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SubjectRe: [PATCH] mtd: spi-nor: cadence-quadspi: write upto 8-bytes data in STIG mode
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Hi, Purna,

On 12/14/2018 04:15 AM, Purna Chandra Mandal wrote:
> cadence-quadspi controller allows upto eight bytes of data to be transferred
> in software Triggered Instruction generator (STIG) mode of operation. Lower
> 4 bytes are written through writedatalower and upper 4 bytes by
> writedataupper register.

Is this supported by all versions of the IP?

>
> This patch allows all the 8 bytes to be written.
>
> Signed-off-by: Purna Chandra Mandal <purna.chandra.mandal@intel.com>
> ---
>
> drivers/mtd/spi-nor/cadence-quadspi.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
> index 04cedd3a2bf6..990934387fea 100644
> --- a/drivers/mtd/spi-nor/cadence-quadspi.c
> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
> @@ -420,7 +420,7 @@ static int cqspi_command_write(struct spi_nor *nor, const u8 opcode,
> unsigned int data;

I know that this is not your change, but data should be u32 and not unsigned
int. reg too ... probably one should submit a patch to change this, I see that
the same error is done in cqspi_command_read().

> int ret;
>
> - if (n_tx > 4 || (n_tx && !txbuf)) {
> + if (n_tx > CQSPI_STIG_DATA_LEN_MAX || (n_tx && !txbuf)) {
> dev_err(nor->dev,
> "Invalid input argument, cmdlen %d txbuf 0x%p\n",
> n_tx, txbuf);
> @@ -435,8 +435,13 @@ static int cqspi_command_write(struct spi_nor *nor, const u8 opcode,
> data = 0;> memcpy(&data, txbuf, n_tx);

You should limit what is copied in data, similar to what is done in
cqspi_command_read():

write_len = (n_tx > 4) ? 4 : n_tx;
memcpy(&data, txbuf, write_len);
txbuf += write_len;



> writel(data, reg_base + CQSPI_REG_CMDWRITEDATALOWER);
> - }
>
> + if (n_tx > 4) {
> + data = 0;
and then:
write_len = n_tx - 4;
memcpy(&data, txbuf, write_len);

Cheers,
ta

> + memcpy(&data, txbuf + 4, n_tx - 4);
> + writel(data, reg_base + CQSPI_REG_CMDWRITEDATAUPPER);
> + }
> + }
> ret = cqspi_exec_flash_cmd(cqspi, reg);
> return ret;
> }
>
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