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serial: mps2-uart: Use port lock wrappers 

JIRA: https://issues.redhat.com/browse/RHEL-24205

commit dab781d277da6d9390ae4ba8f521476a8720e599
Author: Thomas Gleixner <tglx@linutronix.de>
Date:   Thu Sep 14 20:43:57 2023 +0206

    serial: mps2-uart: Use port lock wrappers

    When a serial port is used for kernel console output, then all
    modifications to the UART registers which are done from other contexts,
    e.g. getty, termios, are interference points for the kernel console.

    So far this has been ignored and the printk output is based on the
    principle of hope. The rework of the console infrastructure which aims to
    support threaded and atomic consoles, requires to mark sections which
    modify the UART registers as unsafe. This allows the atomic write function
    to make informed decisions and eventually to restore operational state. It
    also allows to prevent the regular UART code from modifying UART registers
    while printk output is in progress.

    All modifications of UART registers are guarded by the UART port lock,
    which provides an obvious synchronization point with the console
    infrastructure.

    To avoid adding this functionality to all UART drivers, wrap the
    spin_[un]lock*() invocations for uart_port::lock into helper functions
    which just contain the spin_[un]lock*() invocations for now. In a
    subsequent step these helpers will gain the console synchronization
    mechanisms.

    Converted with coccinelle. No functional change.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: John Ogness <john.ogness@linutronix.de>
    Link: https://lore.kernel.org/r/20230914183831.587273-41-john.ogness@linutronix.de
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
This commit is contained in:
Andrew Halaney 2024-03-11 15:12:05 -05:00 committed by Derek Barbosa
parent d7d205b8a9
commit b453a0d1ac
1 changed files with 8 additions and 8 deletions
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16
drivers/tty/serial/mps2-uart.c
View File

@ -188,12 +188,12 @@ static irqreturn_t mps2_uart_rxirq(int irq, void *data)
if (unlikely(!(irqflag & UARTn_INT_RX)))
return IRQ_NONE;
spin_lock(&port->lock);
uart_port_lock(port);
mps2_uart_write8(port, UARTn_INT_RX, UARTn_INT);
mps2_uart_rx_chars(port);
spin_unlock(&port->lock);
uart_port_unlock(port);
return IRQ_HANDLED;
}
@ -206,12 +206,12 @@ static irqreturn_t mps2_uart_txirq(int irq, void *data)
if (unlikely(!(irqflag & UARTn_INT_TX)))
return IRQ_NONE;
spin_lock(&port->lock);
uart_port_lock(port);
mps2_uart_write8(port, UARTn_INT_TX, UARTn_INT);
mps2_uart_tx_chars(port);
spin_unlock(&port->lock);
uart_port_unlock(port);
return IRQ_HANDLED;
}
@ -222,7 +222,7 @@ static irqreturn_t mps2_uart_oerrirq(int irq, void *data)
struct uart_port *port = data;
u8 irqflag = mps2_uart_read8(port, UARTn_INT);
spin_lock(&port->lock);
uart_port_lock(port);
if (irqflag & UARTn_INT_RX_OVERRUN) {
struct tty_port *tport = &port->state->port;
@ -244,7 +244,7 @@ static irqreturn_t mps2_uart_oerrirq(int irq, void *data)
handled = IRQ_HANDLED;
}
spin_unlock(&port->lock);
uart_port_unlock(port);
return handled;
}
@ -356,12 +356,12 @@ mps2_uart_set_termios(struct uart_port *port, struct ktermios *termios,
bauddiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
uart_update_timeout(port, termios->c_cflag, baud);
mps2_uart_write32(port, bauddiv, UARTn_BAUDDIV);
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);