[PATCH 1/2] riscv: ultrarisc: 8250_dw: support DP1000 uart

[Conor Dooley]

On Mon, Mar 16, 2026 at 09:36:18AM +0800, Jia Wang wrote:
> From: Zhang Xincheng <zhangxincheng at ultrarisc.com>
> 
> The UART of DP1000 does not support automatic detection of
> buffer size. skip_autocfg needs to be set to true
> 
> Signed-off-by: Zhang Xincheng <zhangxincheng at ultrarisc.com>
> Signed-off-by: Jia Wang <wangjia at ultrarisc.com>

$subject: riscv: ultrarisc: 8250_dw: support DP1000 uart

Please update this to match other modifications to this file.
"riscv: ultrariscv" doesn't belong at the start.

> ---
>  drivers/tty/serial/8250/8250_dw.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index db73b2ae17fa..6a2acf173331 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -56,6 +56,7 @@
>  #define DW_UART_QUIRK_IS_DMA_FC		BIT(3)
>  #define DW_UART_QUIRK_APMC0D08		BIT(4)
>  #define DW_UART_QUIRK_CPR_VALUE		BIT(5)
> +#define DW_UART_QUIRK_FIXED_TYPE	BIT(6)
>  
>  struct dw8250_platform_data {
>  	u8 usr_reg;
> @@ -514,6 +515,11 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
>  		data->data.dma.prepare_tx_dma = dw8250_prepare_tx_dma;
>  		data->data.dma.prepare_rx_dma = dw8250_prepare_rx_dma;
>  	}
> +	if (quirks & DW_UART_QUIRK_FIXED_TYPE) {
> +		p->flags |= UPF_FIXED_TYPE;
> +		p->type = PORT_16550A;
> +		data->skip_autocfg = true;
> +	}
>  	if (quirks & DW_UART_QUIRK_APMC0D08) {
>  		p->iotype = UPIO_MEM32;
>  		p->regshift = 2;
> @@ -789,6 +795,11 @@ static const struct dw8250_platform_data dw8250_skip_set_rate_data = {
>  	.quirks = DW_UART_QUIRK_SKIP_SET_RATE,
>  };
>  
> +static const struct dw8250_platform_data dw8250_ultrarisc_dp1000_data = {
> +	.usr_reg = DW_UART_USR,
> +	.quirks = DW_UART_QUIRK_FIXED_TYPE,
> +};
> +
>  static const struct of_device_id dw8250_of_match[] = {
>  	{ .compatible = "snps,dw-apb-uart", .data = &dw8250_dw_apb },
>  	{ .compatible = "cavium,octeon-3860-uart", .data = &dw8250_octeon_3860_data },
> @@ -796,6 +807,7 @@ static const struct of_device_id dw8250_of_match[] = {
>  	{ .compatible = "renesas,rzn1-uart", .data = &dw8250_renesas_rzn1_data },
>  	{ .compatible = "sophgo,sg2044-uart", .data = &dw8250_skip_set_rate_data },
>  	{ .compatible = "starfive,jh7100-uart", .data = &dw8250_skip_set_rate_data },
> +	{ .compatible = "ultrarisc,dp1000-uart", .data = &dw8250_ultrarisc_dp1000_data },
>  	{ /* Sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, dw8250_of_match);
> 
> -- 
> 2.34.1
> 
> 
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