Re: [PATCH v4 1/5] serial: 8250_dw: select port setup through platform data

[Andy Shevchenko]

On Tue, Oct 27, 2026 at 05:05:29PM -0600, James Hilliard wrote:
> Select feature discovery and DMA attachment through a platform-data setup
> callback. The generic callback probes the optional registers and attaches
> DMA when a FIFO size is available. Integrations with a fixed configuration
> can supply their own setup before the port is registered.
> 
> Replace skip_autocfg with the Octeon setup selection. On 64-bit builds,
> Octeon continues to skip optional-register probing while retaining its DMA
> setup; on 32-bit builds it retains the generic setup. Keep generic setup
> for devices without matched platform data as well.

...

> +static void dw8250_setup_dma(struct uart_port *p)
> +{
> +	struct dw8250_data *data = to_dw8250_data(p->private_data);
> +	struct uart_8250_port *up = up_to_u8250p(p);

> +	/* DMA setup requires a FIFO. */

The style of the single-line comment in this file is without period at the end.

> +	if (!p->fifosize)
> +		return;
> +
> +	data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
> +	data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
> +	up->dma = &data->data.dma;
> +}

...

> +static void dw8250_octeon_setup(struct uart_port *p)
> +{

> +	if (!IS_ENABLED(CONFIG_64BIT))
> +		dw8250_setup_port(p);

I believe the Cavium OCTEON  is 64-bit only platform, so you can just drop this
conditional altogether.

> +	dw8250_setup_dma(p);
> +}

With this being done, you can kill the entire helper ad use dw8250_setup_dma()
directly in dw8250_octeon_3860_data.

-- 
With Best Regards,
Andy Shevchenko