/*
 *  Probe module for 8250/16550-type Exar chips PCI serial ports.
 *
 *  Based on drivers/tty/serial/8250/8250_pci.c,
 *
 *  Copyright (C) 2017 Sudip Mukherjee, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 */
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tty.h>
#include <linux/8250_pci.h>

#include <asm/byteorder.h>

#include "8250.h"

#define PCI_DEVICE_ID_COMMTECH_4224PCI335	0x0002
#define PCI_DEVICE_ID_COMMTECH_4222PCI335	0x0004
#define PCI_DEVICE_ID_COMMTECH_2324PCI335	0x000a
#define PCI_DEVICE_ID_COMMTECH_2328PCI335	0x000b
#define PCI_DEVICE_ID_COMMTECH_4224PCIE		0x0020
#define PCI_DEVICE_ID_COMMTECH_4228PCIE		0x0021
#define PCI_DEVICE_ID_COMMTECH_4222PCIE		0x0022
#define PCI_DEVICE_ID_EXAR_XR17V4358		0x4358
#define PCI_DEVICE_ID_EXAR_XR17V8358		0x8358

#define UART_EXAR_8XMODE	0x88	/* 8X sampling rate select */

#define UART_EXAR_FCTR		0x08	/* Feature Control Register */
#define UART_FCTR_EXAR_IRDA	0x10	/* IrDa data encode select */
#define UART_FCTR_EXAR_485	0x20	/* Auto 485 half duplex dir ctl */
#define UART_FCTR_EXAR_TRGA	0x00	/* FIFO trigger table A */
#define UART_FCTR_EXAR_TRGB	0x60	/* FIFO trigger table B */
#define UART_FCTR_EXAR_TRGC	0x80	/* FIFO trigger table C */
#define UART_FCTR_EXAR_TRGD	0xc0	/* FIFO trigger table D programmable */

#define UART_EXAR_TXTRG		0x0a	/* Tx FIFO trigger level write-only */
#define UART_EXAR_RXTRG		0x0b	/* Rx FIFO trigger level write-only */

#define UART_EXAR_MPIOINT_7_0	0x8f	/* MPIOINT[7:0] */
#define UART_EXAR_MPIOLVL_7_0	0x90	/* MPIOLVL[7:0] */
#define UART_EXAR_MPIO3T_7_0	0x91	/* MPIO3T[7:0] */
#define UART_EXAR_MPIOINV_7_0	0x92	/* MPIOINV[7:0] */
#define UART_EXAR_MPIOSEL_7_0	0x93	/* MPIOSEL[7:0] */
#define UART_EXAR_MPIOOD_7_0	0x94	/* MPIOOD[7:0] */
#define UART_EXAR_MPIOINT_15_8	0x95	/* MPIOINT[15:8] */
#define UART_EXAR_MPIOLVL_15_8	0x96	/* MPIOLVL[15:8] */
#define UART_EXAR_MPIO3T_15_8	0x97	/* MPIO3T[15:8] */
#define UART_EXAR_MPIOINV_15_8	0x98	/* MPIOINV[15:8] */
#define UART_EXAR_MPIOSEL_15_8	0x99	/* MPIOSEL[15:8] */
#define UART_EXAR_MPIOOD_15_8	0x9a	/* MPIOOD[15:8] */

struct exar8250;

