86 lines
3.2 KiB
Diff
86 lines
3.2 KiB
Diff
From 70ceea48d1051ec15b3a8d66f62386b323e12e4e Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:43:24 +0206
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Subject: [PATCH 034/195] serial: 8250_dma: Use port lock wrappers
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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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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Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-8-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/8250/8250_dma.c | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
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index 7fa66501792d..8b30ca8fdd3f 100644
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--- a/drivers/tty/serial/8250/8250_dma.c
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+++ b/drivers/tty/serial/8250/8250_dma.c
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@@ -22,7 +22,7 @@ static void __dma_tx_complete(void *param)
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dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
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UART_XMIT_SIZE, DMA_TO_DEVICE);
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- spin_lock_irqsave(&p->port.lock, flags);
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+ uart_port_lock_irqsave(&p->port, &flags);
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dma->tx_running = 0;
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@@ -35,7 +35,7 @@ static void __dma_tx_complete(void *param)
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if (ret || !dma->tx_running)
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serial8250_set_THRI(p);
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- spin_unlock_irqrestore(&p->port.lock, flags);
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+ uart_port_unlock_irqrestore(&p->port, flags);
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}
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static void __dma_rx_complete(struct uart_8250_port *p)
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@@ -70,7 +70,7 @@ static void dma_rx_complete(void *param)
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struct uart_8250_dma *dma = p->dma;
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unsigned long flags;
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- spin_lock_irqsave(&p->port.lock, flags);
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+ uart_port_lock_irqsave(&p->port, &flags);
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if (dma->rx_running)
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__dma_rx_complete(p);
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@@ -80,7 +80,7 @@ static void dma_rx_complete(void *param)
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*/
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if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR))
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p->dma->rx_dma(p);
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- spin_unlock_irqrestore(&p->port.lock, flags);
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+ uart_port_unlock_irqrestore(&p->port, flags);
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}
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int serial8250_tx_dma(struct uart_8250_port *p)
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--
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2.43.0
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