Re: [PATCH v2 3/3] mtd: dataflash: Make use of "extened device information"

From: Marek Vasut
Date: Tue Apr 18 2017 - 15:05:55 EST

On 04/18/2017 04:21 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 [v1]:
>
> - Formatting
>
> [v1] http://lkml.kernel.org/r/20170411161722.11164-1-andrew.smirnov@xxxxxxxxx
>
>
> drivers/mtd/devices/mtd_dataflash.c | 113 +++++++++++++++++++++---------------
> 1 file changed, 65 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
> index 5b7a8c3..5d694a4 100644
> --- a/drivers/mtd/devices/mtd_dataflash.c
> +++ b/drivers/mtd/devices/mtd_dataflash.c
> @@ -690,7 +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;
> @@ -713,63 +713,34 @@ 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, i;
> - u8 code = OP_READ_ID;
> - u8 id[3];
> - u32 jedec;
> + int status, i;
> 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) {
> - pr_debug("%s: error %d reading JEDEC ID\n",
> - dev_name(&spi->dev), 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];

Hm, the diff again screwed this up, oh well ...

> for (i = 0, info = dataflash_data;
> i < ARRAY_SIZE(dataflash_data);
> @@ -799,12 +770,58 @@ 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;
> + u8 id[8] = {0};
> + const unsigned int id_size = 5;
> + const unsigned int first_byte = sizeof(id) - id_size;
> + const u64 eid_mask = GENMASK_ULL(63, 16);
> + u64 jedec;
> + 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);
> + if (ret < 0) {
> + pr_debug("%s: error %d reading JEDEC ID\n",
> + dev_name(&spi->dev), ret);

I think you can turn this into:

dev_err(&spi->dev, "error %d reading JEDEC ID\n", ret);

> + return ERR_PTR(ret);
> + }
> +
> + if (id[first_byte] != CFI_MFR_ATMEL)
> + return NULL;
> +
> + jedec = be64_to_cpup((__be64 *)id);
> +
> + info = jedec_lookup(spi, jedec);
> + if (info)
> + return info;
> +
> + /* Clear extended id bits and try to find a match again */
> + jedec &= eid_mask;

Wouldn't that be jedec &= ~eid_mask; (with a tilde) if you want to clear
them ?

Except for those two nits, looks fine, thanks!

> + 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