[PATCH 2/3] 8250_fintek_pci: Add Fintek PCIE UART driver

[Peter Hung]

Add Fintek F81504/508/512 PCIE-to-UART driver 8250_fintek_pci.c

Our device driver had already merge into 8250_pci.c, but it's only
implemented basic UART function. This patch will add new file
8250_fintek_pci.c to implements serial ports and high baudrate
functions.

Signed-off-by: Peter Hung <hpeter+linux_kernel@xxxxxxxxx>
---
 drivers/tty/serial/8250/8250_fintek_pci.c | 417 ++++++++++++++++++++++++++++++
 drivers/tty/serial/8250/Kconfig           |   9 +
 drivers/tty/serial/8250/Makefile          |   1 +
 3 files changed, 427 insertions(+)
 create mode 100644 drivers/tty/serial/8250/8250_fintek_pci.c

diff --git a/drivers/tty/serial/8250/8250_fintek_pci.c b/drivers/tty/serial/8250/8250_fintek_pci.c
new file mode 100644
index 0000000..5d9ea01a
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_fintek_pci.c
@@ -0,0 +1,417 @@
+/*
+ *  Base port operations for Fintek F81504/508/512 PCI-to-UARTs 16550A-type
+ *  serial ports
+ */
+#include <linux/pci.h>
+#include <linux/serial_8250.h>
+#include <linux/module.h>
+#include "8250.h"
+
+#define FINTEK_VID		0x1c29
+#define FINTEK_F81504		0x1104
+#define FINTEK_F81508		0x1108
+#define FINTEK_F81512		0x1112
+
+#define FINTEK_MAX_PORT		12
+#define DRIVER_NAME		"f81504_serial"
+#define DEV_DESC		"Fintek F81504/508/512 PCIE-to-UART"
+
+#define UART_START_ADDR		0x40
+#define UART_MODE_OFFSET	0x07
+#define UART_OFFSET		0x08
+
+/* RTS will control by MCR if this bit is 0 */
+#define RTS_CONTROL_BY_HW	BIT(4)
+/* only worked with FINTEK_RTS_CONTROL_BY_HW on */
+#define RTS_INVERT		BIT(5)
+
+#define CLOCK_RATE_MASK		0xc0
+#define CLKSEL_1DOT846_MHZ	0x00
+#define CLKSEL_18DOT46_MHZ	0x40
+#define CLKSEL_24_MHZ		0x80
+#define CLKSEL_14DOT77_MHZ	0xc0
+
+#define IRQSEL_REG		0xb8
+
+static u32 baudrate_table[] = { 1500000, 1152000, 921600 };
+static u8 clock_table[] = { CLKSEL_24_MHZ, CLKSEL_18DOT46_MHZ,
+		CLKSEL_14DOT77_MHZ };
+
+struct f81504_pci_private {
+	int line[FINTEK_MAX_PORT];
+	u32 uart_count;
+};
+
+/* We should do proper H/W transceiver setting before change to RS485 mode */
+static int f81504_rs485_config(struct uart_port *port,
+			       struct serial_rs485 *rs485)
+{
+	u8 setting;
+	u8 *index = (u8 *)port->private_data;
+	struct pci_dev *pci_dev = container_of(port->dev, struct pci_dev, dev);
+
+	pci_read_config_byte(pci_dev, UART_START_ADDR + UART_OFFSET * *index +
+			UART_MODE_OFFSET, &setting);
+
+	if (!rs485)
+		rs485 = &port->rs485;
+	else if (rs485->flags & SER_RS485_ENABLED)
+		memset(rs485->padding, 0, sizeof(rs485->padding));
+	else
+		memset(rs485, 0, sizeof(*rs485));
+
+	/* F81504/508/512 not support RTS delay before or after send */
+	rs485->flags &= SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND;
+
+	if (rs485->flags & SER_RS485_ENABLED) {
+		/* Enable RTS H/W control mode */
+		setting |= RTS_CONTROL_BY_HW;
+
+		if (rs485->flags & SER_RS485_RTS_ON_SEND) {
+			/* RTS driving high on TX */
+			setting &= ~RTS_INVERT;
+		} else {
+			/* RTS driving low on TX */
+			setting |= RTS_INVERT;
+		}
+
+		rs485->delay_rts_after_send = 0;
