[PATCH linux-next v6 1/8] mtd: spi-nor: read JEDEC ID with multiple I/O protocols
Jonas Gorski
jogo at openwrt.org
Thu Sep 10 03:25:24 PDT 2015
Hi,
On Wed, Sep 9, 2015 at 3:24 PM, Cyrille Pitchen
<cyrille.pitchen at atmel.com> wrote:
> When their quad or dual I/O mode is enabled, Micron and Macronix spi-nor
> memories don't reply to the regular Read ID (0x9f) command. Instead they
> reply to a new dedicated command Read ID Multiple I/O (0xaf).
>
> If the Read ID (0x9f) command fails (the read ID is all 1's or all 0's),
> then the Read ID Multiple I/O (0xaf) is used, first with SPI 4-4-4 protocol
> (supported by both Micron and Macronix memories), lately with SPI-2-2-2
> protocol (supported only by Micron memories).
>
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen at atmel.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 28 +++++++++++++++++++++++++++-
> include/linux/mtd/spi-nor.h | 23 +++++++++++++++++++++--
> 2 files changed, 48 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index f59aedfe1462..80a0db078aaa 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -703,8 +703,9 @@ static const struct flash_info spi_nor_ids[] = {
>
> static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
> {
> - int tmp;
> + int i, tmp;
> u8 id[SPI_NOR_MAX_ID_LEN];
> + enum spi_protocol proto[2] = {SPI_PROTO_4_4_4, SPI_PROTO_2_2_2};
> const struct flash_info *info;
>
> tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
> @@ -713,6 +714,25 @@ static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
> return ERR_PTR(tmp);
> }
>
> + /* Special case for Micron/Macronix qspi nor. */
> + for (i = 0; i < ARRAY_SIZE(proto); ++i) {
> + if (!((id[0] == 0xff && id[1] == 0xff && id[2] == 0xff) ||
> + (id[0] == 0x00 && id[1] == 0x00 && id[2] == 0x00)))
> + break;
you should probably do something like
if (proto == SPI_PROTO_2_2_2 && !(nor->flags & SPI_NOR_DUAL))
continue;
if (proto == SPI_PROTO_4_4_4 && !(nor->flags & SPI_NOR_QUAD))
continue;
> +
> + nor->erase_proto = proto[i];
> + nor->read_proto = proto[i];
> + nor->write_proto = proto[i];
> + nor->reg_proto = proto[i];
> + tmp = nor->read_reg(nor, SPINOR_OP_MIO_RDID,
> + id, SPI_NOR_MAX_ID_LEN);
Not sure if it has any releveance that the MIO_RDID commands can only
return the first three id bytes, and not the full id.
> + if (tmp < 0) {
> + dev_dbg(nor->dev,
> + " error %d reading JEDEC ID (MULTI IO)\n", tmp);
> + return ERR_PTR(tmp);
Or continue here, as the controller might return an error if it does
not support the protocol.
> + }
> + }
> +
> for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
> info = &spi_nor_ids[tmp];
> if (info->id_len) {
> @@ -1013,6 +1033,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
> if (ret)
> return ret;
>
> + /* Reset SPI protocol for all commands */
> + nor->erase_proto = SPI_PROTO_1_1_1;
> + nor->read_proto = SPI_PROTO_1_1_1;
> + nor->write_proto = SPI_PROTO_1_1_1;
> + nor->reg_proto = SPI_PROTO_1_1_1;
> +
> if (name)
> info = spi_nor_match_id(name);
> /* Try to auto-detect if chip name wasn't specified or not found */
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index e5409524bb0a..66a5f144728a 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -57,8 +57,9 @@
> #define SPINOR_OP_BRWR 0x17 /* Bank register write */
>
> /* Used for Micron flashes only. */
> -#define SPINOR_OP_RD_EVCR 0x65 /* Read EVCR register */
> -#define SPINOR_OP_WD_EVCR 0x61 /* Write EVCR register */
> +#define SPINOR_OP_MIO_RDID 0xaf /* Multiple I/O Read JEDEC ID */
> +#define SPINOR_OP_RD_EVCR 0x65 /* Read EVCR register */
> +#define SPINOR_OP_WD_EVCR 0x61 /* Write EVCR register */
>
> /* Status Register bits. */
> #define SR_WIP 1 /* Write in progress */
> @@ -87,6 +88,16 @@ enum read_mode {
> SPI_NOR_QUAD,
> };
>
> +enum spi_protocol {
> + SPI_PROTO_1_1_1, /* SPI */
> + SPI_PROTO_1_1_2, /* Dual Output */
> + SPI_PROTO_1_1_4, /* Quad Output */
> + SPI_PROTO_1_2_2, /* Dual IO */
> + SPI_PROTO_1_4_4, /* Quad IO */
> + SPI_PROTO_2_2_2, /* Dual Command */
> + SPI_PROTO_4_4_4, /* Quad Command */
> +};
I wonder if the spi-nor controller should somehow store which of these
protocols it can support, so we can check for support before using any
of the dual/quad (i/o) commands.
Also I think you should split out the new readid command usage from
the rest of the SPI_PROTO stuff, as they are only semirelated.
And for good definsive programming, you should first make the spi-nor
controller drivers aware of the protocol stuff before starting to use
it, else you risk breaking controllers silently.
> +
> /**
> * struct spi_nor_xfer_cfg - Structure for defining a Serial Flash transfer
> * @wren: command for "Write Enable", or 0x00 for not required
> @@ -142,6 +153,10 @@ enum spi_nor_option_flags {
> * @sst_write_second: used by the SST write operation
> * @flags: flag options for the current SPI-NOR (SNOR_F_*)
> * @cfg: used by the read_xfer/write_xfer
> + * @erase_proto: the SPI protocol used by erase operations
> + * @read_proto: the SPI protocol used by read operations
> + * @write_proto: the SPI protocol used by write operations
> + * @reg_proto the SPI protocol used by read_reg/write_reg operations
> * @cmd_buf: used by the write_reg
> * @prepare: [OPTIONAL] do some preparations for the
> * read/write/erase/lock/unlock operations
> @@ -169,6 +184,10 @@ struct spi_nor {
> u8 read_opcode;
> u8 read_dummy;
> u8 program_opcode;
> + enum spi_protocol erase_proto;
> + enum spi_protocol read_proto;
> + enum spi_protocol write_proto;
> + enum spi_protocol reg_proto;
> enum read_mode flash_read;
> bool sst_write_second;
> u32 flags;
Regards
Jonas
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