[PATCH v3 1/1] serial: 8250: Add support for higher baud rates to Pericom chips

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From: Jay Dolan <jay.dolan@xxxxxxxxxxx>

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@xxxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_pci.c | 97 ++++++++++++++++++++++++------
 1 file 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..9a895ae449c5 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1326,13 +1326,66 @@ 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, UART_PCM_SCR, 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)
 {
 	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;
+
+
+	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;
@@ -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
 	 */
 	{
-- 
2.17.1




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