Serial: Add support for new devices: Exar's XR17V35x family of multi-port PCIe UARTs

Add support for new devices: Exar's XR17V35x family of multi-port PCIe UARTs.

Signed-off-by: Matt Schulte <matts@commtech-fastcom.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 2af83a246499..3624df674a31 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -282,6 +282,15 @@ static const struct serial8250_config uart_config[] = {
 		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
 		.flags		= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR,
 	},
+	[PORT_XR17V35X] = {
+		.name		= "XR17V35X",
+		.fifo_size	= 256,
+		.tx_loadsz	= 256,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
+				  UART_FCR_T_TRIG_11,
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
+				  UART_CAP_SLEEP,
+	},
 	[PORT_LPC3220] = {
 		.name		= "LPC3220",
 		.fifo_size	= 64,
@@ -455,6 +464,7 @@ static void io_serial_out(struct uart_port *p, int offset, int value)
 }
 
 static int serial8250_default_handle_irq(struct uart_port *port);
+static int exar_handle_irq(struct uart_port *port);
 
 static void set_io_from_upio(struct uart_port *p)
 {
@@ -574,6 +584,18 @@ EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
  */
 static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
 {
+	/*
+	 * Exar UARTs have a SLEEP register that enables or disables
+	 * each UART to enter sleep mode separately.  On the XR17V35x the
+	 * register is accessible to each UART at the UART_EXAR_SLEEP
+	 * offset but the UART channel may only write to the corresponding
+	 * bit.
+	 */
+	if (p->port.type == PORT_XR17V35X) {
+		serial_out(p, UART_EXAR_SLEEP, 0xff);
+		return;
+	}
+
 	if (p->capabilities & UART_CAP_SLEEP) {
 		if (p->capabilities & UART_CAP_EFR) {
 			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
@@ -882,6 +904,27 @@ static void autoconfig_16550a(struct uart_8250_port *up)
 	up->capabilities |= UART_CAP_FIFO;
 
 	/*
+	 * XR17V35x UARTs have an extra divisor register, DLD
+	 * that gets enabled with when DLAB is set which will
+	 * cause the device to incorrectly match and assign
+	 * port type to PORT_16650.  The EFR for this UART is
+	 * found at offset 0x09. Instead check the Deice ID (DVID)
+	 * register for a 2, 4 or 8 port UART.
+	 */
+	status1 = serial_in(up, UART_EXAR_DVID);
+	if (status1 == 0x82 || status1 == 0x84 || status1 == 0x88) {
+		if (up->port.flags & UPF_EXAR_EFR) {
+			DEBUG_AUTOCONF("Exar XR17V35x ");
+			up->port.type = PORT_XR17V35X;
+			up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
+						UART_CAP_SLEEP;
+
+			return;
+		}
+
+	}
+
+	/*
 	 * Check for presence of the EFR when DLAB is set.
 	 * Only ST16C650V1 UARTs pass this test.
 	 */
@@ -1516,6 +1559,30 @@ static int serial8250_default_handle_irq(struct uart_port *port)
 }
 
 /*
+ * These Exar UARTs have an extra interrupt indicator that could
+ * fire for a few unimplemented interrupts.  One of which is a
+ * wakeup event when coming out of sleep.  Put this here just
+ * to be on the safe side that these interrupts don't go unhandled.
+ */
+static int exar_handle_irq(struct uart_port *port)
+{
+	unsigned char int0, int1, int2, int3;
+	unsigned int iir = serial_port_in(port, UART_IIR);
+	int ret;
+
+	ret = serial8250_handle_irq(port, iir);
+
+	if (port->type == PORT_XR17V35X) {
+		int0 = serial_port_in(port, 0x80);
+		int1 = serial_port_in(port, 0x81);
+		int2 = serial_port_in(port, 0x82);
+		int3 = serial_port_in(port, 0x83);
+	}
+
+	return ret;
+}
+
+/*
  * This is the serial driver's interrupt routine.
  *
  * Arjan thinks the old way was overly complex, so it got simplified.
@@ -2614,6 +2681,10 @@ static void serial8250_config_port(struct uart_port *port, int flags)
 		serial8250_release_rsa_resource(up);
 	if (port->type == PORT_UNKNOWN)
 		serial8250_release_std_resource(up);
+
+	/* Fixme: probably not the best place for this */
+	if (port->type == PORT_XR17V35X)
+		port->handle_irq = exar_handle_irq;
 }
 
 static int