diff options
Diffstat (limited to 'drivers/serial/8250.c')
| -rw-r--r-- | drivers/serial/8250.c | 87 |
1 files changed, 57 insertions, 30 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 2f5a5ac1b27..f94109cbb46 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -129,7 +129,16 @@ struct uart_8250_port { unsigned char mcr; unsigned char mcr_mask; /* mask of user bits */ unsigned char mcr_force; /* mask of forced bits */ - unsigned char lsr_break_flag; + + /* + * Some bits in registers are cleared on a read, so they must + * be saved whenever the register is read but the bits will not + * be immediately processed. + */ +#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS + unsigned char lsr_saved_flags; +#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA + unsigned char msr_saved_flags; /* * We provide a per-port pm hook. @@ -1238,6 +1247,7 @@ static void serial8250_start_tx(struct uart_port *port) if (up->bugs & UART_BUG_TXEN) { unsigned char lsr, iir; lsr = serial_in(up, UART_LSR); + up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; iir = serial_in(up, UART_IIR) & 0x0f; if ((up->port.type == PORT_RM9000) ? (lsr & UART_LSR_THRE && @@ -1290,18 +1300,10 @@ receive_chars(struct uart_8250_port *up, unsigned int *status) flag = TTY_NORMAL; up->port.icount.rx++; -#ifdef CONFIG_SERIAL_8250_CONSOLE - /* - * Recover the break flag from console xmit - */ - if (up->port.line == up->port.cons->index) { - lsr |= up->lsr_break_flag; - up->lsr_break_flag = 0; - } -#endif + lsr |= up->lsr_saved_flags; + up->lsr_saved_flags = 0; - if (unlikely(lsr & (UART_LSR_BI | UART_LSR_PE | - UART_LSR_FE | UART_LSR_OE))) { + if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) { /* * For statistics only */ @@ -1392,6 +1394,8 @@ static unsigned int check_modem_status(struct uart_8250_port *up) { unsigned int status = serial_in(up, UART_MSR); + status |= up->msr_saved_flags; + up->msr_saved_flags = 0; if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI && up->port.info != NULL) { if (status & UART_MSR_TERI) @@ -1591,7 +1595,8 @@ static void serial8250_timeout(unsigned long data) static void serial8250_backup_timeout(unsigned long data) { struct uart_8250_port *up = (struct uart_8250_port *)data; - unsigned int iir, ier = 0; + unsigned int iir, ier = 0, lsr; + unsigned long flags; /* * Must disable interrupts or else we risk racing with the interrupt @@ -1610,9 +1615,13 @@ static void serial8250_backup_timeout(unsigned long data) * the "Diva" UART used on the management processor on many HP * ia64 and parisc boxes. */ + spin_lock_irqsave(&up->port.lock, flags); + lsr = serial_in(up, UART_LSR); + up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; + spin_unlock_irqrestore(&up->port.lock, flags); if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) && (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) && - (serial_in(up, UART_LSR) & UART_LSR_THRE)) { + (lsr & UART_LSR_THRE)) { iir &= ~(UART_IIR_ID | UART_IIR_NO_INT); iir |= UART_IIR_THRI; } @@ -1631,13 +1640,14 @@ static unsigned int serial8250_tx_empty(struct uart_port *port) { struct uart_8250_port *up = (struct uart_8250_port *)port; unsigned long flags; - unsigned int ret; + unsigned int lsr; spin_lock_irqsave(&up->port.lock, flags); - ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; + lsr = serial_in(up, UART_LSR); + up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS; spin_unlock_irqrestore(&up->port.lock, flags); - return ret; + return lsr & UART_LSR_TEMT ? TIOCSER_TEMT : 0; } static unsigned int serial8250_get_mctrl(struct uart_port *port) @@ -1708,8 +1718,7 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits) do { status = serial_in(up, UART_LSR); - if (status & UART_LSR_BI) - up->lsr_break_flag = UART_LSR_BI; + up->lsr_saved_flags |= status & LSR_SAVE_FLAGS; if (--tmout == 0) break; @@ -1718,8 +1727,12 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits) /* Wait up to 1s for flow control if necessary */ if (up->port.flags & UPF_CONS_FLOW) { - tmout = 1000000; - while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) { + unsigned int tmout; + for (tmout = 1000000; tmout; tmout--) { + unsigned int msr = serial_in(up, UART_MSR); + up->msr_saved_flags |= msr & MSR_SAVE_FLAGS; + if (msr & UART_MSR_CTS) + break; udelay(1); touch_nmi_watchdog(); } @@ -1889,6 +1902,18 @@ static int serial8250_startup(struct uart_port *port) spin_unlock_irqrestore(&up->port.lock, flags); /* + * Clear the interrupt registers again for luck, and clear the + * saved flags to avoid getting false values from polling + * routines or the previous session. + */ + serial_inp(up, UART_LSR); + serial_inp(up, UART_RX); + serial_inp(up, UART_IIR); + serial_inp(up, UART_MSR); + up->lsr_saved_flags = 0; + up->msr_saved_flags = 0; + + /* * Finally, enable interrupts. Note: Modem status interrupts * are set via set_termios(), which will be occurring imminently * anyway, so we don't enable them here. @@ -1906,14 +1931,6 @@ static int serial8250_startup(struct uart_port *port) (void) inb_p(icp); } - /* - * And clear the interrupt registers again for luck. - */ - (void) serial_inp(up, UART_LSR); - (void) serial_inp(up, UART_RX); - (void) serial_inp(up, UART_IIR); - (void) serial_inp(up, UART_MSR); - return 0; } @@ -2484,6 +2501,16 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) wait_for_xmitr(up, BOTH_EMPTY); serial_out(up, UART_IER, ier); + /* + * The receive handling will happen properly because the + * receive ready bit will still be set; it is not cleared + * on read. However, modem control will not, we must + * call it if we have saved something in the saved flags + * while processing with interrupts off. + */ + if (up->msr_saved_flags) + check_modem_status(up); + if (locked) spin_unlock(&up->port.lock); local_irq_restore(flags); @@ -2514,7 +2541,7 @@ static int __init serial8250_console_setup(struct console *co, char *options) return uart_set_options(port, co, baud, parity, bits, flow); } -static int __init serial8250_console_early_setup(void) +static int serial8250_console_early_setup(void) { return serial8250_find_port_for_earlycon(); } |