[PATCH v4 1/4] serial: 8250_dwlib: move DesignWare register definitions to header

Jia Wang
2026-04-24T05:40:25Z

Move the DW_UART_* register offsets and CPR bit/field definitions from
8250_dwlib.c into 8250_dwlib.h so they can be shared by 8250_dw and
8250_dwlib users.

Add an include guard for 8250_dwlib.h.

Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
---
drivers/tty/serial/8250/8250_dw.c | 11 -------
drivers/tty/serial/8250/8250_dwlib.c | 49 ----------------------------
drivers/tty/serial/8250/8250_dwlib.h | 63 ++++++++++++++++++++++++++++++++++++
3 files changed, 63 insertions(+), 60 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 94beadb4024d..467755bf0092 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -34,22 +34,11 @@

#include "8250_dwlib.h"

-/* Offsets for the DesignWare specific registers */
-#define DW_UART_USR 0x1f /* UART Status Register */
-#define DW_UART_DMASA 0xa8 /* DMA Software Ack */
-
#define OCTEON_UART_USR 0x27 /* UART Status Register */

#define RZN1_UART_TDMACR 0x10c /* DMA Control Register Transmit Mode */
#define RZN1_UART_RDMACR 0x110 /* DMA Control Register Receive Mode */

-/* DesignWare specific register fields */
-#define DW_UART_IIR_IID GENMASK(3, 0)
-
-#define DW_UART_MCR_SIRE BIT(6)
-
-#define DW_UART_USR_BUSY BIT(0)
-
/* Renesas specific register fields */
#define RZN1_UART_xDMACR_DMA_EN BIT(0)
#define RZN1_UART_xDMACR_1_WORD_BURST (0 << 1)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index b055d89cfb39..8859e66d2d71 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -13,55 +13,6 @@

#include "8250_dwlib.h"

-/* Offsets for the DesignWare specific registers */
-#define DW_UART_TCR 0xac /* Transceiver Control Register (RS485) */
-#define DW_UART_DE_EN 0xb0 /* Driver Output Enable Register */
-#define DW_UART_RE_EN 0xb4 /* Receiver Output Enable Register */
-#define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */
-#define DW_UART_RAR 0xc4 /* Receive Address Register */
-#define DW_UART_TAR 0xc8 /* Transmit Address Register */
-#define DW_UART_LCR_EXT 0xcc /* Line Extended Control Register */
-#define DW_UART_CPR 0xf4 /* Component Parameter Register */
-#define DW_UART_UCV 0xf8 /* UART Component Version */
-
-/* Receive / Transmit Address Register bits */
-#define DW_UART_ADDR_MASK GENMASK(7, 0)
-
-/* Line Status Register bits */
-#define DW_UART_LSR_ADDR_RCVD BIT(8)
-
-/* Transceiver Control Register bits */
-#define DW_UART_TCR_RS485_EN BIT(0)
-#define DW_UART_TCR_RE_POL BIT(1)
-#define DW_UART_TCR_DE_POL BIT(2)
-#define DW_UART_TCR_XFER_MODE GENMASK(4, 3)
-#define DW_UART_TCR_XFER_MODE_DE_DURING_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 0)
-#define DW_UART_TCR_XFER_MODE_SW_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 1)
-#define DW_UART_TCR_XFER_MODE_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 2)
-
-/* Line Extended Control Register bits */
-#define DW_UART_LCR_EXT_DLS_E BIT(0)
-#define DW_UART_LCR_EXT_ADDR_MATCH BIT(1)
-#define DW_UART_LCR_EXT_SEND_ADDR BIT(2)
-#define DW_UART_LCR_EXT_TRANSMIT_MODE BIT(3)
-
-/* Component Parameter Register bits */
-#define DW_UART_CPR_ABP_DATA_WIDTH GENMASK(1, 0)
-#define DW_UART_CPR_AFCE_MODE BIT(4)
-#define DW_UART_CPR_THRE_MODE BIT(5)
-#define DW_UART_CPR_SIR_MODE BIT(6)
-#define DW_UART_CPR_SIR_LP_MODE BIT(7)
-#define DW_UART_CPR_ADDITIONAL_FEATURES BIT(8)
-#define DW_UART_CPR_FIFO_ACCESS BIT(9)
-#define DW_UART_CPR_FIFO_STAT BIT(10)
-#define DW_UART_CPR_SHADOW BIT(11)
-#define DW_UART_CPR_ENCODED_PARMS BIT(12)
-#define DW_UART_CPR_DMA_EXTRA BIT(13)
-#define DW_UART_CPR_FIFO_MODE GENMASK(23, 16)
-
-/* Helper for FIFO size calculation */
-#define DW_UART_CPR_FIFO_SIZE(a) (FIELD_GET(DW_UART_CPR_FIFO_MODE, (a)) * 16)
-
/*
* divisor = div(I) + div(F)
* "I" means integer, "F" means fractional
diff --git a/drivers/tty/serial/8250/8250_dwlib.h b/drivers/tty/serial/8250/8250_dwlib.h
index 7dd2a8e7b780..5026a123cf42 100644
--- a/drivers/tty/serial/8250/8250_dwlib.h
+++ b/drivers/tty/serial/8250/8250_dwlib.h
@@ -1,11 +1,72 @@
/* SPDX-License-Identifier: GPL-2.0+ */
/* Synopsys DesignWare 8250 library header file. */

