Re: [PATCH v13 10/10] tty: serial: Add Nuvoton ma35d1 serial driver support

From: Jacky Huang
Date: Tue Jun 06 2023 - 04:51:14 EST

On 2023/6/6 下午 04:19, Ilpo Järvinen wrote:
On Mon, 5 Jun 2023, Jacky Huang wrote:

From: Jacky Huang <ychuang3@xxxxxxxxxxx>

This adds UART and console driver for Nuvoton ma35d1 Soc.
It supports full-duplex communication, FIFO control, and
hardware flow control.

Signed-off-by: Jacky Huang <ychuang3@xxxxxxxxxxx>
A few stylistic things below, should be easy to address them I think. In
general, this is in quite good shape already.

---
drivers/tty/serial/Kconfig | 18 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/ma35d1_serial.c | 808 +++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
4 files changed, 830 insertions(+)
create mode 100644 drivers/tty/serial/ma35d1_serial.c

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 3e3fb377d90d..71ea5138adce 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1555,6 +1555,24 @@ config SERIAL_SUNPLUS_CONSOLE
you can alter that using a kernel command line option such as
"console=ttySUPx".
+config SERIAL_NUVOTON_MA35D1
+ tristate "Nuvoton MA35D1 family UART support"
+ depends on ARCH_MA35 || COMPILE_TEST
+ select SERIAL_CORE
+ help
+ This driver supports Nuvoton MA35D1 family UART ports. If you would
+ like to use them, you must answer Y or M to this option. Note that
+ for use as console, it must be included in kernel and not as a
+ module
+
+config SERIAL_NUVOTON_MA35D1_CONSOLE
+ bool "Console on a Nuvotn MA35D1 family UART port"
+ depends on SERIAL_NUVOTON_MA35D1=y
+ select SERIAL_CORE_CONSOLE
+ help
+ Select this options if you'd like to use the UART port0 of the
+ Nuvoton MA35D1 family as a console.
+
endmenu
config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index cd9afd9e3018..0e823851c42c 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -93,3 +93,4 @@ obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
obj-$(CONFIG_SERIAL_KGDB_NMI) += kgdb_nmi.o
obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
+obj-$(CONFIG_SERIAL_NUVOTON_MA35D1) += ma35d1_serial.o
diff --git a/drivers/tty/serial/ma35d1_serial.c b/drivers/tty/serial/ma35d1_serial.c
new file mode 100644
index 000000000000..6c19da7731a6
--- /dev/null
+++ b/drivers/tty/serial/ma35d1_serial.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MA35D1 serial driver
+ * Copyright (C) 2023 Nuvoton Technology Corp.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+#include <linux/units.h>
+
+#define MA35_UART_NR 17
+
+#define MA35_RBR_REG 0x00
+#define MA35_THR_REG 0x00
