Re: [PATCH v3 5/6] mtd: dataflash: Make use of "extened device information"

[Marek Vasut]

On 04/19/2017 05:23 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 [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
> 
>  drivers/mtd/devices/mtd_dataflash.c | 115 +++++++++++++++++++++---------------
>  1 file changed, 68 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
> index 2d3e403..941e8b7 100644
> --- a/drivers/mtd/devices/mtd_dataflash.c
> +++ b/drivers/mtd/devices/mtd_dataflash.c
> @@ -687,7 +687,7 @@ 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;
> @@ -710,62 +710,34 @@ static struct flash_info dataflash_data[] = {
>  	 * These newer chips also support 128-byte security registers (with
>  	 * 64 bytes one-time-programmable) and software write-protection.
>  	 */
> -	{ "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
> -	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB011B",  0x1f22000000, 512, 264, 9, SUP_POW2PS},
> +	{ "at45db011d",  0x1f22000000, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
> -	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB021B",  0x1f23000000, 1024, 264, 9, SUP_POW2PS},
> +	{ "at45db021d",  0x1f23000000, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
> -	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB041x",  0x1f24000000, 2048, 264, 9, SUP_POW2PS},
> +	{ "at45db041d",  0x1f24000000, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
> -	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB081B",  0x1f25000000, 4096, 264, 9, SUP_POW2PS},
> +	{ "at45db081d",  0x1f25000000, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
> -	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB161x",  0x1f26000000, 4096, 528, 10, SUP_POW2PS},
> +	{ "at45db161d",  0x1f26000000, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},		/* rev C */
> +	{ "AT45DB321x",  0x1f27000000, 8192, 528, 10, 0},	/* rev C */
>  
> -	{ "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
> -	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB321x",  0x1f27010000, 8192, 528, 10, SUP_POW2PS},
> +	{ "at45db321d",  0x1f27010000, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
>  
> -	{ "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
> -	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
> +	{ "AT45DB642x",  0x1f28000000, 8192, 1056, 11, SUP_POW2PS},
> +	{ "at45db642d",  0x1f28000000, 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)
>  {
> -	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];
> +	struct flash_info *info;
>  
>  	for (info = dataflash_data;
>  	     info < dataflash_data + ARRAY_SIZE(dataflash_data);
> @@ -793,12 +765,61 @@ static struct flash_info *jedec_probe(struct spi_device *spi)
>  		}
>  	}
>  
> +	return NULL;
> +}
> +
> +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;
> +	const unsigned int first_byte = sizeof(id) - id_size;
> +	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[first_byte], id_size);

Hm, looking at this again, what prevents you from reading these bytes
into &id[0] ? Might be easier, ie.

ret = spi_write_then_read(spi, &code, 1, id, id_size);

> +	if (ret < 0) {
> +		pr_debug("%s: error %d reading JEDEC ID\n",
> +			dev_name(&spi->dev), ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	if (id[first_byte] != CFI_MFR_ATMEL)

if (id[0] != CFI_MFR_ATMEL)

> +		return NULL;
> +
> +	jedec = be64_to_cpup((__be64 *)id);
> +
> +	info = jedec_lookup(spi, jedec);

... define these somewhere at the beginning of the dataflash code ...
#define DATAFLASH_MASK_STD	GENMASK(63, 40)
#define DATAFLASH_MASK_EXT	GENMASK(63, 16)

... then ...
info = jedec_lookup(spi, jedec & DATAFLASH_MASK_EXT);

> +	if (info)
> +		return info;
> +
> +	/*
> +	 * Clear extended id bits (bits 0 through 15) and try to find
> +	 * a match again in case our chip does not support returning
> +	 * extended ID information and we got invalid bits instead
> +	 */
> +	jedec &= GENMASK_ULL(63, 16);

info = jedec_lookup(spi, jedec & DATAFLASH_MASK_STD);

> +	info = jedec_lookup(spi, jedec);
> +	if (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 %010llx not handled\n", jedec);
>  	return ERR_PTR(-ENODEV);
>  }
>  
> 


-- 
Best regards,
Marek Vasut