168 lines
5.4 KiB
Diff
168 lines
5.4 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:43:54 +0206
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Subject: [PATCH 037/134] serial: meson: 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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Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-38-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/meson_uart.c | 30 +++++++++++++++---------------
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1 file changed, 15 insertions(+), 15 deletions(-)
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--- a/drivers/tty/serial/meson_uart.c
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+++ b/drivers/tty/serial/meson_uart.c
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@@ -129,14 +129,14 @@ static void meson_uart_shutdown(struct u
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free_irq(port->irq, port);
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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val = readl(port->membase + AML_UART_CONTROL);
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val &= ~AML_UART_RX_EN;
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val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
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writel(val, port->membase + AML_UART_CONTROL);
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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 void meson_uart_start_tx(struct uart_port *port)
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@@ -238,7 +238,7 @@ static irqreturn_t meson_uart_interrupt(
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{
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struct uart_port *port = (struct uart_port *)dev_id;
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- spin_lock(&port->lock);
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+ uart_port_lock(port);
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if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY))
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meson_receive_chars(port);
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@@ -248,7 +248,7 @@ static irqreturn_t meson_uart_interrupt(
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meson_uart_start_tx(port);
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}
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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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@@ -284,7 +284,7 @@ static int meson_uart_startup(struct uar
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u32 val;
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int ret = 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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val = readl(port->membase + AML_UART_CONTROL);
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val |= AML_UART_CLEAR_ERR;
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@@ -301,7 +301,7 @@ static int meson_uart_startup(struct uar
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val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2));
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writel(val, port->membase + AML_UART_MISC);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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ret = request_irq(port->irq, meson_uart_interrupt, 0,
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port->name, port);
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@@ -341,7 +341,7 @@ static void meson_uart_set_termios(struc
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unsigned long flags;
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u32 val;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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cflags = termios->c_cflag;
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iflags = termios->c_iflag;
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@@ -405,7 +405,7 @@ static void meson_uart_set_termios(struc
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AML_UART_FRAME_ERR;
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uart_update_timeout(port, termios->c_cflag, baud);
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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 int meson_uart_verify_port(struct uart_port *port,
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@@ -464,14 +464,14 @@ static int meson_uart_poll_get_char(stru
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u32 c;
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unsigned long flags;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)
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c = NO_POLL_CHAR;
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else
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c = readl(port->membase + AML_UART_RFIFO);
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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 c;
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}
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@@ -482,7 +482,7 @@ static void meson_uart_poll_put_char(str
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u32 reg;
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int ret;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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/* Wait until FIFO is empty or timeout */
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ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg,
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@@ -506,7 +506,7 @@ static void meson_uart_poll_put_char(str
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dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n");
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out:
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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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#endif /* CONFIG_CONSOLE_POLL */
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@@ -563,9 +563,9 @@ static void meson_serial_port_write(stru
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if (port->sysrq) {
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locked = 0;
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} else if (oops_in_progress) {
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- locked = spin_trylock(&port->lock);
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+ locked = uart_port_trylock(port);
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} else {
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- spin_lock(&port->lock);
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+ uart_port_lock(port);
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locked = 1;
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}
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@@ -577,7 +577,7 @@ static void meson_serial_port_write(stru
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writel(val, port->membase + AML_UART_CONTROL);
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if (locked)
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- spin_unlock(&port->lock);
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+ uart_port_unlock(port);
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local_irq_restore(flags);
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}
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