// SPDX-License-Identifier: GPL-2.0-only
/*
 * Cyclades PC300 synchronous serial card driver for Linux
 *
 * Copyright (C) 2000-2008 Krzysztof Halasa <khc@pm.waw.pl>
 *
 * For information see <https://www.kernel.org/pub/linux/utils/net/hdlc/>.
 *
 * Sources of information:
 *    Hitachi HD64572 SCA-II User's Manual
 *    Original Cyclades PC300 Linux driver
 *
 * This driver currently supports only PC300/RSV (V.24/V.35) and
 * PC300/X21 cards.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <linux/hdlc.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <asm/io.h>

#include "hd64572.h"

#undef DEBUG_PKT
#define DEBUG_RINGS

#define PC300_PLX_SIZE		0x80    /* PLX control window size (128 B) */
#define PC300_SCA_SIZE		0x400   /* SCA window size (1 KB) */
#define MAX_TX_BUFFERS		10

static int pci_clock_freq = 33000000;
static int use_crystal_clock;
static unsigned int CLOCK_BASE;

/* Masks to access the init_ctrl PLX register */
#define PC300_CLKSEL_MASK	 (0x00000004UL)
#define PC300_CHMEDIA_MASK(port) (0x00000020UL << ((port) * 3))
#define PC300_CTYPE_MASK	 (0x00000800UL)

enum { PC300_RSV = 1, PC300_X21, PC300_TE }; /* card types */

/*      PLX PCI9050-1 local configuration and shared runtime registers.
 *      This structure can be used to access 9050 registers (memory mapped).
 */
typedef struct {
	u32 loc_addr_range[4];	/* 00-0Ch : Local Address Ranges */
	u32 loc_rom_range;	/* 10h : Local ROM Range */
	u32 loc_addr_base[4];	/* 14-20h : Local Address Base Addrs */
	u32 loc_rom_base;	/* 24h : Local ROM Base */
	u32 loc_bus_descr[4];	/* 28-34h : Local Bus Descriptors */
	u32 rom_bus_descr;	/* 38h : ROM Bus Descriptor */
	u32 cs_base[4];		/* 3C-48h : Chip Select Base Addrs */
	u32 intr_ctrl_stat;	/* 4Ch : Interrupt Control/Status */
	u32 init_ctrl;		/* 50h : EEPROM ctrl, Init Ctrl, etc */
} plx9050;

typedef struct port_s {
	struct napi_struct napi;
	struct net_device *netdev;
	struct card_s *card;
	spinlock_t lock;	/* TX lock */
	sync_serial_settings settings;
	int rxpart;		/* partial frame received, next frame invalid*/
	unsigned short encoding;
	unsigned short parity;
	unsigned int iface;
	u16 rxin;		/* rx ring buffer 'in' pointer */
	u16 txin;		/* tx ring buffer 'in' and 'last' pointers */
	u16 txlast;
	u8 rxs, txs, tmc;	/* SCA registers */
	u8 chan;		/* physical port # - 0 or 1 */
} port_t;

typedef struct card_s {
	int type;		/* RSV, X21, etc. */
	int n_ports;		/* 1 or 2 ports */
	u8 __iomem *rambase;	/* buffer memory base (virtual) */
	u8 __iomem *scabase;	/* SCA memory base (virtual) */
	plx9050 __iomem *plxbase; /* PLX registers memory base (virtual) */
	u32 init_ctrl_value;	/* Saved value - 9050 bug workaround */
	u16 rx_ring_buffers;	/* number of buffers in a ring */
	u16 tx_ring_buffers;
	u16 buff_offset;	/* offset of first buffer of first channel */
	u8 irq;			/* interrupt request level */

	port_t ports[2];
} card_t;

#define get_port(card, port)	     ((port) < (card)->n_ports ? \
					 (&(card)->ports[port]) : (NULL))

#include "hd64572.c"

static void pc300_set_iface(port_t *port)
{
	card_t *card = port->card;
	u32 __iomem *init_ctrl = &card->plxbase->init_ctrl;
	u16 msci = get_msci(port);
	u8 rxs = port->rxs & CLK_BRG_MASK;
	u8 txs = port->txs & CLK_BRG_MASK;

	sca_out(EXS_TES1, (port->chan ? MSCI1_OFFSET : MSCI0_OFFSET) + EXS,
		port->card);
	switch (port->settings.clock_type) {
	case CLOCK_INT:
		rxs |= CLK_BRG; /* BRG output */
		txs |= CLK_PIN_OUT | CLK_TX_RXCLK; /* RX clock */
		break;

	case CLOCK_TXINT:
		rxs |= CLK_LINE; /* RXC input */
		txs |= CLK_PIN_OUT | CLK_BRG; /* BRG output */
		break;

