[PATCH 0/2] serial: 8250_dw: Add support for UltraRISC DP1000 uart

[PATCH 0/2] serial: 8250_dw: Add support for UltraRISC DP1000 uart

[Jia Wang]

This patch series adds support for the UltraRISC DP1000 UART controller.

The series includes two patches:
1. Update device tree bindings to document the DP1000 UART compatible string
   and required properties.
2. Add driver support in the 8250_dw driver by handling the DP1000-specific
   initialization and configuration.

The patches have been tested on Ultrarisc DP1000 development board with
Linux 7.0-rc2, verifying basic UART functionality and runtime suspend/resume.

Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
---
Jia Wang (1):
      dt-bindings: serial: update bindings of ultrarisc dp1000 uart

Zhang Xincheng (1):
      riscv: ultrarisc: 8250_dw: support DP1000 uart

 .../devicetree/bindings/serial/snps-dw-apb-uart.yaml         |  2 ++
 drivers/tty/serial/8250/8250_dw.c                            | 12 ++++++++++++
 2 files changed, 14 insertions(+)
---
base-commit: af4e9ef3d78420feb8fe58cd9a1ab80c501b3c08
change-id: 20260309-ultrarisc-serial-64ff637edf26

Best regards,
--  
Jia Wang <wangjia@ultrarisc.com>


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

[Jia Wang]

From: Zhang Xincheng <zhangxincheng@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@ultrarisc.com>
Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
---
 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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Re: [PATCH 1/2] riscv: ultrarisc: 8250_dw: support DP1000 uart

[Conor Dooley]

[-- Attachment #1.1: Type: text/plain, Size: 2778 bytes --]

On Mon, Mar 16, 2026 at 09:36:18AM +0800, Jia Wang wrote:
> From: Zhang Xincheng <zhangxincheng@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@ultrarisc.com>
> Signed-off-by: Jia Wang <wangjia@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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> linux-riscv@lists.infradead.org
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[PATCH 2/2] dt-bindings: serial: update bindings of ultrarisc dp1000 uart

[Jia Wang]

Add UltraRISC vendor-prefix information
Add DP1000 UART compatible information

Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
---
 Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 6efe43089a74..0040ed28e35b 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -78,6 +78,8 @@ properties:
               - starfive,jh7100-uart
               - starfive,jh7110-uart
           - const: snps,dw-apb-uart
+      - items:
+          - const: ultrarisc,dp1000-uart
       - const: snps,dw-apb-uart
 
   reg:

-- 
2.34.1


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Re: [PATCH 2/2] dt-bindings: serial: update bindings of ultrarisc dp1000 uart

[Yao Zi]

On Mon, Mar 16, 2026 at 09:36:19AM +0800, Jia Wang wrote:
> Add UltraRISC vendor-prefix information

You don't add any new vendor prefixes in this patch. This commit message
should probably be updated.

> Add DP1000 UART compatible information
> 
> Signed-off-by: Jia Wang <wangjia@ultrarisc.com>

And the dt-bindings patch should go before the driver changes.

> ---
>  Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 2 ++
>  1 file changed, 2 insertions(+)

Best regards,
Yao Zi

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Re: [PATCH 2/2] dt-bindings: serial: update bindings of ultrarisc dp1000 uart

[Jia Wang]

On 2026-03-16 04:39 +0000, Yao Zi wrote:
> On Mon, Mar 16, 2026 at 09:36:19AM +0800, Jia Wang wrote:
> > Add UltraRISC vendor-prefix information
> 
> You don't add any new vendor prefixes in this patch. This commit message
> should probably be updated.
> 
> > Add DP1000 UART compatible information
> > 
> > Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
> 
> And the dt-bindings patch should go before the driver changes.
> 
Thanks for the review!

I will update the commit message in v2 as suggested, and
reorder the dt-bindings patch before the driver changes.

Best regards,
Jia Wang
> > ---
> >  Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 2 ++
> >  1 file changed, 2 insertions(+)
> 
> Best regards,
> Yao Zi
> 



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Re: [PATCH 2/2] dt-bindings: serial: update bindings of ultrarisc dp1000 uart

[Conor Dooley]

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On Mon, Mar 16, 2026 at 09:36:19AM +0800, Jia Wang wrote:
> Add UltraRISC vendor-prefix information
> Add DP1000 UART compatible information

$subject: update bindings of ultrarisc dp1000 uart

You're not updating, you're adding it.

> 
> Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
> ---
>  Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> index 6efe43089a74..0040ed28e35b 100644
> --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> @@ -78,6 +78,8 @@ properties:
>                - starfive,jh7100-uart
>                - starfive,jh7110-uart
>            - const: snps,dw-apb-uart
> +      - items:
> +          - const: ultrarisc,dp1000-uart
>        - const: snps,dw-apb-uart


This doesn't look right to me. An items list with one const is just the
same as having "const", like the snps,dw-apb-uart entry below it.

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