180 lines
6.2 KiB
Diff
180 lines
6.2 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:44:00 +0206
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Subject: [PATCH 043/134] serial: omap: Use port lock wrappers
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
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When a serial port is used for kernel console output, then all
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modifications to the UART registers which are done from other contexts,
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e.g. getty, termios, are interference points for the kernel console.
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So far this has been ignored and the printk output is based on the
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principle of hope. The rework of the console infrastructure which aims to
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support threaded and atomic consoles, requires to mark sections which
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modify the UART registers as unsafe. This allows the atomic write function
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to make informed decisions and eventually to restore operational state. It
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also allows to prevent the regular UART code from modifying UART registers
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while printk output is in progress.
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All modifications of UART registers are guarded by the UART port lock,
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which provides an obvious synchronization point with the console
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infrastructure.
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To avoid adding this functionality to all UART drivers, wrap the
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spin_[un]lock*() invocations for uart_port::lock into helper functions
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which just contain the spin_[un]lock*() invocations for now. In a
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subsequent step these helpers will gain the console synchronization
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mechanisms.
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Converted with coccinelle. No functional change.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-44-john.ogness@linutronix.de
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/tty/serial/omap-serial.c | 38 +++++++++++++++++++-------------------
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1 file changed, 19 insertions(+), 19 deletions(-)
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--- a/drivers/tty/serial/omap-serial.c
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+++ b/drivers/tty/serial/omap-serial.c
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@@ -390,10 +390,10 @@ static void serial_omap_throttle(struct
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struct uart_omap_port *up = to_uart_omap_port(port);
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unsigned long flags;
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
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serial_out(up, UART_IER, up->ier);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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}
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static void serial_omap_unthrottle(struct uart_port *port)
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@@ -401,10 +401,10 @@ static void serial_omap_unthrottle(struc
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struct uart_omap_port *up = to_uart_omap_port(port);
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unsigned long flags;
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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up->ier |= UART_IER_RLSI | UART_IER_RDI;
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serial_out(up, UART_IER, up->ier);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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}
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static unsigned int check_modem_status(struct uart_omap_port *up)
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@@ -527,7 +527,7 @@ static irqreturn_t serial_omap_irq(int i
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irqreturn_t ret = IRQ_NONE;
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int max_count = 256;
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- spin_lock(&up->port.lock);
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+ uart_port_lock(&up->port);
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do {
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iir = serial_in(up, UART_IIR);
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@@ -563,7 +563,7 @@ static irqreturn_t serial_omap_irq(int i
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}
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} while (max_count--);
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- spin_unlock(&up->port.lock);
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+ uart_port_unlock(&up->port);
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tty_flip_buffer_push(&up->port.state->port);
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@@ -579,9 +579,9 @@ static unsigned int serial_omap_tx_empty
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unsigned int ret = 0;
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dev_dbg(up->port.dev, "serial_omap_tx_empty+%d\n", up->port.line);
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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return ret;
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}
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@@ -647,13 +647,13 @@ static void serial_omap_break_ctl(struct
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unsigned long flags;
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dev_dbg(up->port.dev, "serial_omap_break_ctl+%d\n", up->port.line);
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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if (break_state == -1)
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up->lcr |= UART_LCR_SBC;
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else
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up->lcr &= ~UART_LCR_SBC;
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serial_out(up, UART_LCR, up->lcr);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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}
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static int serial_omap_startup(struct uart_port *port)
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@@ -701,13 +701,13 @@ static int serial_omap_startup(struct ua
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* Now, initialize the UART
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*/
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serial_out(up, UART_LCR, UART_LCR_WLEN8);
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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/*
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* Most PC uarts need OUT2 raised to enable interrupts.
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*/
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up->port.mctrl |= TIOCM_OUT2;
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serial_omap_set_mctrl(&up->port, up->port.mctrl);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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up->msr_saved_flags = 0;
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/*
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@@ -742,10 +742,10 @@ static void serial_omap_shutdown(struct
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up->ier = 0;
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serial_out(up, UART_IER, 0);
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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up->port.mctrl &= ~TIOCM_OUT2;
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serial_omap_set_mctrl(&up->port, up->port.mctrl);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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/*
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* Disable break condition and FIFOs
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@@ -815,7 +815,7 @@ serial_omap_set_termios(struct uart_port
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* Ok, we're now changing the port state. Do it with
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* interrupts disabled.
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*/
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- spin_lock_irqsave(&up->port.lock, flags);
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+ uart_port_lock_irqsave(&up->port, &flags);
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/*
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* Update the per-port timeout.
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@@ -1013,7 +1013,7 @@ serial_omap_set_termios(struct uart_port
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serial_omap_set_mctrl(&up->port, up->port.mctrl);
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- spin_unlock_irqrestore(&up->port.lock, flags);
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+ uart_port_unlock_irqrestore(&up->port, flags);
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dev_dbg(up->port.dev, "serial_omap_set_termios+%d\n", up->port.line);
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}
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@@ -1216,9 +1216,9 @@ serial_omap_console_write(struct console
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if (up->port.sysrq)
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locked = 0;
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else if (oops_in_progress)
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- locked = spin_trylock(&up->port.lock);
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+ locked = uart_port_trylock(&up->port);
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else
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- spin_lock(&up->port.lock);
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+ uart_port_lock(&up->port);
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/*
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* First save the IER then disable the interrupts
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@@ -1245,7 +1245,7 @@ serial_omap_console_write(struct console
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check_modem_status(up);
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if (locked)
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- spin_unlock(&up->port.lock);
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+ uart_port_unlock(&up->port);
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local_irq_restore(flags);
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}
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