	case CLOCK_TXFROMRX:
		rxs |= CLK_LINE; /* RXC input */
		txs |= CLK_PIN_OUT | CLK_TX_RXCLK; /* RX clock */
		break;

	default:		/* EXTernal clock */
		rxs |= CLK_LINE; /* RXC input */
		txs |= CLK_PIN_OUT | CLK_LINE; /* TXC input */
		break;
	}

	port->rxs = rxs;
	port->txs = txs;
	sca_out(rxs, msci + RXS, card);
	sca_out(txs, msci + TXS, card);
	sca_set_port(port);

	if (port->card->type == PC300_RSV) {
		if (port->iface == IF_IFACE_V35)
			writel(card->init_ctrl_value |
			       PC300_CHMEDIA_MASK(port->chan), init_ctrl);
		else
			writel(card->init_ctrl_value &
			       ~PC300_CHMEDIA_MASK(port->chan), init_ctrl);
	}
}

static int pc300_open(struct net_device *dev)
{
	port_t *port = dev_to_port(dev);
	int result = hdlc_open(dev);

	if (result)
		return result;

	sca_open(dev);
	pc300_set_iface(port);
	return 0;
}

static int pc300_close(struct net_device *dev)
{
	sca_close(dev);
	hdlc_close(dev);
	return 0;
}

static int pc300_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
				void __user *data, int cmd)
{
#ifdef DEBUG_RINGS
	if (cmd == SIOCDEVPRIVATE) {
		sca_dump_rings(dev);
		return 0;
	}
#endif
	return -EOPNOTSUPP;
}

static int pc300_ioctl(struct net_device *dev, struct if_settings *ifs)
{
	const size_t size = sizeof(sync_serial_settings);
	sync_serial_settings new_line;
	sync_serial_settings __user *line = ifs->ifs_ifsu.sync;
	int new_type;
	port_t *port = dev_to_port(dev);

	if (ifs->type == IF_GET_IFACE) {
		ifs->type = port->iface;
		if (ifs->size < size) {
			ifs->size = size; /* data size wanted */
			return -ENOBUFS;
		}
		if (copy_to_user(line, &port->settings, size))
			return -EFAULT;
		return 0;
	}

	if (port->card->type == PC300_X21 &&
	    (ifs->type == IF_IFACE_SYNC_SERIAL ||
	     ifs->type == IF_IFACE_X21))
		new_type = IF_IFACE_X21;

	else if (port->card->type == PC300_RSV &&
		 (ifs->type == IF_IFACE_SYNC_SERIAL ||
		  ifs->type == IF_IFACE_V35))
		new_type = IF_IFACE_V35;

	else if (port->card->type == PC300_RSV &&
		 ifs->type == IF_IFACE_V24)
		new_type = IF_IFACE_V24;

	else
		return hdlc_ioctl(dev, ifs);

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	if (copy_from_user(&new_line, line, size))
		return -EFAULT;

	if (new_line.clock_type != CLOCK_EXT &&
	    new_line.clock_type != CLOCK_TXFROMRX &&
	    new_line.clock_type != CLOCK_INT &&
	    new_line.clock_type != CLOCK_TXINT)
		return -EINVAL;	/* No such clock setting */

	if (new_line.loopback != 0 && new_line.loopback != 1)
		return -EINVAL;

	memcpy(&port->settings, &new_line, size); /* Update settings */
	port->iface = new_type;
	pc300_set_iface(port);
	return 0;
}

static void pc300_pci_remove_one(struct pci_dev *pdev)
{
	int i;
	card_t *card = pci_get_drvdata(pdev);

	for (i = 0; i < 2; i++)
		if (card->ports[i].card)
			unregister_hdlc_device(card->ports[i].netdev);

	if (card->irq)
		free_irq(card->irq, card);

	if (card->rambase)
		iounmap(card->rambase);
	if (card->scabase)
		iounmap(card->scabase);
	if (card->plxbase)
		iounmap(card->plxbase);

	pci_release_regions(pdev);
	pci_disable_device(pdev);
	if (card->ports[0].netdev)
		free_netdev(card->ports[0].netdev);
	if (card->ports[1].netdev)
		free_netdev(card->ports[1].netdev);
	kfree(card);
}

static const struct net_device_ops pc300_ops = {
	.ndo_open       = pc300_open,
	.ndo_stop       = pc300_close,
	.ndo_start_xmit = hdlc_start_xmit,
	.ndo_siocwandev = pc300_ioctl,
	.ndo_siocdevprivate = pc300_siocdevprivate,
};

