diff options
Diffstat (limited to 'drivers/serial/8250.c')
| -rw-r--r-- | drivers/serial/8250.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 90621c3312bc..194362d9f5a3 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -308,6 +308,7 @@ static unsigned int serial_in(struct uart_8250_port *up, int offset) return inb(up->port.iobase + 1); case UPIO_MEM: + case UPIO_DWAPB: return readb(up->port.membase + offset); case UPIO_MEM32: @@ -333,6 +334,8 @@ static unsigned int serial_in(struct uart_8250_port *up, int offset) static void serial_out(struct uart_8250_port *up, int offset, int value) { + /* Save the offset before it's remapped */ + int save_offset = offset; offset = map_8250_out_reg(up, offset) << up->port.regshift; switch (up->port.iotype) { @@ -359,6 +362,18 @@ serial_out(struct uart_8250_port *up, int offset, int value) writeb(value, up->port.membase + offset); break; + case UPIO_DWAPB: + /* Save the LCR value so it can be re-written when a + * Busy Detect interrupt occurs. */ + if (save_offset == UART_LCR) + up->lcr = value; + writeb(value, up->port.membase + offset); + /* Read the IER to ensure any interrupt is cleared before + * returning from ISR. */ + if (save_offset == UART_TX || save_offset == UART_IER) + value = serial_in(up, UART_IER); + break; + default: outb(value, up->port.iobase + offset); } @@ -373,6 +388,7 @@ serial_out_sync(struct uart_8250_port *up, int offset, int value) #ifdef CONFIG_SERIAL_8250_AU1X00 case UPIO_AU: #endif + case UPIO_DWAPB: serial_out(up, offset, value); serial_in(up, UART_LCR); /* safe, no side-effects */ break; @@ -1389,6 +1405,19 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) handled = 1; end = NULL; + } else if (up->port.iotype == UPIO_DWAPB && + (iir & UART_IIR_BUSY) == UART_IIR_BUSY) { + /* The DesignWare APB UART has an Busy Detect (0x07) + * interrupt meaning an LCR write attempt occured while the + * UART was busy. The interrupt must be cleared by reading + * the UART status register (USR) and the LCR re-written. */ + unsigned int status; + status = *(volatile u32 *)up->port.private_data; + serial_out(up, UART_LCR, up->lcr); + + handled = 1; + + end = NULL; } else if (end == NULL) end = l; @@ -2090,6 +2119,7 @@ static int serial8250_request_std_resource(struct uart_8250_port *up) case UPIO_TSI: case UPIO_MEM32: case UPIO_MEM: + case UPIO_DWAPB: if (!up->port.mapbase) break; @@ -2127,6 +2157,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up) case UPIO_TSI: case UPIO_MEM32: case UPIO_MEM: + case UPIO_DWAPB: if (!up->port.mapbase) break; |