[SERIAL] 8250: add tsi108 serial support

The following patch gets rid of CONFIG_TSI108_BRIDGE. I add UPIO_TSI to
handle IIR and IER register in serial_in and serial_out.

(1) the reason to rewrite serial_in:

TSI108 rev Z1 version ERRATA. Reading the UART's Interrupt
Identification Register (IIR) clears the Transmit Holding Register
Empty (THRE) and Transmit buffer Empty (TEMP) interrupts even if they
are not enabled in the Interrupt Enable Register (IER). This leads to
loss of the interrupts. Interrupts are not cleared when reading UART
registers as 32-bit word.

(2) the reason to rewrite serial_out:

Check for UART_IER_UUE bit in the autoconfig routine. This section
of autoconfig is excluded for Tsi108/109 because bits 7 and 6 are
reserved for internal use. They are R/W bits. In addition to
incorrect identification, changing these bits (from 00) will make
Tsi108/109 UART non-functional.

Signed-off-by: Roy Zang <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Russell King <[e-mail]>

drivers/serial/8250.c

···
 
 static unsigned int serial_in(struct uart_8250_port *up, int offset)
 {
+	unsigned int tmp;
 	offset = map_8250_in_reg(up, offset) << up->port.regshift;
 
 	switch (up->port.iotype) {
···
 	case UPIO_AU:
 		return __raw_readl(up->port.membase + offset);
 #endif
+
+	case UPIO_TSI:
+		if (offset == UART_IIR) {
+			tmp = readl((u32 *)(up->port.membase + UART_RX));
+			return (cpu_to_le32(tmp) >> 8) & 0xff;
+		} else
+			return readb(up->port.membase + offset);
 
 	default:
 		return inb(up->port.iobase + offset);
···
 		__raw_writel(value, up->port.membase + offset);
 		break;
 #endif
+	case UPIO_TSI:
+		if (!((offset == UART_IER) && (value & UART_IER_UUE)))
+			writeb(value, up->port.membase + offset);
+		break;
 
 	default:
 		outb(value, up->port.iobase + offset);

drivers/serial/serial_core.c

···
 	case UPIO_MEM:
 	case UPIO_MEM32:
 	case UPIO_AU:
+	case UPIO_TSI:
 		snprintf(address, sizeof(address),
 			 "MMIO 0x%lx", port->mapbase);
 		break;

include/linux/serial_core.h

···
 #define UPIO_MEM		(2)
 #define UPIO_MEM32		(3)
 #define UPIO_AU			(4)			/* Au1x00 type IO */
+#define UPIO_TSI		(5)			/* Tsi108/109 type IO */
 
 	unsigned int		read_status_mask;	/* driver specific */
 	unsigned int		ignore_status_mask;	/* driver specific */