+		rs485->delay_rts_before_send = 0;
+	} else {
+		/* Disable RTS H/W control mode */
+		setting &= ~(RTS_CONTROL_BY_HW | RTS_INVERT);
+	}
+
+	pci_write_config_byte(pci_dev, UART_START_ADDR + UART_OFFSET * *index +
+			UART_MODE_OFFSET, setting);
+
+	if (rs485 != &port->rs485)
+		port->rs485 = *rs485;
+
+	return 0;
+}
+
+static int f81504_check_baudrate(u32 baud, int *idx)
+{
+	size_t index;
+	u32 quot, rem;
+
+	for (index = 0; index < ARRAY_SIZE(baudrate_table); ++index) {
+		/* Clock source must largeer than desire baudrate */
+		if (baud > baudrate_table[index])
+			continue;
+
+		quot = DIV_ROUND_CLOSEST(baudrate_table[index], baud);
+		/* find divisible clock source */
+		rem = baudrate_table[index] % baud;
+
+		if (quot && !rem) {
+			if (idx)
+				*idx = index;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static void f81504_set_termios(struct uart_port *port,
+		struct ktermios *termios, struct ktermios *old)
+{
+	struct pci_dev *dev = container_of(port->dev, struct pci_dev, dev);
+	unsigned int baud = tty_termios_baud_rate(termios);
+	u8 tmp, *offset = (u8 *)port->private_data;
+	int i;
+
+	do {
+		/* read current clock source (masked with CLOCK_RATE_MASK) */
+		pci_read_config_byte(dev, UART_START_ADDR + *offset *
+				UART_OFFSET, &tmp);
+
+		if (baud <= 115200) {
+			/*
+			 * direct use 1.8432MHz when baudrate smaller then or
+			 * equal 115200bps
+			 */
+			port->uartclk = 115200 * 16;
+			pci_write_config_byte(dev, UART_START_ADDR + *offset *
+					UART_OFFSET, tmp & ~CLOCK_RATE_MASK);
+			break;
+		}
+
+		if (!f81504_check_baudrate(baud, &i)) {
+			/* had optimize value */
+			port->uartclk = baudrate_table[i] * 16;
+			tmp = (tmp & ~CLOCK_RATE_MASK) | clock_table[i];
+			pci_write_config_byte(dev, UART_START_ADDR + *offset *
+					UART_OFFSET, tmp);
+			break;
+		}
+
+		if (old && !f81504_check_baudrate(tty_termios_baud_rate(old),
+				NULL)) {
+			/*
+			 * If it can't found suitable clock source but had old
+			 * accpetable baudrate, we'll use it
+			 */
+			baud = tty_termios_baud_rate(old);
+		} else {
+			/*
+			 * If it can't found suitable clock source and not old
+			 * config, we'll direct set 115200bps for future use
+			 */
+			baud = 115200;
+		}
+
+		if (tty_termios_baud_rate(termios))
+			tty_termios_encode_baud_rate(termios, baud, baud);
+	} while (1);
+
+	serial8250_do_set_termios(port, termios, old);
+}
+
+static int f81504_register_port(struct pci_dev *dev, unsigned long address,
+				int idx)
+{
+	struct uart_8250_port port;
+	u8 *data;
+
+	memset(&port, 0, sizeof(port));
+
+	data = devm_kzalloc(&dev->dev, sizeof(u8), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	*data = idx;
+	port.port.iotype = UPIO_PORT;
+	port.port.mapbase = 0;
+	port.port.membase = NULL;
+	port.port.regshift = 0;
+	port.port.irq = dev->irq;
+	port.port.flags = UPF_SKIP_TEST | UPF_FIXED_TYPE | UPF_BOOT_AUTOCONF |
+			UPF_SHARE_IRQ;
+	port.port.uartclk = 115200 * 16;
+	port.port.dev = &dev->dev;
+	port.port.iobase = address;
+	port.port.type = PORT_16550A;
+	port.port.fifosize = 128;
+	port.tx_loadsz = 32;
+	port.port.private_data = data;	/* save current idx */
