diff options
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | drivers/serial/8250.c | 54 | ||||
| -rw-r--r-- | drivers/serial/8250.h | 3 |
2 files changed, 47 insertions, 10 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 30e8beb71430..79f67fd863ec 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -132,9 +132,9 @@ struct uart_8250_port { struct uart_port port; struct timer_list timer; /* "no irq" timer */ struct list_head list; /* ports on this IRQ */ - unsigned int capabilities; /* port capabilities */ + unsigned short capabilities; /* port capabilities */ + unsigned short bugs; /* port bugs */ unsigned int tx_loadsz; /* transmit fifo load size */ - unsigned short rev; unsigned char acr; unsigned char ier; unsigned char lcr; @@ -560,7 +560,14 @@ static void autoconfig_has_efr(struct uart_8250_port *up) if (id1 == 0x16 && id2 == 0xC9 && (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) { up->port.type = PORT_16C950; - up->rev = rev | (id3 << 8); + + /* + * Enable work around for the Oxford Semiconductor 952 rev B + * chip which causes it to seriously miscalculate baud rates + * when DLL is 0. + */ + if (id3 == 0x52 && rev == 0x01) + up->bugs |= UART_BUG_QUOT; return; } @@ -577,8 +584,6 @@ static void autoconfig_has_efr(struct uart_8250_port *up) id2 = id1 >> 8; if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) { - if (id2 == 0x10) - up->rev = id1 & 255; up->port.type = PORT_16850; return; } @@ -809,6 +814,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags) // save_flags(flags); cli(); up->capabilities = 0; + up->bugs = 0; if (!(up->port.flags & UPF_BUGGY_UART)) { /* @@ -1021,6 +1027,8 @@ static void serial8250_stop_tx(struct uart_port *port, unsigned int tty_stop) } } +static void transmit_chars(struct uart_8250_port *up); + static void serial8250_start_tx(struct uart_port *port, unsigned int tty_start) { struct uart_8250_port *up = (struct uart_8250_port *)port; @@ -1028,6 +1036,14 @@ static void serial8250_start_tx(struct uart_port *port, unsigned int tty_start) if (!(up->ier & UART_IER_THRI)) { up->ier |= UART_IER_THRI; serial_out(up, UART_IER, up->ier); + + if (up->bugs & UART_BUG_TXEN) { + unsigned char lsr, iir; + lsr = serial_in(up, UART_LSR); + iir = serial_in(up, UART_IIR); + if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) + transmit_chars(up); + } } /* * We only do this from uart_start @@ -1433,6 +1449,7 @@ static int serial8250_startup(struct uart_port *port) { struct uart_8250_port *up = (struct uart_8250_port *)port; unsigned long flags; + unsigned char lsr, iir; int retval; up->capabilities = uart_config[up->port.type].flags; @@ -1536,6 +1553,26 @@ static int serial8250_startup(struct uart_port *port) up->port.mctrl |= TIOCM_OUT2; serial8250_set_mctrl(&up->port, up->port.mctrl); + + /* + * Do a quick test to see if we receive an + * interrupt when we enable the TX irq. + */ + serial_outp(up, UART_IER, UART_IER_THRI); + lsr = serial_in(up, UART_LSR); + iir = serial_in(up, UART_IIR); + serial_outp(up, UART_IER, 0); + + if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) { + if (!(up->bugs & UART_BUG_TXEN)) { + up->bugs |= UART_BUG_TXEN; + pr_debug("ttyS%d - enabling bad tx status workarounds\n", + port->line); + } + } else { + up->bugs &= ~UART_BUG_TXEN; + } + spin_unlock_irqrestore(&up->port.lock, flags); /* @@ -1677,12 +1714,9 @@ serial8250_set_termios(struct uart_port *port, struct termios *termios, quot = serial8250_get_divisor(port, baud); /* - * Work around a bug in the Oxford Semiconductor 952 rev B - * chip which causes it to seriously miscalculate baud rates - * when DLL is 0. + * Oxford Semi 952 rev B workaround */ - if ((quot & 0xff) == 0 && up->port.type == PORT_16C950 && - up->rev == 0x5201) + if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0) quot ++; if (up->capabilities & UART_CAP_FIFO && up->port.fifosize > 1) { diff --git a/drivers/serial/8250.h b/drivers/serial/8250.h index 4f3d62f222f4..9225c82faeb8 100644 --- a/drivers/serial/8250.h +++ b/drivers/serial/8250.h @@ -51,6 +51,9 @@ struct serial8250_config { #define UART_CAP_AFE (1 << 11) /* MCR-based hw flow control */ #define UART_CAP_UUE (1 << 12) /* UART needs IER bit 6 set (Xscale) */ +#define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */ +#define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */ + #if defined(__i386__) && (defined(CONFIG_M386) || defined(CONFIG_M486)) #define _INLINE_ inline #else |