+#define MA35_IER_REG 0x04
+#define MA35_FCR_REG 0x08
+#define MA35_LCR_REG 0x0C
+#define MA35_MCR_REG 0x10
+#define MA35_MSR_REG 0x14
+#define MA35_FSR_REG 0x18
+#define MA35_ISR_REG 0x1C
+#define MA35_TOR_REG 0x20
+#define MA35_BAUD_REG 0x24
+#define MA35_ALTCTL_REG 0x2C
+#define MA35_FUN_SEL_REG 0x30
+#define MA35_WKCTL_REG 0x40
+#define MA35_WKSTS_REG 0x44
+
+/* MA35_IER_REG - Interrupt Enable Register */
+#define MA35_IER_RDA_IEN BIT(0) /* RBR Available Interrupt Enable */
+#define MA35_IER_THRE_IEN BIT(1) /* THR Empty Interrupt Enable */
+#define MA35_IER_RLS_IEN BIT(2) /* RX Line Status Interrupt Enable */
+#define MA35_IER_RTO_IEN BIT(4) /* RX Time-out Interrupt Enable */
+#define MA35_IER_BUFERR_IEN BIT(5) /* Buffer Error Interrupt Enable */
+#define MA35_IER_TIME_OUT_EN BIT(11) /* RX Buffer Time-out Counter Enable */
+#define MA35_IER_AUTO_RTS BIT(12) /* nRTS Auto-flow Control Enable */
+#define MA35_IER_AUTO_CTS BIT(13) /* nCTS Auto-flow Control Enable */
+
+/* MA35_FCR_REG - FIFO Control Register */
+#define MA35_FCR_RFR BIT(1) /* RX Field Software Reset */
+#define MA35_FCR_TFR BIT(2) /* TX Field Software Reset */
+#define MA35_FCR_RFITL_MASK GENMASK(7, 4) /* RX FIFO Interrupt Trigger Level */
+#define MA35_FCR_RFITL_1BYTE FIELD_PREP(MA35_FCR_RFITL_MASK, 0)
+#define MA35_FCR_RFITL_4BYTES FIELD_PREP(MA35_FCR_RFITL_MASK, 1)
+#define MA35_FCR_RFITL_8BYTES FIELD_PREP(MA35_FCR_RFITL_MASK, 2)
+#define MA35_FCR_RFITL_14BYTES FIELD_PREP(MA35_FCR_RFITL_MASK, 3)
+#define MA35_FCR_RFITL_30BYTES FIELD_PREP(MA35_FCR_RFITL_MASK, 4)
+#define MA35_FCR_RTSTL_MASK GENMASK(19, 16) /* nRTS Trigger Level */
+#define MA35_FCR_RTSTL_1BYTE FIELD_PREP(MA35_FCR_RTSTL_MASK, 0)
+#define MA35_FCR_RTSTL_4BYTES FIELD_PREP(MA35_FCR_RTSTL_MASK, 1)
+#define MA35_FCR_RTSTL_8BYTES FIELD_PREP(MA35_FCR_RTSTL_MASK, 2)
+#define MA35_FCR_RTSTL_14BYTES FIELD_PREP(MA35_FCR_RTSTL_MASK, 3)
+#define MA35_FCR_RTSTLL_30BYTES FIELD_PREP(MA35_FCR_RTSTL_MASK, 4)
+
+/* MA35_LCR_REG - Line Control Register */
+#define MA35_LCR_NSB BIT(2) /* Number of “STOP Bit” */
+#define MA35_LCR_PBE BIT(3) /* Parity Bit Enable */
+#define MA35_LCR_EPE BIT(4) /* Even Parity Enable */
+#define MA35_LCR_SPE BIT(5) /* Stick Parity Enable */
+#define MA35_LCR_BREAK BIT(6) /* Break Control */
+#define MA35_LCR_WLS_MASK GENMASK(1, 0) /* Word Length Selection */
+#define MA35_LCR_WLS_5BITS FIELD_PREP(MA35_LCR_WLS_MASK, 0)
+#define MA35_LCR_WLS_6BITS FIELD_PREP(MA35_LCR_WLS_MASK, 1)
+#define MA35_LCR_WLS_7BITS FIELD_PREP(MA35_LCR_WLS_MASK, 2)
+#define MA35_LCR_WLS_8BITS FIELD_PREP(MA35_LCR_WLS_MASK, 3)
+
