Re: [PATCH v6 04/19] spi: spi-mem: allow specifying a command's extension

Boris Brezillon
2020-05-21T18:23:06Z

On Wed, 20 May 2020 22:00:38 +0530
Pratyush Yadav <p.yadav@ti.com> wrote:

> In xSPI mode, flashes expect 2-byte opcodes. The second byte is called
> the "command extension". There can be 3 types of extensions in xSPI:
> repeat, invert, and hex. When the extension type is "repeat", the same
> opcode is sent twice. When it is "invert", the second byte is the
> inverse of the opcode. When it is "hex" an additional opcode byte based
> is sent with the command whose value can be anything.
>
> So, make opcode a 16-bit value and add a 'nbytes', similar to how
> multiple address widths are handled.
>
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> ---
> include/linux/spi/spi-mem.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> index e3dcb956bf61..731bb64c6ba6 100644
> --- a/include/linux/spi/spi-mem.h
> +++ b/include/linux/spi/spi-mem.h
> @@ -69,6 +69,8 @@ enum spi_mem_data_dir {
>
> /**
> * struct spi_mem_op - describes a SPI memory operation
> + * @cmd.nbytes: number of opcode bytes (only 1 or 2 are valid). The opcode is
> + * sent MSB-first.
> * @cmd.buswidth: number of IO lines used to transmit the command
> * @cmd.opcode: operation opcode
> * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
> @@ -94,9 +96,10 @@ enum spi_mem_data_dir {
> */
> struct spi_mem_op {
> struct {
> + u8 nbytes;
> u8 buswidth;
> u8 dtr : 1;
> - u8 opcode;
> + u16 opcode;
> } cmd;
>
> struct {

As mentioned in one of my previous review, you should patch the mxic
driver before extending the opcode field:

--->8---
diff --git a/drivers/spi/spi-mxic.c b/drivers/spi/spi-mxic.c
index 69491f3a515d..c3f4136a7c1d 100644
--- a/drivers/spi/spi-mxic.c
+++ b/drivers/spi/spi-mxic.c
@@ -356,6 +356,7 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
int nio = 1, i, ret;
u32 ss_ctrl;
u8 addr[8];
+ u8 cmd[2];

ret = mxic_spi_set_freq(mxic, mem->spi->max_speed_hz);
if (ret)
@@ -393,7 +394,10 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
writel(readl(mxic->regs + HC_CFG) | HC_CFG_MAN_CS_ASSERT,
mxic->regs + HC_CFG);

- ret = mxic_spi_data_xfer(mxic, &op->cmd.opcode, NULL, 1);
+ for (i = 0; i < op->cmd.nbytes; i++)
+ cmd[i] = op->cmd.opcode >> (8 * (op->cmd.nbytes - i - 1));
+
+ ret = mxic_spi_data_xfer(mxic, cmd, NULL, op->cmd.nbytes);
if (ret)
goto out;