Re: [PATCH v2 03/14] mtd: spinand: Patch spi_mem_op for the SPI IO protocol using reg_proto

Boris Brezillon
2021-10-12T06:40:55Z

On Tue, 12 Oct 2021 02:16:08 +0530
Apurva Nandan <a-nandan@ti.com> wrote:

> Currently, the op macros in spinand.h don't give the option to setup
> any non-array access instructions for Dual/Quad/Octal DTR SPI bus.
> Having a function that patches the op based on reg_proto would be
> better than trying to write all the setup logic in op macros.
>
> Create a spimem_patch_op() that would patch cmd, addr, dummy and data
> phase of the spi_mem op, for the given spinand->reg_proto. And hence,
> call the spimem_patch_op() before executing any spi_mem op.

I'm honestly not sure this rule will stand over time, and patching
operations at submission time has a cost (ok, it's negligible compared
to the IO duration, but still), so I'd rather see this done statically
with all relevant macros taking an extra dtr argument.

>
> Note: In this commit, spimem_patch_op() isn't called in the
> read_reg_op(), write_reg_op() and wait() functions, as they need
> modifications in address value and data nbytes when in Octal DTR mode.
> This will be fixed in a later commit.

See, that's what I'm talking about.

>
> Signed-off-by: Apurva Nandan <a-nandan@ti.com>
> ---
> drivers/mtd/nand/spi/core.c | 49 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> index d82a3e6d9bb5..11746d858f87 100644
> --- a/drivers/mtd/nand/spi/core.c
> +++ b/drivers/mtd/nand/spi/core.c
> @@ -20,6 +20,49 @@
> #include <linux/spi/spi.h>
> #include <linux/spi/spi-mem.h>
>
> +/**
> + * spinand_patch_op() - Helper function to patch the spi_mem op based on the
> + * spinand->reg_proto
> + * @spinand: the spinand device
> + * @op: the spi_mem op to patch
> + *
> + * Set up buswidth and dtr fields for cmd, addr, dummy and data phase. Also
> + * adjust cmd opcode and dummy nbytes. This function doesn't make any changes
> + * to addr val or data buf.
> + */
> +static void spinand_patch_op(const struct spinand_device *spinand,
> + struct spi_mem_op *op)
> +{
> + u8 op_buswidth = SPINAND_PROTO_BUSWIDTH(spinand->reg_proto);
> + u8 op_is_dtr = SPINAND_PROTO_IS_DTR(spinand->reg_proto);
> +
> + if (spinand->reg_proto == SPINAND_SINGLE_STR)
> + return;
> +
> + op->cmd.buswidth = op_buswidth;
> + op->cmd.dtr = op_is_dtr;
> + if (spinand->reg_proto == SPINAND_OCTAL_DTR) {
> + op->cmd.opcode = (op->cmd.opcode << 8) | op->cmd.opcode;
> + op->cmd.nbytes = 2;
> + }
> +
> + if (op->addr.nbytes) {
> + op->addr.buswidth = op_buswidth;
> + op->addr.dtr = op_is_dtr;
> + }
> +
> + if (op->dummy.nbytes) {
> + op->dummy.buswidth = op_buswidth;
> + op->dummy.dtr = op_is_dtr;
> + op->dummy.nbytes <<= op_is_dtr;
> + }
> +
> + if (op->data.nbytes) {
> + op->data.buswidth = op_buswidth;
> + op->data.dtr = op_is_dtr;
> + }
> +}
> +
> static int spinand_read_reg_op(struct spinand_device *spinand, u8 reg, u8 *val)
> {
> struct spi_mem_op op = SPINAND_GET_FEATURE_OP(reg,
> @@ -343,6 +386,7 @@ static int spinand_write_enable_op(struct spinand_device *spinand)
> {
> struct spi_mem_op op = SPINAND_WR_EN_DIS_OP(true);
>
> + spinand_patch_op(spinand, &op);
> return spi_mem_exec_op(spinand->spimem, &op);
> }
>
> @@ -353,6 +397,7 @@ static int spinand_load_page_op(struct spinand_device *spinand,
> unsigned int row = nanddev_pos_to_row(nand, &req->pos);
> struct spi_mem_op op = SPINAND_PAGE_READ_OP(row);
>
> + spinand_patch_op(spinand, &op);
> return spi_mem_exec_op(spinand->spimem, &op);
> }
>
> @@ -477,6 +522,7 @@ static int spinand_program_op(struct spinand_device *spinand,
> unsigned int row = nanddev_pos_to_row(nand, &req->pos);
> struct spi_mem_op op = SPINAND_PROG_EXEC_OP(row);
>
> + spinand_patch_op(spinand, &op);
> return spi_mem_exec_op(spinand->spimem, &op);
> }
>
> @@ -487,6 +533,7 @@ static int spinand_erase_op(struct spinand_device *spinand,
> unsigned int row = nanddev_pos_to_row(nand, pos);
> struct spi_mem_op op = SPINAND_BLK_ERASE_OP(row);
>
> + spinand_patch_op(spinand, &op);
> return spi_mem_exec_op(spinand->spimem, &op);
> }
>
> @@ -533,6 +580,7 @@ static int spinand_read_id_op(struct spinand_device *spinand, u8 naddr,
> naddr, ndummy, spinand->scratchbuf, SPINAND_MAX_ID_LEN);
> int ret;
>
> + spinand_patch_op(spinand, &op);
> ret = spi_mem_exec_op(spinand->spimem, &op);
> if (!ret)
> memcpy(buf, spinand->scratchbuf, SPINAND_MAX_ID_LEN);
> @@ -545,6 +593,7 @@ static int spinand_reset_op(struct spinand_device *spinand)
> struct spi_mem_op op = SPINAND_RESET_OP;
> int ret;
>
> + spinand_patch_op(spinand, &op);
> ret = spi_mem_exec_op(spinand->spimem, &op);
> if (ret)
> return ret;