+/* MA35_MCR_REG - Modem Control Register */
+#define MA35_MCR_RTS_CTRL BIT(1) /* nRTS Signal Control */
+#define MA35_MCR_RTSACTLV BIT(9) /* nRTS Pin Active Level */
+#define MA35_MCR_RTSSTS BIT(13) /* nRTS Pin Status (Read Only) */
+
+/* MA35_MSR_REG - Modem Status Register */
+#define MA35_MSR_CTSDETF BIT(0) /* Detect nCTS State Change Flag */
+#define MA35_MSR_CTSSTS BIT(4) /* nCTS Pin Status (Read Only) */
+#define MA35_MSR_CTSACTLV BIT(8) /* nCTS Pin Active Level */
+
+/* MA35_FSR_REG - FIFO Status Register */
+#define MA35_FSR_RX_OVER_IF BIT(0) /* RX Overflow Error Interrupt Flag */
+#define MA35_FSR_PEF BIT(4) /* Parity Error Flag*/
+#define MA35_FSR_FEF BIT(5) /* Framing Error Flag */
+#define MA35_FSR_BIF BIT(6) /* Break Interrupt Flag */
+#define MA35_FSR_RX_EMPTY BIT(14) /* Receiver FIFO Empty (Read Only) */
+#define MA35_FSR_RX_FULL BIT(15) /* Receiver FIFO Full (Read Only) */
+#define MA35_FSR_TX_EMPTY BIT(22) /* Transmitter FIFO Empty (Read Only) */
+#define MA35_FSR_TX_FULL BIT(23) /* Transmitter FIFO Full (Read Only) */
+#define MA35_FSR_TX_OVER_IF BIT(24) /* TX Overflow Error Interrupt Flag */
+#define MA35_FSR_TE_FLAG BIT(28) /* Transmitter Empty Flag (Read Only) */
+#define MA35_FSR_RXPTR_MSK GENMASK(13, 8) /* TX FIFO Pointer mask */
+#define MA35_FSR_TXPTR_MSK GENMASK(21, 16) /* RX FIFO Pointer mask */
+
+/* MA35_ISR_REG - Interrupt Status Register */
+#define MA35_ISR_RDA_IF BIT(0) /* RBR Available Interrupt Flag */
+#define MA35_ISR_THRE_IF BIT(1) /* THR Empty Interrupt Flag */
+#define MA35_ISR_RLSIF BIT(2) /* Receive Line Interrupt Flag */
+#define MA35_ISR_MODEMIF BIT(3) /* MODEM Interrupt Flag */
+#define MA35_ISR_RXTO_IF BIT(4) /* RX Time-out Interrupt Flag */
+#define MA35_ISR_BUFEIF BIT(5) /* Buffer Error Interrupt Flag */
+#define MA35_ISR_WK_IF BIT(6) /* UART Wake-up Interrupt Flag */
+#define MA35_ISR_RDAINT BIT(8) /* RBR Available Interrupt Indicator */
+#define MA35_ISR_THRE_INT BIT(9) /* THR Empty Interrupt Indicator */
+#define MA35_ISR_ALL 0xFFFFFFFF
+
+/* MA35_BAUD_REG - Baud Rate Divider Register */
+#define MA35_BAUD_MODE_MASK GENMASK(29, 28)
+#define MA35_BAUD_MODE0 FIELD_PREP(MA35_BAUD_MODE_MASK, 0)
+#define MA35_BAUD_MODE1 FIELD_PREP(MA35_BAUD_MODE_MASK, 2)
+#define MA35_BAUD_MODE2 FIELD_PREP(MA35_BAUD_MODE_MASK, 3)
+#define MA35_BAUD_MASK GENMASK(15, 0)
+
+/* MA35_ALTCTL_REG - Alternate Control/Status Register */
+#define MA35_ALTCTL_RS485AUD BIT(10) /* RS-485 Auto Direction Function */
+
+/* MA35_FUN_SEL_REG - Function Select Register */
+#define MA35_FUN_SEL_MASK GENMASK(2, 0)
