cc770_isa.c

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/*
 * Driver for CC770 and AN82527 CAN controllers on the legacy ISA bus
 *
 * Copyright (C) 2009, 2011 Wolfgang Grandegger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

/*
 * 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 <[email protected]>");
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 __devinitdata irq[MAXDEV];
static int __devinitdata clk[MAXDEV];
static u8 __devinitdata cir[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static u8 __devinitdata cor[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static u8 __devinitdata bcr[MAXDEV] = {[0 ... (MAXDEV - 1)] = 0xff};
static int __devinitdata indirect[MAXDEV] = {[0 ... (MAXDEV - 1)] = -1};

module_param_array(port, ulong, NULL, S_IRUGO);
MODULE_PARM_DESC(port, "I/O port number");

module_param_array(mem, ulong, NULL, S_IRUGO);
MODULE_PARM_DESC(mem, "I/O memory address");

module_param_array(indirect, int, NULL, S_IRUGO);
MODULE_PARM_DESC(indirect, "Indirect access via address and data port");

module_param_array(irq, int, NULL, S_IRUGO);
MODULE_PARM_DESC(irq, "IRQ number");

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

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

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

module_param_array(bcr, byte, NULL, S_IRUGO);
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 __devinit 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_nocache(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;

    dev_set_drvdata(&pdev->dev, 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_unmap;
    }

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

 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 int __devexit cc770_isa_remove(struct platform_device *pdev)
{
    struct net_device *dev = dev_get_drvdata(&pdev->dev);
    struct cc770_priv *priv = netdev_priv(dev);
    int idx = pdev->id;

    unregister_cc770dev(dev);
    dev_set_drvdata(&pdev->dev, NULL);

    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);

    return 0;
}

static struct platform_driver cc770_isa_driver = {
    .probe = cc770_isa_probe,
    .remove = __devexit_p(cc770_isa_remove),
    .driver = {
        .name = KBUILD_MODNAME,
        .owner = THIS_MODULE,
    },
};

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);