// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for CC770 and AN82527 CAN controllers on the legacy ISA bus
 *
 * Copyright (C) 2009, 2011 Wolfgang Grandegger <wg@grandegger.com>
 */

/*
 * Bosch CC770 and Intel AN82527 CAN controllers on the ISA or PC-104 bus.
 * The I/O port or memory address and the IRQ number must be specified via
 * module parameters:
 *
 *   insmod cc770_isa.ko port=0x310,0x380 irq=7,11
 *
 * for ISA devices using I/O ports or:
 *
 *   insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11
 *
 * for memory mapped ISA devices.
 *
 * Indirect access via address and data port is supported as well:
 *
 *   insmod cc770_isa.ko port=0x310,0x380 indirect=1 irq=7,11
 *
 * Furthermore, the following mode parameter can be defined:
 *
 *   clk: External oscillator clock frequency (default=16000000 [16 MHz])
 *   cir: CPU interface register (default=0x40 [DSC])
 *   bcr: Bus configuration register (default=0x40 [CBY])
 *   cor: Clockout register (default=0x00)
 *
 * Note: for clk, cir, bcr and cor, the first argument re-defines the
 * default for all other devices, e.g.:
 *
 *   insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11 clk=24000000
 *
 * is equivalent to
 *
 *   insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11 clk=24000000,24000000
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/platform/cc770.h>

#include "cc770.h"

#define MAXDEV 8

MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
MODULE_DESCRIPTION("Socket-CAN driver for CC770 on the ISA bus");
MODULE_LICENSE("GPL v2");

#define CLK_DEFAULT     16000000        /* 16 MHz */
#define COR_DEFAULT     0x00
#define BCR_DEFAULT     BUSCFG_CBY

static unsigned long port[MAXDEV];
static unsigned long mem[MAXDEV];
static int irq[MAXDEV];
static int clk[MAXDEV];
static u8 cir[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static u8 cor[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static u8 bcr[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static int indirect[MAXDEV] = {[0 ... (MAXDEV - 1)] = -1};

module_param_hw_array(port, ulong, ioport, NULL, 0444);
MODULE_PARM_DESC(port, "I/O port number");

module_param_hw_array(mem, ulong, iomem, NULL, 0444);
MODULE_PARM_DESC(mem, "I/O memory address");

module_param_hw_array(indirect, int, ioport, NULL, 0444);
MODULE_PARM_DESC(indirect, "Indirect access via address and data port");

module_param_hw_array(irq, int, irq, NULL, 0444);
MODULE_PARM_DESC(irq, "IRQ number");

module_param_array(clk, int, NULL, 0444);
MODULE_PARM_DESC(clk, "External oscillator clock frequency "
                 "(default=16000000 [16 MHz])");

module_param_array(cir, byte, NULL, 0444);
MODULE_PARM_DESC(cir, "CPU interface register (default=0x40 [DSC])");

module_param_array(cor, byte, NULL, 0444);
MODULE_PARM_DESC(cor, "Clockout register (default=0x00)");

module_param_array(bcr, byte, NULL, 0444);
MODULE_PARM_DESC(bcr, "Bus configuration register (default=0x40 [CBY])");

#define CC770_IOSIZE          0x20
#define CC770_IOSIZE_INDIRECT 0x02

/* Spinlock for cc770_isa_port_write_reg_indirect
 * and cc770_isa_port_read_reg_indirect
 */
static DEFINE_SPINLOCK(cc770_isa_port_lock);

static struct platform_device *cc770_isa_devs[MAXDEV];

static u8 cc770_isa_mem_read_reg(const struct cc770_priv *priv, int reg)
{
        return readb(priv->reg_base + reg);
}

static void cc770_isa_mem_write_reg(const struct cc770_priv *priv,
                                      int reg, u8 val)
{
        writeb(val, priv->reg_base + reg);
}