/**
 * struct exar8250_board - board information
 * @num_ports: number of serial ports
 * @reg_shift: describes UART register mapping in PCI memory
 */
struct exar8250_board {
	unsigned int num_ports;
	unsigned int reg_shift;
	bool has_slave;
	int	(*setup)(struct exar8250 *, struct pci_dev *,
			 struct uart_8250_port *, int);
	void	(*exit)(struct pci_dev *pcidev);
};

struct exar8250 {
	unsigned int		nr;
	struct exar8250_board	*board;
	int			line[0];
};

static int default_setup(struct exar8250 *priv, struct pci_dev *pcidev,
			 int idx, unsigned int offset,
			 struct uart_8250_port *port)
{
	const struct exar8250_board *board = priv->board;
	unsigned int bar = 0;

	if (!pcim_iomap_table(pcidev)[bar] && !pcim_iomap(pcidev, bar, 0))
		return -ENOMEM;

	port->port.iotype = UPIO_MEM;
	port->port.mapbase = pci_resource_start(pcidev, bar) + offset;
	port->port.membase = pcim_iomap_table(pcidev)[bar] + offset;
	port->port.regshift = board->reg_shift;

	return 0;
}

static int
pci_fastcom335_setup(struct exar8250 *priv, struct pci_dev *pcidev,
		     struct uart_8250_port *port, int idx)
{
	unsigned int offset = idx * 0x200;
	unsigned int baud = 1843200;
	u8 __iomem *p;
	int err;

	port->port.uartclk = baud * 16;

	err = default_setup(priv, pcidev, idx, offset, port);
	if (err)
		return err;

	p = port->port.membase;

	writeb(0x00, p + UART_EXAR_8XMODE);
	writeb(UART_FCTR_EXAR_TRGD, p + UART_EXAR_FCTR);
	writeb(32, p + UART_EXAR_TXTRG);
	writeb(32, p + UART_EXAR_RXTRG);

	/*
	 * Setup Multipurpose Input/Output pins.
	 */
	if (idx == 0) {
		switch (pcidev->device) {
		case PCI_DEVICE_ID_COMMTECH_4222PCI335:
		case PCI_DEVICE_ID_COMMTECH_4224PCI335:
			writeb(0x78, p + UART_EXAR_MPIOLVL_7_0);
			writeb(0x00, p + UART_EXAR_MPIOINV_7_0);
			writeb(0x00, p + UART_EXAR_MPIOSEL_7_0);
			break;
		case PCI_DEVICE_ID_COMMTECH_2324PCI335:
		case PCI_DEVICE_ID_COMMTECH_2328PCI335:
			writeb(0x00, p + UART_EXAR_MPIOLVL_7_0);
			writeb(0xc0, p + UART_EXAR_MPIOINV_7_0);
			writeb(0xc0, p + UART_EXAR_MPIOSEL_7_0);
			break;
		}
		writeb(0x00, p + UART_EXAR_MPIOINT_7_0);
		writeb(0x00, p + UART_EXAR_MPIO3T_7_0);
		writeb(0x00, p + UART_EXAR_MPIOOD_7_0);
	}

	return 0;
}

static int
pci_connect_tech_setup(struct exar8250 *priv, struct pci_dev *pcidev,
		       struct uart_8250_port *port, int idx)
{
	unsigned int offset = idx * 0x200;
	unsigned int baud = 1843200;

	port->port.uartclk = baud * 16;
	return default_setup(priv, pcidev, idx, offset, port);
}

static int
pci_xr17c154_setup(struct exar8250 *priv, struct pci_dev *pcidev,
		   struct uart_8250_port *port, int idx)
{
	unsigned int offset = idx * 0x200;
	unsigned int baud = 921600;

	port->port.uartclk = baud * 16;
	return default_setup(priv, pcidev, idx, offset, port);
}

static void setup_gpio(u8 __iomem *p)
{
	writeb(0x00, p + UART_EXAR_MPIOINT_7_0);
	writeb(0x00, p + UART_EXAR_MPIOLVL_7_0);
	writeb(0x00, p + UART_EXAR_MPIO3T_7_0);
	writeb(0x00, p + UART_EXAR_MPIOINV_7_0);
	writeb(0xff, p + UART_EXAR_MPIOSEL_7_0);
	writeb(0x00, p + UART_EXAR_MPIOOD_7_0);
	writeb(0x00, p + UART_EXAR_MPIOINT_15_8);
	writeb(0x00, p + UART_EXAR_MPIOLVL_15_8);
	writeb(0x00, p + UART_EXAR_MPIO3T_15_8);
	writeb(0x00, p + UART_EXAR_MPIOINV_15_8);
	writeb(0xff, p + UART_EXAR_MPIOSEL_15_8);
	writeb(0x00, p + UART_EXAR_MPIOOD_15_8);
}

