[PATCH v2 2/2] riscv: ultrarisc: 8250_dw: support DP1000 uart
From: Jia Wang via B4 Relay
Date: Mon Mar 16 2026 - 02:34:11 EST
From: Zhang Xincheng <zhangxincheng@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Jia Wang <wangjia@xxxxxxxxxxxxx>
---
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