static u8 cc770_isa_port_read_reg(const struct cc770_priv *priv, int reg)
{
        return inb((unsigned long)priv->reg_base + reg);
}

static void cc770_isa_port_write_reg(const struct cc770_priv *priv,
                                       int reg, u8 val)
{
        outb(val, (unsigned long)priv->reg_base + reg);
}

static u8 cc770_isa_port_read_reg_indirect(const struct cc770_priv *priv,
                                             int reg)
{
        unsigned long base = (unsigned long)priv->reg_base;
        unsigned long flags;
        u8 val;

        spin_lock_irqsave(&cc770_isa_port_lock, flags);
        outb(reg, base);
        val = inb(base + 1);
        spin_unlock_irqrestore(&cc770_isa_port_lock, flags);

        return val;
}

static void cc770_isa_port_write_reg_indirect(const struct cc770_priv *priv,
                                                int reg, u8 val)
{
        unsigned long base = (unsigned long)priv->reg_base;
        unsigned long flags;

        spin_lock_irqsave(&cc770_isa_port_lock, flags);
        outb(reg, base);
        outb(val, base + 1);
        spin_unlock_irqrestore(&cc770_isa_port_lock, flags);
}

static int cc770_isa_probe(struct platform_device *pdev)
{
        struct net_device *dev;
        struct cc770_priv *priv;
        void __iomem *base = NULL;
        int iosize = CC770_IOSIZE;
        int idx = pdev->id;
        int err;
        u32 clktmp;

        dev_dbg(&pdev->dev, "probing idx=%d: port=%#lx, mem=%#lx, irq=%d\n",
                idx, port[idx], mem[idx], irq[idx]);
        if (mem[idx]) {
                if (!request_mem_region(mem[idx], iosize, KBUILD_MODNAME)) {
                        err = -EBUSY;
                        goto exit;
                }
                base = ioremap(mem[idx], iosize);
                if (!base) {
                        err = -ENOMEM;
                        goto exit_release;
                }
        } else {
                if (indirect[idx] > 0 ||
                    (indirect[idx] == -1 && indirect[0] > 0))
                        iosize = CC770_IOSIZE_INDIRECT;
                if (!request_region(port[idx], iosize, KBUILD_MODNAME)) {
                        err = -EBUSY;
                        goto exit;
                }
        }

        dev = alloc_cc770dev(0);
        if (!dev) {
                err = -ENOMEM;
                goto exit_unmap;
        }
        priv = netdev_priv(dev);

        dev->irq = irq[idx];
        priv->irq_flags = IRQF_SHARED;
        if (mem[idx]) {
                priv->reg_base = base;
                dev->base_addr = mem[idx];
                priv->read_reg = cc770_isa_mem_read_reg;
                priv->write_reg = cc770_isa_mem_write_reg;
        } else {
                priv->reg_base = (void __iomem *)port[idx];
                dev->base_addr = port[idx];

                if (iosize == CC770_IOSIZE_INDIRECT) {
                        priv->read_reg = cc770_isa_port_read_reg_indirect;
                        priv->write_reg = cc770_isa_port_write_reg_indirect;
                } else {
                        priv->read_reg = cc770_isa_port_read_reg;
                        priv->write_reg = cc770_isa_port_write_reg;
                }
        }

        if (clk[idx])
                clktmp = clk[idx];
        else if (clk[0])
                clktmp = clk[0];
        else
                clktmp = CLK_DEFAULT;
        priv->can.clock.freq = clktmp;

        if (cir[idx] != 0xff) {
                priv->cpu_interface = cir[idx];
        } else if (cir[0] != 0xff) {
                priv->cpu_interface = cir[0];
        } else {
                /* The system clock may not exceed 10 MHz */
                if (clktmp > 10000000) {
                        priv->cpu_interface |= CPUIF_DSC;
                        clktmp /= 2;
                }
                /* The memory clock may not exceed 8 MHz */
                if (clktmp > 8000000)
                        priv->cpu_interface |= CPUIF_DMC;
        }

