mxser: store FCR state in mxser_port::FCR

We force the FCR contents on many places in the code instead of writing
what was actually set in mxser_change_speed() (by ->activate() or
->set_serial_info()).

So introduce mxser_port::FCR to hold the proper contents and bitwise-OR
the value to what needs to be set on all those locations. That is,
clearing RX and/or TX FIFOs. Those flags are self-clearing, so no need
to set them to mxser_port::FCR.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210922075938.31390-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 4ce21cd..93a95a1 100644 (file)
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -249,6 +249,7 @@ struct mxser_port {
        unsigned char x_char;   /* xon/xoff character */
        u8 IER;                 /* Interrupt Enable Register */
        u8 MCR;                 /* Modem control register */
+       u8 FCR;                 /* FIFO control register */
 
        bool ldisc_stop_rx;
 
@@ -562,7 +563,7 @@ static void mxser_handle_cts(struct tty_struct *tty, struct mxser_port *info,
 static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_termios)
 {
        struct mxser_port *info = tty->driver_data;
-       unsigned cflag, cval, fcr;
+       unsigned cflag, cval;
 
        cflag = tty->termios.c_cflag;
 
@@ -600,25 +601,25 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
        if (cflag & CMSPAR)
                cval |= UART_LCR_SPAR;
 
-       fcr = 0;
+       info->FCR = 0;
        if (info->board->must_hwid) {
-               fcr |= UART_FCR_ENABLE_FIFO |
+               info->FCR |= UART_FCR_ENABLE_FIFO |
                        MOXA_MUST_FCR_GDA_MODE_ENABLE;
                mxser_set_must_fifo_value(info);
        } else if (info->type != PORT_8250 && info->type != PORT_16450) {
-               fcr |= UART_FCR_ENABLE_FIFO;
+               info->FCR |= UART_FCR_ENABLE_FIFO;
                switch (info->rx_high_water) {
                case 1:
-                       fcr |= UART_FCR_TRIGGER_1;
+                       info->FCR |= UART_FCR_TRIGGER_1;
                        break;
                case 4:
-                       fcr |= UART_FCR_TRIGGER_4;
+                       info->FCR |= UART_FCR_TRIGGER_4;
                        break;
                case 8:
-                       fcr |= UART_FCR_TRIGGER_8;
+                       info->FCR |= UART_FCR_TRIGGER_8;
                        break;
                default:
-                       fcr |= UART_FCR_TRIGGER_14;
+                       info->FCR |= UART_FCR_TRIGGER_14;
                        break;
                }
        }
@@ -679,7 +680,7 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
        }
 
 
-       outb(fcr, info->ioaddr + UART_FCR);     /* set fcr */
+       outb(info->FCR, info->ioaddr + UART_FCR);
        outb(cval, info->ioaddr + UART_LCR);
 }
 
@@ -865,7 +866,7 @@ static void mxser_flush_buffer(struct tty_struct *tty)
        spin_lock_irqsave(&info->slock, flags);
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
 
-       outb(UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
+       outb(info->FCR | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
                info->ioaddr + UART_FCR);
 
        spin_unlock_irqrestore(&info->slock, flags);
@@ -1572,8 +1573,7 @@ static u8 mxser_receive_chars_old(struct tty_struct *tty,
 
                ch = inb(port->ioaddr + UART_RX);
                if (hwid && (status & UART_LSR_OE))
-                       outb(UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
-                                       MOXA_MUST_FCR_GDA_MODE_ENABLE,
+                       outb(port->FCR | UART_FCR_CLEAR_RCVR,
                                        port->ioaddr + UART_FCR);
                status &= port->read_status_mask;
                if (status & port->ignore_status_mask) {
@@ -1685,8 +1685,7 @@ static bool mxser_port_isr(struct mxser_port *port)
        tty = tty_port_tty_get(&port->port);
        if (!tty || port->closing || !tty_port_initialized(&port->port)) {
                status = inb(port->ioaddr + UART_LSR);
-               outb(MOXA_MUST_FCR_GDA_MODE_ENABLE | UART_FCR_ENABLE_FIFO |
-                               UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
+               outb(port->FCR | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
                                port->ioaddr + UART_FCR);
                inb(port->ioaddr + UART_MSR);