+#ifndef _SERIAL_8250_DWLIB_H_
+#define _SERIAL_8250_DWLIB_H_
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
#include <linux/io.h>
#include <linux/types.h>

#include "8250.h"

+/* Offsets for the DesignWare specific registers */
+#define DW_UART_USR 0x1f /* UART Status Register */
+#define DW_UART_DMASA 0xa8 /* DMA Software Ack */
+#define DW_UART_TCR 0xac /* Transceiver Control Register (RS485) */
+#define DW_UART_DE_EN 0xb0 /* Driver Output Enable Register */
+#define DW_UART_RE_EN 0xb4 /* Receiver Output Enable Register */
+#define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */
+#define DW_UART_RAR 0xc4 /* Receive Address Register */
+#define DW_UART_TAR 0xc8 /* Transmit Address Register */
+#define DW_UART_LCR_EXT 0xcc /* Line Extended Control Register */
+#define DW_UART_CPR 0xf4 /* Component Parameter Register */
+#define DW_UART_UCV 0xf8 /* UART Component Version */
+
+/* Receive / Transmit Address Register bits */
+#define DW_UART_ADDR_MASK GENMASK(7, 0)
+
+/* Line Status Register bits */
+#define DW_UART_LSR_ADDR_RCVD BIT(8)
+
+/* Transceiver Control Register bits */
+#define DW_UART_TCR_RS485_EN BIT(0)
+#define DW_UART_TCR_RE_POL BIT(1)
+#define DW_UART_TCR_DE_POL BIT(2)
+#define DW_UART_TCR_XFER_MODE GENMASK(4, 3)
+#define DW_UART_TCR_XFER_MODE_DE_DURING_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 0)
+#define DW_UART_TCR_XFER_MODE_SW_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 1)
+#define DW_UART_TCR_XFER_MODE_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 2)
+
+/* Line Extended Control Register bits */
+#define DW_UART_LCR_EXT_DLS_E BIT(0)
+#define DW_UART_LCR_EXT_ADDR_MATCH BIT(1)
+#define DW_UART_LCR_EXT_SEND_ADDR BIT(2)
+#define DW_UART_LCR_EXT_TRANSMIT_MODE BIT(3)
+
+/* Component Parameter Register bits */
+#define DW_UART_CPR_ABP_DATA_WIDTH GENMASK(1, 0)
+#define DW_UART_CPR_AFCE_MODE BIT(4)
+#define DW_UART_CPR_THRE_MODE BIT(5)
+#define DW_UART_CPR_SIR_MODE BIT(6)
+#define DW_UART_CPR_SIR_LP_MODE BIT(7)
+#define DW_UART_CPR_ADDITIONAL_FEATURES BIT(8)
+#define DW_UART_CPR_FIFO_ACCESS BIT(9)
+#define DW_UART_CPR_FIFO_STAT BIT(10)
+#define DW_UART_CPR_SHADOW BIT(11)
+#define DW_UART_CPR_ENCODED_PARMS BIT(12)
+#define DW_UART_CPR_DMA_EXTRA BIT(13)
+#define DW_UART_CPR_FIFO_MODE GENMASK(23, 16)
+
+/* DesignWare specific register fields */
+#define DW_UART_IIR_IID GENMASK(3, 0)
+#define DW_UART_MCR_SIRE BIT(6)
+#define DW_UART_USR_BUSY BIT(0)
+
+/* Helper for FIFO size calculation */
+#define DW_UART_CPR_FIFO_SIZE(a) (FIELD_GET(DW_UART_CPR_FIFO_MODE, (a)) * 16)
+
struct dw8250_port_data {
/* Port properties */
int line;
@@ -38,3 +99,5 @@ static inline void dw8250_writel_ext(struct uart_port *p, int offset, u32 reg)
else
writel(reg, p->membase + offset);
}
+
+#endif /* _SERIAL_8250_DWLIB_H_ */

--
2.34.1