static void *
xr17v35x_register_gpio(struct pci_dev *pcidev)
{
	struct platform_device *pdev;

	pdev = platform_device_alloc("gpio_exar", PLATFORM_DEVID_AUTO);
	if (!pdev)
		return NULL;

	platform_set_drvdata(pdev, pcidev);
	if (platform_device_add(pdev) < 0) {
		platform_device_put(pdev);
		return NULL;
	}

	return pdev;
}

static int
pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,
		   struct uart_8250_port *port, int idx)
{
	const struct exar8250_board *board = priv->board;
	unsigned int offset = idx * 0x400;
	unsigned int baud = 7812500;
	u8 __iomem *p;
	int ret;

	port->port.uartclk = baud * 16;
	/*
	 * Setup the uart clock for the devices on expansion slot to
	 * half the clock speed of the main chip (which is 125MHz)
	 */
	if (board->has_slave && idx >= 8)
		port->port.uartclk /= 2;

	ret = default_setup(priv, pcidev, idx, offset, port);
	if (ret)
		return ret;

	p = port->port.membase;

	writeb(0x00, p + UART_EXAR_8XMODE);
	writeb(UART_FCTR_EXAR_TRGD, p + UART_EXAR_FCTR);
	writeb(128, p + UART_EXAR_TXTRG);
	writeb(128, p + UART_EXAR_RXTRG);

	if (idx == 0) {
		/* Setup Multipurpose Input/Output pins. */
		setup_gpio(p);

		port->port.private_data = xr17v35x_register_gpio(pcidev);
	}

	return 0;
}

static void pci_xr17v35x_exit(struct pci_dev *pcidev)
{
	struct exar8250 *priv = pci_get_drvdata(pcidev);
	struct uart_8250_port *port = serial8250_get_port(priv->line[0]);
	struct platform_device *pdev = port->port.private_data;

	platform_device_unregister(pdev);
	port->port.private_data = NULL;
}

static int
exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
{
	unsigned int nr_ports, i, bar = 0, maxnr;
	struct exar8250_board *board;
	struct uart_8250_port uart;
	struct exar8250 *priv;
	int rc;

	board = (struct exar8250_board *)ent->driver_data;
	if (!board)
		return -EINVAL;

	rc = pcim_enable_device(pcidev);
	if (rc)
		return rc;

	maxnr = pci_resource_len(pcidev, bar) >> (board->reg_shift + 3);

	nr_ports = board->num_ports ? board->num_ports : pcidev->device & 0x0f;

	priv = devm_kzalloc(&pcidev->dev, sizeof(*priv) +
			    sizeof(unsigned int) * nr_ports,
			    GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->board = board;

	pci_set_master(pcidev);

	rc = pci_alloc_irq_vectors(pcidev, 1, 1, PCI_IRQ_ALL_TYPES);
	if (rc < 0)
		return rc;

	memset(&uart, 0, sizeof(uart));
	uart.port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ
			  | UPF_EXAR_EFR;
	uart.port.irq = pci_irq_vector(pcidev, 0);
	uart.port.dev = &pcidev->dev;

	for (i = 0; i < nr_ports && i < maxnr; i++) {
		rc = board->setup(priv, pcidev, &uart, i);
		if (rc) {
			dev_err(&pcidev->dev, "Failed to setup port %u\n", i);
			break;
		}

		dev_dbg(&pcidev->dev, "Setup PCI port: port %lx, irq %d, type %d\n",
			uart.port.iobase, uart.port.irq, uart.port.iotype);

