev C and newer chips handle it, and
> +	 * only Atmel sells these chips.
> +	 */
> +	ret = spi_write_then_read(spi, &code, 1, id, id_size);
> +	if (ret < 0) {
> +		dev_dbg(&spi->dev, "error %d reading JEDEC ID\n", ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	if (id[0] != CFI_MFR_ATMEL)
> +		return NULL;
> +
> +	jedec = be64_to_cpup((__be64 *)id);
> +
> +	/*
> +	 * First, try to match device using extended device
> +	 * information
> +	 */
> +	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_EXTID, true);
> +	if (!IS_ERR(info))
> +		return info;
> +	/*
> +	 * If that fails, make another pass using regular ID
> +	 * information
> +	 */
> +	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_ID, false);
> +	if (!IS_ERR(info))
> +		return info;
>  	/*
>  	 * Treat other chips as errors ... we won't know the right page
>  	 * size (it might be binary) even when we can tell which density
>  	 * class is involved (legacy chip id scheme).
>  	 */
> -	dev_warn(&spi->dev, "JEDEC id %06x not handled\n", jedec);
> +	dev_warn(&spi->dev, "JEDEC id %016llx not handled\n", jedec);
>  	return ERR_PTR(-ENODEV);
>  }
>  
> 


-- 
Best regards,
Marek Vasut