diff options
Diffstat (limited to 'debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch')
-rw-r--r-- | debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch b/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..cc261d43ee --- /dev/null +++ b/debian/patches-rt/0064-serial-stm32-Use-port-lock-wrappers.patch @@ -0,0 +1,184 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:21 +0206 +Subject: [PATCH 064/134] serial: stm32: 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/20230914183831.587273-65-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/stm32-usart.c | 38 +++++++++++++++++++------------------- + 1 file changed, 19 insertions(+), 19 deletions(-) + +--- a/drivers/tty/serial/stm32-usart.c ++++ b/drivers/tty/serial/stm32-usart.c +@@ -537,7 +537,7 @@ static void stm32_usart_rx_dma_complete( + unsigned int size; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq_irqrestore(port, flags); + if (size) +@@ -643,9 +643,9 @@ static void stm32_usart_tx_dma_complete( + stm32_usart_tx_dma_terminate(stm32port); + + /* Let's see if we have pending data to send */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_transmit_chars(port); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void stm32_usart_tx_interrupt_enable(struct uart_port *port) +@@ -889,7 +889,7 @@ static irqreturn_t stm32_usart_interrupt + if (!stm32_port->throttled) { + if (((sr & USART_SR_RXNE) && !stm32_usart_rx_dma_started(stm32_port)) || + ((sr & USART_SR_ERR_MASK) && stm32_usart_rx_dma_started(stm32_port))) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) +@@ -898,14 +898,14 @@ static irqreturn_t stm32_usart_interrupt + } + + if ((sr & USART_SR_TXE) && !(stm32_port->tx_ch)) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + stm32_usart_transmit_chars(port); +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + } + + /* Receiver timeout irq for DMA RX */ + if (stm32_usart_rx_dma_started(stm32_port) && !stm32_port->throttled) { +- spin_lock(&port->lock); ++ uart_port_lock(port); + size = stm32_usart_receive_chars(port, false); + uart_unlock_and_check_sysrq(port); + if (size) +@@ -993,7 +993,7 @@ static void stm32_usart_throttle(struct + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Pause DMA transfer, so the RX data gets queued into the FIFO. +@@ -1006,7 +1006,7 @@ static void stm32_usart_throttle(struct + stm32_usart_clr_bits(port, ofs->cr3, stm32_port->cr3_irq); + + stm32_port->throttled = true; +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Unthrottle the remote, the input buffer can now accept data. */ +@@ -1016,7 +1016,7 @@ static void stm32_usart_unthrottle(struc + const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + unsigned long flags; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_set_bits(port, ofs->cr1, stm32_port->cr1_irq); + if (stm32_port->cr3_irq) + stm32_usart_set_bits(port, ofs->cr3, stm32_port->cr3_irq); +@@ -1030,7 +1030,7 @@ static void stm32_usart_unthrottle(struc + if (stm32_port->rx_ch) + stm32_usart_rx_dma_start_or_resume(port); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + /* Receive stop */ +@@ -1158,7 +1158,7 @@ static void stm32_usart_set_termios(stru + + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8); + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, +@@ -1349,7 +1349,7 @@ static void stm32_usart_set_termios(stru + writel_relaxed(cr1, port->membase + ofs->cr1); + + stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + + /* Handle modem control interrupts */ + if (UART_ENABLE_MS(port, termios->c_cflag)) +@@ -1399,9 +1399,9 @@ static void stm32_usart_pm(struct uart_p + pm_runtime_get_sync(port->dev); + break; + case UART_PM_STATE_OFF: +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + pm_runtime_put_sync(port->dev); + break; + } +@@ -1884,9 +1884,9 @@ static void stm32_usart_console_write(st + int locked = 1; + + if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* Save and disable interrupts, enable the transmitter */ + old_cr1 = readl_relaxed(port->membase + ofs->cr1); +@@ -1900,7 +1900,7 @@ static void stm32_usart_console_write(st + writel_relaxed(old_cr1, port->membase + ofs->cr1); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int stm32_usart_console_setup(struct console *co, char *options) +@@ -2035,7 +2035,7 @@ static int __maybe_unused stm32_usart_se + * low-power mode. + */ + if (stm32_port->rx_ch) { +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + /* Poll data from DMA RX buffer if any */ + if (!stm32_usart_rx_dma_pause(stm32_port)) + size += stm32_usart_receive_chars(port, true); |