		priv->line[i] = serial8250_register_8250_port(&uart);
		if (priv->line[i] < 0) {
			dev_err(&pcidev->dev,
				"Couldn't register serial port %lx, irq %d, type %d, error %d\n",
				uart.port.iobase, uart.port.irq,
				uart.port.iotype, priv->line[i]);
			break;
		}
	}
	priv->nr = i;
	pci_set_drvdata(pcidev, priv);
	return 0;
}

static void exar_pci_remove(struct pci_dev *pcidev)
{
	struct exar8250 *priv = pci_get_drvdata(pcidev);
	unsigned int i;

	for (i = 0; i < priv->nr; i++)
		serial8250_unregister_port(priv->line[i]);

	if (priv->board->exit)
		priv->board->exit(pcidev);
}

static int __maybe_unused exar_suspend(struct device *dev)
{
	struct pci_dev *pcidev = to_pci_dev(dev);
	struct exar8250 *priv = pci_get_drvdata(pcidev);
	unsigned int i;

	for (i = 0; i < priv->nr; i++)
		if (priv->line[i] >= 0)
			serial8250_suspend_port(priv->line[i]);

	/* Ensure that every init quirk is properly torn down */
	if (priv->board->exit)
		priv->board->exit(pcidev);

	return 0;
}

static int __maybe_unused exar_resume(struct device *dev)
{
	struct pci_dev *pcidev = to_pci_dev(dev);
	struct exar8250 *priv = pci_get_drvdata(pcidev);
	unsigned int i;

	for (i = 0; i < priv->nr; i++)
		if (priv->line[i] >= 0)
			serial8250_resume_port(priv->line[i]);

	return 0;
}

static SIMPLE_DEV_PM_OPS(exar_pci_pm, exar_suspend, exar_resume);

static const struct exar8250_board pbn_fastcom335_2 = {
	.num_ports	= 2,
	.setup		= pci_fastcom335_setup,
};

static const struct exar8250_board pbn_fastcom335_4 = {
	.num_ports	= 4,
	.setup		= pci_fastcom335_setup,
};

static const struct exar8250_board pbn_fastcom335_8 = {
	.num_ports	= 8,
	.setup		= pci_fastcom335_setup,
};

static const struct exar8250_board pbn_connect = {
	.setup		= pci_connect_tech_setup,
};

static const struct exar8250_board pbn_exar_ibm_saturn = {
	.num_ports	= 1,
	.setup		= pci_xr17c154_setup,
};

static const struct exar8250_board pbn_exar_XR17C15x = {
	.setup		= pci_xr17c154_setup,
};

static const struct exar8250_board pbn_exar_XR17V35x = {
	.setup		= pci_xr17v35x_setup,
	.exit		= pci_xr17v35x_exit,
};

static const struct exar8250_board pbn_exar_XR17V4358 = {
	.num_ports	= 12,
	.has_slave	= true,
	.setup		= pci_xr17v35x_setup,
	.exit		= pci_xr17v35x_exit,
};

static const struct exar8250_board pbn_exar_XR17V8358 = {
	.num_ports	= 16,
	.has_slave	= true,
	.setup		= pci_xr17v35x_setup,
	.exit		= pci_xr17v35x_exit,
};

#define CONNECT_DEVICE(devid, sdevid, bd) {				\
	PCI_DEVICE_SUB(							\
		PCI_VENDOR_ID_EXAR,					\
		PCI_DEVICE_ID_EXAR_##devid,				\
		PCI_SUBVENDOR_ID_CONNECT_TECH,				\
		PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_##sdevid), 0, 0,	\
		(kernel_ulong_t)&bd					\
	}

#define EXAR_DEVICE(vend, devid, bd) {					\
	PCI_VDEVICE(vend, PCI_DEVICE_ID_##devid), (kernel_ulong_t)&bd	\
	}

