diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_dw.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dw.c | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index cd1b94a0f451..6fcdb90f616a 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -9,6 +9,7 @@ * LCR is written whilst busy. If it is, then a busy detect interrupt is * raised, the LCR needs to be rewritten and the uart status register read. */ +#include <linux/delay.h> #include <linux/device.h> #include <linux/io.h> #include <linux/module.h> @@ -119,10 +120,27 @@ static void dw8250_check_lcr(struct uart_port *p, int value) */ } +/* Returns once the transmitter is empty or we run out of retries */ +static void dw8250_tx_wait_empty(struct uart_port *p, int tries) +{ + unsigned int lsr; + + while (tries--) { + lsr = readb (p->membase + (UART_LSR << p->regshift)); + if (lsr & UART_LSR_TEMT) + break; + udelay (10); + } +} + static void dw8250_serial_out(struct uart_port *p, int offset, int value) { struct dw8250_data *d = p->private_data; + /* Allow the TX to drain before we reconfigure */ + if (offset == UART_LCR) + dw8250_tx_wait_empty(p, 1000); + writeb(value, p->membase + (offset << p->regshift)); if (offset == UART_LCR && !d->uart_16550_compatible) @@ -339,17 +357,11 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data) p->serial_in = dw8250_serial_in32be; p->serial_out = dw8250_serial_out32be; } - } else if (has_acpi_companion(p->dev)) { - const struct acpi_device_id *id; - - id = acpi_match_device(p->dev->driver->acpi_match_table, - p->dev); - if (id && !strcmp(id->id, "APMC0D08")) { - p->iotype = UPIO_MEM32; - p->regshift = 2; - p->serial_in = dw8250_serial_in32; - data->uart_16550_compatible = true; - } + } else if (acpi_dev_present("APMC0D08", NULL, -1)) { + p->iotype = UPIO_MEM32; + p->regshift = 2; + p->serial_in = dw8250_serial_in32; + data->uart_16550_compatible = true; } /* Platforms with iDMA */ |