U6715 16550A serial driver support

UART Features extract from STEricsson U6715 data-sheet (arm926 SoC for mobile phone):
* Fully compatible with industry standard 16C550 and 16C450 from various
manufacturers
* RX and TX 64 byte FIFO reduces CPU interrupts
* Full double buffering
* Modem control signals include CTS, RTS, (and DSR, DTR on UART1 only)
* Automatic baud rate selection
* Manual or automatic RTS/CTS smart hardware flow control
* Programmable serial characteristics:
– Baud rate generation (50 to 3.25M baud)
– 5, 6, 7 or 8-bit characters
– Even, odd or no-parity bit generation and detection
– 1, 1.5 or 2 stop bit generation
* Independent control of transmit, receive, line status, data set interrupts and FIFOs
* Full status-reporting capabilities
* Separate DMA signaling for RX and TX
* Timed interrupt to spread receive interrupt on known duration
* DMA time-out interrupt to allow detection of end of reception
* Carkit pulse coding and decoding compliant with USB carkit control interface [40]

In 16550A auto-configuration, if the fifo size is 64 then it's an U6 16550A port
Add set_termios hook & export serial8250_do_set_termios to change uart
clock following baudrate

Signed-off-by: Philippe Langlais <philippe.langlais@stericsson.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 34 insertions, 3 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 355148dc085e..24110f6f61e0 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -300,6 +300,13 @@ static const struct serial8250_config uart_config[] = {
                 .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
                 .flags          = UART_CAP_FIFO | UART_CAP_AFE,
         },
+        [PORT_U6_16550A] = {
+                .name           = "U6_16550A",
+                .fifo_size      = 64,
+                .tx_loadsz      = 64,
+                .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+                .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+        },
 };
 
 #if defined(CONFIG_MIPS_ALCHEMY)
@@ -1070,6 +1077,15 @@ static void autoconfig_16550a(struct uart_8250_port *up)
                 DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
         }
         serial_outp(up, UART_IER, iersave);
+
+        /*
+         * We distinguish between 16550A and U6 16550A by counting
+         * how many bytes are in the FIFO.
+         */
+        if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
+                up->port.type = PORT_U6_16550A;
+                up->capabilities |= UART_CAP_AFE;
+        }
 }
 
 /*
@@ -2224,9 +2240,9 @@ static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int
         return quot;
 }
 
-static void
-serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
-                       struct ktermios *old)
+void
+serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
+                          struct ktermios *old)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
         unsigned char cval, fcr = 0;
@@ -2402,6 +2418,17 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
         if (tty_termios_baud_rate(termios))
                 tty_termios_encode_baud_rate(termios, baud, baud);
 }
+EXPORT_SYMBOL(serial8250_do_set_termios);
+
+static void
+serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+                       struct ktermios *old)
+{
+        if (port->set_termios)
+                port->set_termios(port, termios, old);
+        else
+                serial8250_do_set_termios(port, termios, old);
+}
 
 static void
 serial8250_set_ldisc(struct uart_port *port, int new)
@@ -2982,6 +3009,7 @@ static int __devinit serial8250_probe(struct platform_device *dev)
                 port.type               = p->type;
                 port.serial_in          = p->serial_in;
                 port.serial_out         = p->serial_out;
+                port.set_termios        = p->set_termios;
                 port.dev                = &dev->dev;
                 port.irqflags           |= irqflag;
                 ret = serial8250_register_port(&port);
@@ -3145,6 +3173,9 @@ int serial8250_register_port(struct uart_port *port)
                         uart->port.serial_in = port->serial_in;
                 if (port->serial_out)
                         uart->port.serial_out = port->serial_out;
+                /*  Possibly override set_termios call */
+                if (port->set_termios)
+                        uart->port.set_termios = port->set_termios;
 
                 ret = uart_add_one_port(&serial8250_reg, &uart->port);
                 if (ret == 0)