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

Marek Vasut
2017-04-19T16:09:27Z

On 04/19/2017 06:01 PM, Andrey Smirnov wrote:
> 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.

Or do >>= 24 on the jedec ID :)

>>> + 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
>

--
Best regards,
Marek Vasut