diff options
Diffstat (limited to 'debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch b/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..d2efb460bc --- /dev/null +++ b/debian/patches-rt/0037-serial-meson-Use-port-lock-wrappers.patch @@ -0,0 +1,168 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:54 +0206 +Subject: [PATCH 037/134] serial: meson: 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> +Acked-by: Neil Armstrong <neil.armstrong@linaro.org> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-38-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/meson_uart.c | 30 +++++++++++++++--------------- + 1 file changed, 15 insertions(+), 15 deletions(-) + +--- a/drivers/tty/serial/meson_uart.c ++++ b/drivers/tty/serial/meson_uart.c +@@ -129,14 +129,14 @@ static void meson_uart_shutdown(struct u + + free_irq(port->irq, port); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = readl(port->membase + AML_UART_CONTROL); + val &= ~AML_UART_RX_EN; + val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN); + writel(val, port->membase + AML_UART_CONTROL); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void meson_uart_start_tx(struct uart_port *port) +@@ -238,7 +238,7 @@ static irqreturn_t meson_uart_interrupt( + { + struct uart_port *port = (struct uart_port *)dev_id; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)) + meson_receive_chars(port); +@@ -248,7 +248,7 @@ static irqreturn_t meson_uart_interrupt( + meson_uart_start_tx(port); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -284,7 +284,7 @@ static int meson_uart_startup(struct uar + u32 val; + int ret = 0; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + val = readl(port->membase + AML_UART_CONTROL); + val |= AML_UART_CLEAR_ERR; +@@ -301,7 +301,7 @@ static int meson_uart_startup(struct uar + val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2)); + writel(val, port->membase + AML_UART_MISC); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + ret = request_irq(port->irq, meson_uart_interrupt, 0, + port->name, port); +@@ -341,7 +341,7 @@ static void meson_uart_set_termios(struc + unsigned long flags; + u32 val; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + cflags = termios->c_cflag; + iflags = termios->c_iflag; +@@ -405,7 +405,7 @@ static void meson_uart_set_termios(struc + AML_UART_FRAME_ERR; + + uart_update_timeout(port, termios->c_cflag, baud); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int meson_uart_verify_port(struct uart_port *port, +@@ -464,14 +464,14 @@ static int meson_uart_poll_get_char(stru + u32 c; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY) + c = NO_POLL_CHAR; + else + c = readl(port->membase + AML_UART_RFIFO); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + return c; + } +@@ -482,7 +482,7 @@ static void meson_uart_poll_put_char(str + u32 reg; + int ret; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Wait until FIFO is empty or timeout */ + ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg, +@@ -506,7 +506,7 @@ static void meson_uart_poll_put_char(str + dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n"); + + out: +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + #endif /* CONFIG_CONSOLE_POLL */ +@@ -563,9 +563,9 @@ static void meson_serial_port_write(stru + if (port->sysrq) { + locked = 0; + } else if (oops_in_progress) { +- locked = spin_trylock(&port->lock); ++ locked = uart_port_trylock(port); + } else { +- spin_lock(&port->lock); ++ uart_port_lock(port); + locked = 1; + } + +@@ -577,7 +577,7 @@ static void meson_serial_port_write(stru + writel(val, port->membase + AML_UART_CONTROL); + + if (locked) +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + local_irq_restore(flags); + } + |