+#define MA35_FUN_SEL_UART FIELD_PREP(MA35_FUN_SEL_MASK, 0)
+#define MA35_FUN_SEL_RS485 FIELD_PREP(MA35_FUN_SEL_MASK, 3)
+
+/* The constrain for MA35D1 UART baud rate divider */
+#define MA35_BAUD_DIV_MAX 0xFFFF
+#define MA35_BAUD_DIV_MIN 11
+
+/* UART FIFO depth */
+#define MA35_UART_FIFO_DEPTH 32
+/* UART console clock */
+#define MA35_UART_CONSOLE_CLK (24 * HZ_PER_MHZ)
+/* UART register ioremap size */
+#define MA35_UART_REG_SIZE 0x100
+/* Rx Timeout */
+#define MA35_UART_RX_TOUT 0x40
+
+#define MA35_ISR_IF_CHECK (MA35_ISR_RDA_IF | MA35_ISR_RXTO_IF | \
+ MA35_ISR_THRE_INT | MA35_ISR_BUFEIF)
+
+static struct uart_driver ma35d1serial_reg;
+
+struct uart_ma35d1_port {
+ struct uart_port port;
+ struct clk *clk;
+ u16 capabilities; /* port capabilities */
+ u8 ier;
+ u8 lcr;
+ u8 mcr;
+ u32 baud_rate;
+ u32 console_baud_rate;
+ u32 console_line;
+ u32 console_int;
+};
+
+static struct uart_ma35d1_port ma35d1serial_ports[MA35_UART_NR];
+
+static struct uart_ma35d1_port *to_ma35d1_uart_port(struct uart_port *uart)
+{
+ return container_of(uart, struct uart_ma35d1_port, port);
+}
+
+static u32 serial_in(struct uart_ma35d1_port *p, u32 offset)
+{
+ return readl_relaxed(p->port.membase + offset);
+}
+
+static void serial_out(struct uart_ma35d1_port *p, u32 offset, u32 value)
+{
+ writel_relaxed(value, p->port.membase + offset);
+}
+
+static void __stop_tx(struct uart_ma35d1_port *p)
+{
+ u32 ier;
+
+ ier = serial_in(p, MA35_IER_REG);
+ if (ier & MA35_IER_THRE_IEN)
+ serial_out(p, MA35_IER_REG, ier & ~MA35_IER_THRE_IEN);
+}
+
+static void ma35d1serial_stop_tx(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+
+ __stop_tx(up);
+}
+
+static void transmit_chars(struct uart_ma35d1_port *up)
+{
+ u32 count;
+ u8 ch;
+
+ if (uart_tx_stopped(&up->port)) {
+ ma35d1serial_stop_tx(&up->port);
+ return;
+ }
+ count = MA35_UART_FIFO_DEPTH - FIELD_GET(MA35_FSR_TXPTR_MSK,
+ serial_in(up, MA35_FSR_REG));
+ uart_port_tx_limited(&up->port, ch, count,
+ !(serial_in(up, MA35_FSR_REG) & MA35_FSR_TX_FULL),
+ serial_out(up, MA35_THR_REG, ch),
+ ({}));
+}
+
+static void ma35d1serial_start_tx(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 ier;
+
+ ier = serial_in(up, MA35_IER_REG);
+ serial_out(up, MA35_IER_REG, ier & ~MA35_IER_THRE_IEN);
+ transmit_chars(up);
+ serial_out(up, MA35_IER_REG, ier | MA35_IER_THRE_IEN);
+}
+
+static void ma35d1serial_stop_rx(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+
+ serial_out(up, MA35_IER_REG, serial_in(up, MA35_IER_REG) & ~MA35_IER_RDA_IEN);
These should be split up to:
reg = serial_in(...)
reg &= ~MA35_IER_RDA_IEN;
serial_out(...)

