[PATCH v2 1/3] mtd: rawnand: Check the data only read pattern only once

[liao jaime]

> Instead of checking if a pattern is supported each time we need it,
> let's create a bitfield that only the core would be allowed to fill at
> startup time. The core and the individual drivers may then use it in
> order to check what operation they should use. This bitfield is supposed
> to grow over time.
>
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---
> drivers/mtd/nand/raw/nand_base.c  | 20 ++++++++++++++++++++
> drivers/mtd/nand/raw/nand_jedec.c |  3 +--
> drivers/mtd/nand/raw/nand_onfi.c  |  3 +--
> include/linux/mtd/rawnand.h       |  8 ++++++++
> 4 files changed, 30 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 33f2c98a030e..83bfb1ba2fa3 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -4991,6 +4991,24 @@ nand_manufacturer_name(const struct nand_manufacturer_desc *manufacturer_desc)
>  return manufacturer_desc ? manufacturer_desc->name : "Unknown";
> }

> +static void rawnand_check_data_only_read_support(struct nand_chip *chip)
> +{
> + /* Use an arbitrary size for the check */
> + if (!nand_read_data_op(chip, NULL, SZ_512, true, true))
> + chip->controller->supported_op.data_only_read = 1;
> +}
> +
> +static void rawnand_early_check_supported_ops(struct nand_chip *chip)
> +{
> + /* The supported_op fields should not be set by individual drivers */
> + WARN_ON_ONCE(chip->controller->supported_op.data_only_read);
> +
> + if (!nand_has_exec_op(chip))
> + return;
> +
> + rawnand_check_data_only_read_support(chip);
> +}
> +
> /*
> * Get the flash and manufacturer id and lookup if the type is supported.
> */
> @@ -5023,6 +5041,8 @@ static int nand_detect(struct nand_chip *chip, struct nand_flash_dev *type)
>  /* Select the device */
>  nand_select_target(chip, 0);

> + rawnand_early_check_supported_ops(chip);
> +
>  /* Send the command for reading device ID */
>  ret = nand_readid_op(chip, 0, id_data, 2);
>  if (ret)
> diff --git a/drivers/mtd/nand/raw/nand_jedec.c b/drivers/mtd/nand/raw/nand_jedec.c
> index 85b6d9372d80..836757717660 100644
> --- a/drivers/mtd/nand/raw/nand_jedec.c
> +++ b/drivers/mtd/nand/raw/nand_jedec.c
> @@ -46,8 +46,7 @@ int nand_jedec_detect(struct nand_chip *chip)
>  if (!p)
>  return -ENOMEM;
>
> - if (!nand_has_exec_op(chip) ||
> -    !nand_read_data_op(chip, p, sizeof(*p), true, true))
> + if (!nand_has_exec_op(chip) || chip->controller->supported_op.data_only_read)
>  use_datain = true;
>
>  for (i = 0; i < JEDEC_PARAM_PAGES; i++) {
> diff --git a/drivers/mtd/nand/raw/nand_onfi.c b/drivers/mtd/nand/raw/nand_onfi.c
> index 7586befce7f9..f15ef90aec8c 100644
> --- a/drivers/mtd/nand/raw/nand_onfi.c
> +++ b/drivers/mtd/nand/raw/nand_onfi.c
> @@ -166,8 +166,7 @@ int nand_onfi_detect(struct nand_chip *chip)
>  if (!pbuf)
>  return -ENOMEM;
>
> - if (!nand_has_exec_op(chip) ||
> -    !nand_read_data_op(chip, &pbuf[0], sizeof(*pbuf), true, true))
> + if (!nand_has_exec_op(chip) || chip->controller->supported_op.data_only_read)
>  use_datain = true;
>
>  for (i = 0; i < ONFI_PARAM_PAGES; i++) {
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index dcf90144d70b..28c5dce782dd 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -1094,10 +1094,18 @@ struct nand_controller_ops {
>  *
>  * @lock: lock used to serialize accesses to the NAND controller
>  * @ops: NAND controller operations.
> + * @supported_op: NAND controller known-to-be-supported operations,
> + * only writable by the core after initial checking.
> + * @supported_op.data_only_read: The controller supports reading more data from
> + * the bus without restarting an entire read operation nor
> + * changing the column.
>  */
> struct nand_controller {
>  struct mutex lock;
>  const struct nand_controller_ops *ops;
> + struct {
> + unsigned int data_only_read: 1;
> + } supported_op;
> };
>
> static inline void nand_controller_init(struct nand_controller *nfc)
> --
> 2.34.1

Tested-by: Liao Jaime <jaimeliao.tw at gmail.com>