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

Andrey Smirnov
2017-04-19T16:01:29Z

On Wed, Apr 19, 2017 at 8:42 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> 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@gmail.com
>> Cc: David Woodhouse <dwmw2@infradead.org>
>> Cc: Brian Norris <computersforpeace@gmail.com>
>> Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
>> Cc: Marek Vasut <marek.vasut@gmail.com>
>> Cc: Richard Weinberger <richard@nod.at>
>> Cc: Cyrille Pitchen <cyrille.pitchen@atmel.com>
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> ---
>>
>> 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@gmail.com
>> [v2] http://lkml.kernel.org/r/20170418142127.23301-3-andrew.smirnov@gmail.com
>>
>> 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);
>

Then I'd have to add 6 more '0's to each of the IDs in dataflash_data,
which would make that code even less readable.

>> + 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);
>

Sure, OK.

Thanks,
Andrey Smirnov