static int pc300_pci_init_one(struct pci_dev *pdev,
			      const struct pci_device_id *ent)
{
	card_t *card;
	u32 __iomem *p;
	int i;
	u32 ramsize;
	u32 ramphys;		/* buffer memory base */
	u32 scaphys;		/* SCA memory base */
	u32 plxphys;		/* PLX registers memory base */

	i = pci_enable_device(pdev);
	if (i)
		return i;

	i = pci_request_regions(pdev, "PC300");
	if (i) {
		pci_disable_device(pdev);
		return i;
	}

	card = kzalloc(sizeof(card_t), GFP_KERNEL);
	if (!card) {
		pci_release_regions(pdev);
		pci_disable_device(pdev);
		return -ENOBUFS;
	}
	pci_set_drvdata(pdev, card);

	if (pci_resource_len(pdev, 0) != PC300_PLX_SIZE ||
	    pci_resource_len(pdev, 2) != PC300_SCA_SIZE ||
	    pci_resource_len(pdev, 3) < 16384) {
		pr_err("invalid card EEPROM parameters\n");
		pc300_pci_remove_one(pdev);
		return -EFAULT;
	}

	plxphys = pci_resource_start(pdev, 0) & PCI_BASE_ADDRESS_MEM_MASK;
	card->plxbase = ioremap(plxphys, PC300_PLX_SIZE);

	scaphys = pci_resource_start(pdev, 2) & PCI_BASE_ADDRESS_MEM_MASK;
	card->scabase = ioremap(scaphys, PC300_SCA_SIZE);

	ramphys = pci_resource_start(pdev, 3) & PCI_BASE_ADDRESS_MEM_MASK;
	card->rambase = pci_ioremap_bar(pdev, 3);

	if (!card->plxbase || !card->scabase || !card->rambase) {
		pr_err("ioremap() failed\n");
		pc300_pci_remove_one(pdev);
		return -ENOMEM;
	}

	/* PLX PCI 9050 workaround for local configuration register read bug */
	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0, scaphys);
	card->init_ctrl_value = readl(&((plx9050 __iomem *)card->scabase)->init_ctrl);
	pci_write_config_dword(pdev, PCI_BASE_ADDRESS_0, plxphys);

	if (pdev->device == PCI_DEVICE_ID_PC300_TE_1 ||
	    pdev->device == PCI_DEVICE_ID_PC300_TE_2)
		card->type = PC300_TE; /* not fully supported */
	else if (card->init_ctrl_value & PC300_CTYPE_MASK)
		card->type = PC300_X21;
	else
		card->type = PC300_RSV;

	if (pdev->device == PCI_DEVICE_ID_PC300_RX_1 ||
	    pdev->device == PCI_DEVICE_ID_PC300_TE_1)
		card->n_ports = 1;
	else
		card->n_ports = 2;

	for (i = 0; i < card->n_ports; i++) {
		card->ports[i].netdev = alloc_hdlcdev(&card->ports[i]);
		if (!card->ports[i].netdev) {
			pr_err("unable to allocate memory\n");
			pc300_pci_remove_one(pdev);
			return -ENOMEM;
		}
	}

	/* Reset PLX */
	p = &card->plxbase->init_ctrl;
	writel(card->init_ctrl_value | 0x40000000, p);
	readl(p);		/* Flush the write - do not use sca_flush */
	udelay(1);

	writel(card->init_ctrl_value, p);
	readl(p);		/* Flush the write - do not use sca_flush */
	udelay(1);

	/* Reload Config. Registers from EEPROM */
	writel(card->init_ctrl_value | 0x20000000, p);
	readl(p);		/* Flush the write - do not use sca_flush */
	udelay(1);

	writel(card->init_ctrl_value, p);
	readl(p);		/* Flush the write - do not use sca_flush */
	udelay(1);

	ramsize = sca_detect_ram(card, card->rambase,
				 pci_resource_len(pdev, 3));

	if (use_crystal_clock)
		card->init_ctrl_value &= ~PC300_CLKSEL_MASK;
	else
		card->init_ctrl_value |= PC300_CLKSEL_MASK;

	writel(card->init_ctrl_value, &card->plxbase->init_ctrl);
	/* number of TX + RX buffers for one port */
	i = ramsize / (card->n_ports * (sizeof(pkt_desc) + HDLC_MAX_MRU));
	card->tx_ring_buffers = min(i / 2, MAX_TX_BUFFERS);
	card->rx_ring_buffers = i - card->tx_ring_buffers;

	card->buff_offset = card->n_ports * sizeof(pkt_desc) *
		(card->tx_ring_buffers + card->rx_ring_buffers);

	pr_info("PC300/%s, %u KB RAM at 0x%x, IRQ%u, using %u TX + %u RX packets rings\n",
		card->type == PC300_X21 ? "X21" :
		card->type == PC300_TE ? "TE" : "RSV",
		ramsize / 1024, ramphys, pdev->irq,
		card->tx_ring_buffers, card->rx_ring_buffers);

	if (card->tx_ring_buffers < 1) {
		pr_err("RAM test failed\n");
		pc300_pci_remove_one(pdev);
		return -EFAULT;
	}

