Re: [PATCH 4/4] mtd: spi-nor: aspeed: use command mode for reads

[Marek Vasut <marek.vasut@gmail.com>]

On 04/20/2017 01:56 PM, Cédric Le Goater wrote:
> When reading flash contents, try to use the "command mode" if the AHB
> window configured for the flash module is big enough. Else, just fall
> back to the "user mode" to perform the read.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
> 
>  Changes since initial version :
> 
>  - rebased on current patchset which removed DMA support
> 
>  drivers/mtd/spi-nor/aspeed-smc.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/aspeed-smc.c b/drivers/mtd/spi-nor/aspeed-smc.c
> index 60c020482946..43015aec4557 100644
> --- a/drivers/mtd/spi-nor/aspeed-smc.c
> +++ b/drivers/mtd/spi-nor/aspeed-smc.c
> @@ -394,6 +394,31 @@ static ssize_t aspeed_smc_read_user(struct spi_nor *nor, loff_t from,
>  
>  	aspeed_smc_read_from_ahb(read_buf, chip->ahb_base, len);
>  	aspeed_smc_stop_user(nor);
> +	return 0;
> +}
> +
> +static ssize_t aspeed_smc_read(struct spi_nor *nor, loff_t from, size_t len,
> +			       u_char *read_buf)
> +{
> +	struct aspeed_smc_chip *chip = nor->priv;
> +
> +	/*
> +	 * The AHB window configured for the chip is too small for the
> +	 * read offset. Use the "User mode" of the controller to
> +	 * perform the read.
> +	 */
> +	if (from >= chip->ahb_window_size) {
> +		aspeed_smc_read_user(nor, from, len, read_buf);
> +		goto out;

What about turning this into dumb if () {} else {} and dropping the goto ?

> +	}
> +
> +	/*
> +	 * Use the "Command mode" to do a direct read from the AHB
> +	 * window configured for the chip. This should be the default.
> +	 */
> +	memcpy_fromio(read_buf, chip->ahb_base + from, len);
> +
> +out:
>  	return len;
>  }
>  
> @@ -817,7 +842,7 @@ static int aspeed_smc_setup_flash(struct aspeed_smc_controller *controller,
>  		nor->dev = dev;
>  		nor->priv = chip;
>  		spi_nor_set_flash_node(nor, child);
> -		nor->read = aspeed_smc_read_user;
> +		nor->read = aspeed_smc_read;
>  		nor->write = aspeed_smc_write_user;
>  		nor->read_reg = aspeed_smc_read_reg;
>  		nor->write_reg = aspeed_smc_write_reg;
> 


-- 
Best regards,
Marek Vasut