        if (priv->cpu_interface & CPUIF_DSC)
                priv->can.clock.freq /= 2;

        if (bcr[idx] != 0xff)
                priv->bus_config = bcr[idx];
        else if (bcr[0] != 0xff)
                priv->bus_config = bcr[0];
        else
                priv->bus_config = BCR_DEFAULT;

        if (cor[idx] != 0xff)
                priv->clkout = cor[idx];
        else if (cor[0] != 0xff)
                priv->clkout = cor[0];
        else
                priv->clkout = COR_DEFAULT;

        platform_set_drvdata(pdev, dev);
        SET_NETDEV_DEV(dev, &pdev->dev);

        err = register_cc770dev(dev);
        if (err) {
                dev_err(&pdev->dev,
                        "couldn't register device (err=%d)\n", err);
                goto exit_free;
        }

        dev_info(&pdev->dev, "device registered (reg_base=0x%p, irq=%d)\n",
                 priv->reg_base, dev->irq);
        return 0;

exit_free:
        free_cc770dev(dev);
exit_unmap:
        if (mem[idx])
                iounmap(base);
exit_release:
        if (mem[idx])
                release_mem_region(mem[idx], iosize);
        else
                release_region(port[idx], iosize);
exit:
        return err;
}

static void cc770_isa_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct cc770_priv *priv = netdev_priv(dev);
        int idx = pdev->id;

        unregister_cc770dev(dev);

        if (mem[idx]) {
                iounmap(priv->reg_base);
                release_mem_region(mem[idx], CC770_IOSIZE);
        } else {
                if (priv->read_reg == cc770_isa_port_read_reg_indirect)
                        release_region(port[idx], CC770_IOSIZE_INDIRECT);
                else
                        release_region(port[idx], CC770_IOSIZE);
        }
        free_cc770dev(dev);
}

static struct platform_driver cc770_isa_driver = {
        .probe = cc770_isa_probe,
        .remove = cc770_isa_remove,
        .driver = {
                .name = KBUILD_MODNAME,
        },
};

static int __init cc770_isa_init(void)
{
        int idx, err;

        for (idx = 0; idx < ARRAY_SIZE(cc770_isa_devs); idx++) {
                if ((port[idx] || mem[idx]) && irq[idx]) {
                        cc770_isa_devs[idx] =
                                platform_device_alloc(KBUILD_MODNAME, idx);
                        if (!cc770_isa_devs[idx]) {
                                err = -ENOMEM;
                                goto exit_free_devices;
                        }
                        err = platform_device_add(cc770_isa_devs[idx]);
                        if (err) {
                                platform_device_put(cc770_isa_devs[idx]);
                                goto exit_free_devices;
                        }
                        pr_debug("platform device %d: port=%#lx, mem=%#lx, "
                                 "irq=%d\n",
                                 idx, port[idx], mem[idx], irq[idx]);
                } else if (idx == 0 || port[idx] || mem[idx]) {
                        pr_err("insufficient parameters supplied\n");
                        err = -EINVAL;
                        goto exit_free_devices;
                }
        }

        err = platform_driver_register(&cc770_isa_driver);
        if (err)
                goto exit_free_devices;

        pr_info("driver for max. %d devices registered\n", MAXDEV);

        return 0;

exit_free_devices:
        while (--idx >= 0) {
                if (cc770_isa_devs[idx])
                        platform_device_unregister(cc770_isa_devs[idx]);
        }

        return err;
}
module_init(cc770_isa_init);

static void __exit cc770_isa_exit(void)
{
        int idx;

        platform_driver_unregister(&cc770_isa_driver);
        for (idx = 0; idx < ARRAY_SIZE(cc770_isa_devs); idx++) {
                if (cc770_isa_devs[idx])
                        platform_device_unregister(cc770_isa_devs[idx]);
        }
}
module_exit(cc770_isa_exit);