diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_port.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_port.c | 43 |
1 files changed, 32 insertions, 11 deletions
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 90a93c001e16..7ac6bb38948f 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -136,7 +136,8 @@ static const struct serial8250_config uart_config[] = { .name = "16C950/954", .fifo_size = 128, .tx_loadsz = 128, - .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10, + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01, + .rxtrig_bytes = {16, 32, 112, 120}, /* UART_CAP_EFR breaks billionon CF bluetooth card. */ .flags = UART_CAP_FIFO | UART_CAP_SLEEP, }, @@ -314,7 +315,11 @@ static const struct serial8250_config uart_config[] = { /* Uart divisor latch read */ static int default_serial_dl_read(struct uart_8250_port *up) { - return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8; + /* Assign these in pieces to truncate any bits above 7. */ + unsigned char dll = serial_in(up, UART_DLL); + unsigned char dlm = serial_in(up, UART_DLM); + + return dll | dlm << 8; } /* Uart divisor latch write */ @@ -1302,9 +1307,11 @@ static void autoconfig(struct uart_8250_port *up) serial_out(up, UART_LCR, 0); serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO); - scratch = serial_in(up, UART_IIR) >> 6; - switch (scratch) { + /* Assign this as it is to truncate any bits above 7. */ + scratch = serial_in(up, UART_IIR); + + switch (scratch >> 6) { case 0: autoconfig_8250(up); break; @@ -1527,7 +1534,6 @@ static inline void __stop_tx(struct uart_8250_port *p) return; em485->active_timer = NULL; - hrtimer_cancel(&em485->start_tx_timer); __stop_tx_rs485(p); } @@ -1591,8 +1597,6 @@ static inline void start_tx_rs485(struct uart_port *port) serial8250_stop_rx(&up->port); em485->active_timer = NULL; - if (hrtimer_is_queued(&em485->stop_tx_timer)) - hrtimer_cancel(&em485->stop_tx_timer); mcr = serial8250_in_MCR(up); if (!!(up->port.rs485.flags & SER_RS485_RTS_ON_SEND) != @@ -1865,6 +1869,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) unsigned char status; unsigned long flags; struct uart_8250_port *up = up_to_u8250p(port); + bool skip_rx = false; if (iir & UART_IIR_NO_INT) return 0; @@ -1873,7 +1878,20 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) status = serial_port_in(port, UART_LSR); - if (status & (UART_LSR_DR | UART_LSR_BI)) { + /* + * If port is stopped and there are no error conditions in the + * FIFO, then don't drain the FIFO, as this may lead to TTY buffer + * overflow. Not servicing, RX FIFO would trigger auto HW flow + * control when FIFO occupancy reaches preset threshold, thus + * halting RX. This only works when auto HW flow control is + * available. + */ + if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) && + (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) && + !(port->read_status_mask & UART_LSR_DR)) + skip_rx = true; + + if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) { if (!up->dma || handle_rx_dma(up, iir)) status = serial8250_rx_chars(up, status); } @@ -2264,6 +2282,10 @@ int serial8250_do_startup(struct uart_port *port) if (port->irq && !(up->port.flags & UPF_NO_THRE_TEST)) { unsigned char iir1; + + if (port->irqflags & IRQF_SHARED) + disable_irq_nosync(port->irq); + /* * Test for UARTs that do not reassert THRE when the * transmitter is idle and the interrupt has already @@ -2273,8 +2295,6 @@ int serial8250_do_startup(struct uart_port *port) * allow register changes to become visible. */ spin_lock_irqsave(&port->lock, flags); - if (up->port.irqflags & IRQF_SHARED) - disable_irq_nosync(port->irq); wait_for_xmitr(up, UART_LSR_THRE); serial_port_out_sync(port, UART_IER, UART_IER_THRI); @@ -2286,9 +2306,10 @@ int serial8250_do_startup(struct uart_port *port) iir = serial_port_in(port, UART_IIR); serial_port_out(port, UART_IER, 0); + spin_unlock_irqrestore(&port->lock, flags); + if (port->irqflags & IRQF_SHARED) enable_irq(port->irq); - spin_unlock_irqrestore(&port->lock, flags); /* * If the interrupt is not reasserted, or we otherwise |