Re: [PATCH v9 06/13] spi: spi-mem: Add an ecc parameter to the spi_mem_op structure

[Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>]

On Tue,  4 Jan 2022 09:36:24 +0100
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:

> Soon the SPI-NAND core will need a way to request a SPI controller to
> enable ECC support for a given operation. This is because of the
> pipelined integration of certain ECC engines, which are directly managed
> by the SPI controller itself.
> 
> Introduce a spi_mem_op additional field for this purpose: ecc.
> 
> So far this field is left unset and checked to be false by all
> the SPI controller drivers in their ->supports_op() hook, as they all
> call spi_mem_default_supports_op().
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> Acked-by: Pratyush Yadav <p.yadav@xxxxxx>
> ---
>  drivers/spi/spi-mem.c       | 5 +++++
>  include/linux/spi/spi-mem.h | 5 +++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index ed966d8129eb..f38ac31961c9 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -178,6 +178,11 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
>  			return false;
>  	}
>  
> +	if (op->data.ecc) {
> +		if (!spi_mem_controller_is_capable(ctlr, ecc))
> +			return false;
> +	}

Nit:

	if (op->data.ecc &&
	    !spi_mem_controller_is_capable(ctlr, ecc))
		return false;

> +
>  	return spi_mem_check_buswidth(mem, op);
>  }
>  EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> index 4a1bfe689872..051050b40309 100644
> --- a/include/linux/spi/spi-mem.h
> +++ b/include/linux/spi/spi-mem.h
> @@ -89,6 +89,7 @@ enum spi_mem_data_dir {
>   * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>   * @data.buswidth: number of IO lanes used to send/receive the data
>   * @data.dtr: whether the data should be sent in DTR mode or not
> + * @data.ecc: whether error correction is required or not
>   * @data.dir: direction of the transfer
>   * @data.nbytes: number of data bytes to send/receive. Can be zero if the
>   *		 operation does not involve transferring data
> @@ -119,6 +120,7 @@ struct spi_mem_op {
>  	struct {
>  		u8 buswidth;
>  		u8 dtr : 1;
> +		u8 ecc : 1;
>  		enum spi_mem_data_dir dir;
>  		unsigned int nbytes;
>  		union {
> @@ -126,6 +128,7 @@ struct spi_mem_op {
>  			const void *out;
>  		} buf;
>  	} data;
> +
>  };
>  
>  #define SPI_MEM_OP(__cmd, __addr, __dummy, __data)		\
> @@ -288,9 +291,11 @@ struct spi_controller_mem_ops {
>  /**
>   * struct spi_controller_mem_caps - SPI memory controller capabilities
>   * @dtr: Supports DTR operations
> + * @ecc: Supports operations with error correction
>   */
>  struct spi_controller_mem_caps {
>  	bool dtr;
> +	bool ecc;
>  };
>  
>  #define spi_mem_controller_is_capable(ctlr, cap)	\