There are other cases too besides this one, convert them all. It will help
with some line splitting challenges too you seem to have below.

+}
+
+static void receive_chars(struct uart_ma35d1_port *up)
+{
+ u8 ch, flag;
+ u32 fsr;
+ int max_count = 256;
+
+ fsr = serial_in(up, MA35_FSR_REG);
+ do {
+ flag = TTY_NORMAL;
+ up->port.icount.rx++;
+
+ if (unlikely(fsr & (MA35_FSR_BIF | MA35_FSR_FEF |
+ MA35_FSR_PEF | MA35_FSR_RX_OVER_IF))) {
+ if (fsr & MA35_FSR_BIF) {
+ up->port.icount.brk++;
+ if (uart_handle_break(&up->port))
+ continue;
+ }
+ if (fsr & MA35_FSR_FEF)
+ up->port.icount.frame++;
+ if (fsr & MA35_FSR_PEF)
+ up->port.icount.parity++;
+ if (fsr & MA35_FSR_RX_OVER_IF)
+ up->port.icount.overrun++;
+
+ serial_out(up, MA35_FSR_REG,
+ fsr & (MA35_FSR_BIF | MA35_FSR_FEF |
+ MA35_FSR_PEF | MA35_FSR_RX_OVER_IF));
+ if (fsr & MA35_FSR_BIF)
+ flag = TTY_BREAK;
+ else if (fsr & MA35_FSR_PEF)
+ flag = TTY_PARITY;
+ else if (fsr & MA35_FSR_FEF)
+ flag = TTY_FRAME;
+ }
+
+ ch = serial_in(up, MA35_RBR_REG);
+ if (uart_handle_sysrq_char(&up->port, ch))
+ continue;
+
+ spin_lock(&up->port.lock);
+ uart_insert_char(&up->port, fsr, MA35_FSR_RX_OVER_IF, ch, flag);
+ spin_unlock(&up->port.lock);
+
+ fsr = serial_in(up, MA35_FSR_REG);
+ } while (!(fsr & MA35_FSR_RX_EMPTY) && (max_count-- > 0));
+
+ spin_lock(&up->port.lock);
+ tty_flip_buffer_push(&up->port.state->port);
+ spin_unlock(&up->port.lock);
+}
+
+static irqreturn_t ma35d1serial_interrupt(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 isr, fsr;
+
+ isr = serial_in(up, MA35_ISR_REG);
+ fsr = serial_in(up, MA35_FSR_REG);
+
+ if (!(isr & MA35_ISR_IF_CHECK))
+ return IRQ_NONE;
+
+ if (isr & (MA35_ISR_RDA_IF | MA35_ISR_RXTO_IF))
+ receive_chars(up);
+ if (isr & MA35_ISR_THRE_INT)
+ transmit_chars(up);
+ if (fsr & MA35_FSR_TX_OVER_IF)
+ serial_out(up, MA35_FSR_REG, MA35_FSR_TX_OVER_IF);
+
+ return IRQ_HANDLED;
+}
+
+static u32 ma35d1serial_tx_empty(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 fsr;
+
+ fsr = serial_in(up, MA35_FSR_REG);
+ return (fsr & (MA35_FSR_TE_FLAG | MA35_FSR_TX_EMPTY)) ==
+ (MA35_FSR_TE_FLAG | MA35_FSR_TX_EMPTY) ? TIOCSER_TEMT : 0;
To make this check cleaner, add this and use it here:

