(Hit send too early; a few more comments)
On Mon, Dec 07, 2015 at 03:09:10PM +0100, Cyrille Pitchen wrote:
> drivers/mtd/spi-nor/spi-nor.c | 52
> +++++++++++++++++++++++++++++++++++++++----
> include/linux/mtd/spi-nor.h | 23 +++++++++++++++++--
> 2 files changed, 69 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 3b2460efc019..bf17736750c1 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -73,6 +73,11 @@ struct flash_info {
>
> #define JEDEC_MFR(info) ((info)->id[0])
>
> +struct read_id_config {
> + enum read_mode mode;
> + enum spi_protocol proto;
> +};
> +
> static const struct flash_info *spi_nor_match_id(const char *name);
>
> /*
> @@ -867,11 +872,16 @@ static const struct flash_info spi_nor_ids[] = {
> { },
> };
>
> -static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
> +static const struct flash_info *spi_nor_read_id(struct spi_nor *nor,
> + enum read_mode mode)
> {
> - int tmp;
> + int i, tmp;
> u8 id[SPI_NOR_MAX_ID_LEN];
> const struct flash_info *info;
> + static const struct read_id_config configs[] = {
> + {SPI_NOR_QUAD, SPI_PROTO_4_4_4},
> + {SPI_NOR_DUAL, SPI_PROTO_2_2_2}
> + };
>
> tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
> if (tmp < 0) {
> @@ -879,6 +889,34 @@ static const struct flash_info *spi_nor_read_id(struct
> spi_nor *nor)
> return ERR_PTR(tmp);
> }
>
> + /* Special case for Micron/Macronix qspi nor. */
> + if ((id[0] == 0xff && id[1] == 0xff && id[2] == 0xff) ||
> + (id[0] == 0x00 && id[1] == 0x00 && id[2] == 0x00))
Is this specified anywhere, or is this just a heuristic, to guess
whether we're getting valid IDs? Do we know anything about what opcodes
look like ...
> + for (i = 0; i < ARRAY_SIZE(configs); ++i) {
> + if (configs[i].mode != mode)
> + continue;
> +
> + /* Set this protocol for all commands. */
> + nor->reg_proto = configs[i].proto;
> + nor->read_proto = configs[i].proto;
> + nor->write_proto = configs[i].proto;
> + nor->erase_proto = configs[i].proto;
> +
> + /*
> + * Multiple I/O Read ID only returns the Manufacturer ID
> + * (1 byte) and the Device ID (2 bytes). So we reset the
> + * remaining bytes.
> + */
Ugh, does that mean we get different IDs returned via the different
modes? That sounds like a disaster. What about all the flash that we
need 5+ bytes to differentiate? Just be glad we haven't come across any
Micron or Macronix like that yet?
> + memset(id, 0, sizeof(id));
> + tmp = nor->read_reg(nor, SPINOR_OP_MIO_RDID, id, 3);
Hmm, so you're passing implicit configuration data via the
nor->reg_proto field. So, spi-nor drivers now have to read that field
during every read_reg() invocation? Seems like either this should be:
(a) a driver hook/callback, so we can just reconfigure a handful of
times or
(b) part of a parameter that gets passed as part of the function
signature
> + if (tmp < 0) {
> + dev_dbg(nor->dev,
> + "error %d reading JEDEC ID Multi I/O\n",
> + tmp);
> + return ERR_PTR(tmp);
> + }
> + }
> +
> for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
> info = &spi_nor_ids[tmp];
> if (info->id_len) {
[...]
Brian
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