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serial: amba-pl010: Use port lock wrappers 

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

commit 01d6461ad7d062a23fcbdf2a19cde723d30919cf
Author: Thomas Gleixner <tglx@linutronix.de>
Date:   Thu Sep 14 20:43:33 2023 +0206

    serial: amba-pl010: 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/20230914183831.587273-17-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 15:05:06 -05:00 committed by Derek Barbosa
parent 53003dd817
commit 0118e3a477
1 changed files with 10 additions and 10 deletions
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20
drivers/tty/serial/amba-pl010.c
View File

@ -207,7 +207,7 @@ static irqreturn_t pl010_int(int irq, void *dev_id)
unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
int handled = 0;
spin_lock(&port->lock);
uart_port_lock(port);
status = readb(port->membase + UART010_IIR);
if (status) {
@ -228,7 +228,7 @@ static irqreturn_t pl010_int(int irq, void *dev_id)
handled = 1;
}
spin_unlock(&port->lock);
uart_port_unlock(port);
return IRQ_RETVAL(handled);
}
@ -270,14 +270,14 @@ static void pl010_break_ctl(struct uart_port *port, int break_state)
unsigned long flags;
unsigned int lcr_h;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
lcr_h = readb(port->membase + UART010_LCRH);
if (break_state == -1)
lcr_h |= UART01x_LCRH_BRK;
else
lcr_h &= ~UART01x_LCRH_BRK;
writel(lcr_h, port->membase + UART010_LCRH);
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
static int pl010_startup(struct uart_port *port)
@ -385,7 +385,7 @@ pl010_set_termios(struct uart_port *port, struct ktermios *termios,
if (port->fifosize > 1)
lcr_h |= UART01x_LCRH_FEN;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
/*
* Update the per-port timeout.
@ -438,22 +438,22 @@ pl010_set_termios(struct uart_port *port, struct ktermios *termios,
writel(lcr_h, port->membase + UART010_LCRH);
writel(old_cr, port->membase + UART010_CR);
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
{
if (termios->c_line == N_PPS) {
port->flags |= UPF_HARDPPS_CD;
spin_lock_irq(&port->lock);
uart_port_lock_irq(port);
pl010_enable_ms(port);
spin_unlock_irq(&port->lock);
uart_port_unlock_irq(port);
} else {
port->flags &= ~UPF_HARDPPS_CD;
if (!UART_ENABLE_MS(port, termios->c_cflag)) {
spin_lock_irq(&port->lock);
uart_port_lock_irq(port);
pl010_disable_ms(port);
spin_unlock_irq(&port->lock);
uart_port_unlock_irq(port);
}
}
}