serial: 8250: Add support for higher baud rates to Pericom chips

The Pericom chips can achieve additional baud rates by programming the
sample clock register. The baud rates can be described as
921600 * 16 / (16 - scr) for scr values 5 to 15. The divisor is set to 1
for these baud rates.

Adds new quirk for Pericom chips other than the four port chips to use
the

Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 79 insertions, 18 deletions

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index df41397de478..7ba1c3b2381d 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1326,7 +1326,36 @@ static int pci_default_setup(struct serial_private *priv,
 
 	return setup_port(priv, port, bar, offset, board->reg_shift);
 }
-
+void
+pericom_do_set_divisor(struct uart_port *port, unsigned int baud,
+			       unsigned int quot, unsigned int quot_frac)
+{
+	int scr;
+	int lcr;
+	int actual_baud;
+	int tolerance;
+
+	for (scr = 5 ; scr <= 15 ; scr++) {
+		actual_baud = 921600 * 16 / scr;
+		tolerance = actual_baud / 50;
+
+		if ((baud < actual_baud + tolerance) &&
+			(baud > actual_baud - tolerance)) {
+
+			lcr = serial_port_in(port, UART_LCR);
+			serial_port_out(port, UART_LCR, lcr | 0x80);
+
+			serial_port_out(port, UART_DLL, 1);
+			serial_port_out(port, UART_DLM, 0);
+			serial_port_out(port, 2, 16 - scr);
+			serial_port_out(port, UART_LCR, lcr);
+			return;
+		} else if (baud > actual_baud) {
+			break;
+		}
+	}
+	serial8250_do_set_divisor(port, baud, quot, quot_frac);
+}
 static int pci_pericom_setup(struct serial_private *priv,
 		  const struct pciserial_board *board,
 		  struct uart_8250_port *port, int idx)
@@ -1339,6 +1368,30 @@ static int pci_pericom_setup(struct serial_private *priv,
 	else
 		offset += idx * board->uart_offset;
 
+
+	maxnr = (pci_resource_len(priv->dev, bar) - board->first_offset) >>
+		(board->reg_shift + 3);
+
+	if (board->flags & FL_REGION_SZ_CAP && idx >= maxnr)
+		return 1;
+
+	port->port.set_divisor = pericom_do_set_divisor;
+
+	return setup_port(priv, port, bar, offset, board->reg_shift);
+}
+
+static int pci_pericom_setup_four_at_eight(struct serial_private *priv,
+		  const struct pciserial_board *board,
+		  struct uart_8250_port *port, int idx)
+{
+	unsigned int bar, offset = board->first_offset, maxnr;
+
+	bar = FL_GET_BASE(board->flags);
+	if (board->flags & FL_BASE_BARS)
+		bar += idx;
+	else
+		offset += idx * board->uart_offset;
+
 	if (idx==3)
 		offset = 0x38;
 
@@ -1348,6 +1401,8 @@ static int pci_pericom_setup(struct serial_private *priv,
 	if (board->flags & FL_REGION_SZ_CAP && idx >= maxnr)
 		return 1;
 
+	port->port.set_divisor = pericom_do_set_divisor;
+
 	return setup_port(priv, port, bar, offset, board->reg_shift);
 }
 
@@ -1995,7 +2050,7 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = {
 		.device		= PCI_DEVICE_ID_PERICOM_PI7C9X7954,
 		.subvendor	= PCI_ANY_ID,
 		.subdevice	= PCI_ANY_ID,
-		.setup		= pci_pericom_setup,
+		.setup		= pci_pericom_setup_four_at_eight,
 	},
 	/*
 	 * PLX
@@ -2032,107 +2087,113 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = {
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SDB,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4S,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4DB,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SMDB,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4SM,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM422_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM485_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SM,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
 	{
 		.vendor     = PCI_VENDOR_ID_ACCESIO,
 		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4SM,
 		.subvendor  = PCI_ANY_ID,
 		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
+		.setup      = pci_pericom_setup_four_at_eight,
 	},
-	/*
+	{
+		.vendor     = PCI_VENDOR_ID_ACCESIO,
+		.device     = PCI_ANY_ID,
+		.subvendor  = PCI_ANY_ID,
+		.subdevice  = PCI_ANY_ID,
+		.setup      = pci_pericom_setup,
+	},	/*
 	 * SBS Technologies, Inc., PMC-OCTALPRO 232
 	 */
 	{