101 lines
3.9 KiB
Diff
101 lines
3.9 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:43:55 +0206
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Subject: [PATCH 038/134] serial: milbeaut_usio: 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/20230914183831.587273-39-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/milbeaut_usio.c | 16 ++++++++--------
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1 file changed, 8 insertions(+), 8 deletions(-)
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--- a/drivers/tty/serial/milbeaut_usio.c
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+++ b/drivers/tty/serial/milbeaut_usio.c
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@@ -207,9 +207,9 @@ static irqreturn_t mlb_usio_rx_irq(int i
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{
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struct uart_port *port = dev_id;
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- spin_lock(&port->lock);
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+ uart_port_lock(port);
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mlb_usio_rx_chars(port);
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- spin_unlock(&port->lock);
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+ uart_port_unlock(port);
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return IRQ_HANDLED;
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}
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@@ -218,10 +218,10 @@ static irqreturn_t mlb_usio_tx_irq(int i
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{
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struct uart_port *port = dev_id;
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- spin_lock(&port->lock);
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+ uart_port_lock(port);
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if (readb(port->membase + MLB_USIO_REG_SSR) & MLB_USIO_SSR_TBI)
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mlb_usio_tx_chars(port);
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- spin_unlock(&port->lock);
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+ uart_port_unlock(port);
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return IRQ_HANDLED;
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}
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@@ -267,7 +267,7 @@ static int mlb_usio_startup(struct uart_
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escr = readb(port->membase + MLB_USIO_REG_ESCR);
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if (of_property_read_bool(port->dev->of_node, "auto-flow-control"))
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escr |= MLB_USIO_ESCR_FLWEN;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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writeb(0, port->membase + MLB_USIO_REG_SCR);
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writeb(escr, port->membase + MLB_USIO_REG_ESCR);
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writeb(MLB_USIO_SCR_UPCL, port->membase + MLB_USIO_REG_SCR);
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@@ -282,7 +282,7 @@ static int mlb_usio_startup(struct uart_
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writeb(MLB_USIO_SCR_TXE | MLB_USIO_SCR_RIE | MLB_USIO_SCR_TBIE |
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MLB_USIO_SCR_RXE, port->membase + MLB_USIO_REG_SCR);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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return 0;
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}
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@@ -337,7 +337,7 @@ static void mlb_usio_set_termios(struct
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else
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quot = 0;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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uart_update_timeout(port, termios->c_cflag, baud);
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port->read_status_mask = MLB_USIO_SSR_ORE | MLB_USIO_SSR_RDRF |
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MLB_USIO_SSR_TDRE;
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@@ -367,7 +367,7 @@ static void mlb_usio_set_termios(struct
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writew(BIT(12), port->membase + MLB_USIO_REG_FBYTE);
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writeb(MLB_USIO_SCR_RIE | MLB_USIO_SCR_RXE | MLB_USIO_SCR_TBIE |
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MLB_USIO_SCR_TXE, port->membase + MLB_USIO_REG_SCR);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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}
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static const char *mlb_usio_type(struct uart_port *port)
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