Re: [PATCH v4] mtd: spi-mem: Add the default transfer length adjustments

[Boris Brezillon <boris.brezillon@bootlin.com>]

Hi Chuanhua,

On Tue, 21 Aug 2018 15:08:18 +0800
Chuanhua Han <chuanhua.han@nxp.com> wrote:

Seriously?! Still not the right prefix. So I'm giving you the full
subject line:

"spi: spi-mem: Adjust op len based on message/transfer size limitations"

>     We need that to adjust the len of the 2nd transfer (called data in spi-mem)

Remove the spaces at the beginning of this line.

> if it's too long to fit in a  SPI message or SPI transfer.
> 
> Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")
> Cc: <stable@vger.kernel.org>
> 

Remove the this blank line.

> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

Remove my SoB. If you want you can add

Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>

though I'm not sure this is needed, since all I did was reviewing your
patch.

> Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
> ---
> Changes in v4:
>   -Rename variable name "opcode_addr_dummy_sum" to "len".
>   -The comparison of "spi_max_message_size(mem->spi)" and "len" was removed.
>   -Adjust their order when comparing the sizes of "spi_max_message_size(mem->spi)" and "len".
>   -Changing the "unsigned long" type in the code to "size_t".
> Changes in v3:
>   -Rename variable name "val" to "opcode_addr_dummy_sum".
>   -Place the legitimacy of the transfer size(i.e., "spi_max_message_size(mem->spi)" and
>   -"opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr-> mem_ops->exec_op) {"
> structure and add "spi_max_transfer_size(mem->spi) and opcode_addr_dummy_sum".
>   -Adjust the formatting alignment of the code.
>   -"(unsigned long)op->data.nbytes" was modified to "(unsigned long)(op->data.nbytes)".
> Changes in v2:
>   -Place the adjusted transfer bytes code in spi_mem_adjust_op_size() and  check 
> spi_max_message_size(mem->spi) value before subtracting opcode, addr and dummy bytes.
>   -Change the code from fsl-espi controller to generic code(The adjustment of spi transmission
> length was originally modified in the "drivers/spi/spi-fsl-espi.c" file, and now the adjustment
> of transfer length is made in the "drivers/spi/spi-mem.c" file).
> 
>  drivers/spi/spi-mem.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index 990770d..5374606 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -328,10 +328,23 @@ EXPORT_SYMBOL_GPL(spi_mem_exec_op);
>  int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  {
>  	struct spi_controller *ctlr = mem->spi->controller;
> +	size_t len = sizeof(op->cmd.opcode) +
> +			    op->addr.nbytes +
> +			    op->dummy.nbytes;

What about David's suggestion to assign len after its declaration so that
it does not exceeds 80 chars?

>  
>  	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
>  		return ctlr->mem_ops->adjust_op_size(mem, op);
>  
> +	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> +		if (len > spi_max_transfer_size(mem->spi))
> +			return -EINVAL;
> +
> +		op->data.nbytes = min3((size_t)(op->data.nbytes),
> +				       spi_max_transfer_size(mem->spi),
> +				       spi_max_message_size(mem->spi) -
> +				       len);

You should probably add:

		if (!op->data.nbytes)
			return -EINVAL;

> +	}
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);

Regards,

Boris