[SERIAL] Support Au1x00 8250 UARTs using the generic 8250 driver.

The offsets of the registers are in a different place, and
some parts cannot handle a full set of modem control signals.

Signed-off-by: Pantelis Antoniou <pantelis@embeddedalley.ocm>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 70 insertions, 3 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index f47d2c454e33..186e96c47b3d 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -251,9 +251,53 @@ static const struct serial8250_config uart_config[] = {
         },
 };
 
+#ifdef CONFIG_SERIAL_8250_AU1X00
+
+/* Au1x00 UART hardware has a weird register layout */
+static const u8 au_io_in_map[] = {
+        [UART_RX]  = 0,
+        [UART_IER] = 2,
+        [UART_IIR] = 3,
+        [UART_LCR] = 5,
+        [UART_MCR] = 6,
+        [UART_LSR] = 7,
+        [UART_MSR] = 8,
+};
+
+static const u8 au_io_out_map[] = {
+        [UART_TX]  = 1,
+        [UART_IER] = 2,
+        [UART_FCR] = 4,
+        [UART_LCR] = 5,
+        [UART_MCR] = 6,
+};
+
+/* sane hardware needs no mapping */
+static inline int map_8250_in_reg(struct uart_8250_port *up, int offset)
+{
+        if (up->port.iotype != UPIO_AU)
+                return offset;
+        return au_io_in_map[offset];
+}
+
+static inline int map_8250_out_reg(struct uart_8250_port *up, int offset)
+{
+        if (up->port.iotype != UPIO_AU)
+                return offset;
+        return au_io_out_map[offset];
+}
+
+#else
+
+/* sane hardware needs no mapping */
+#define map_8250_in_reg(up, offset) (offset)
+#define map_8250_out_reg(up, offset) (offset)
+
+#endif
+
 static _INLINE_ unsigned int serial_in(struct uart_8250_port *up, int offset)
 {
-        offset <<= up->port.regshift;
+        offset = map_8250_in_reg(up, offset) << up->port.regshift;
 
         switch (up->port.iotype) {
         case UPIO_HUB6:
@@ -266,6 +310,11 @@ static _INLINE_ unsigned int serial_in(struct uart_8250_port *up, int offset)
         case UPIO_MEM32:
                 return readl(up->port.membase + offset);
 
+#ifdef CONFIG_SERIAL_8250_AU1X00
+        case UPIO_AU:
+                return __raw_readl(up->port.membase + offset);
+#endif
+
         default:
                 return inb(up->port.iobase + offset);
         }
@@ -274,7 +323,7 @@ static _INLINE_ unsigned int serial_in(struct uart_8250_port *up, int offset)
 static _INLINE_ void
 serial_out(struct uart_8250_port *up, int offset, int value)
 {
-        offset <<= up->port.regshift;
+        offset = map_8250_out_reg(up, offset) << up->port.regshift;
 
         switch (up->port.iotype) {
         case UPIO_HUB6:
@@ -290,6 +339,12 @@ serial_out(struct uart_8250_port *up, int offset, int value)
                 writel(value, up->port.membase + offset);
                 break;
 
+#ifdef CONFIG_SERIAL_8250_AU1X00
+        case UPIO_AU:
+                __raw_writel(value, up->port.membase + offset);
+                break;
+#endif
+
         default:
                 outb(value, up->port.iobase + offset);
         }
@@ -910,6 +965,13 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
                 }
         }
 #endif
+
+#ifdef CONFIG_SERIAL_8250_AU1X00
+        /* if access method is AU, it is a 16550 with a quirk */
+        if (up->port.type == PORT_16550A && up->port.iotype == UPIO_AU)
+                up->bugs |= UART_BUG_NOMSR;
+#endif
+
         serial_outp(up, UART_LCR, save_lcr);
 
         if (up->capabilities != uart_config[up->port.type].flags) {
@@ -1057,6 +1119,10 @@ static void serial8250_enable_ms(struct uart_port *port)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
 
+        /* no MSR capabilities */
+        if (up->bugs & UART_BUG_NOMSR)
+                return;
+
         up->ier |= UART_IER_MSI;
         serial_out(up, UART_IER, up->ier);
 }
@@ -1774,7 +1840,8 @@ serial8250_set_termios(struct uart_port *port, struct termios *termios,
          * CTS flow control flag and modem status interrupts
          */
         up->ier &= ~UART_IER_MSI;
-        if (UART_ENABLE_MS(&up->port, termios->c_cflag))
+        if (!(up->bugs & UART_BUG_NOMSR) &&
+                        UART_ENABLE_MS(&up->port, termios->c_cflag))
                 up->ier |= UART_IER_MSI;
         if (up->capabilities & UART_CAP_UUE)
                 up->ier |= UART_IER_UUE | UART_IER_RTOIE;