#define MA35_FSR_TX_BOTH_EMPTY (MA35_FSR_TE_FLAG | MA35_FSR_TX_EMPTY)

+}
+
+static u32 ma35d1serial_get_mctrl(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 status;
+ u32 ret = 0;
+
+ status = serial_in(up, MA35_MSR_REG);
+ if (!(status & MA35_MSR_CTSSTS))
+ ret |= TIOCM_CTS;
+ return ret;
+}
+
+static void ma35d1serial_set_mctrl(struct uart_port *port, u32 mctrl)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 mcr;
+ u32 ier;
+
+ mcr = serial_in(up, MA35_MCR_REG);
+ mcr &= ~MA35_MCR_RTS_CTRL;
+
+ if (mctrl & TIOCM_RTS)
+ mcr |= MA35_MCR_RTSACTLV;
+ else
+ mcr &= ~MA35_MCR_RTSACTLV;
+
+ if (up->mcr & UART_MCR_AFE) {
+ serial_out(up, MA35_IER_REG, (serial_in(up, MA35_IER_REG) |
+ MA35_IER_AUTO_RTS |
+ MA35_IER_AUTO_CTS));
+ up->port.flags |= UPF_HARD_FLOW;
+ } else {
+ ier = serial_in(up, MA35_IER_REG);
+ ier &= ~(MA35_IER_AUTO_RTS | MA35_IER_AUTO_CTS);
+ serial_out(up, MA35_IER_REG, ier);
+ up->port.flags &= ~UPF_HARD_FLOW;
+ }
+ serial_out(up, MA35_MSR_REG, (serial_in(up, MA35_MSR_REG) |
+ MA35_MSR_CTSACTLV));
+ serial_out(up, MA35_MCR_REG, mcr);
+}
+
+static void ma35d1serial_break_ctl(struct uart_port *port, int break_state)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ unsigned long flags;
+ u32 lcr;
+
+ spin_lock_irqsave(&up->port.lock, flags);
+ lcr = serial_in(up, MA35_LCR_REG);
+ if (break_state != 0)
+ lcr |= MA35_LCR_BREAK;
+ else
+ lcr &= ~MA35_LCR_BREAK;
+ serial_out(up, MA35_LCR_REG, lcr);
+ spin_unlock_irqrestore(&up->port.lock, flags);
+}
+
+static int ma35d1serial_startup(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ int retval;
+
+ /* Reset FIFO */
+ serial_out(up, MA35_FCR_REG, MA35_FCR_TFR | MA35_FCR_RFR);
+
+ /* Clear pending interrupts */
+ serial_out(up, MA35_ISR_REG, MA35_ISR_ALL);
+
+ retval = request_irq(port->irq, ma35d1serial_interrupt, 0,
+ dev_name(port->dev), port);
+ if (retval) {
+ dev_err(up->port.dev, "request irq failed.\n");
+ return retval;
+ }
+
+ serial_out(up, MA35_FCR_REG, serial_in(up, MA35_FCR_REG) |
+ MA35_FCR_RFITL_4BYTES | MA35_FCR_RTSTL_8BYTES);
+ serial_out(up, MA35_LCR_REG, MA35_LCR_WLS_8BITS);
+ serial_out(up, MA35_TOR_REG, MA35_UART_RX_TOUT);
+ serial_out(up, MA35_IER_REG, MA35_IER_RTO_IEN | MA35_IER_RDA_IEN |
+ MA35_IER_TIME_OUT_EN | MA35_IER_BUFERR_IEN);
Align to the parameter like this:
serial_out(up, MA35_IER_REG, MA35_IER_RTO_IEN | MA35_IER_RDA_IEN |
MA35_IER_TIME_OUT_EN | MA35_IER_BUFERR_IEN);