#define IBM_DEVICE(devid, sdevid, bd) {			\
	PCI_DEVICE_SUB(					\
		PCI_VENDOR_ID_EXAR,			\
		PCI_DEVICE_ID_EXAR_##devid,		\
		PCI_VENDOR_ID_IBM,			\
		PCI_SUBDEVICE_ID_IBM_##sdevid), 0, 0,	\
		(kernel_ulong_t)&bd			\
	}

static struct pci_device_id exar_pci_tbl[] = {
	CONNECT_DEVICE(XR17C152, UART_2_232, pbn_connect),
	CONNECT_DEVICE(XR17C154, UART_4_232, pbn_connect),
	CONNECT_DEVICE(XR17C158, UART_8_232, pbn_connect),
	CONNECT_DEVICE(XR17C152, UART_1_1, pbn_connect),
	CONNECT_DEVICE(XR17C154, UART_2_2, pbn_connect),
	CONNECT_DEVICE(XR17C158, UART_4_4, pbn_connect),
	CONNECT_DEVICE(XR17C152, UART_2, pbn_connect),
	CONNECT_DEVICE(XR17C154, UART_4, pbn_connect),
	CONNECT_DEVICE(XR17C158, UART_8, pbn_connect),
	CONNECT_DEVICE(XR17C152, UART_2_485, pbn_connect),
	CONNECT_DEVICE(XR17C154, UART_4_485, pbn_connect),
	CONNECT_DEVICE(XR17C158, UART_8_485, pbn_connect),

	IBM_DEVICE(XR17C152, SATURN_SERIAL_ONE_PORT, pbn_exar_ibm_saturn),

	/* Exar Corp. XR17C15[248] Dual/Quad/Octal UART */
	EXAR_DEVICE(EXAR, EXAR_XR17C152, pbn_exar_XR17C15x),
	EXAR_DEVICE(EXAR, EXAR_XR17C154, pbn_exar_XR17C15x),
	EXAR_DEVICE(EXAR, EXAR_XR17C158, pbn_exar_XR17C15x),

	/* Exar Corp. XR17V[48]35[248] Dual/Quad/Octal/Hexa PCIe UARTs */
	EXAR_DEVICE(EXAR, EXAR_XR17V352, pbn_exar_XR17V35x),
	EXAR_DEVICE(EXAR, EXAR_XR17V354, pbn_exar_XR17V35x),
	EXAR_DEVICE(EXAR, EXAR_XR17V358, pbn_exar_XR17V35x),
	EXAR_DEVICE(EXAR, EXAR_XR17V4358, pbn_exar_XR17V4358),
	EXAR_DEVICE(EXAR, EXAR_XR17V8358, pbn_exar_XR17V8358),
	EXAR_DEVICE(COMMTECH, COMMTECH_4222PCIE, pbn_exar_XR17V35x),
	EXAR_DEVICE(COMMTECH, COMMTECH_4224PCIE, pbn_exar_XR17V35x),
	EXAR_DEVICE(COMMTECH, COMMTECH_4228PCIE, pbn_exar_XR17V35x),

	EXAR_DEVICE(COMMTECH, COMMTECH_4222PCI335, pbn_fastcom335_2),
	EXAR_DEVICE(COMMTECH, COMMTECH_4224PCI335, pbn_fastcom335_4),
	EXAR_DEVICE(COMMTECH, COMMTECH_2324PCI335, pbn_fastcom335_4),
	EXAR_DEVICE(COMMTECH, COMMTECH_2328PCI335, pbn_fastcom335_8),
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, exar_pci_tbl);

static struct pci_driver exar_pci_driver = {
	.name		= "exar_serial",
	.probe		= exar_pci_probe,
	.remove		= exar_pci_remove,
	.driver         = {
		.pm     = &exar_pci_pm,
	},
	.id_table	= exar_pci_tbl,
};
module_pci_driver(exar_pci_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Exar Serial Driver");
MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");