+	port.port.set_termios = f81504_set_termios;
+	port.port.rs485_config = f81504_rs485_config;
+
+	return serial8250_register_8250_port(&port);
+}
+
+static int f81504_port_init(struct pci_dev *dev)
+{
+	size_t i;
+	u32 max_port, iobase;
+	u32 bar_data[3];
+	u16 tmp;
+	u8 config_base;
+	struct f81504_pci_private *priv = pci_get_drvdata(dev);
+	struct uart_8250_port *port;
+
+	switch (dev->device) {
+	case FINTEK_F81504: /* 4 ports */
+	case FINTEK_F81508: /* 8 ports */
+		max_port = dev->device & 0xff;
+		break;
+	case FINTEK_F81512: /* 12 ports */
+		max_port = 12;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Get the UART IO address dispatch from the BIOS */
+	pci_read_config_dword(dev, 0x24, &bar_data[0]);
+	pci_read_config_dword(dev, 0x20, &bar_data[1]);
+	pci_read_config_dword(dev, 0x1c, &bar_data[2]);
+
+	/* Compatible for newer step IC */
+	pci_read_config_word(dev, IRQSEL_REG, &tmp);
+	tmp |= BIT(8);
+	pci_write_config_word(dev, IRQSEL_REG, tmp);
+
+	for (i = 0; i < max_port; ++i) {
+		/* UART0 configuration offset start from 0x40 */
+		config_base = UART_START_ADDR + UART_OFFSET * i;
+
+		/* Calculate Real IO Port */
+		iobase = (bar_data[i / 4] & 0xffffffe0) + (i % 4) * 8;
+
+		/* Enable UART I/O port */
+		pci_write_config_byte(dev, config_base + 0x00, 0x01);
+
+		/* Select 128-byte FIFO and 8x FIFO threshold */
+		pci_write_config_byte(dev, config_base + 0x01, 0x33);
+
+		/* LSB UART */
+		pci_write_config_byte(dev, config_base + 0x04,
+				(u8)(iobase & 0xff));
+
+		/* MSB UART */
+		pci_write_config_byte(dev, config_base + 0x05,
+				(u8)((iobase & 0xff00) >> 8));
+
+		pci_write_config_byte(dev, config_base + 0x06, dev->irq);
+
+		/* First init. force init to RS232 Mode */
+		pci_write_config_byte(dev, config_base + 0x07, 0x01);
+	}
+
+	if (!priv)
+		return 0;
+
+	/* re-apply RS232/485 mode when f81504_resume() */
+	for (i = 0; i < priv->uart_count; ++i) {
+		port = serial8250_get_port(priv->line[i]);
+		f81504_rs485_config(&port->port, NULL);
+	}
+
+	return 0;
+}
+
+static int f81504_probe(struct pci_dev *dev, const struct pci_device_id
+				*dev_id)
+{
+	int status;
+	size_t i;
+	u16 iobase;
+	u8 tmp;
+	struct f81504_pci_private *priv;
+
+	status = pci_enable_device(dev);
+	if (status)
+		return status;
+
+	/* Init PCI Configuration Space */
+	status = f81504_port_init(dev);
+	if (status)
+		return status;
+
+	priv = devm_kzalloc(&dev->dev, sizeof(struct f81504_pci_private),
+				GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	pci_set_drvdata(dev, priv);
+
+	/* Generate UART Ports */
+	for (i = 0; i < dev_id->driver_data; ++i) {
+		/* Check UART is enabled */
+		pci_read_config_byte(dev, UART_START_ADDR + i * UART_OFFSET,
+					&tmp);
+		if (!tmp)
+			continue;
+
+		/* Get UART IO Address */
+		pci_read_config_word(dev, UART_START_ADDR + i * UART_OFFSET +
+					4, &iobase);
+
+		/* Register to serial port */
+		priv->line[priv->uart_count] = f81504_register_port(dev,
+								iobase, i);
+		++priv->uart_count;
+	}
+
+	return 0;
+}
+
+static void f81504_remove(struct pci_dev *dev)
+{
+	struct f81504_pci_private *priv = pci_get_drvdata(dev);
+	size_t i;
+