	/* Enable interrupts on the PCI bridge, LINTi1 active low */
	writew(0x0041, &card->plxbase->intr_ctrl_stat);

	/* Allocate IRQ */
	if (request_irq(pdev->irq, sca_intr, IRQF_SHARED, "pc300", card)) {
		pr_warn("could not allocate IRQ%d\n", pdev->irq);
		pc300_pci_remove_one(pdev);
		return -EBUSY;
	}
	card->irq = pdev->irq;

	sca_init(card, 0);

	// COTE not set - allows better TX DMA settings
	// sca_out(sca_in(PCR, card) | PCR_COTE, PCR, card);

	sca_out(0x10, BTCR, card);

	for (i = 0; i < card->n_ports; i++) {
		port_t *port = &card->ports[i];
		struct net_device *dev = port->netdev;
		hdlc_device *hdlc = dev_to_hdlc(dev);

		port->chan = i;

		spin_lock_init(&port->lock);
		dev->irq = card->irq;
		dev->mem_start = ramphys;
		dev->mem_end = ramphys + ramsize - 1;
		dev->tx_queue_len = 50;
		dev->netdev_ops = &pc300_ops;
		hdlc->attach = sca_attach;
		hdlc->xmit = sca_xmit;
		port->settings.clock_type = CLOCK_EXT;
		port->card = card;
		if (card->type == PC300_X21)
			port->iface = IF_IFACE_X21;
		else
			port->iface = IF_IFACE_V35;

		sca_init_port(port);
		if (register_hdlc_device(dev)) {
			pr_err("unable to register hdlc device\n");
			port->card = NULL;
			pc300_pci_remove_one(pdev);
			return -ENOBUFS;
		}

		netdev_info(dev, "PC300 channel %d\n", port->chan);
	}
	return 0;
}

static const struct pci_device_id pc300_pci_tbl[] = {
	{ PCI_VENDOR_ID_CYCLADES, PCI_DEVICE_ID_PC300_RX_1, PCI_ANY_ID,
	  PCI_ANY_ID, 0, 0, 0 },
	{ PCI_VENDOR_ID_CYCLADES, PCI_DEVICE_ID_PC300_RX_2, PCI_ANY_ID,
	  PCI_ANY_ID, 0, 0, 0 },
	{ PCI_VENDOR_ID_CYCLADES, PCI_DEVICE_ID_PC300_TE_1, PCI_ANY_ID,
	  PCI_ANY_ID, 0, 0, 0 },
	{ PCI_VENDOR_ID_CYCLADES, PCI_DEVICE_ID_PC300_TE_2, PCI_ANY_ID,
	  PCI_ANY_ID, 0, 0, 0 },
	{ 0, }
};

static struct pci_driver pc300_pci_driver = {
	.name =          "PC300",
	.id_table =      pc300_pci_tbl,
	.probe =         pc300_pci_init_one,
	.remove =        pc300_pci_remove_one,
};

static int __init pc300_init_module(void)
{
	if (pci_clock_freq < 1000000 || pci_clock_freq > 80000000) {
		pr_err("Invalid PCI clock frequency\n");
		return -EINVAL;
	}
	if (use_crystal_clock != 0 && use_crystal_clock != 1) {
		pr_err("Invalid 'use_crystal_clock' value\n");
		return -EINVAL;
	}

	CLOCK_BASE = use_crystal_clock ? 24576000 : pci_clock_freq;

	return pci_register_driver(&pc300_pci_driver);
}

static void __exit pc300_cleanup_module(void)
{
	pci_unregister_driver(&pc300_pci_driver);
}

MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
MODULE_DESCRIPTION("Cyclades PC300 serial port driver");
MODULE_LICENSE("GPL v2");
MODULE_DEVICE_TABLE(pci, pc300_pci_tbl);
module_param(pci_clock_freq, int, 0444);
MODULE_PARM_DESC(pci_clock_freq, "System PCI clock frequency in Hz");
module_param(use_crystal_clock, int, 0444);
MODULE_PARM_DESC(use_crystal_clock,
		 "Use 24.576 MHz clock instead of PCI clock");
module_init(pc300_init_module);
module_exit(pc300_cleanup_module);