diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_port.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 75 |
1 files changed, 45 insertions, 30 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index cc94af2d578a..328711b5df1a 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -18,6 +18,7 @@ #include <linux/irq.h> #include <linux/console.h> #include <linux/gpio/consumer.h> +#include <linux/lockdep.h> #include <linux/sysrq.h> #include <linux/delay.h> #include <linux/platform_device.h> @@ -488,7 +489,7 @@ serial_port_out_sync(struct uart_port *p, int offset, int value) /* * FIFO support. */ -static void serial8250_clear_fifos(struct uart_8250_port *p) +void serial8250_clear_fifos(struct uart_8250_port *p) { if (p->capabilities & UART_CAP_FIFO) { serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO); @@ -497,6 +498,7 @@ static void serial8250_clear_fifos(struct uart_8250_port *p) serial_out(p, UART_FCR, 0); } } +EXPORT_SYMBOL_NS_GPL(serial8250_clear_fifos, "SERIAL_8250"); static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t); static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t); @@ -1782,20 +1784,16 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) } /* - * This handles the interrupt from one port. + * Context: port's lock must be held by the caller. */ -int serial8250_handle_irq(struct uart_port *port, unsigned int iir) +void serial8250_handle_irq_locked(struct uart_port *port, unsigned int iir) { struct uart_8250_port *up = up_to_u8250p(port); struct tty_port *tport = &port->state->port; bool skip_rx = false; - unsigned long flags; u16 status; - if (iir & UART_IIR_NO_INT) - return 0; - - uart_port_lock_irqsave(port, &flags); + lockdep_assert_held_once(&port->lock); status = serial_lsr_in(up); @@ -1828,8 +1826,19 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) else if (!up->dma->tx_running) __stop_tx(up); } +} +EXPORT_SYMBOL_NS_GPL(serial8250_handle_irq_locked, "SERIAL_8250"); + +/* + * This handles the interrupt from one port. + */ +int serial8250_handle_irq(struct uart_port *port, unsigned int iir) +{ + if (iir & UART_IIR_NO_INT) + return 0; - uart_unlock_and_check_sysrq_irqrestore(port, flags); + guard(uart_port_lock_irqsave)(port); + serial8250_handle_irq_locked(port, iir); return 1; } @@ -2147,8 +2156,7 @@ static void serial8250_THRE_test(struct uart_port *port) if (up->port.flags & UPF_NO_THRE_TEST) return; - if (port->irqflags & IRQF_SHARED) - disable_irq_nosync(port->irq); + disable_irq(port->irq); /* * Test for UARTs that do not reassert THRE when the transmitter is idle and the interrupt @@ -2170,8 +2178,7 @@ static void serial8250_THRE_test(struct uart_port *port) serial_port_out(port, UART_IER, 0); } - if (port->irqflags & IRQF_SHARED) - enable_irq(port->irq); + enable_irq(port->irq); /* * If the interrupt is not reasserted, or we otherwise don't trust the iir, setup a timer to @@ -2350,6 +2357,7 @@ static int serial8250_startup(struct uart_port *port) void serial8250_do_shutdown(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); + u32 lcr; serial8250_rpm_get(up); /* @@ -2376,13 +2384,13 @@ void serial8250_do_shutdown(struct uart_port *port) port->mctrl &= ~TIOCM_OUT2; serial8250_set_mctrl(port, port->mctrl); + + /* Disable break condition */ + lcr = serial_port_in(port, UART_LCR); + lcr &= ~UART_LCR_SBC; + serial_port_out(port, UART_LCR, lcr); } - /* - * Disable break condition and FIFOs - */ - serial_port_out(port, UART_LCR, - serial_port_in(port, UART_LCR) & ~UART_LCR_SBC); serial8250_clear_fifos(up); rsa_disable(up); @@ -2392,6 +2400,12 @@ void serial8250_do_shutdown(struct uart_port *port) * the IRQ chain. */ serial_port_in(port, UART_RX); + /* + * LCR writes on DW UART can trigger late (unmaskable) IRQs. + * Handle them before releasing the handler. + */ + synchronize_irq(port->irq); + serial8250_rpm_put(up); up->ops->release_irq(up); @@ -3185,6 +3199,17 @@ void serial8250_set_defaults(struct uart_8250_port *up) } EXPORT_SYMBOL_GPL(serial8250_set_defaults); +void serial8250_fifo_wait_for_lsr_thre(struct uart_8250_port *up, unsigned int count) +{ + unsigned int i; + + for (i = 0; i < count; i++) { + if (wait_for_lsr(up, UART_LSR_THRE)) + return; + } +} +EXPORT_SYMBOL_NS_GPL(serial8250_fifo_wait_for_lsr_thre, "SERIAL_8250"); + #ifdef CONFIG_SERIAL_8250_CONSOLE static void serial8250_console_putchar(struct uart_port *port, unsigned char ch) @@ -3226,16 +3251,6 @@ static void serial8250_console_restore(struct uart_8250_port *up) serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS); } -static void fifo_wait_for_lsr(struct uart_8250_port *up, unsigned int count) -{ - unsigned int i; - - for (i = 0; i < count; i++) { - if (wait_for_lsr(up, UART_LSR_THRE)) - return; - } -} - /* * Print a string to the serial port using the device FIFO * @@ -3254,7 +3269,7 @@ static void serial8250_console_fifo_write(struct uart_8250_port *up, while (s != end) { /* Allow timeout for each byte of a possibly full FIFO */ - fifo_wait_for_lsr(up, fifosize); + serial8250_fifo_wait_for_lsr_thre(up, fifosize); for (i = 0; i < fifosize && s != end; ++i) { if (*s == '\n' && !cr_sent) { @@ -3272,7 +3287,7 @@ static void serial8250_console_fifo_write(struct uart_8250_port *up, * Allow timeout for each byte written since the caller will only wait * for UART_LSR_BOTH_EMPTY using the timeout of a single character */ - fifo_wait_for_lsr(up, tx_count); + serial8250_fifo_wait_for_lsr_thre(up, tx_count); } /* |