diff options
Diffstat (limited to 'debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch')
-rw-r--r-- | debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch b/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..46dbf785d0 --- /dev/null +++ b/debian/patches-rt/0014-serial-altera_jtaguart-Use-port-lock-wrappers.patch @@ -0,0 +1,133 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:31 +0206 +Subject: [PATCH 014/134] serial: altera_jtaguart: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +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/20230914183831.587273-15-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/altera_jtaguart.c | 28 ++++++++++++++-------------- + 1 file changed, 14 insertions(+), 14 deletions(-) + +--- a/drivers/tty/serial/altera_jtaguart.c ++++ b/drivers/tty/serial/altera_jtaguart.c +@@ -147,14 +147,14 @@ static irqreturn_t altera_jtaguart_inter + isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> + ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) + altera_jtaguart_rx_chars(port); + if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) + altera_jtaguart_tx_chars(port); + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_RETVAL(isr); + } +@@ -180,14 +180,14 @@ static int altera_jtaguart_startup(struc + return ret; + } + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Enable RX interrupts now */ + port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return 0; + } +@@ -196,14 +196,14 @@ static void altera_jtaguart_shutdown(str + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Disable all interrupts now */ + port->read_status_mask = 0; + writel(port->read_status_mask, + port->membase + ALTERA_JTAGUART_CONTROL_REG); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + free_irq(port->irq, port); + } +@@ -264,33 +264,33 @@ static void altera_jtaguart_console_putc + unsigned long flags; + u32 status; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + while (!altera_jtaguart_tx_space(port, &status)) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { + return; /* no connection activity */ + } + + cpu_relax(); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #else + static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) + { + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + while (!altera_jtaguart_tx_space(port, NULL)) { +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + cpu_relax(); +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + } + writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + #endif + |