+	for (i = 0; i < priv->uart_count; ++i) {
+		if (priv->line[i] < 0)
+			continue;
+
+		serial8250_unregister_port(priv->line[i]);
+	}
+
+	pci_disable_device(dev);
+}
+
+#ifdef CONFIG_PM
+static int f81504_suspend(struct pci_dev *dev, pm_message_t state)
+{
+	size_t i;
+	int status;
+	struct f81504_pci_private *priv = pci_get_drvdata(dev);
+
+	status = pci_save_state(dev);
+	if (status)
+		return status;
+
+	status = pci_set_power_state(dev, pci_choose_state(dev, state));
+	if (status)
+		return status;
+
+	for (i = 0; i < priv->uart_count; ++i) {
+		if (priv->line[i] < 0)
+			continue;
+
+		serial8250_suspend_port(priv->line[i]);
+	}
+
+	return 0;
+}
+
+static int f81504_resume(struct pci_dev *dev)
+{
+	size_t i;
+	int status;
+	struct f81504_pci_private *priv = pci_get_drvdata(dev);
+
+	status = pci_set_power_state(dev, PCI_D0);
+	if (status)
+		return status;
+
+	pci_restore_state(dev);
+
+	/* Init PCI Configuration Space */
+	status = f81504_port_init(dev);
+	if (status)
+		return status;
+
+	for (i = 0; i < priv->uart_count; ++i) {
+		if (priv->line[i] < 0)
+			continue;
+
+		serial8250_resume_port(priv->line[i]);
+	}
+
+	return 0;
+}
+#else
+#define f81504_suspend NULL
+#define f81504_resume NULL
+#endif
+
+static const struct pci_device_id f81504_dev_table[] = {
+	/* Fintek PCI serial cards */
+	{PCI_DEVICE(FINTEK_VID, FINTEK_F81504), .driver_data = 4},
+	{PCI_DEVICE(FINTEK_VID, FINTEK_F81508), .driver_data = 8},
+	{PCI_DEVICE(FINTEK_VID, FINTEK_F81512), .driver_data = 12},
+	{}
+};
+
+MODULE_DEVICE_TABLE(pci, f81504_dev_table);
+
+static struct pci_driver f81504_driver = {
+	.name = DRIVER_NAME,
+	.probe = f81504_probe,
+	.remove = f81504_remove,
+	.suspend = f81504_suspend,
+	.resume = f81504_resume,
+	.id_table = f81504_dev_table,
+};
+
+module_pci_driver(f81504_driver);
+
+MODULE_DESCRIPTION(DEV_DESC);
+MODULE_AUTHOR("Peter Hong <Peter_Hong@xxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index b03cb517..0533a6b 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -116,6 +116,15 @@ config SERIAL_8250_PCI
 	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
 	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
 
+config SERIAL_8250_FINTEK_PCI
+        tristate "Fintek F81504/508/512 PCI-E to Multi Serial Ports support"
+        depends on SERIAL_8250 && PCI
+        default m
+        help
+          This driver works for Fintek F81504/508/512 PCIE-to-UART/GPIO
+          multi-function device. We'll use GPIOLIB interface to control
+          GPIOs if your card vendor reserve some pin as gpio.
+
 config SERIAL_8250_HP300
 	tristate
 	depends on SERIAL_8250 && HP300
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index b9b9bca..83ed91f 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_SERIAL_8250)		+= 8250.o 8250_base.o
 8250_base-$(CONFIG_SERIAL_8250_DMA)	+= 8250_dma.o
 obj-$(CONFIG_SERIAL_8250_GSC)		+= 8250_gsc.o
 obj-$(CONFIG_SERIAL_8250_PCI)		+= 8250_pci.o
+obj-$(CONFIG_SERIAL_8250_FINTEK_PCI)	+= 8250_fintek_pci.o
 obj-$(CONFIG_SERIAL_8250_HP300)		+= 8250_hp300.o
 obj-$(CONFIG_SERIAL_8250_CS)		+= serial_cs.o
 obj-$(CONFIG_SERIAL_8250_ACORN)		+= 8250_acorn.o
-- 
1.9.1