+ return 0;
+}
+
+static void ma35d1serial_shutdown(struct uart_port *port)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+
+ serial_out(up, MA35_IER_REG, 0);
+ free_irq(port->irq, port);
+}
+
+static void ma35d1serial_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ const struct ktermios *old)
+{
+ struct uart_ma35d1_port *up = to_ma35d1_uart_port(port);
+ u32 lcr = 0;
+ unsigned long flags;
+ u32 baud, quot;
+
+ lcr = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag));
+
+ if (termios->c_cflag & CSTOPB)
+ lcr |= MA35_LCR_NSB;
+ if (termios->c_cflag & PARENB)
+ lcr |= MA35_LCR_PBE;
+ if (!(termios->c_cflag & PARODD))
+ lcr |= MA35_LCR_EPE;
+ if (termios->c_cflag & CMSPAR)
+ lcr |= MA35_LCR_SPE;
+
+ baud = uart_get_baud_rate(port, termios, old,
+ port->uartclk / MA35_BAUD_DIV_MAX,
+ port->uartclk / MA35_BAUD_DIV_MIN);
+
+ /* MA35D1 UART baud rate equation: baudrate = UART_CLK / (quot + 2) */
+ quot = (port->uartclk / baud) - 2;
+
+ /*
+ * Ok, we're now changing the port state. Do it with
+ * interrupts disabled.
+ */
+ spin_lock_irqsave(&up->port.lock, flags);
+
+ up->port.read_status_mask = MA35_FSR_RX_OVER_IF;
+ if (termios->c_iflag & INPCK)
+ up->port.read_status_mask |= MA35_FSR_FEF | MA35_FSR_PEF;
+ if (termios->c_iflag & (BRKINT | PARMRK))
+ up->port.read_status_mask |= MA35_FSR_BIF;
+
+ /* Characteres to ignore */
+ up->port.ignore_status_mask = 0;
+ if (termios->c_iflag & IGNPAR)
+ up->port.ignore_status_mask |= MA35_FSR_FEF | MA35_FSR_PEF;
+ if (termios->c_iflag & IGNBRK) {
+ up->port.ignore_status_mask |= MA35_FSR_BIF;
+ /*
+ * If we're ignoring parity and break indicators,
+ * ignore overruns too (for real raw support).
+ */
+ if (termios->c_iflag & IGNPAR)
+ up->port.ignore_status_mask |= MA35_FSR_RX_OVER_IF;
+ }
+ if (termios->c_cflag & CRTSCTS)
+ up->mcr |= UART_MCR_AFE;
+ else
+ up->mcr &= ~UART_MCR_AFE;
+
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+ ma35d1serial_set_mctrl(&up->port, up->port.mctrl);
+
+ serial_out(up, MA35_BAUD_REG, MA35_BAUD_MODE2 | FIELD_PREP(MA35_BAUD_MASK, quot));
+
+ serial_out(up, MA35_LCR_REG, lcr);
+
+ spin_unlock_irqrestore(&up->port.lock, flags);
+}
+
+static const char *ma35d1serial_type(struct uart_port *port)
+{
+ return port->type == PORT_MA35 ? "ma35d1-uart" : NULL;
+}
+
+static void ma35d1serial_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE)
+ port->type = PORT_MA35;
+}
+
+static int ma35d1serial_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+ if (port->type != PORT_UNKNOWN && ser->type != PORT_MA35)
+ return -EINVAL;
+
+ return 0;
+}
+
+static const struct uart_ops ma35d1serial_ops = {
+ .tx_empty = ma35d1serial_tx_empty,
+ .set_mctrl = ma35d1serial_set_mctrl,
+ .get_mctrl = ma35d1serial_get_mctrl,
+ .stop_tx = ma35d1serial_stop_tx,
+ .start_tx = ma35d1serial_start_tx,
+ .stop_rx = ma35d1serial_stop_rx,
+ .break_ctl = ma35d1serial_break_ctl,
+ .startup = ma35d1serial_startup,
+ .shutdown = ma35d1serial_shutdown,
+ .set_termios = ma35d1serial_set_termios,
+ .type = ma35d1serial_type,
+ .config_port = ma35d1serial_config_port,
+ .verify_port = ma35d1serial_verify_port,
+};
+
+static const struct of_device_id ma35d1_serial_of_match[] = {
+ { .compatible = "nuvoton,ma35d1-uart" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ma35d1_serial_of_match);
+
+#ifdef CONFIG_SERIAL_NUVOTON_MA35D1_CONSOLE
+
+static struct device_node *ma35d1serial_uart_nodes[MA35_UART_NR];
+
+static void wait_for_xmitr(struct uart_ma35d1_port *up)
+{
+ unsigned int tmout;
+
+ /* Wait up to 10ms for the character(s) to be sent. */
+ tmout = 10000;
+ while (--tmout) {
+ if (serial_in(up, MA35_FSR_REG) & MA35_FSR_TX_EMPTY)
+ break;
+ udelay(1);
+ }
This can be written as:

unsigned int reg;

read_poll_timeout_atomic(serial_in, reg, reg & MA35_FSR_TX_EMPTY,
1, 10000, false,
up, MA35_FSR_REG);



Dear Ilpo,

Thank you for your suggestions and the provided examples for modifications.
I will modify the driver based on your suggestions. After a few days, if no
further comments are received, I will submit the next version of this one patch.


Best Regards.
Jacky Huang